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Sondhi Y, Messcher RL, Bellantuono AJ, Storer CG, Cinel SD, Godfrey RK, Mongue AJ, Weng YM, Glass D, St Laurent RA, Hamilton CA, Earl C, Brislawn CJ, Kitching IJ, Bybee SM, Theobald JC, Kawahara AY. Day-night gene expression reveals circadian gene disco as a candidate for diel-niche evolution in moths. Proc Biol Sci 2024; 291:20240591. [PMID: 39194299 DOI: 10.1098/rspb.2024.0591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 08/29/2024] Open
Abstract
Temporal ecological niche partitioning is an underappreciated driver of speciation. While insects have long been models for circadian biology, the genes and circuits that allow adaptive changes in diel-niches remain poorly understood. We compared gene expression in closely related day- and night-active non-model wild silk moths, with otherwise similar ecologies. Using an ortholog-based pipeline to compare RNA-Seq patterns across two moth species, we find over 25 pairs of gene orthologs showing differential expression. Notably, the gene disco, involved in circadian control, optic lobe and clock neuron development in Drosophila, shows robust adult circadian mRNA cycling in moth heads. Disco is highly conserved in moths and has additional zinc-finger domains with specific nocturnal and diurnal mutations. We propose disco as a candidate gene for the diversification of temporal diel-niche in moths.
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Affiliation(s)
- Yash Sondhi
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
- Department of Biology, Florida International University , Miami, FL 33174, USA
- Institute for Environment, Florida International University , Miami, FL 33174, USA
| | - Rebeccah L Messcher
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
| | | | - Caroline G Storer
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
| | - Scott D Cinel
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
| | - R Keating Godfrey
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
- Department of Biology, Florida International University , Miami, FL 33174, USA
| | - Andrew J Mongue
- Department of Entomology and Nematology, University of Florida , Gainesville, FL 32611, USA
| | - Yi-Ming Weng
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
| | - Deborah Glass
- School of Life Sciences, University of Sussex, Sussex House , Brighton BN1 9RH, UK
- Natural History Museum, Cromwell Road , London SW7 5BD, UK
| | - Ryan A St Laurent
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
- Department of Entomology, Smithsonian Institution, National Museum of Natural History , Washington, DC, USA
| | - Chris A Hamilton
- Department of Entomology, Plant Pathology & Nematology, University of Idaho , Moscow, ID 83844, USA
| | - Chandra Earl
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
- Biodiversity Knowledge Integration Center, School of Life Sciences, Arizona State University , Tempe, AZ 852281, USA
| | | | - Ian J Kitching
- Natural History Museum, Cromwell Road , London SW7 5BD, UK
| | - Seth M Bybee
- Department of Biology, Monte L. Bean Museum, Brigham Young University, 4102 Life Science Building , Provo, UT 84602, USA
| | - Jamie C Theobald
- Department of Biology, Florida International University , Miami, FL 33174, USA
- Institute for Environment, Florida International University , Miami, FL 33174, USA
| | - Akito Y Kawahara
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida , Gainesville, FL 32611, USA
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Tatarsky RL, Akbari N, Wang K, Xu C, Bass AH. Label-free multiphoton imaging reveals volumetric shifts across development in sensory-related brain regions of a miniature transparent vertebrate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.18.604134. [PMID: 39091824 PMCID: PMC11291088 DOI: 10.1101/2024.07.18.604134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Animals integrate information from different sensory modalities as they mature and perform increasingly complex behaviors. This may parallel differential investment in specific brain regions depending on the demands of changing sensory inputs. To investigate developmental changes in the volume of canonical sensory integration brain regions, we used third harmonic generation imaging for morphometric analysis of forebrain and midbrain regions from 5 to 90 days post fertilization (dpf) in Danionella dracula , a transparent, miniature teleost fish whose brain is optically accessible throughout its lifespan. Relative to whole brain volume, increased volume or investment in telencephalon, a higher order sensory integration center, and torus longitudinalis (TL), a midbrain visuomotor integration center, is relatively consistent from 5 to 30 dpf, until it increases at 60 dpf, followed by another increase at 90 dpf, as animals reach adulthood. In contrast, investment in midbrain optic tectum (TeO), a retinal-recipient target, progressively decreases from 30-90 dpf, whereas investment is relatively consistent across all stages for the midbrain torus semicircularis (TS), a secondary auditory and mechanosensory lateral line center, and the olfactory bulb (OB), a direct target of the olfactory epithelium. In sum, increased investment in higher order integration centers (telencephalon, TL) occurs as juveniles reach adulthood and exhibit more complex cognitive tasks, whereas investment in modality-dominant regions occurs in earlier stages (TeO) or is relatively consistent across development (TS, OB). Complete optical access throughout Danionella 's lifespan provides a unique opportunity to investigate how changing brain structure over development correlates with changes in connectivity, microcircuitry, or behavior.
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Merchant A, Zhou X. Caste-biased patterns of brain investment in the subterranean termite Reticulitermes flavipes. iScience 2024; 27:110052. [PMID: 38883809 PMCID: PMC11176635 DOI: 10.1016/j.isci.2024.110052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/04/2024] [Accepted: 05/17/2024] [Indexed: 06/18/2024] Open
Abstract
Investment into neural tissue is expected to reflect the specific sensory and behavioral capabilities of a particular organism. Termites are eusocial insects that exhibit a caste system in which individuals can develop into one of several morphologically and behaviorally distinct castes. However, it is unclear to what extent these differences between castes are reflected in the anatomy of the brain. To address this question, we used deformation-based morphometry to conduct pairwise comparisons between the brains of different castes in the eastern subterranean termite, Reticulitermes flavipes. Workers exhibited enlargement in the antennal lobes and mushroom bodies, while reproductives showed increased investment into the optic lobes and central body. In addition, caste-specific enlargement was observed in regions that could not be mapped to distinct neuropils, most notably in soldiers. These findings demonstrate a significant influence of caste development on brain anatomy in termites alongside convergence with eusocial hymenopteran systems.
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Affiliation(s)
- Austin Merchant
- Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY 40546, USA
| | - Xuguo Zhou
- Department of Entomology, School of Integrative Biology, College of Liberal Arts & Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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4
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Niimura Y, Biswa BB, Kishida T, Toyoda A, Fujiwara K, Ito M, Touhara K, Inoue-Murayama M, Jenkins SH, Adenyo C, Kayang BB, Koide T. Synchronized Expansion and Contraction of Olfactory, Vomeronasal, and Taste Receptor Gene Families in Hystricomorph Rodents. Mol Biol Evol 2024; 41:msae071. [PMID: 38649162 PMCID: PMC11035023 DOI: 10.1093/molbev/msae071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/02/2024] [Accepted: 03/03/2024] [Indexed: 04/25/2024] Open
Abstract
Chemical senses, including olfaction, pheromones, and taste, are crucial for the survival of most animals. There has long been a debate about whether different types of senses might influence each other. For instance, primates with a strong sense of vision are thought to have weakened olfactory abilities, although the oversimplified trade-off theory is now being questioned. It is uncertain whether such interactions between different chemical senses occur during evolution. To address this question, we examined four receptor gene families related to olfaction, pheromones, and taste: olfactory receptor (OR), vomeronasal receptor type 1 and type 2 (V1R and V2R), and bitter taste receptor (T2R) genes in Hystricomorpha, which is morphologically and ecologically the most diverse group of rodents. We also sequenced and assembled the genome of the grasscutter, Thryonomys swinderianus. By examining 16 available genome assemblies alongside the grasscutter genome, we identified orthologous gene groups among hystricomorph rodents for these gene families to separate the gene gain and loss events in each phylogenetic branch of the Hystricomorpha evolutionary tree. Our analysis revealed that the expansion or contraction of the four gene families occurred synchronously, indicating that when one chemical sense develops or deteriorates, the others follow suit. The results also showed that V1R/V2R genes underwent the fastest evolution, followed by OR genes, and T2R genes were the most evolutionarily stable. This variation likely reflects the difference in ligands of V1R/V2Rs, ORs, and T2Rs: species-specific pheromones, environment-based scents, and toxic substances common to many animals, respectively.
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Affiliation(s)
- Yoshihito Niimura
- Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Bhim B Biswa
- Mouse Genomics Resource Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Shizuoka, Japan
| | - Takushi Kishida
- Curatorial Division, Museum of Natural and Environmental History, Shizuoka, Japan
- Present address: College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Kazumichi Fujiwara
- Mouse Genomics Resource Laboratory, National Institute of Genetics, Mishima, Japan
| | - Masato Ito
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | | | - Scott H Jenkins
- Wildlife Research Center, Kyoto University, Kyoto, Japan
- Present address: Biosphere Informatics Laboratory, Department of Social Informatics, Graduate School of Informatics, Kyoto, Japan
| | - Christopher Adenyo
- Livestock and Poultry Research Centre, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Boniface B Kayang
- Department of Animal Science, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Tsuyoshi Koide
- Mouse Genomics Resource Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Shizuoka, Japan
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5
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Liao BY, Weng MP, Chang TY, Chang AYF, Ching YH, Wu CH. Degeneration of the Olfactory System in a Murid Rodent that Evolved Diurnalism. Mol Biol Evol 2024; 41:msae037. [PMID: 38376543 PMCID: PMC10906987 DOI: 10.1093/molbev/msae037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/03/2024] [Accepted: 02/13/2024] [Indexed: 02/21/2024] Open
Abstract
In mammalian research, it has been debated what can initiate an evolutionary tradeoff between different senses, and the phenomenon of sensory tradeoff in rodents, the most abundant mammalian clade, is not evident. The Nile rat (Arvicanthis niloticus), a murid rodent, recently adapted to a diurnal niche through an evolutionary acquisition of daylight vision with enhanced visual acuity. As such, this model provides an opportunity for a cross-species investigation where comparative morphological and multi-omic analyses of the Nile rat are made with its closely related nocturnal species, e.g. the mouse (Mus musculus) and the rat (Rattus norvegicus). Thus, morphological examinations were performed, and evolutionary reductions in relative sizes of turbinal bone surfaces, the cribriform plate, and the olfactory bulb were discovered in Nile rats. Subsequently, we compared multiple murid genomes, and profiled olfactory epithelium transcriptomes of mice and Nile rats at various ages with RNA sequencing. The results further demonstrate that, in comparison with mouse olfactory receptor (OR) genes, Nile rat OR genes have experienced less frequent gain, more frequent loss, and more frequent expression reduction during their evolution. Furthermore, functional degeneration of coding sequences in the Nile rat lineage was found in OR genes, yet not in other genes. Taken together, these results suggest that acquisition of improved vision in the Nile rat has been accompanied by degeneration of both olfaction-related anatomical structures and OR gene repertoires, consistent with the hypothesis of an olfaction-vision tradeoff initiated by the switch from a nocturnal to a diurnal lifestyle in mammals.
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Affiliation(s)
- Ben-Yang Liao
- Institute of Population Health Sciences, National Health Research Institutes, Taiwan, Republic of China
| | - Meng-Pin Weng
- Institute of Population Health Sciences, National Health Research Institutes, Taiwan, Republic of China
| | - Ting-Yan Chang
- Institute of Population Health Sciences, National Health Research Institutes, Taiwan, Republic of China
| | - Andrew Ying-Fei Chang
- Institute of Population Health Sciences, National Health Research Institutes, Taiwan, Republic of China
| | - Yung-Hao Ching
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Taiwan, Republic of China
| | - Chia-Hwa Wu
- Laboratory Animal Center, National Health Research Institutes, Taiwan, Republic of China
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6
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Aksamit IC, Dorigão-Guimarães F, Gronenberg W, Godfrey RK. Brain size scaling through development in the whitelined sphinx moth (Hyles lineata) shows mass and cell number comparable to flies, bees, and wasps. ARTHROPOD STRUCTURE & DEVELOPMENT 2024; 78:101329. [PMID: 38171085 DOI: 10.1016/j.asd.2023.101329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/13/2023] [Accepted: 12/13/2023] [Indexed: 01/05/2024]
Abstract
Factors regulating larval growth and determinants of adult body size are described for several holometabolous insects, but less is known about brain size scaling through development. Here we use the isotropic fractionation ("brain soup") method to estimate the number of brain cells and cell density for the whitelined sphinx moth (Lepidoptera: Hyles lineata) from the first instar through the adult stage. We measure mass and brain cell number and find that, during the larval stages, body mass shows an exponential relationship with head width, while the total number of brain cells increases asymptotically. Larval brain cell number increases by a factor of ten from nearly 8000 in the first instar to over 80,000 in the fifth instar. Brain cell number increases by another factor of 10 during metamorphosis, with the adult brain containing more than 900,000 cells. This is similar to increases during development in the vinegar fly (Drosophila melanogaster) and the black soldier fly (Hermetia illucens). The adult brain falls slightly below the brain-to-body allometry for wasps and bees but is comparable in the number of cells per unit brain mass, indicating a general conservation of brain cell density across these divergent lineages.
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Affiliation(s)
- Isabel C Aksamit
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Felipe Dorigão-Guimarães
- Biodiversity Graduate Program, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences (IBILCE), São José do Rio Preto, SP, Brazil
| | | | - R Keating Godfrey
- Entomology and Nematology Department, University of Florida, Gainesville, FL, USA.
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7
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Wainwright JB, Schofield C, Conway M, Phillips D, Martin-Silverstone E, Brodrick EA, Cicconardi F, How MJ, Roberts NW, Montgomery SH. Multiple axes of visual system diversity in Ithomiini, an ecologically diverse tribe of mimetic butterflies. J Exp Biol 2023; 226:jeb246423. [PMID: 37921078 PMCID: PMC10714147 DOI: 10.1242/jeb.246423] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/31/2023] [Indexed: 11/04/2023]
Abstract
The striking structural variation seen in arthropod visual systems can be explained by the overall quantity and spatio-temporal structure of light within habitats coupled with developmental and physiological constraints. However, little is currently known about how fine-scale variation in visual structures arises across shorter evolutionary and ecological scales. In this study, we characterise patterns of interspecific (between species), intraspecific (between sexes) and intraindividual (between eye regions) variation in the visual system of four ithomiine butterfly species. These species are part of a diverse 26-million-year-old Neotropical radiation where changes in mimetic colouration are associated with fine-scale shifts in ecology, such as microhabitat preference. Using a combination of selection analyses on visual opsin sequences, in vivo ophthalmoscopy, micro-computed tomography (micro-CT), immunohistochemistry, confocal microscopy and neural tracing, we quantify and describe physiological, anatomical and molecular traits involved in visual processing. Using these data, we provide evidence of substantial variation within the visual systems of Ithomiini, including: (i) relaxed selection on visual opsins, perhaps mediated by habitat preference, (ii) interspecific shifts in visual system physiology and anatomy, and (iii) extensive sexual dimorphism, including the complete absence of a butterfly-specific optic neuropil in the males of some species. We conclude that considerable visual system variation can exist within diverse insect radiations, hinting at the evolutionary lability of these systems to rapidly develop specialisations to distinct visual ecologies, with selection acting at the perceptual, processing and molecular level.
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Affiliation(s)
- J. Benito Wainwright
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Corin Schofield
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Max Conway
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Daniel Phillips
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Elizabeth Martin-Silverstone
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Emelie A. Brodrick
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Francesco Cicconardi
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Martin J. How
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Nicholas W. Roberts
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Stephen H. Montgomery
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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8
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Jernigan CM, Uy FM. Impact of the social environment in insect sensory systems. CURRENT OPINION IN INSECT SCIENCE 2023; 59:101083. [PMID: 37423425 DOI: 10.1016/j.cois.2023.101083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/11/2023]
Abstract
The social environment has a direct impact on sensory systems and unquestionable consequences on allocation of neural tissue. Although neuroplasticity is adaptive, responses to different social contexts may be mediated by energetic constraints and/or trade-offs between sensory modalities. However, general patterns of sensory plasticity remain elusive due to variability in experimental approaches. Here, we highlight recent studies in social Hymenoptera showing effects of the social environment on sensory systems. Further, we propose to identify a core set of socially mediated mechanisms that drive sensory plasticity. We hope this approach is widely adopted in different insect clades under a phylogenetic framework, which will allow for a more direct integration of the how and why questions exploring sensory plasticity evolution.
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Affiliation(s)
- Christopher M Jernigan
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, NY, USA.
| | - Floria Mk Uy
- Department of Biology, University of Rochester, Rochester, NY, USA.
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9
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Sehadová H, Podlahová Š, Reppert SM, Sauman I. 3D reconstruction of larval and adult brain neuropils of two giant silk moth species: Hyalophora cecropia and Antheraea pernyi. JOURNAL OF INSECT PHYSIOLOGY 2023; 149:104546. [PMID: 37451537 DOI: 10.1016/j.jinsphys.2023.104546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/21/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
We present a detailed analysis of the brain anatomy of two saturniid species, the cecropia silk moth, Hyalophora cecropia, and the Chinese oak silk moth, Antheraea pernyi, including 3D reconstructions of the major brain neuropils in the larva and in male and female adults. The 3D reconstructions, prepared from high-resolution optical sections, showed that the corresponding neuropils of these saturniid species are virtually identical. Similarities between the two species include a pronounced sexual dimorphism in the adults in the form of a male-specific assembly of markedly enlarged glomeruli forming the so-called macroglomerular complex. From the reports published to date, it can be concluded that the neuropil architecture of saturniids resembles that of other nocturnal moths, including the sibling family Sphingidae. In addition, compared with previous anatomical data on diurnal lepidopteran species, significant differences were observed in the two saturniid species, which include the thickness of the Y-tract of the mushroom body, the size of the main neuropils of the optic lobes, and the sexual dimorphisms of the antennal lobes.
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Affiliation(s)
- Hana Sehadová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Šárka Podlahová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Steven M Reppert
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
| | - Ivo Sauman
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
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10
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Akiyama T, Uchiyama H, Yajima S, Arikawa K, Terai Y. Parallel evolution of opsin visual pigments in hawkmoths by tuning of spectral sensitivities during transition from a nocturnal to a diurnal ecology. J Exp Biol 2022; 225:285920. [PMID: 36408938 PMCID: PMC10112871 DOI: 10.1242/jeb.244541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 11/15/2022] [Indexed: 11/23/2022]
Abstract
Light environments differ dramatically between day and night. The transition between diurnal and nocturnal visual ecology has happened repeatedly throughout evolution in many species. However, the molecular mechanism underlying the evolution of vision in recent diurnal-nocturnal transition is poorly understood. Here, we focus on hawkmoths (Lepidoptera: Sphingidae) to address this question by investigating five nocturnal and five diurnal species. We performed RNA-sequencing analysis and identified opsin genes corresponding to the ultraviolet (UV), short-wavelength (SW) and long-wavelength (LW)-absorbing visual pigments. We found no significant differences in the expression patterns of opsin genes between the nocturnal and diurnal species. We then constructed the phylogenetic trees of hawkmoth species and opsins. The diurnal lineages had emerged at least three times from the nocturnal ancestors. The evolutionary rates of amino acid substitutions in the three opsins differed between the nocturnal and diurnal species. We found an excess number of parallel amino acid substitutions in the opsins in three independent diurnal lineages. The numbers were significantly more than those inferred from neutral evolution, suggesting that positive selection acted on these parallel substitutions. Moreover, we predicted the visual pigment absorption spectra based on electrophysiologically determined spectral sensitivity in two nocturnal and two diurnal species belonging to different clades. In the diurnal species, the LW pigments shift 10 nm towards shorter wavelengths, and the SW pigments shift 10 nm in the opposite direction. Taken together, our results suggest that parallel evolution of opsins may have enhanced the colour discrimination properties of diurnal hawkmoths in ambient light.
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Affiliation(s)
- Tokiho Akiyama
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Hironobu Uchiyama
- NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Shunsuke Yajima
- NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan.,Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Kentaro Arikawa
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Yohey Terai
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
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11
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Abstract
The ability to see colour at night is known only from a handful of animals. First discovered in the elephant hawk moth Deilephila elpenor, nocturnal colour vision is now known from two other species of hawk moths, a single species of carpenter bee, a nocturnal gecko and two species of anurans. The reason for this rarity—particularly in vertebrates—is the immense challenge of achieving a sufficient visual signal-to-noise ratio to support colour discrimination in dim light. Although no less challenging for nocturnal insects, unique optical and neural adaptations permit reliable colour vision and colour constancy even in starlight. Using the well-studied Deilephila elpenor, we describe the visual light environment at night, the visual challenges that this environment imposes and the adaptations that have evolved to overcome them. We also explain the advantages of colour vision for nocturnal insects and its usefulness in discriminating night-opening flowers. Colour vision is probably widespread in nocturnal insects, particularly pollinators, where it is likely crucial for nocturnal pollination. This relatively poorly understood but vital ecosystem service is threatened from increasingly abundant and spectrally abnormal sources of anthropogenic light pollution, which can disrupt colour vision and thus the discrimination and pollination of flowers. This article is part of the theme issue ‘Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods’.
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Affiliation(s)
- Eric Warrant
- Department of Biology, University of Lund, Sölvegatan 35, 22362 Lund, Sweden
| | - Hema Somanathan
- School of Biology, Indian Institute of Science Education and Research, Maruthamala PO, Vithura, Thiruvananthapuram, Kerala 695551, India
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12
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Stöckl AL, Foster JJ. Night skies through animals' eyes-Quantifying night-time visual scenes and light pollution as viewed by animals. Front Cell Neurosci 2022; 16:984282. [PMID: 36274987 PMCID: PMC9582234 DOI: 10.3389/fncel.2022.984282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
A large proportion of animal species enjoy the benefits of being active at night, and have evolved the corresponding optical and neural adaptations to cope with the challenges of low light intensities. However, over the past century electric lighting has introduced direct and indirect light pollution into the full range of terrestrial habitats, changing nocturnal animals' visual worlds dramatically. To understand how these changes affect nocturnal behavior, we here propose an animal-centered analysis method based on environmental imaging. This approach incorporates the sensitivity and acuity limits of individual species, arriving at predictions of photon catch relative to noise thresholds, contrast distributions, and the orientation cues nocturnal species can extract from visual scenes. This analysis relies on just a limited number of visual system parameters known for each species. By accounting for light-adaptation in our analysis, we are able to make more realistic predictions of the information animals can extract from nocturnal visual scenes under different levels of light pollution. With this analysis method, we aim to provide context for the interpretation of behavioral findings, and to allow researchers to generate specific hypotheses for the behavior of nocturnal animals in observed light-polluted scenes.
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Affiliation(s)
- Anna Lisa Stöckl
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
- Zukunftskolleg, Universität Konstanz, Konstanz, Germany
| | - James Jonathan Foster
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
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13
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Farnworth MS, Bucher G, Hartenstein V. An atlas of the developing Tribolium castaneum brain reveals conservation in anatomy and divergence in timing to Drosophila melanogaster. J Comp Neurol 2022; 530:2335-2371. [PMID: 35535818 PMCID: PMC9646932 DOI: 10.1002/cne.25335] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 11/11/2022]
Abstract
Insect brains are formed by conserved sets of neural lineages whose fibers form cohesive bundles with characteristic projection patterns. Within the brain neuropil, these bundles establish a system of fascicles constituting the macrocircuitry of the brain. The overall architecture of the neuropils and the macrocircuitry appear to be conserved. However, variation is observed, for example, in size, shape, and timing of development. Unfortunately, the developmental and genetic basis of this variation is poorly understood, although the rise of new genetically tractable model organisms such as the red flour beetle Tribolium castaneum allows the possibility to gain mechanistic insights. To facilitate such work, we present an atlas of the developing brain of T. castaneum, covering the first larval instar, the prepupal stage, and the adult, by combining wholemount immunohistochemical labeling of fiber bundles (acetylated tubulin) and neuropils (synapsin) with digital 3D reconstruction using the TrakEM2 software package. Upon comparing this anatomical dataset with the published work in Drosophila melanogaster, we confirm an overall high degree of conservation. Fiber tracts and neuropil fascicles, which can be visualized by global neuronal antibodies like antiacetylated tubulin in all invertebrate brains, create a rich anatomical framework to which individual neurons or other regions of interest can be referred to. The framework of a largely conserved pattern allowed us to describe differences between the two species with respect to parameters such as timing of neuron proliferation and maturation. These features likely reflect adaptive changes in developmental timing that govern the change from larval to adult brain.
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Affiliation(s)
- Max S Farnworth
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, University of Göttingen, Göttingen, Germany
- Evolution of Brains and Behaviour lab, School of Biological Sciences, University of Bristol, Bristol, UK
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, University of Göttingen, Göttingen, Germany
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California/Los Angeles, Los Angeles, USA
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14
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Wainwright JB, Montgomery SH. Neuroanatomical shifts mirror patterns of ecological divergence in three diverse clades of mimetic butterflies. Evolution 2022; 76:1806-1820. [PMID: 35767896 PMCID: PMC9540801 DOI: 10.1111/evo.14547] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 05/30/2022] [Accepted: 06/06/2022] [Indexed: 01/22/2023]
Abstract
Microhabitat partitioning in heterogenous environments can support more diverse communities but may expose partitioned species to distinct perceptual challenges. Divergence across microhabitats could therefore lead to local adaptation to contrasting sensory conditions across small spatial scales, but this aspect of community structuring is rarely explored. Diverse communities of ithomiine butterflies provide an example where closely related species partition tropical forests, where shifts in mimetic coloration are tightly associated with shifts in habitat preference. We test the hypothesis that these mimetic and ecological shifts are associated with distinct patterns of sensory neural investment by comparing brain structure across 164 individuals of 16 species from three ithomiine clades. We find distinct brain morphologies between Oleriina and Hypothyris, which are mimetically homogenous and occupy a single microhabitat. Oleriina, which occurs in low-light microhabitats, invests less in visual brain regions than Hypothyris, with one notable exception, Hyposcada anchiala, the only Oleriina sampled to have converged on mimicry rings found in Hypothyris. We also find that Napeogenes, which has diversified into a range of mimicry rings, shows intermediate patterns of sensory investment. We identify flight height as a critical factor shaping neuroanatomical diversity, with species that fly higher in the canopy investing more in visual structures. Our work suggests that the sensory ecology of species may be impacted by, and interact with, the ways in which communities of closely related organisms are adaptively assembled.
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15
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Stöckl A, Grittner R, Taylor G, Rau C, Bodey AJ, Kelber A, Baird E. Allometric scaling of a superposition eye optimizes sensitivity and acuity in large and small hawkmoths. Proc Biol Sci 2022; 289:20220758. [PMID: 35892218 PMCID: PMC9326294 DOI: 10.1098/rspb.2022.0758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Animals vary widely in body size within and across species. This has consequences for the function of organs and body parts in both large and small individuals. How these scale, in relation to body size, reveals evolutionary investment strategies, often resulting in trade-offs between functions. Eyes exemplify these trade-offs, as they are limited by their absolute size in two key performance features: sensitivity and spatial acuity. Due to their size polymorphism, insect compound eyes are ideal models for studying the allometric scaling of eye performance. Previous work on apposition compound eyes revealed that allometric scaling led to poorer spatial resolution and visual sensitivity in small individuals, across a range of insect species. Here, we used X-ray microtomography to investigate allometric scaling in superposition compound eyes-the second most common eye type in insects-for the first time. Our results reveal a novel strategy to cope with the trade-off between sensitivity and spatial acuity, as we show that the eyes of the hummingbird hawkmoth retain an optimal balance between these performance measures across all body sizes.
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Affiliation(s)
- Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Gavin Taylor
- Institute for Globally Distributed Open Research and Education (IGDORE), Ribeirão Preto, Brazil
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Andrew J. Bodey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
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16
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Pham HT, Elgar MA, van Lieshout E, McNamara KB. Experimental immune challenges reduce the quality of male antennae and female pheromone output. Sci Rep 2022; 12:3578. [PMID: 35246550 PMCID: PMC8897396 DOI: 10.1038/s41598-022-07100-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/01/2022] [Indexed: 11/17/2022] Open
Abstract
Sexual signalling is a key feature of reproductive investment, yet the effects of immune system activation on investment into chemical signalling, and especially signal receiver traits such as antennae, are poorly understood. We explore how upregulation of juvenile immunity affects male antennal functional morphology and female pheromone attractiveness in the gumleaf skeletonizer moth, Uraba lugens. We injected final-instar larvae with a high or low dose of an immune elicitor or a control solution and measured male antennal morphological traits, gonad investment and female pheromone attractiveness. Immune activation affected male and female signalling investment: immune challenged males had a lower density of antennal sensilla, and the pheromone of immune-challenged females was less attractive to males than their unchallenged counterparts. Immune challenge affected female investment into ovary development but not in a linear, dose-dependent manner. While there was no effect of immune challenge on testes size, there was a trade-off between male pre- and post-copulatory investment: male antennal length was negatively correlated with testes size. Our study highlights the costs of elaborate antennae and pheromone production and demonstrates the capacity for honest signalling in species where the costs of pheromone production were presumed to be trivial.
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Affiliation(s)
- Hieu T Pham
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Entomology, Faculty of Agronomy, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Mark A Elgar
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Emile van Lieshout
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Kathryn B McNamara
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
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17
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Dell’Aglio DD, McMillan WO, Montgomery SH. Shifting balances in the weighting of sensory modalities are predicted by divergence in brain morphology in incipient species of Heliconius butterflies. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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18
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Polidori C, Piwczynski M, Ronchetti F, Johnston NP, Szpila K. Host-trailing satellite flight behaviour is associated with greater investment in peripheral visual sensory system in miltogrammine flies. Sci Rep 2022; 12:2773. [PMID: 35177753 PMCID: PMC8854417 DOI: 10.1038/s41598-022-06704-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/02/2022] [Indexed: 11/24/2022] Open
Abstract
Insect sensory systems are the subjects of different selective pressures that shape their morphology. In many species of the flesh fly subfamily Miltogramminae (Diptera: Sarcophagidae) that are kleptoparasitic on bees and wasps, females perch on objects close to the host nests and, once a returning host is detected, they follow it in flight at a fixed distance behind until reaching the nest. We hypothesized that such satellite (SAT) flight behaviour, which implies a finely coordinated trailing flight, is associated with an improved visual system, compared to species adopting other, non-satellite (NON-SAT) strategies. After looking at body size and common ancestry, we found that SAT species have a greater number of ommatidia and a greater eye surface area when compared to NON-SAT species. Ommatidium area is only affected by body size, suggesting that selection changes disproportionately (relative to body size variation) the number of ommatidia and as a consequence the eye area, instead of ommatidium size. SAT species also tend to have larger ocelli, but their role in host-finding was less clear. This suggests that SAT species may have a higher visual acuity by increasing ommatidia number, as well as better stability during flight and motion perception through larger ocelli. Interestingly, antennal length was significantly reduced in SAT species, and ommatidia number negatively correlated with antennal length. While this finding does not imply a selection pressure of improved antennal sensory system in species adopting NON-SAT strategies, it suggests an inverse resource (i.e. a single imaginal disc) allocation between eyes and antennae in this fly subfamily.
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Affiliation(s)
- Carlo Polidori
- Dipartimento di Scienze e Politiche Ambientali, Università Degli Studi di Milano, via Celoria 26, 20133, Milan, Italy.
| | - Marcin Piwczynski
- Department of Ecology and Biogeography, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland
| | - Federico Ronchetti
- Department of Animal Ecology and Tropical Biology, University of Wuerzburg, Hubland Nord, 97074, Würzburg, Germany
| | - Nikolas P Johnston
- School of Life Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia
| | - Krzysztof Szpila
- Department of Ecology and Biogeography, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland
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19
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Gandia KM, Cappa F, Baracchi D, Hauber ME, Beani L, Uy FMK. Caste, Sex, and Parasitism Influence Brain Plasticity in a Social Wasp. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.803437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brain plasticity is widespread in nature, as it enables adaptive responses to sensory demands associated with novel stimuli, environmental changes and social conditions. Social Hymenoptera are particularly well-suited to study neuroplasticity, because the division of labor amongst females and the different life histories of males and females are associated with specific sensory needs. Here, we take advantage of the social wasp Polistes dominula to explore if brain plasticity is influenced by caste and sex, and the exploitation by the strepsipteran parasite Xenos vesparum. Within sexes, male wasps had proportionally larger optic lobes, while females had larger antennal lobes, which is consistent with the sensory needs of sex-specific life histories. Within castes, reproductive females had larger mushroom body calyces, as predicted by their sensory needs for extensive within-colony interactions and winter aggregations, than workers who frequently forage for nest material and prey. Parasites had different effects on female and male hosts. Contrary to our predictions, female workers were castrated and behaviorally manipulated by female or male parasites, but only showed moderate differences in brain tissue allocation compared to non-parasitized workers. Parasitized males maintained their reproductive apparatus and sexual behavior. However, they had smaller brains and larger sensory brain regions than non-parasitized males. Our findings confirm that caste and sex mediate brain plasticity in P. dominula, and that parasitic manipulation drives differential allocation of brain regions depending on host sex.
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20
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Rozanski AN, Cini A, Lopreto TE, Gandia KM, Hauber ME, Cervo R, Uy FMK. Differential investment in visual and olfactory brain regions is linked to the sensory needs of a wasp social parasite and its host. J Comp Neurol 2021; 530:756-767. [PMID: 34473851 DOI: 10.1002/cne.25242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 08/03/2021] [Accepted: 08/31/2021] [Indexed: 01/30/2023]
Abstract
Obligate insect social parasites evolve traits to effectively locate and then exploit their hosts, whereas hosts have complex social behavioral repertoires, which include sensory recognition to reject potential conspecific intruders and heterospecific parasites. While social parasites and host behaviors have been studied extensively, less is known about how their sensory systems function to meet their specific selective pressures. Here, we compare investment in visual and olfactory brain regions in the paper wasp Polistes dominula, and its obligate social parasite P. sulcifer, to explore the links among sensory systems,brain and behavior. Our results show significant relative volumetric differences between these two closely related species, consistent with their very different life histories. Social parasites show proportionally larger optic lobes and central complex to likely navigate long-distance migrations and unfamiliar landscapes to locate the specific species of hosts they usurp. Contrastingly, hosts have larger antennal lobes and calyces of the mushroom bodies compared with social parasites, as predicted by their sensory means to maintain social cohesion via olfactory signals, allocate colony tasks, forage, and recognize conspecific and heterospecific intruders. Our work suggests how this tradeoff between visual and olfactory brain regions may facilitate different sensory adaptations needed to perform social and foraging tasks by the host, including recognition of parasites, or to fly long distances and successful host localizing by the social parasite.
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Affiliation(s)
| | - Alessandro Cini
- Department of Biology, University of Florence, Sesto Fiorentino, Firenze, Italy.,Centre for Biodiversity and Environment Research, University College London, London, UK
| | - Taylor E Lopreto
- Department of Biology, University of Miami, Coral Gables, Florida, USA
| | - Kristine M Gandia
- Department of Biology, University of Miami, Coral Gables, Florida, USA
| | - Mark E Hauber
- Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Rita Cervo
- Department of Biology, University of Florence, Sesto Fiorentino, Firenze, Italy
| | - Floria M K Uy
- Department of Biology, University of Miami, Coral Gables, Florida, USA.,Department of Biology, University of Rochester, Rochester, New York, USA
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21
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Morris BJ, Couto A, Aydin A, Montgomery SH. Re-emergence and diversification of a specialized antennal lobe morphology in ithomiine butterflies. Evolution 2021; 75:3191-3202. [PMID: 34383301 DOI: 10.1111/evo.14324] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/15/2021] [Accepted: 08/02/2021] [Indexed: 11/29/2022]
Abstract
How an organism's sensory system functions is central to how it navigates its environment. The insect olfactory system is a prominent model for investigating how ecological factors impact sensory reception and processing. Notably, work in Lepidoptera led to the discovery of vastly expanded structures, termed macroglomerular complexes (MGCs), within the primary olfactory processing centre. MGCs typically process pheromonal cues, are usually larger in males, and provide classic examples of how variation in the size of neural structures reflects the importance of sensory cues. Though prevalent across moths, MGCs were lost during the origin of butterflies, consistent with evidence that courtship initiation in butterflies is primarily reliant on visual cues, rather than long distance chemical signals. However, an MGC was recently described in a species of ithomiine butterfly, suggesting that this once lost neural adaptation has re-emerged in this tribe. Here, we show that MGC-like morphologies are widely distributed across ithomiines, but vary in both their structure and prevalence of sexual dimorphism. Based on this interspecific variation we suggest that the ithomiine MGC is involved in processing both plant and pheromonal cues, which have similarities in their chemical constitution, and co-evolved with an increased importance of plant derived chemical compounds.
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Affiliation(s)
- Billy J Morris
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Antoine Couto
- Department of Zoology, University of Cambridge, Cambridge, UK.,School of Biological Sciences, University of Bristol, Bristol, UK
| | - Asli Aydin
- School of Medicine, Koc University, Rumelifeneri Yolu, Istanbul, Turkey
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22
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Freelance CB, Tierney SM, Rodriguez J, Stuart-Fox DM, Wong BBM, Elgar MA. The eyes have it: dim-light activity is associated with the morphology of eyes but not antennae across insect orders. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The perception of cues and signals in visual, olfactory and auditory modalities underpins all animal interactions and provides crucial fitness-related information. Sensory organ morphology is under strong selection to optimize detection of salient cues and signals in a given signalling environment, the most well-studied example being selection on eye design in different photic environments. Many dim-light active species have larger compound eyes relative to body size, but little is known about differences in non-visual sensory organ morphology between diurnal and dim-light active insects. Here, we compare the micromorphology of the compound eyes (visual receptors) and antennae (olfactory and mechanical receptors) in representative pairs of day active and dim-light active species spanning multiple taxonomic orders of insects. We find that dim-light activity is associated with larger compound eye ommatidia and larger overall eye surface area across taxonomic orders but find no evidence that morphological adaptations that enhance the sensitivity of the eye in dim-light active insects are accompanied by morphological traits of the antennae that may increase sensitivity to olfactory, chemical or physical stimuli. This suggests that the ecology and natural history of species is a stronger driver of sensory organ morphology than is selection for complementary investment between sensory modalities.
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Affiliation(s)
| | - Simon M Tierney
- School of BioSciences, The University of Melbourne, Victoria, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, Australia
| | - Juanita Rodriguez
- Australian National Insect Collection, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT 2601, Australia
| | - Devi M Stuart-Fox
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Bob B M Wong
- School of Biological Sciences, Monash University, Victoria, Australia
| | - Mark A Elgar
- School of BioSciences, The University of Melbourne, Victoria, Australia
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23
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Neural divergence and hybrid disruption between ecologically isolated Heliconius butterflies. Proc Natl Acad Sci U S A 2021; 118:2015102118. [PMID: 33547240 DOI: 10.1073/pnas.2015102118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The importance of behavioral evolution during speciation is well established, but we know little about how this is manifest in sensory and neural systems. A handful of studies have linked specific neural changes to divergence in host or mate preferences associated with speciation. However, the degree to which brains are adapted to local environmental conditions, and whether this contributes to reproductive isolation between close relatives that have diverged in ecology, remains unknown. Here, we examine divergence in brain morphology and neural gene expression between closely related, but ecologically distinct, Heliconius butterflies. Despite ongoing gene flow, sympatric species pairs within the melpomene-cydno complex are consistently separated across a gradient of open to closed forest and decreasing light intensity. By generating quantitative neuroanatomical data for 107 butterflies, we show that Heliconius melpomene and Heliconius cydno clades have substantial shifts in brain morphology across their geographic range, with divergent structures clustered in the visual system. These neuroanatomical differences are mirrored by extensive divergence in neural gene expression. Differences in both neural morphology and gene expression are heritable, exceed expected rates of neutral divergence, and result in intermediate traits in first-generation hybrid offspring. Strong evidence of divergent selection implies local adaptation to distinct selective optima in each parental microhabitat, suggesting the intermediate traits of hybrids are poorly matched to either condition. Neural traits may therefore contribute to coincident barriers to gene flow, thereby helping to facilitate speciation.
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24
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Neuroanatomical differentiation associated with alternative reproductive tactics in male arid land bees, Centris pallida and Amegilla dawsoni. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:497-504. [PMID: 34091709 DOI: 10.1007/s00359-021-01492-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/19/2021] [Accepted: 05/22/2021] [Indexed: 12/18/2022]
Abstract
Alternative reproductive tactics (ARTs) occur when there is categorical variation in the reproductive strategies of a sex within a population. These different behavioral phenotypes can expose animals to distinct cognitive challenges, which may be addressed through neuroanatomical differentiation. The dramatic phenotypic plasticity underlying ARTs provides a powerful opportunity to study how intraspecific nervous system variation can support distinct cognitive abilities. We hypothesized that conspecific animals pursuing ARTs would exhibit dissimilar brain architecture. Dimorphic males of the bee species Centris pallida and Amegilla dawsoni use alternative mate location strategies that rely primarily on either olfaction (large-morph) or vision (small-morph) to find females. This variation in behavior led us to predict increased volumes of the brain regions supporting their primarily chemosensory or visual mate location strategies. Large-morph males relying mainly on olfaction had relatively larger antennal lobes and relatively smaller optic lobes than small-morph males relying primarily on visual cues. In both species, as relative volumes of the optic lobe increased, the relative volume of the antennal lobe decreased. In addition, A. dawsoni large males had relatively larger mushroom body lips, which process olfactory inputs. Our results suggest that the divergent behavioral strategies in ART systems can be associated with neuroanatomical differentiation.
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25
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A Review of Effects of Environment on Brain Size in Insects. INSECTS 2021; 12:insects12050461. [PMID: 34067515 PMCID: PMC8156428 DOI: 10.3390/insects12050461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary What makes a big brain is fascinating since it is considered as a measure of intelligence. Above all, brain size is associated with body size. If species that have evolved with complex social behaviours possess relatively bigger brains than those deprived of such behaviours, this does not constitute the only factor affecting brain size. Other factors such as individual experience or surrounding environment also play roles in the size of the brain. In this review, I summarize the recent findings about the effects of environment on brain size in insects. I also discuss evidence about how the environment has an impact on sensory systems and influences brain size. Abstract Brain size fascinates society as well as researchers since it is a measure often associated with intelligence and was used to define species with high “intellectual capabilities”. In general, brain size is correlated with body size. However, there are disparities in terms of relative brain size between species that may be explained by several factors such as the complexity of social behaviour, the ‘social brain hypothesis’, or learning and memory capabilities. These disparities are used to classify species according to an ‘encephalization quotient’. However, environment also has an important role on the development and evolution of brain size. In this review, I summarise the recent studies looking at the effects of environment on brain size in insects, and introduce the idea that the role of environment might be mediated through the relationship between olfaction and vision. I also discussed this idea with studies that contradict this way of thinking.
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26
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Jernigan CM, Zaba NC, Sheehan MJ. Age and social experience induced plasticity across brain regions of the paper wasp Polistes fuscatus. Biol Lett 2021; 17:20210073. [PMID: 33849349 PMCID: PMC8086938 DOI: 10.1098/rsbl.2021.0073] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022] Open
Abstract
Developmental studies of brain volumes can reveal which portions of neural circuits are sensitive to environmental inputs. In social insects, differences in relative investment across brain regions emerge as behavioural repertoires change during ontogeny or as a result of experience. Here, we test the effects of maturation and social experience on morphological brain development in Polistes fuscatus paper wasps, focusing on brain regions involved in visual and olfactory processing. We find that mature wasps regardless of social experience have relatively larger brains than newly emerged wasps and this difference is driven by changes to mushroom body calyx and visual regions but not olfactory processing neuropils. Notably, social wasps invest more in the anterior optic tubercle (AOT), a visual glomerulus involved in colour and object processing in other taxa, relative to other visual integration centres the mushroom body calyces compared with aged socially naive wasps. Differences in developmental plasticity between visual and olfactory neuropil volumes are discussed in light of behavioural maturation in paper wasps, especially as it relates to social recognition. Previous research has shown that P. fuscatus need social experience to develop specialized visual processing of faces, which is used to individually recognize conspecifics. The present study suggests that the AOT is a candidate brain region that could mediate facial processing in this species.
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Affiliation(s)
| | - Natalie C. Zaba
- Department of Neurobiology and Behaviour, Cornell University, Ithaca, NY 14853, USA
| | - Michael J. Sheehan
- Department of Neurobiology and Behaviour, Cornell University, Ithaca, NY 14853, USA
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van der Kooi CJ, Stavenga DG, Arikawa K, Belušič G, Kelber A. Evolution of Insect Color Vision: From Spectral Sensitivity to Visual Ecology. ANNUAL REVIEW OF ENTOMOLOGY 2021; 66:435-461. [PMID: 32966103 DOI: 10.1146/annurev-ento-061720-071644] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Color vision is widespread among insects but varies among species, depending on the spectral sensitivities and interplay of the participating photoreceptors. The spectral sensitivity of a photoreceptor is principally determined by the absorption spectrum of the expressed visual pigment, but it can be modified by various optical and electrophysiological factors. For example, screening and filtering pigments, rhabdom waveguide properties, retinal structure, and neural processing all influence the perceived color signal. We review the diversity in compound eye structure, visual pigments, photoreceptor physiology, and visual ecology of insects. Based on an overview of the current information about the spectral sensitivities of insect photoreceptors, covering 221 species in 13 insect orders, we discuss the evolution of color vision and highlight present knowledge gaps and promising future research directions in the field.
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Affiliation(s)
- Casper J van der Kooi
- Faculty of Science and Engineering, University of Groningen, 9700 AK Groningen, The Netherlands;
| | - Doekele G Stavenga
- Faculty of Science and Engineering, University of Groningen, 9700 AK Groningen, The Netherlands;
| | - Kentaro Arikawa
- Department of Evolutionary Studies of Biosystems, SOKENDAI Graduate University for Advanced Studies, Kanagawa 240-0193, Japan;
| | - Gregor Belušič
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia;
| | - Almut Kelber
- Lund Vision Group, Department of Biology, University of Lund, 22362 Lund, Sweden;
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Polilov AA, Makarova AA. Constant neuropilar ratio in the insect brain. Sci Rep 2020; 10:21426. [PMID: 33293636 PMCID: PMC7722839 DOI: 10.1038/s41598-020-78599-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/27/2020] [Indexed: 01/10/2023] Open
Abstract
Revealing scaling rules is necessary for understanding the morphology, physiology and evolution of living systems. Studies of animal brains have revealed both general patterns, such as Haller's rule, and patterns specific for certain animal taxa. However, large-scale studies aimed at studying the ratio of the entire neuropil and the cell body rind in the insect brain have never been performed. Here we performed morphometric study of the adult brain in 37 insect species of 26 families and ten orders, ranging in volume from the smallest to the largest by a factor of more than 4,000,000, and show that all studied insects display a similar ratio of the volume of the neuropil to the cell body rind, 3:2. Allometric analysis for all insects shows that the ratio of the volume of the neuropil to the volume of the brain changes strictly isometrically. Analyses within particular taxa, size groups, and metamorphosis types also reveal no significant differences in the relative volume of the neuropil; isometry is observed in all cases. Thus, we establish a new scaling rule, according to which the relative volume of the entire neuropil in insect brain averages 60% and remains constant.
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Affiliation(s)
- Alexey A Polilov
- Department of Entomology, Biological Faculty, Lomonosov Moscow State University, 119234, Moscow, Russia.
| | - Anastasia A Makarova
- Department of Entomology, Biological Faculty, Lomonosov Moscow State University, 119234, Moscow, Russia
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Eriksson M, Janz N, Nylin S, Carlsson MA. Structural plasticity of olfactory neuropils in relation to insect diapause. Ecol Evol 2020; 10:14423-14434. [PMID: 33391725 PMCID: PMC7771155 DOI: 10.1002/ece3.7046] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 12/14/2022] Open
Abstract
Many insects that live in temperate zones spend the cold season in a state of dormancy, referred to as diapause. As the insect must rely on resources that were gathered before entering diapause, keeping a low metabolic rate is of utmost importance. Organs that are metabolically expensive to maintain, such as the brain, can therefore become a liability to survival if they are too large.Insects that go through diapause as adults generally do so before entering the season of reproduction. This order of events introduces a conflict between maintaining low metabolism during dormancy and emerging afterward with highly developed sensory systems that improve fitness during the mating season.We investigated the timing of when investments into the olfactory system are made by measuring the volumes of primary and secondary olfactory neuropils in the brain as they fluctuate in size throughout the extended diapause life-period of adult Polygonia c-album butterflies.Relative volumes of both olfactory neuropils increase significantly during early adult development, indicating the importance of olfaction to this species, but still remain considerably smaller than those of nondiapausing conspecifics. However, despite butterflies being kept under the same conditions as before the dormancy, their olfactory neuropil volumes decreased significantly during the postdormancy period.The opposing directions of change in relative neuropil volumes before and after diapause dormancy indicate that the investment strategies governing structural plasticity during the two life stages could be functionally distinct. As butterflies were kept in stimulus-poor conditions, we find it likely that investments into these brain regions rely on experience-expectant processes before diapause and experience-dependent processes after diapause conditions are broken.As the shift in investment strategies coincides with a hard shift from premating season to mating season, we argue that these developmental characteristics could be adaptations that mitigate the trade-off between dormancy survival and reproductive fitness.
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Affiliation(s)
| | - Niklas Janz
- Department of ZoologyStockholm UniversityStockholmSweden
| | - Sören Nylin
- Department of ZoologyStockholm UniversityStockholmSweden
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Bouchebti S, Arganda S. Insect lifestyle and evolution of brain morphology. CURRENT OPINION IN INSECT SCIENCE 2020; 42:90-96. [PMID: 33038535 DOI: 10.1016/j.cois.2020.09.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
Insect lifestyles are extremely diversified and have important consequences for brain function. Lifestyle determines the resources and information that brains might access and also those that are required to produce adaptive behaviors. Most of the observed adaptations in brain morphology to variation in lifestyle are related to the first stages of sensory information processing (e.g. adaptations to diel habits). However, morphological signatures of lifestyles related to higher order processing of information are more difficult to demonstrate. Co-option of existing neural structures for new behaviors might hinder the detection of morphological changes at a large scale. Current methodological advances will make it possible to investigate finer structural changes (e.g. variation in the connectivity between neurons) and might shed light on whether or not some lifestyles (e.g. eusociality) require morphological adaptations.
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Affiliation(s)
- Sofia Bouchebti
- Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain
| | - Sara Arganda
- Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain.
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López-Palafox T, Macías-Ordóñez R, Cordero CR. The size of signal detection and emission organs in a synchronous firefly: sexual dimorphism, allometry and assortative mating. PeerJ 2020; 8:e10127. [PMID: 33194388 PMCID: PMC7597648 DOI: 10.7717/peerj.10127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 09/17/2020] [Indexed: 11/25/2022] Open
Abstract
The size of the organs responsible for emitting and detecting sexual communication signals is a likely target for selection. Communication via bioluminescent signals in synchronous fireflies is a promising model to test hypotheses regarding differences between males and females in the effect of the size of signal emission and detection organs on fitness components. Synchronous firefly species congregate in large numbers during the mating season, displaying bioluminescent signals aimed at potential mates during relatively short nightly periods. Operational sex ratios are male-biased and, thus, the so-called typical sex roles (indiscriminate males and choosy females) are expected to evolve. We studied the synchronous firefly Photinus palaciosi, a species that during the mating season congregates in forests of central Mexico offering a magnificent natural show that attracts numerous tourists. P. palaciosi females have reduced wings (brachyptery) and cannot fly. Our field study tested the hypothesis that the male-biased operational sex ratio and the short daily mating period result in strong male-male competition that selects for males with larger lanterns and larger eyes, and against male mate choice, whereas female-female mate competition is absent and, thus, no selection on lantern or eye size is expected. Even though lantern, eye or body size do not predict the probability of being found in copula for either sex, sexual dimorphism in these features, along with allometric slopes of lantern size and assortative mating in terms of relative lantern size, support not only the hypothesis of intense sexual selection among males, but the possibility of subtle mechanisms of sexual selection among females. Trade-offs between investment in signaling (lanterns) versus detection (eyes) structures, or with pressures different from sexual selection such as those imposed by predators, are also likely to be important in shaping the evolution of sexual signaling in these fireflies.
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Affiliation(s)
- Tania López-Palafox
- Posgrado en Ciencias Biomédicas, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Carlos R. Cordero
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, México
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Moth Mating: Modeling Female Pheromone Calling and Male Navigational Strategies to Optimize Reproductive Success. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10186543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Male and female moths communicate in complex ways to search for and to select a mate. In a process termed calling, females emit small quantities of pheromones, generating plumes that spread in the environment. Males detect the plume through their antennae and navigate toward the female. The reproductive process is marked by female choice and male–male competition, since multiple males aim to reach the female but only the first can mate with her. This provides an opportunity for female selection on male traits such as chemosensitivity to pheromone molecules and mobility. We develop a mathematical framework to investigate the overall mating likelihood, the mean first arrival time, and the quality of the first male to reach the female for four experimentally observed female calling strategies unfolding over a typical one-week mating period. We present both analytical solutions of a simplified model as well as results from agent-based numerical simulations. Our findings suggest that, by adjusting call times and the amount of released pheromone, females can optimize the mating process. In particular, shorter calling times and lower pheromone titers at onset of the mating period that gradually increase over time allow females to aim for higher-quality males while still ensuring that mating occurs by the end of the mating period.
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Chu X, Heinze S, Ian E, Berg BG. A Novel Major Output Target for Pheromone-Sensitive Projection Neurons in Male Moths. Front Cell Neurosci 2020; 14:147. [PMID: 32581719 PMCID: PMC7294775 DOI: 10.3389/fncel.2020.00147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/04/2020] [Indexed: 01/13/2023] Open
Abstract
Even though insects have comparably small brains, they achieve astoundingly complex behaviors. One example is flying moths tracking minute amounts of pheromones using olfactory circuits. The tracking distance can be up to 1 km, which makes it essential that male moths respond efficiently and reliably to very few pheromone molecules. The male-specific macroglomerular complex (MGC) in the moth antennal lobe contains circuitry dedicated to pheromone processing. Output neurons from this region project along three parallel pathways, the medial, mediolateral, and lateral tracts. The MGC-neurons of the lateral tract are least described and their functional significance is mainly unknown. We used mass staining, calcium imaging, and intracellular recording/staining to characterize the morphological and physiological properties of these neurons in the noctuid moth, Helicoverpa armigera. All lateral-tract MGC neurons targeted the column, a small region within the superior intermediate neuropil. We identified this region as a unique converging site for MGC lateral-tract neurons responsive to pheromones, as well as a dense congregating site for plant odor information since a substantial number of lateral-tract neurons from ordinary glomeruli (OG) also terminates in this region. The lateral-tract MGC-neurons responded with a shorter peak latency than the well-described neurons in the medial tract. Different from the medial-tract MGC neurons encoding odor quality important for species-specific signal identification, those in the lateral tract convey a more robust and rapid signal-potentially important for fast control of hard-wired behavior.
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Affiliation(s)
- Xi Chu
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Elena Ian
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente G. Berg
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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Arganda S, Hoadley AP, Razdan ES, Muratore IB, Traniello JFA. The neuroplasticity of division of labor: worker polymorphism, compound eye structure and brain organization in the leafcutter ant Atta cephalotes. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:651-662. [PMID: 32506318 DOI: 10.1007/s00359-020-01423-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/23/2020] [Accepted: 05/14/2020] [Indexed: 12/24/2022]
Abstract
Our understanding of how sensory structure design is coupled with neural processing capacity to adaptively support division of labor is limited. Workers of the remarkably polymorphic fungus-growing ant Atta cephalotes are behaviorally specialized by size: the smallest workers (minims) tend fungi in dark subterranean chambers while larger workers perform tasks outside the nest. Strong differences in worksite light conditions are predicted to influence sensory and processing requirements for vision. Analyzing confocal scans of worker eyes and brains, we found that eye structure and visual neuropils appear to have been selected to maximize task performance according to light availability. Minim eyes had few ommatidia, large interommatidial angles and eye parameter values, suggesting selection for visual sensitivity over acuity. Large workers had larger eyes with disproportionally more and larger ommatidia, and smaller interommatidial angles and eye parameter values, indicating peripheral sensory adaptation to ambient rainforest light. Optic lobes and mushroom body collars were disproportionately small in minims. Within the optic lobe, lamina and lobula relative volumes increased with worker size whereas medulla volume decreased. Visual system phenotypes thus correspond to task specializations in dark or light environments and illustrate a functional neuroplasticity underpinning division of labor in this socially complex agricultural ant.
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Affiliation(s)
- Sara Arganda
- Department of Biology, Boston University, Boston, USA.
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, 31062, Toulouse, France.
- Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain.
| | | | - Evan S Razdan
- Department of Biology, Boston University, Boston, USA
| | | | - James F A Traniello
- Department of Biology, Boston University, Boston, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, 02215, USA
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35
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Karaoglan M, Er HC, Aytaç EH, Keskin M. The trade-off between the olfactory bulb and eyeball volume in precocious puberty. J Pediatr Endocrinol Metab 2020; 33:271-277. [PMID: 31926097 DOI: 10.1515/jpem-2019-0450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 11/15/2019] [Indexed: 11/15/2022]
Abstract
Background The olfactory bulb (OB) and eyeball size change depending on age and puberty. There is a well-established trade-off between sensory structures of the brain such as the eye and the olfactory bulb that depend on environmental circumstances in the evolutionary history of animals. The aim of this study was to developmentally investigate the potential reciprocal changes between OB and eyeball volumes (EV) in girls with precocious puberty (PP). Methods A total of 148 girls aged between 5 and 8 years (63 PP, 85 healthy) were included in the study. Exclusion criteria: Cases of anosmia/hyposmia, neurodegenerative disorder, refractive errors and trauma. The pituitary height (PH), EV and OB volumes were measured on segmentation of a magnetic resonance image (MRI) slice using manual countering. The corrected measurements by body surface were used in all statistical analyses. Results In girls with PP, the means of the OB volume and PH were larger (71.11 ± 20.64 mL) and higher (4.62 ± 1.18 mm), respectively, while the mean of EVs was smaller (11.24 ± 2.62 cm3) (p = 0.000). Cut-off values were 62.27 mL, 10.7 cm3 and 4.71 mm for OB volume, EV and PH, respectively. While negative correlations were found between OB volume-EV and EV-PH (r63 = -0.224, p = 0.001 and r63 = -0.116, p = 0.001, respectively), OB volume was positively correlated with PH (r63 = 0.578, p = 0.001). Conclusions The present study demonstrates that girls with PP have significantly larger OB volume, but smaller EV, and there is negative correlation between the two structures. These results indicate that there is trade-off between anatomical dimensions of OB and eyeball in favor of OB in PP girls.
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Affiliation(s)
- Murat Karaoglan
- Department of Pediatric Endocrinology, Gaziantep University Faculty of Medicine, 27070 Gaziantep, Turkey
| | - Hale Colakoğlu Er
- Department of Radiology, Gaziantep University Faculty of Medicine, Gaziantep, Turkey
| | - Emel Hatun Aytaç
- Department of Pediatric Endocrinology, Gaziantep University Faculty of Medicine, 27070 Gaziantep, Turkey
| | - Mehmet Keskin
- Department of Pediatric Endocrinology, Gaziantep University Faculty of Medicine, 27070 Gaziantep, Turkey
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Adden A, Wibrand S, Pfeiffer K, Warrant E, Heinze S. The brain of a nocturnal migratory insect, the Australian Bogong moth. J Comp Neurol 2020; 528:1942-1963. [PMID: 31994724 DOI: 10.1002/cne.24866] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/16/2020] [Accepted: 01/18/2020] [Indexed: 12/12/2022]
Abstract
Every year, millions of Australian Bogong moths (Agrotis infusa) complete an astonishing journey: In Spring, they migrate over 1,000 km from their breeding grounds to the alpine regions of the Snowy Mountains, where they endure the hot summer in the cool climate of alpine caves. In autumn, the moths return to their breeding grounds, where they mate, lay eggs and die. These moths can use visual cues in combination with the geomagnetic field to guide their flight, but how these cues are processed and integrated into the brain to drive migratory behavior is unknown. To generate an access point for functional studies, we provide a detailed description of the Bogong moth's brain. Based on immunohistochemical stainings against synapsin and serotonin (5HT), we describe the overall layout as well as the fine structure of all major neuropils, including the regions that have previously been implicated in compass-based navigation. The resulting average brain atlas consists of 3D reconstructions of 25 separate neuropils, comprising the most detailed account of a moth brain to date. Our results show that the Bogong moth brain follows the typical lepidopteran ground pattern, with no major specializations that can be attributed to their spectacular migratory lifestyle. These findings suggest that migratory behavior does not require widespread modifications of brain structure, but might be achievable via small adjustments of neural circuitry in key brain areas. Locating these subtle changes will be a challenging task for the future, for which our study provides an essential anatomical framework.
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Affiliation(s)
- Andrea Adden
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Sara Wibrand
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Eric Warrant
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden.,NanoLund, Department of Biology, Lund University, Lund, Sweden
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Nicholas S, Leibbrandt R, Nordström K. Visual motion sensitivity in descending neurons in the hoverfly. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:149-163. [PMID: 31989217 PMCID: PMC7069906 DOI: 10.1007/s00359-020-01402-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/06/2019] [Indexed: 01/11/2023]
Abstract
Many animals use motion vision information to control dynamic behaviors. For example, flying insects must decide whether to pursue a prey or not, to avoid a predator, to maintain their current flight trajectory, or to land. The neural mechanisms underlying the computation of visual motion have been particularly well investigated in the fly optic lobes. However, the descending neurons, which connect the optic lobes with the motor command centers of the ventral nerve cord, remain less studied. To address this deficiency, we describe motion vision sensitive descending neurons in the hoverfly Eristalis tenax. We describe how the neurons can be identified based on their receptive field properties, and how they respond to moving targets, looming stimuli and to widefield optic flow. We discuss their similarities with previously published visual neurons, in the optic lobes and ventral nerve cord, and suggest that they can be classified as target-selective, looming sensitive and optic flow sensitive, based on these similarities. Our results highlight the importance of using several visual stimuli as the neurons can rarely be identified based on only one response characteristic. In addition, they provide an understanding of the neurophysiology of visual neurons that are likely to affect behavior.
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Affiliation(s)
- Sarah Nicholas
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Richard Leibbrandt
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Karin Nordström
- Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia. .,Department of Neuroscience, Uppsala University, Box 593, 751 24 , Uppsala, Sweden.
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Groothuis J, Pfeiffer K, El Jundi B, Smid HM. The Jewel Wasp Standard Brain: Average shape atlas and morphology of the female Nasonia vitripennis brain. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 51:41-51. [PMID: 31357033 DOI: 10.1016/j.asd.2019.100878] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
Nasonia, a genus of parasitoid wasps, is a promising model system in the study of developmental and evolutionary genetics, as well as complex traits such as learning. Of these "jewel wasps", the species Nasonia vitripennis is widely spread and widely studied. To accelerate neuroscientific research in this model species, fundamental knowledge of its nervous system is needed. To this end, we present an average standard brain of recently eclosed naïve female N. vitripennis wasps obtained by the iterative shape averaging method. This "Jewel Wasp Standard Brain" includes the optic lobe (excluding the lamina), the anterior optic tubercle, the antennal lobe, the lateral horn, the mushroom body, the central complex, and the remaining unclassified neuropils in the central brain. Furthermore, we briefly describe these well-defined neuropils and their subregions in the N. vitripennis brain. A volumetric analysis of these neuropils is discussed in the context of brains of other insect species. The Jewel Wasp Standard Brain will provide a framework to integrate and consolidate the results of future neurobiological studies in N. vitripennis. In addition, the volumetric analysis provides a baseline for future work on age- and experience-dependent brain plasticity.
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Affiliation(s)
- Jitte Groothuis
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Keram Pfeiffer
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Basil El Jundi
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Hans M Smid
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands.
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Kamhi JF, Ilieş I, Traniello JFA. Social Complexity and Brain Evolution: Comparative Analysis of Modularity and Integration in Ant Brain Organization. BRAIN, BEHAVIOR AND EVOLUTION 2019; 93:4-18. [PMID: 30982030 DOI: 10.1159/000497267] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 01/27/2019] [Indexed: 11/19/2022]
Abstract
The behavioral demands of living in social groups have been linked to the evolution of brain size and structure, but how social organization shapes investment and connectivity within and among functionally specialized brain regions remains unclear. To understand the influence of sociality on brain evolution in ants, a premier clade of eusocial insects, we statistically analyzed patterns of brain region size covariation as a proxy for brain region connectivity. We investigated brain structure covariance in young and old workers of two formicine ants, the Australasian weaver ant Oecophylla smaragdina, a pinnacle of social complexity in insects, and its socially basic sister clade Formica subsericea. As previously identified in other ant species, we predicted that our analysis would recognize in both species an olfaction-related brain module underpinning social information processing in the brain, and a second neuroanatomical cluster involved in nonolfactory sensorimotor processes, thus reflecting conservation of compartmental connectivity. Furthermore, we hypothesized that covariance patterns would reflect divergence in social organization and life histories either within this species pair or compared to other ant species. Contrary to our predictions, our covariance analyses revealed a weakly defined visual, rather than olfactory, sensory processing cluster in both species. This pattern may be linked to the reliance on vision for worker behavioral performance outside of the nest and the correlated expansion of the optic lobes to meet navigational demands in both species. Additionally, we found that colony size and social organization, key measures of social complexity, were only weakly correlated with brain modularity in these formicine ants. Worker age also contributed to variance in brain organization, though in different ways in each species. These findings suggest that brain organization may be shaped by the divergent life histories of the two study species. We compare our findings with patterns of brain organization of other eusocial insects.
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Affiliation(s)
- J Frances Kamhi
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, USA, .,Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia,
| | - Iulian Ilieş
- Healthcare Systems Engineering Institute, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts, USA
| | - James F A Traniello
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, USA.,Department of Biology, Boston University, Boston, Massachusetts, USA
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40
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Stöckl AL, Kelber A. Fuelling on the wing: sensory ecology of hawkmoth foraging. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:399-413. [PMID: 30880349 PMCID: PMC6579779 DOI: 10.1007/s00359-019-01328-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/25/2019] [Accepted: 03/05/2019] [Indexed: 11/28/2022]
Abstract
Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and olfactory cues including CO2 and humidity to detect and recognise rewarding flowers; they find the nectary in the flowers by means of mechanoreceptors on the proboscis and vision, evaluate it with gustatory receptors on the proboscis, and control their hovering flight position using antennal mechanoreception and vision. Here, we review what is presently known about the sensory organs and sensory-guided behaviour that control feeding behaviour of this fascinating pollinator taxon. We also suggest that more experiments on hawkmoth behaviour in natural settings are needed to fully appreciate their sensory capabilities.
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Affiliation(s)
- Anna Lisa Stöckl
- Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
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41
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Sumner-Rooney L. The Kingdom of the Blind: Disentangling Fundamental Drivers in the Evolution of Eye Loss. Integr Comp Biol 2019; 58:372-385. [PMID: 29873729 DOI: 10.1093/icb/icy047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Light is a fundamentally important biological cue used by almost every animal on earth, to maintain daily rhythms, navigate, forage, find mates, or avoid predators. But an enormous number of species live in darkness: in subterranean caves, deep oceans, underground burrows, and within parasitic host bodies, and the loss of eyes appears consistently across these ecosystems. However, the evolutionary mechanisms that lead to the reduction of the visual system remain the subject of great interest and debate more than 150 years after Darwin tackled the issue. Studies of model taxa have discovered significant roles for natural selection, neutral evolution, and pleiotropy, but the interplay between them remains unclear. To nail down unifying concepts surrounding the evolution of eye loss, we must embrace the enormous range of affected animals and habitats. The fine developmental details of model systems such as the Mexican cave tetra Astyanax mexicanus have transformed and enriched the field, but these should be complemented by wider studies to identify truly overarching patterns that apply throughout animals. Here, the major evolutionary drivers are placed within a conceptual cost-benefit framework that incorporates the fundamental constraints and forces that influence evolution in the dark. Major physiological, ecological, and environmental factors are considered within the context of this framework, which appears faithful to observed patterns in deep-sea and cavernicolous animals. To test evolutionary hypotheses, a comparative phylogenetic approach is recommended, with the goal of studying large groups exhibiting repeated reduction, and then comparing these across habitats, taxa, and lifestyles. Currently, developmental and physiological methods cannot feasibly be used on such large scales, but penetrative imaging techniques could provide detailed morphological data non-invasively and economically for large numbers of species. Comprehensive structural datasets can then be contextualized phylogenetically to examine recurrent trends and associations, and to reconstruct character histories through multiple independent transitions into darkness. By assessing these evolutionary trajectories within an energetic cost-benefit framework, the relationships between fundamental influences can be inferred and compared across different biological and physical parameters. However, substantial numbers of biological and environmental factors affect the evolutionary trajectory of loss, and it is critical that researchers make fair and reasonable comparisons between objectively similar groups.
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42
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Keesey IW, Grabe V, Gruber L, Koerte S, Obiero GF, Bolton G, Khallaf MA, Kunert G, Lavista-Llanos S, Valenzano DR, Rybak J, Barrett BA, Knaden M, Hansson BS. Inverse resource allocation between vision and olfaction across the genus Drosophila. Nat Commun 2019; 10:1162. [PMID: 30858374 PMCID: PMC6411718 DOI: 10.1038/s41467-019-09087-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 02/14/2019] [Indexed: 11/09/2022] Open
Abstract
Divergent populations across different environments are exposed to critical sensory information related to locating a host or mate, as well as avoiding predators and pathogens. These sensory signals generate evolutionary changes in neuroanatomy and behavior; however, few studies have investigated patterns of neural architecture that occur between sensory systems, or that occur within large groups of closely-related organisms. Here we examine 62 species within the genus Drosophila and describe an inverse resource allocation between vision and olfaction, which we consistently observe at the periphery, within the brain, as well as during larval development. This sensory variation was noted across the entire genus and appears to represent repeated, independent evolutionary events, where one sensory modality is consistently selected for at the expense of the other. Moreover, we provide evidence of a developmental genetic constraint through the sharing of a single larval structure, the eye-antennal imaginal disc. In addition, we examine the ecological implications of visual or olfactory bias, including the potential impact on host-navigation and courtship.
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Affiliation(s)
- Ian W Keesey
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Veit Grabe
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Lydia Gruber
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Sarah Koerte
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - George F Obiero
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
- Department of Biochemistry and Biotechnology, Technical University of Kenya, Haille-Sellasie Avenue, Workshop Road, 0200, Nairobi, Kenya
| | - Grant Bolton
- University of Missouri, Division of Plant Sciences, 3-22I Agriculture Building, Columbia, Missouri, 65211, USA
| | - Mohammed A Khallaf
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Grit Kunert
- Max Planck Institute for Chemical Ecology, Department of Biochemistry, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Sofia Lavista-Llanos
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Dario Riccardo Valenzano
- Max Planck Institute for Biology of Ageing and CECAD at University of Cologne, Joseph-Stelzmann-Str 9b and 26, Cologne, 50931, Germany
| | - Jürgen Rybak
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Bruce A Barrett
- University of Missouri, Division of Plant Sciences, 3-22I Agriculture Building, Columbia, Missouri, 65211, USA
| | - Markus Knaden
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany.
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, D-07745, Jena, Germany.
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43
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Sheehan ZBV, Kamhi JF, Seid MA, Narendra A. Differential investment in brain regions for a diurnal and nocturnal lifestyle in Australian Myrmecia ants. J Comp Neurol 2019; 527:1261-1277. [PMID: 30592041 DOI: 10.1002/cne.24617] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/07/2018] [Accepted: 12/22/2018] [Indexed: 12/29/2022]
Abstract
Animals are active at different times of the day. Each temporal niche offers a unique light environment, which affects the quality of the available visual information. To access reliable visual signals in dim-light environments, insects have evolved several visual adaptations to enhance their optical sensitivity. The extent to which these adaptations reflect on the sensory processing and integration capabilities within the brain of a nocturnal insect is unknown. To address this, we analyzed brain organization in congeneric species of the Australian bull ant, Myrmecia, that rely predominantly on visual information and range from being strictly diurnal to strictly nocturnal. Weighing brains and optic lobes of seven Myrmecia species, showed that after controlling for body mass, the brain mass was not significantly different between diurnal and nocturnal ants. However, the optic lobe mass, after controlling for central brain mass, differed between day- and night-active ants. Detailed volumetric analyses showed that the nocturnal ants invested relatively less in the primary visual processing regions but relatively more in both the primary olfactory processing regions and in the integration centers of visual and olfactory sensory information. We discuss how the temporal niche occupied by each species may affect cognitive demands, thus shaping brain organization among insects active in dim-light conditions.
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Affiliation(s)
- Zachary B V Sheehan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - J Frances Kamhi
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Marc A Seid
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.,Biology Department, Neuroscience Program, The University of Scranton, Scranton, Pennsylvania
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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Wang Q, Shang Y, Hilton DS, Inthavong K, Zhang D, Elgar MA. Antennal scales improve signal detection efficiency in moths. Proc Biol Sci 2019. [PMID: 29540519 DOI: 10.1098/rspb.2017.2832] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The elaborate bipectinate antennae of male moths are thought to increase their sensitivity to female sex pheromones, and so should be favoured by selection. Yet simple filamentous antennae are the most common structure among moths. The stereotypic arrangements of scales on the surface of antennae may resolve this paradox. We use computational fluid dynamics techniques to model how scales on the filamentous antennae of moths affect the passage of different particles in the airflow across the flagellum in both small and large moths. We found that the scales provide an effective solution to improve the efficacy of filamentous antennae, by increasing the concentration of nanoparticles, which resemble pheromones, around the antennae. The smaller moths have a greater increase in antennal efficiency than larger moths. The scales also divert microparticles, which resemble dust, away from the antennal surface, thereby reducing contamination. The positive correlations between antennal scale angles and sensilla number across Heliozelidae moths are consistent with the predictions of our model.
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Affiliation(s)
- Qike Wang
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Yidan Shang
- School of Engineering, RMIT University, Victoria 3083, Australia
| | - Douglas S Hilton
- Walter and Eliza Hall Institute of Medical Research, Victoria 3052, Australia
| | - Kiao Inthavong
- School of Engineering, RMIT University, Victoria 3083, Australia
| | - Dong Zhang
- School of Nature Conservation, Beijing Forestry University, Beijing 100083, People's Republic of China
| | - Mark A Elgar
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
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45
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Makarova AA, Meyer-Rochow VB, Polilov AA. Morphology and scaling of compound eyes in the smallest beetles (Coleoptera: Ptiliidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 48:83-97. [PMID: 30625373 DOI: 10.1016/j.asd.2019.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/20/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
The coleopteran family Ptiliidae (featherwing beetles) includes some of the smallest insects known with most of the representatives of this family measuring less than 1 mm in body length. A small body size largely determines the morphology, physiology, and biology of an organism and affects the organization of complex sense organs. Information on the organization of the compound eyes of Ptiliidae is scarce. Using scanning electron microscopy we analyzed the eyes of representatives of all subfamilies and tribes and provide a detailed description of the eye ultrastructure of four species (Nephanes titan, Porophila mystacea, Nanosella sp. and Acrotrichis grandicollis) using transmission electron microscopy. The results are compared with available data on larger species of related groups of Staphyliniformia and scale quantitative analyses are performed. The eyes of Ptiliidae consist of 15-50 ommatidia 6-13 μm in diameter and all conform to the apposition acone type of eye with fused rhabdoms of banded organization. Each ommatidium has the typical cellular arrangement present also in the eyes of larger staphyliniform beetles, but strongly curved lenses, short cones, reduced pigment cells, a high density of pigment granules and certain modifications of the rhabdom seem typical of ptiliid eyes. Allometric analyses show that as body size decreases, the number of facets drops more steeply than their average size does.
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Affiliation(s)
| | - V Benno Meyer-Rochow
- Department of Ecology and Genetics, Oulu University, Oulu, Finland; Department of Plant Medicals, Andong National University, Andong, Republic of Korea
| | - Alexey A Polilov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia; Joint Russian-Vietnamese Tropical Research and Technological Center, Hanoi, Viet Nam
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46
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Elgar MA, Zhang D, Wang Q, Wittwer B, Thi Pham H, Johnson TL, Freelance CB, Coquilleau M. Insect Antennal Morphology: The Evolution of Diverse Solutions to Odorant Perception. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2018; 91:457-469. [PMID: 30588211 PMCID: PMC6302626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Chemical communication involves the production, transmission, and perception of odors. Most adult insects rely on chemical signals and cues to locate food resources, oviposition sites or reproductive partners and, consequently, numerous odors provide a vital source of information. Insects detect these odors with receptors mostly located on the antennae, and the diverse shapes and sizes of these antennae (and sensilla) are both astonishing and puzzling: what selective pressures are responsible for these different solutions to the same problem - to perceive signals and cues? This review describes the selection pressures derived from chemical communication that are responsible for shaping the diversity of insect antennal morphology. In particular, we highlight new technologies and techniques that offer exciting opportunities for addressing this surprisingly neglected and yet crucial component of chemical communication.
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Affiliation(s)
- Mark A. Elgar
- School of BioSciences, The University of Melbourne, Victoria, Australia,To whom all correspondence should be addressed: Mark A. Elgar, School of BioSciences, The University of Melbourne, Victoria 3010, Australia; FAX: +61 3 8344 7909;
| | - Dong Zhang
- School of Nature Conservation, Beijing Forestry University, Beijing, China
| | - Qike Wang
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | | | - Hieu Thi Pham
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Tamara L. Johnson
- School of BioSciences, The University of Melbourne, Victoria, Australia
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47
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Diakova AV, Makarova AA, Polilov AA. Between extreme simplification and ideal optimization: antennal sensilla morphology of miniaturized Megaphragma wasps (Hymenoptera: Trichogrammatidae). PeerJ 2018; 6:e6005. [PMID: 30533303 PMCID: PMC6276593 DOI: 10.7717/peerj.6005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/26/2018] [Indexed: 12/28/2022] Open
Abstract
One of the major trends in the evolution of parasitoid wasps is miniaturization, which has produced the smallest known insects. Megaphragma spp. (Hymenoptera: Trichogrammatidae) are smaller than some unicellular organisms, with an adult body length of the smallest only 170 µm. Their parasitoid lifestyle depends on retention of a high level of sensory reception comparable to that in parasitoid wasps that may have antennae hundreds of times larger. Antennal sensilla of males and females of Megaphragma amalphitanum and M. caribea and females of the parthenogenetic M. mymaripenne are described, including sensillum size, external morphology, and distribution. Eight different morphological types of sensilla were discovered, two of them appearing exclusively on female antennae. Two of the types, sensilla styloconica and aporous placoid sensilla, have not been described previously. Regression analyses were performed to detect and evaluate possible miniaturization trends by comparing available data for species of larger parasitoid wasps. The number of antennal sensilla was found to decrease with the body size; M. amalphitanum males have only 39 sensilla per antenna. The number of antennal sensilla types and sizes of the sensilla, however, show little to no correlation with the body size. Our findings on the effects of miniaturization on the antennal sensilla of Megaphragma provide material for discussion on the limits to the reduction of insect antenna.
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Affiliation(s)
- Anna V Diakova
- Department of Entomology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Anastasia A Makarova
- Department of Entomology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Alexey A Polilov
- Department of Entomology, Biological Faculty, Moscow State University, Moscow, Russia
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48
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Potier S, Duriez O, Célérier A, Liegeois JL, Bonadonna F. Sight or smell: which senses do scavenging raptors use to find food? Anim Cogn 2018; 22:49-59. [PMID: 30367315 PMCID: PMC6326982 DOI: 10.1007/s10071-018-1220-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 10/15/2018] [Accepted: 10/21/2018] [Indexed: 11/29/2022]
Abstract
Raptors are usually considered to be mainly visually dependent, and the use of other sensory modalities has rarely been studied in these birds. Here, we investigated experimentally which senses (vision and/or olfaction) Turkey vultures (Cathartes aura) and Southern caracaras (Caracara plancus) use to find hidden food. First, two identical stainless-steel perforated balls, one containing a putrefied piece of meat and the other an odorless control, were presented to birds in binary choice experiments. Both species interacted more with the smelling ball than with the control, suggesting that they were attracted by the odor of the hidden meat. In a second experiment, individuals were accustomed to eat in one specifically colored ball (blue or green). In the test phase, the meat was hidden in the opposite color with respect to the one each bird had become accustomed to. Vultures still interacted more with the smelly ball disregarding the color, while caracaras interacted equally with the two balls. The prevalence of olfaction in Turkey vultures may partly explain why they are the first raptors to find carcasses in tropical forests. In contrast, caracaras forage on the ground opportunistically, a strategy where both olfaction and sight may be involved. Our experiments suggest that both species are able to use olfactory cues for foraging. However, olfaction could be the predominant sense in Turkey vultures while olfaction and sight could play an equivalent role in Southern caracaras.
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Affiliation(s)
- Simon Potier
- CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE-1919 Route de Mende, 34293, Montpellier Cedex 5, France. .,Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
| | - Olivier Duriez
- CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE-1919 Route de Mende, 34293, Montpellier Cedex 5, France
| | - Aurélie Célérier
- CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE-1919 Route de Mende, 34293, Montpellier Cedex 5, France
| | - Jean-Louis Liegeois
- Académie de Fauconnerie du Grand Parc du Puy du Fou, CS 70 025, 85590, Les Epesses, France
| | - Francesco Bonadonna
- CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE-1919 Route de Mende, 34293, Montpellier Cedex 5, France
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El Jundi B, Warrant EJ, Pfeiffer K, Dacke M. Neuroarchitecture of the dung beetle central complex. J Comp Neurol 2018; 526:2612-2630. [PMID: 30136721 DOI: 10.1002/cne.24520] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/12/2018] [Accepted: 08/15/2018] [Indexed: 01/09/2023]
Abstract
Despite their tiny brains, insects show impressive abilities when navigating over short distances during path integration or during migration over thousands of kilometers across entire continents. Celestial compass cues often play an important role as references during navigation. In contrast to many other insects, South African dung beetles rely exclusively on celestial cues for visual reference during orientation. After finding a dung pile, these animals cut off a piece of dung from the pat, shape it into a ball and roll it away along a straight path until a suitable place for underground consumption is found. To maintain a constant bearing, a brain region in the beetle's brain, called the central complex, is crucially involved in the processing of skylight cues, similar to what has already been shown for path-integrating and migrating insects. In this study, we characterized the neuroanatomy of the sky-compass network and the central complex in the dung beetle brain in detail. Using tracer injections, combined with imaging and 3D modeling, we describe the anatomy of the possible sky-compass network in the central brain. We used a quantitative approach to study the central-complex network and found that several types of neuron exhibit a highly organized connectivity pattern. The architecture of the sky-compass network and central complex is similar to that described in insects that perform path integration or are migratory. This suggests that, despite their different orientation behaviors, this neural circuitry for compass orientation is highly conserved among the insects.
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Affiliation(s)
- Basil El Jundi
- Biocenter, Zoology II, Emmy Noether Animal Navigation Group, University of Würzburg, Germany
| | - Eric J Warrant
- Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Marie Dacke
- Vision Group, Department of Biology, Lund University, Lund, Sweden
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50
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Borges RM. Dark Matters: Challenges of Nocturnal Communication Between Plants and Animals in Delivery of Pollination Services. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2018; 91:33-42. [PMID: 29599655 PMCID: PMC5872639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The night is a special niche characterized by dim light, lower temperatures, and higher humidity compared to the day. Several animals have made the transition from the day into the night and have acquired unique adaptations to cope with the challenges of performing nocturnal activities. Several plant species have opted to bloom at night, possibly as a response to aridity to prevent excessive water loss through evapotranspiration since flowering is often a water-demanding process, or to protect pollen from heat stress. Nocturnal pollinators have visual adaptations to function under dim light conditions but may also trade off vision against olfaction when they are dependent on nectar-rewarding and scented flowers. Nocturnal pollinators may use CO2 and humidity cues emanating from freshly-opened flowers as indicators of nectar-rich resources. Some endothermic nocturnal insect pollinators are attracted to thermogenic flowers within which they remain to obtain heat as a reward to increase their energy budget. This review focuses on mechanisms that pollinators use to find flowers at night, and the signals that nocturnally blooming flowers may employ to attract pollinators under dim light conditions. It also indicates gaps in our knowledge. While millions of years of evolutionary time have given pollinators and plants solutions to the delivery of pollination services and to the offering of appropriate rewards, this history of successful evolution is being threatened by artificial light at night. Excessive and inappropriate illumination associated with anthropogenic activities has resulted in significant light pollution which serves to undermine life processes governed by dim light.
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Affiliation(s)
- Renee M. Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
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