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Yue J, Yan Z, Liu W, Liu J, Yang D. A visual pollination mechanism of a new specialized pollinating weevil-plant reciprocity system. FRONTIERS IN PLANT SCIENCE 2024; 15:1432263. [PMID: 39220015 PMCID: PMC11362035 DOI: 10.3389/fpls.2024.1432263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024]
Abstract
Introduction Pollinating flower-consuming mutualisms are considered exemplary models for studying coevolution due to their rarity. Visual cues are considered to have a major role in facilitating the evolution of floral patterns in these systems. We present a new specialized pollinating flower-consuming mutualism from the plant Wurfbainia villosa, which is a traditional Chinese herbal medicine, by a pollinating weevil, Xenysmoderes sp. Methods In this study, We utilized monochrome plates for binary-choice tests to determine weevil color preferences, conducted behavioral choice experiments, using trackballs, photographed flowers and weevils, and employed blue sticky boards to attract weevils in the field. Results Tests were conducted using colorpreferring weevils in both indoor and outdoor field systems, and validation experiments were performed. Behavioral tests were conducted to investigate the role of the visual cues in the pollinator attraction of W. villosa, which is a selfcompatible insect-pollinated plant that relies primarily on the Xenysmoderes sp. weevil for pollination due to its specialized gynandrium-like structure. Behavioral tests demonstrated that a blue color wavelength of 480 nm and the blue color system, as along with the UV-style pattern of the flowers, particularly the parts with specialized gynandrium-like structures in the labellum, were significantly attractive to both male and female weevils. These results were further confirmed through the field blue sticky board trap method. Discussion These findings indicated that the interaction between W. villosa and Xenysmoderes sp. weevil was a novel symbiotic relationship involving pollinator flower consumption. Additionally, Wurfbainia villosa flowers developed specific visual cues of UV patterns and specialized structures that played a crucial role in attracting pollinators.
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Affiliation(s)
- Jianjun Yue
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
- School of Traditional Dai-Thai Medicine, West Yunnan University of Applied Sciences, Jinghong, China
| | - Zhen Yan
- Yunnan Key Laboratory of Southern Medicine Utilization, Institute of Medicinal Plant Development Yunnan Branch, Chinese Academy of Medical Sciences and Peking Union Medical College, Jinghong, China
| | - Wei Liu
- School of Traditional Dai-Thai Medicine, West Yunnan University of Applied Sciences, Jinghong, China
| | - Ju Liu
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Depo Yang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
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2
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Talarico F, Koçak Y, Macirella R, Sesti S, Yüksel E, Brunelli E. Eye morphology in four species of tiger beetles (Coleoptera: Cicindelidae). ZOOLOGY 2024; 165:126173. [PMID: 38820711 DOI: 10.1016/j.zool.2024.126173] [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: 01/15/2024] [Revised: 04/27/2024] [Accepted: 05/15/2024] [Indexed: 06/02/2024]
Abstract
Compound eyes undoubtedly represent the widespread eye architecture in the animal kingdom. The insects' compound eye shows a wide variety of designs, and insects use their visual capacity to accomplish several tasks, including avoiding enemies, searching for food and shelter, locating a mate, and acquiring information about the environment and its surroundings. Broad literature data support the concept that visual ability lies in the way the eyes are built. Since the resolution and sensitivity of the compound eye are partly determined by the density of the ommatidia and the size of the facets. Morphological parameters of the compound eyes could influence the function of the visual organ and its capacity to process information, also representing a sensitive indicator of different habitat demands. In this study, we compared compound eyes' parameters in four closely related species of tiger beetles to disclose differences arising from different habitats. Furthermore, to investigate whether there are consistent intersexual differences, we also compared the most relevant parameters of the eye in males and females of four selected species. Our results show sex-related and interspecific differences that occur in examined species.
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Affiliation(s)
- Federica Talarico
- Department of Biology, Ecology and Earth Science (DiBEST), University of Calabria, Via P. Bucci 4/B, Rende, Cosenza 87036, Italy.
| | - Yavuz Koçak
- Ankara Hacı Bayram Veli University, Faculty of Polatlı Art and Science, Department of Biology, Ankara 06900, Turkey
| | - Rachele Macirella
- Department of Biology, Ecology and Earth Science (DiBEST), University of Calabria, Via P. Bucci 4/B, Rende, Cosenza 87036, Italy.
| | - Settimio Sesti
- Department of Biology, Ecology and Earth Science (DiBEST), University of Calabria, Via P. Bucci 4/B, Rende, Cosenza 87036, Italy
| | - Eşref Yüksel
- Gazi University, Faculty of Science, Department of Biology, Teknikokullar, Ankara 06500, Turkey
| | - Elvira Brunelli
- Department of Biology, Ecology and Earth Science (DiBEST), University of Calabria, Via P. Bucci 4/B, Rende, Cosenza 87036, Italy.
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Wright DS, Rodriguez-Fuentes J, Ammer L, Darragh K, Kuo CY, McMillan WO, Jiggins CD, Montgomery SH, Merrill RM. Selection drives divergence of eye morphology in sympatric Heliconius butterflies. Evolution 2024; 78:1338-1346. [PMID: 38736286 PMCID: PMC7616201 DOI: 10.1093/evolut/qpae073] [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: 11/05/2023] [Revised: 05/02/2024] [Accepted: 05/10/2024] [Indexed: 05/14/2024]
Abstract
When populations experience different sensory conditions, natural selection may favor sensory system divergence, affecting peripheral structures and/or downstream neural pathways. We characterized the outer eye morphology of sympatric Heliconius butterflies from different forest types and their first-generation reciprocal hybrids to test for adaptive visual system divergence and hybrid disruption. In Panama, Heliconius cydno occurs in closed forests, whereas Heliconius melpomene resides at the forest edge. Among wild individuals, H. cydno has larger eyes than H. melpomene, and there are heritable, habitat-associated differences in the visual brain structures that exceed neutral divergence expectations. Notably, hybrids have intermediate neural phenotypes, suggesting disruption. To test for similar effects in the visual periphery, we reared both species and their hybrids in common garden conditions. We confirm that H. cydno has larger eyes and provide new evidence that this is driven by selection. Hybrid eye morphology is more H. melpomene-like despite body size being intermediate, contrasting with neural trait intermediacy. Overall, our results suggest that eye morphology differences between H. cydno and H. melpomene are adaptive and that hybrids may suffer fitness costs due to a mismatch between the peripheral visual structures and previously described neural traits that could affect visual performance.
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Affiliation(s)
- Daniel Shane Wright
- Division of Evolutionary Biology, Faculty of Biology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Juliana Rodriguez-Fuentes
- Division of Evolutionary Biology, Faculty of Biology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Lisa Ammer
- Division of Evolutionary Biology, Faculty of Biology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Kathy Darragh
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Chi-Yun Kuo
- Division of Evolutionary Biology, Faculty of Biology, Ludwig Maximilian University of Munich, Munich, Germany
| | | | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Stephen H Montgomery
- Smithsonian Tropical Research Institute, Gamboa, Panama
- School of Biological Science, University of Bristol, Bristol, United Kingdom
| | - Richard M Merrill
- Division of Evolutionary Biology, Faculty of Biology, Ludwig Maximilian University of Munich, Munich, Germany
- Smithsonian Tropical Research Institute, Gamboa, Panama
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4
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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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Wright DS, Manel AN, Guachamin-Rosero M, Chamba-Vaca P, Bacquet CN, Merrill RM. Quantifying visual acuity in Heliconius butterflies. Biol Lett 2023; 19:20230476. [PMID: 38087940 PMCID: PMC10716659 DOI: 10.1098/rsbl.2023.0476] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Heliconius butterflies are well-known for their colourful wing patterns, which advertise distastefulness to potential predators and are used during mate choice. However, the relative importance of different aspects of these signals will depend on the visual abilities of Heliconius and their predators. Previous studies have investigated colour sensitivity and neural anatomy, but visual acuity (the ability to perceive detail) has not been studied in these butterflies. Here, we provide the first estimate of visual acuity in Heliconius: from a behavioural optomotor assay, we found that mean visual acuity = 0.49 cycles-per-degree (cpd), with higher acuity in males than females. We also examined eye morphology and report more ommatidia in male eyes. Finally, we estimated how visual acuity affects Heliconius visual perception compared to a potential avian predator. Whereas the bird predator maintained high resolving power, Heliconius lost the ability to resolve detail at greater distances, though colours may remain salient. These results will inform future studies of Heliconius wing pattern evolution, as well as other aspects in these highly visual butterflies, which have emerged as an important system in studies of adaptation and speciation.
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Affiliation(s)
- Daniel Shane Wright
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Anupama Nayak Manel
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Michelle Guachamin-Rosero
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
- Universidad Regional Amazónica IKIAM, Tena, Ecuador
| | - Pamela Chamba-Vaca
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
- Universidad Regional Amazónica IKIAM, Tena, Ecuador
| | | | - Richard M. Merrill
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
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Chmielewski MW, Naya S, Borghi M, Cortese J, Fernie AR, Swartz MT, Zografou K, Sewall BJ, Spigler RB. Phenology and foraging bias contribute to sex-specific foraging patterns in the rare declining butterfly Argynnis idalia idalia. Ecol Evol 2023; 13:e10287. [PMID: 37475725 PMCID: PMC10353922 DOI: 10.1002/ece3.10287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023] Open
Abstract
Variation in pollinator foraging behavior can influence pollination effectiveness, community diversity, and plant-pollinator network structure. Although effects of interspecific variation have been widely documented, studies of intraspecific variation in pollinator foraging are relatively rare. Sex-specific differences in resource use are a strong potential source of intraspecific variation, especially in species where the phenology of males and females differ. Differences may arise from encountering different flowering communities, sex-specific traits, nutritional requirements, or a combination of these factors. We evaluated sex-specific foraging patterns in the eastern regal fritillary butterfly (Argynnis idalia idalia), leveraging a 21-year floral visitation dataset. Because A. i. idalia is protandrous, we determined whether foraging differences were due to divergent phenology by comparing visitation patterns between the entire season with restricted periods of male-female overlap. We quantified nectar carbohydrate and amino acid contents of the most visited plant species and compared those visited more frequently by males versus females. We demonstrate significant differences in visitation patterns between male and female A. i. idalia over two decades. Females visit a greater diversity of species, while dissimilarity in foraging patterns between sexes is persistent and comparable to differences between species. While differences are diminished or absent in some years during periods of male-female overlap, remaining signatures of foraging dissimilarity during implicate mechanisms other than phenology. Nectar of plants visited more by females had greater concentrations of total carbohydrates, glucose, and fructose and individual amino acids than male-associated plants. Further work can test whether nutritional differences are a cause of visitation patterns or consequence, reflecting seasonal shifts in the nutritional landscape encountered by male and female A. i. idalia. We highlight the importance of considering sex-specific foraging patterns when studying interaction networks, and in making conservation management decisions for this at-risk butterfly and other species exhibiting strong intraspecific variation.
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Affiliation(s)
| | - Skyler Naya
- Department of BiologyTemple UniversityPhiladelphiaPennsylvaniaUSA
| | - Monica Borghi
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGermany
- Present address:
Department of BiologyUtah State UniversityLoganUtahUSA
| | - Jen Cortese
- Department of BiologyTemple UniversityPhiladelphiaPennsylvaniaUSA
| | | | - Mark T. Swartz
- The Pennsylvania Department of Military and Veterans AffairsFort Indiantown Gap National Guard Training CenterAnnvillePennsylvaniaUSA
| | | | - Brent J. Sewall
- Department of BiologyTemple UniversityPhiladelphiaPennsylvaniaUSA
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Chen QX, Lyu QH, Chen YW, Song YQ. Phylogenetic implications based on an ultrastructural study with emphasis on the tracheal system of the compound eyes of three species of nymphalid butterflies. ARTHROPOD STRUCTURE & DEVELOPMENT 2023; 72:101230. [PMID: 36706509 DOI: 10.1016/j.asd.2022.101230] [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: 08/28/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 06/18/2023]
Abstract
Compound eyes are the prominent visual organs of insects and can provide valuable information for the reconstruction of insect phylogeny. Although the largest butterfly family (Nymphalidae) has been well defined, the infrafamilial phylogenetic relationships remain controversial hitherto. In the present study the ultrastructure of the compound eyes of three nymphalids Neptis beroe, Childrena zenobia, and Palaeonympha opalina was investigated using light and transmission electron microscopy in an attempt to seek potentially important phylogenetic characters. The compound eyes of the nymphalids share a tracheal system in a "1-4-8" branching pattern. The eight tracheal subbranches exhibit distinct distribution patterns along the basal retinula cell as follows: the tracheal subbranches of Palaeonympha opaline are close to the rhabdom in the distance from the distalmost part of the basal retinula cell to the rhabdom end, while those of N. beroe and C. zenobia are on the periphery of the retinula along almost the whole basal retinula cell and become close to the rhabdom just at the proximal end of the basal retinula cell. The tracheal structure of the three nymphalids is discussed for their potential phylogenetic implications.
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Affiliation(s)
- Qing-Xiao Chen
- Laboratory of Insect Evolution and Systematics, College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, Henan, 471023, China.
| | - Qi-Hui Lyu
- Laboratory of Insect Evolution and Systematics, College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, Henan, 471023, China
| | - Ying-Wu Chen
- Laboratory of Insect Evolution and Systematics, College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, Henan, 471023, China
| | - Yue-Qin Song
- Laboratory of Insect Evolution and Systematics, College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, Henan, 471023, China
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Ilić M, Chen PJ, Pirih P, Meglič A, Prevc J, Yago M, Belušič G, Arikawa K. Simple and complex, sexually dimorphic retinal mosaic of fritillary butterflies. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210276. [PMID: 36058236 PMCID: PMC9441240 DOI: 10.1098/rstb.2021.0276] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/30/2022] [Indexed: 01/23/2023] Open
Abstract
Butterflies have variable sets of spectral photoreceptors that underlie colour vision. The photoreceptor organization may be optimized for the detection of body coloration. Fritillaries (Argynnini) are nymphalid butterflies exhibiting varying degrees of sexual dimorphism in wing coloration. In two sister species, the females have orange (Argynnis paphia) and dark wings (Argynnis sagana), respectively, while the males of both species have orange wings with large patches of pheromone-producing androconia. In spite of the differences in female coloration, the eyes of both species exhibit an identical sexual dimorphism. The female eyeshine is uniform yellow, while the males have a complex retinal mosaic with yellow and red-reflecting ommatidia. We found the basic set of ultraviolet-, blue- and green-peaking photoreceptors in both sexes. Males additionally have three more photoreceptor classes, peaking in green, yellow and red, respectively. The latter is the basal R9, indirectly measured through hyperpolarizations in the green-peaking R1-2. In many nymphalid tribes, including the closely related Heliconiini, the retinal mosaic is complex in both sexes. We hypothesize that the simple mosaic of female Argynnini is a secondary reduction, possibly driven by the use of olfaction for intraspecific recognition, whereas vision remains the primary sense for the task in the males. 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)
- Marko Ilić
- Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
- Laboratory of Neuroethology, Sokendai - The Graduate University for Advanced Studies, 240-0193 Hayama, Japan
| | - Pei-Ju Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
- Laboratory of Neuroethology, Sokendai - The Graduate University for Advanced Studies, 240-0193 Hayama, Japan
| | - Primož Pirih
- Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Andrej Meglič
- Eye Hospital, University Medical Centre, Grablovičeva 46, 1000 Ljubljana, Slovenia
| | - Jošt Prevc
- Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Masaya Yago
- The University Museum, The University of Tokyo, Hongo, 113-0033 Tokyo, Japan
| | - Gregor Belušič
- Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Kentaro Arikawa
- Laboratory of Neuroethology, Sokendai - The Graduate University for Advanced Studies, 240-0193 Hayama, Japan
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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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Exploring Compound Eyes in Adults of Four Coleopteran Species Using Synchrotron X-ray Phase-Contrast Microtomography (SR-PhC Micro-CT). Life (Basel) 2022; 12:life12050741. [PMID: 35629408 PMCID: PMC9145526 DOI: 10.3390/life12050741] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/13/2022] [Accepted: 05/15/2022] [Indexed: 11/17/2022] Open
Abstract
Compound eyes in insects are primary visual receptors of surrounding environments. They show considerable design variations, from the apposition vision of most day-active species to the superposition vision of nocturnal insects, that sacrifice resolution to increase sensitivity and are able to overcome the challenges of vision during lightless hours or in dim habitats. In this study, Synchrotron radiation X-ray phase-contrast microtomography was used to describe the eye structure of four coleopteran species, showing species-specific habitat demands and different feeding habits, namely the saproxylic Clinidium canaliculatum (Costa, 1839) (Rhysodidae), the omnivorous Tenebrio molitor (Linnaeus, 1758) and Tribolium castaneum (Herbest, 1797) (Tenebrionidae), and the generalist predator Pterostichus melas italicus (Dejean, 1828) (Carabidae). Virtual sections and 3D volume renderings of the heads were performed to evaluate the application and limitations of this technique for studying the internal dioptrical and sensorial parts of eyes, and to avoid time-consuming methods such as ultrastructural analyses and classic histology. Morphological parameters such as the area of the corneal facet lens and cornea, interocular distance, facet density and corneal lens thickness were measured, and differences among the studied species were discussed concerning the differences in lifestyle and habitat preferences making different demands on the visual system. Our imaging results provide, for the first time, morphological descriptions of the compound eyes in these species, supplementing their ecological and behavioural traits.
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Brodrick EA, How MJ, Hemmi JM. Fiddler crab electroretinograms reveal vast circadian shifts in visual sensitivity and temporal summation in dim light. J Exp Biol 2022; 225:274663. [PMID: 35156128 PMCID: PMC8976941 DOI: 10.1242/jeb.243693] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 02/04/2022] [Indexed: 11/20/2022]
Abstract
Many animals with compound eyes undergo major optical changes to adjust visual sensitivity from day to night, often under control of a circadian clock. In fiddler crabs, this presents most conspicuously in the huge volume increase of photopigment-packed rhabdoms and the widening of crystalline cone apertures at night. These changes are hypothesised to adjust the light flux to the photoreceptors and to alter optical sensitivity as the eye moves between light- and dark-adapted states. Here, we compare optical sensitivity in fiddler crab eyes (Gelasimus dampieri) during daytime and night via three electroretinogram (ERG) experiments performed on light- and dark-adapted crabs.
1) Light intensity required to elicit a threshold ERG response varied over six orders of magnitude, allowing more sensitive vision for discriminating small contrasts in dim light after dusk. During daytime, the eyes remained relatively insensitive, which would allow effective vision on bright mudflats, even after prolonged dark adaptation.
2) Flicker fusion frequency (FFF) experiments indicated that temporal summation is employed in dim light to increase light-gathering integration times and enhance visual sensitivity during both night and day.
3) ERG responses to flickering lights during 60 mins of dark adaptation increased at a faster rate and greater extent after sunset compared to daytime. However, even brief, dim and intermittent light exposure strongly disrupted dark-adaptation processes.
Together, these findings demonstrate effective light adaptation to optimise vision over the large range of light intensities that these animals experience.
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Affiliation(s)
| | - Martin J. How
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Jan M. Hemmi
- School of Biological Sciences & UWA Oceans Institute, University of Western Australia, Perth, WA 6009, Australia
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Influence of photoperiod on thermal responses in body size, growth and development in Lycaena phlaeas (Lepidoptera: Lycaenidae). CURRENT RESEARCH IN INSECT SCIENCE 2022; 2:100034. [PMID: 36003275 PMCID: PMC9387441 DOI: 10.1016/j.cris.2022.100034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 11/22/2022]
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14
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Grittner R, Baird E, Stöckl A. Spatial tuning of translational optic flow responses in hawkmoths of varying body size. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:279-296. [PMID: 34893928 PMCID: PMC8934765 DOI: 10.1007/s00359-021-01530-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
To safely navigate their environment, flying insects rely on visual cues, such as optic flow. Which cues insects can extract from their environment depends closely on the spatial and temporal response properties of their visual system. These in turn can vary between individuals that differ in body size. How optic flow-based flight control depends on the spatial structure of visual cues, and how this relationship scales with body size, has previously been investigated in insects with apposition compound eyes. Here, we characterised the visual flight control response limits and their relationship to body size in an insect with superposition compound eyes: the hummingbird hawkmoth Macroglossum stellatarum. We used the hawkmoths’ centring response in a flight tunnel as a readout for their reception of translational optic flow stimuli of different spatial frequencies. We show that their responses cut off at different spatial frequencies when translational optic flow was presented on either one, or both tunnel walls. Combined with differences in flight speed, this suggests that their flight control was primarily limited by their temporal rather than spatial resolution. We also observed strong individual differences in flight performance, but no correlation between the spatial response cutoffs and body or eye size.
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Affiliation(s)
- Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany.
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15
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Moradinour Z, Wiklund C, Jie VW, Restrepo CE, Gotthard K, Miettinen A, Perl CD, Baird E. Sensory Organ Investment Varies with Body Size and Sex in the Butterfly Pieris napi. INSECTS 2021; 12:insects12121064. [PMID: 34940152 PMCID: PMC8707955 DOI: 10.3390/insects12121064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022]
Abstract
In solitary insect pollinators such as butterflies, sensory systems must be adapted for multiple tasks, including nectar foraging, mate-finding, and locating host-plants. As a result, the energetic investments between sensory organs can vary at the intraspecific level and even among sexes. To date, little is known about how these investments are distributed between sensory systems and how it varies among individuals of different sex. We performed a comprehensive allometric study on males and females of the butterfly Pieris napi where we measured the sizes and other parameters of sensory traits including eyes, antennae, proboscis, and wings. Our findings show that among all the sensory traits measured, only antenna and wing size have an allometric relationship with body size and that the energetic investment in different sensory systems varies between males and females. Moreover, males had absolutely larger antennae and eyes, indicating that they invest more energy in these organs than females of the same body size. Overall, the findings of this study reveal that the size of sensory traits in P. napi are not necessarily related to body size and raises questions about other factors that drive sensory trait investment in this species and in other insect pollinators in general.
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Affiliation(s)
- Zahra Moradinour
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
- Correspondence:
| | - Christer Wiklund
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Vun Wen Jie
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Carlos E. Restrepo
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Karl Gotthard
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Arttu Miettinen
- Swiss Light Source, Paul Scherrer Institute, 5234 Villigen, Switzerland;
- Department of Physics, University of Jyvaskyla, 40014 Jyvaskyla, Finland
| | - Craig D. Perl
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
- Department of Biology, Lund University, 223 62 Lund, Sweden
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Emily Baird
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
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16
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Bergman M, Smolka J, Nilsson DE, Kelber A. Seeing the world through the eyes of a butterfly: visual ecology of the territorial males of Pararge aegeria (Lepidoptera: Nymphalidae). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:701-713. [PMID: 34709430 PMCID: PMC8568875 DOI: 10.1007/s00359-021-01520-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 11/13/2022]
Abstract
Combining studies of animal visual systems with exact imaging of their visual environment can get us a step closer to understand how animals see their “Umwelt”. Here, we have combined both methods to better understand how males of the speckled wood butterfly, Pararge aegeria, see the surroundings of their perches. These males are well known to sit and wait for a chance to mate with a passing females, in sunspot territories in European forests. We provide a detailed description of the males' body and head posture, viewing direction, visual field and spatial resolution, as well as the visual environment. Pararge aegeria has sexually dimorphic eyes, the smallest interommatidial angles of males are around 1°, those of females 1.5°. Perching males face the antisolar direction with their retinal region of the highest resolution pointing at an angle of about 45° above the horizon; thus, looking at a rather even and dark background in front of which they likely have the best chance to detect a sunlit female passing through the sunspot.
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Affiliation(s)
- Martin Bergman
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62, Lund, Sweden
| | - Jochen Smolka
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62, Lund, Sweden
| | - Dan-Eric Nilsson
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62, Lund, Sweden
| | - Almut Kelber
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62, Lund, Sweden.
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17
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Richter A, Nakamura G, Agra Iserhard C, da Silva Duarte L. The hidden side of diversity: Effects of imperfect detection on multiple dimensions of biodiversity. Ecol Evol 2021; 11:12508-12519. [PMID: 34594516 PMCID: PMC8462181 DOI: 10.1002/ece3.7995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/15/2021] [Indexed: 11/08/2022] Open
Abstract
Studies on ecological communities often address patterns of species distribution and abundance, but few consider uncertainty in counts of both species and individuals when computing diversity measures.We evaluated the extent to which imperfect detection may influence patterns of taxonomic, functional, and phylogenetic diversity in ecological communities.We estimated the true abundance of fruit-feeding butterflies sampled in canopy and understory strata in a subtropical forest. We compared the diversity values calculated by observed and estimated abundance data through the hidden diversity framework. This framework evaluates the deviation of observed diversity when compared with diversities derived from estimated true abundances and whether such deviation represents a bias or a noise in the observed diversity pattern.The hidden diversity values differed between strata for all diversity measures, except for functional richness. The taxonomic measure was the only one where we observed an inversion of the most diverse stratum when imperfect detection was included. Regarding phylogenetic and functional measures, the strata showed distinct responses to imperfect detection, despite the tendency to overestimate observed diversity. While the understory showed noise for the phylogenetic measure, since the observed pattern was maintained, the canopy had biased diversity for the functional metric. This bias occurred since no significant differences were found between strata for observed diversity, but rather for estimated diversity, with the canopy being more clustered.We demonstrate that ignore imperfect detection may lead to unrealistic estimates of diversity and hence to erroneous interpretations of patterns and processes that structure biological communities. For fruit-feeding butterflies, according to their phylogenetic position or functional traits, the undetected individuals triggered different responses in the relationship of the diversity measures to the environmental factor. This highlights the importance to evaluate and include the uncertainty in species detectability before calculating biodiversity measures to describe communities.
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Affiliation(s)
- Aline Richter
- Departamento de EcologiaUniversidade Federal do Rio Grande do SulPorto AlegreBrazil
| | - Gabriel Nakamura
- Departamento de BiologiaUniversidade Federal do CearáFortalezaBrazil
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18
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Shephard AM, Mitchell TS, Snell-Rood EC. Monarch caterpillars are robust to combined exposure to the roadside micronutrients sodium and zinc. CONSERVATION PHYSIOLOGY 2021; 9:coab061. [PMID: 34386239 PMCID: PMC8354372 DOI: 10.1093/conphys/coab061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/08/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
Human activities are increasing the environmental availability of micronutrients, including sodium and some essential metals. Micronutrients are often limiting in animal diets but may have negative effects when consumed in excess. Though prior research has documented how elevated exposure to individual micronutrients can impact organismal development and fitness, we know less about combined effects of multiple micronutrients. In the wild, monarch butterfly larvae (Danaus plexippus) commonly consume plants in roadside habitats that contain elevated levels of sodium (from road salt) and zinc (from vehicle wear-and-tear). We reared monarch caterpillars to adulthood to test individual and combined effects of dietary sodium and zinc on components of fitness, sodium-linked phenotypes (proxies for neural and flight muscle development) and concentrations of sodium and zinc in adult butterflies. Monarch survival was not impacted by elevated sodium or zinc individually or in combination. Yet, monarchs feeding on sodium-treated milkweed developed relatively larger eyes, consistent with a positive effect of sodium on neural development. Measurements of element concentrations in butterfly and plant tissue indicated that monarchs had higher zinc levels than those present in zinc-treated milkweed but lower sodium levels than those present in sodium-treated milkweed. Monarchs developing on sodium-treated milkweed also had prolonged development time, which might be a cost associated with developing extra neural tissue or investing in mechanisms to excrete excess dietary sodium during the larval stage. Our results indicate that sodium, more than zinc, is likely influencing phenotypic development and performance of insect pollinators in roadside habitats. Yet, in contrast to previous work, our experiment suggests that the highest levels of sodium found along roads are not always harmful for developing monarchs. Future work could consider how potentially stressful effects of micronutrients could be mitigated by increased macronutrient availability or how developmental factors such as migratory status might increase micronutrient requirements.
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Affiliation(s)
- Alexander M Shephard
- Corresponding author: Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, Saint Paul, MN 55108, USA.
| | - Timothy S Mitchell
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Twin Cities, Saint Paul, MN 55108, USA
| | - Emilie C Snell-Rood
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Twin Cities, Saint Paul, MN 55108, USA
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19
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A new comprehensive trait database of European and Maghreb butterflies, Papilionoidea. Sci Data 2020; 7:351. [PMID: 33060594 PMCID: PMC7567092 DOI: 10.1038/s41597-020-00697-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/14/2020] [Indexed: 11/08/2022] Open
Abstract
Trait-based analyses explaining the different responses of species and communities to environmental changes are increasing in frequency. European butterflies are an indicator group that responds rapidly to environmental changes with extensive citizen science contributions to documenting changes of abundance and distribution. Species traits have been used to explain long- and short-term responses to climate, land-use and vegetation changes. Studies are often characterised by limited trait sets being used, with risks that the relative roles of different traits are not fully explored. Butterfly trait information is dispersed amongst various sources and descriptions sometimes differ between sources. We have therefore drawn together multiple information sets to provide a comprehensive trait database covering 542 taxa and 25 traits described by 217 variables and sub-states of the butterflies of Europe and Maghreb (northwest Africa) which should serve for improved trait-based ecological, conservation-related, phylogeographic and evolutionary studies of this group of insects. We provide this data in two forms; the basic data and as processed continuous and multinomial data, to enhance its potential usage. Measurement(s) | resources • Egg Laying • larval environment • pupal environment • geographic location • behavior • size • voltinism • phenology • host plant | Technology Type(s) | digital curation | Factor Type(s) | species | Sample Characteristic - Organism | Papilionoidea | Sample Characteristic - Location | Europe • Northwest Africa |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12998828
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20
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Snell‐Rood EC, Swanson EM, Espeset A, Jaumann S, Philips K, Walker C, Semke B, Mori AS, Boenisch G, Kattge J, Seabloom EW, Borer ET. Nutritional constraints on brain evolution: Sodium and nitrogen limit brain size. Evolution 2020; 74:2304-2319. [DOI: 10.1111/evo.14072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 07/07/2020] [Accepted: 07/25/2020] [Indexed: 12/30/2022]
Affiliation(s)
- Emilie C. Snell‐Rood
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
| | - Eli M. Swanson
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
| | - Anne Espeset
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
- Department of Biology University of Nevada‐Reno Reno Nevada 89557
| | - Sarah Jaumann
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
- Department of Biological Sciences George Washington University Washington District of Columbia 20052
| | - Kinsey Philips
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
| | - Courtney Walker
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
| | - Brandon Semke
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
| | - Akira S. Mori
- Graduate School of Environment and Information Sciences Yokohama National University Yokohama Japan
| | | | - Jens Kattge
- Max‐Planck‐Institute for Biogeochemistry Jena Germany
| | - Eric W. Seabloom
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
| | - Elizabeth T. Borer
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota 55455
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21
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Jones BM, Seymoure BM, Comi TJ, Loew ER. Species and sex differences in eye morphometry and visual responsivity of two crepuscular sweat bee species ( Megalopta spp., Hymenoptera: Halictidae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Visually dependent dim-light foraging has evolved repeatedly, broadening the ecological niches of some species. Many dim-light foraging lineages evolved from diurnal ancestors, requiring immense visual sensitivity increases to compensate for light levels a billion times dimmer than daylight. Some taxa, such as bees, are anatomically constrained by apposition compound eyes, which function well in daylight but not in starlight. Even with this constraint, the bee genus Megalopta has incredibly sensitive eyes, foraging in light levels up to nine orders of magnitude dimmer than diurnal relatives. Despite many behavioural studies, variation in visual sensitivity and eye morphometry has not been investigated within and across Megalopta species. Here we quantify external eye morphology (corneal area and facet size) for sympatric species of Megalopta, M. genalis and M. amoena, which forage during twilight. We use electroretinograms to show that males, despite being smaller than females, have equivalent visual sensitivity and increased retinal responsivity. Although males have relatively larger eyes compared with females, corneal area and facet size were not correlated with retinal responsivity, suggesting that males have additional non-morphological adaptations to increase retinal responsiveness. These findings provide the foundation for future work into the neural and physiological mechanisms that interface with morphology to influence visual sensitivity, with implications for understanding niche exploitation.
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Affiliation(s)
- Beryl M Jones
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Brett M Seymoure
- Smithsonian Tropical Research Institute, Panama City, Panama
- Living Earth Collaborative, Washington University in St. Louis, St. Louis, MO, USA
- Sound and Light Ecology Team, Colorado State University, Fort Collins, CO, USA
| | - Troy J Comi
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ellis R Loew
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
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22
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Chen QX, Chen YW, Li WL. Ultrastructural comparison of the compound eyes of the Asian corn borer Ostrinia furnacalis (Lepidoptera: Crambidae) under light/dark adaptation. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 53:100901. [PMID: 31760197 DOI: 10.1016/j.asd.2019.100901] [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: 08/06/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 06/10/2023]
Abstract
The Asian corn borer Ostrinia furnacalis is one of the most destructive pests of maize throughout eastern Asia and the South Pacific. In the present study the fine structure of the compound eyes of adult O. furnacalis was investigated under light/dark adaptation using light and electron microscopy. The compound eyes of male and female O. furnacalis are superposition eyes with electron-lucent clear zones. The sexual differences of the compound eyes of O. furnacalis are mainly reflected in eye size rather than ommatidial ultrastructure. Each ommatidium of both sexes contains 12 retinula cells, one of which is the basal retinula cell. All the retinula cells form a centrally-fused, two-tiered rhabdom, whose distal layer passes through the clear zone and distally connects with the crystalline cone. The ultrastructural changes under light/dark conditions mainly involve the rhabdom occupation ratio to retinula cell volume in the proximal layer of the rhabdom as well as the dimensions of the subcorneal zone and the crystalline tract. Pigment movements occur within the retinula cells and primary pigment cells, but are undetectable within the secondary pigment cells. Regardless of light or dark adaptation, in other words, the pigments never migrate into the clear zone.
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Affiliation(s)
- Qing-Xiao Chen
- Laboratory of Insect Evolution and Systematics, Forestry College, Henan University of Science and Technology, Luoyang, Henan, 471023, China.
| | - Ying-Wu Chen
- Laboratory of Insect Evolution and Systematics, Forestry College, Henan University of Science and Technology, Luoyang, Henan, 471023, China
| | - Wen-Liang Li
- Laboratory of Insect Evolution and Systematics, Forestry College, Henan University of Science and Technology, Luoyang, Henan, 471023, China
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23
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Spaniol RL, Duarte LDS, Mendonça MDS, Iserhard CA. Combining functional traits and phylogeny to disentangling Amazonian butterfly assemblages on anthropogenic gradients. Ecosphere 2019. [DOI: 10.1002/ecs2.2837] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- Ricardo Luís Spaniol
- Programa de Pós‐graduação em Ecologia Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brasil
| | - Leandro da Silva Duarte
- Programa de Pós‐graduação em Ecologia Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brasil
| | - Milton de Souza Mendonça
- Programa de Pós‐graduação em Ecologia Universidade Federal do Rio Grande do Sul Porto Alegre Rio Grande do Sul Brasil
| | - Cristiano Agra Iserhard
- Programa de Pós‐graduação em Biologia Animal Universidade Federal de Pelotas Capão do Leão Rio Grande do Sul Brasil
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24
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Taylor GJ, Tichit P, Schmidt MD, Bodey AJ, Rau C, Baird E. Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity. eLife 2019; 8:40613. [PMID: 30803484 PMCID: PMC6391067 DOI: 10.7554/elife.40613] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 12/23/2018] [Indexed: 12/19/2022] Open
Abstract
The quality of visual information that is available to an animal is limited by the size of its eyes. Differences in eye size can be observed even between closely related individuals, yet we understand little about how this affects vision. Insects are good models for exploring the effects of size on visual systems because many insect species exhibit size polymorphism. Previous work has been limited by difficulties in determining the 3D structure of eyes. We have developed a novel method based on x-ray microtomography to measure the 3D structure of insect eyes and to calculate predictions of their visual capabilities. We used our method to investigate visual allometry in the bumblebee Bombus terrestris and found that size affects specific aspects of vision, including binocular overlap, optical sensitivity, and dorsofrontal visual resolution. This reveals that differential scaling between eye areas provides flexibility that improves the visual capabilities of larger bumblebees. Bees fly through complex environments in search of nectar from flowers. They are aided in this quest by excellent eyesight. Scientists have extensively studied the eyesight of honeybees to learn more about how such tiny eyes work and how they process and learn visual information. Less is known about the honeybee’s larger cousins, the bumblebees, which are also important pollinators. Bumblebees come in different sizes and one question scientists have is how eye size affects vision. Bigger bumblebees are known to have bigger eyes, and bigger eyes are usually better. But which aspects of vision are improved in larger eyes is not clear. For example, does the size of a bee’s eyes affect how large their field of view is, or how sensitive they are to light? Or does it impact their visual acuity, a measurement of the smallest objects the eye can see? Scaling up an eye would likely improve all these aspects of sight slightly, but changes in a small area of the eye might more drastically improve some parts of vision. Now, Taylor et al. show that larger bumblebees with bigger eyes have better vision than their smaller counterparts. In the experiments, a technique called microtomography was used to measure the 3D structure of bumblebee eyes. The measurements were then applied to build 3D models of the bumblebee eyes, and computational geometry was used to calculate the sensitivity, acuity, and viewing direction across the entire surface of each model eye. Taylor et al. found that larger bees had improved ability to see small objects in front or slightly above them. They had a bigger area of overlap between the sight in both eyes when they looked forward and up. They were also more sensitive to light across the eye. The experiments show that improvements in eyesight with larger size are very specific and likely help larger bees to adapt to their environment. Behavioral studies could help scientists better understand how these changes help bigger bees and how the traits evolved. These findings might also help engineers trying to design miniature cameras to help small, flying autonomous vehicles navigate. Bees fly through complex environments and face challenges similar to those small flying vehicles would face. Emulating the design of bee eyes and how they change with size might lead to the development of better cameras for these vehicles.
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Affiliation(s)
| | - Pierre Tichit
- Department of Biology, Lund University, Lund, Sweden
| | - Marie D Schmidt
- Department of Biology, Lund University, Lund, Sweden.,Westphalian University of Applied Sciences, Bocholt, Germany
| | | | | | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
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25
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Javoiš J, Davis RB, Tammaru T. A comparative morphometric study of sensory capacity in geometrid moths. J Evol Biol 2019; 32:380-389. [DOI: 10.1111/jeb.13422] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 01/27/2019] [Accepted: 01/28/2019] [Indexed: 12/01/2022]
Affiliation(s)
- Juhan Javoiš
- Department of ZoologyInstitute of Ecology and Earth SciencesUniversity of Tartu Tartu Estonia
| | - Robert B. Davis
- Department of ZoologyInstitute of Ecology and Earth SciencesUniversity of Tartu Tartu Estonia
| | - Toomas Tammaru
- Department of ZoologyInstitute of Ecology and Earth SciencesUniversity of Tartu Tartu Estonia
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26
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Stanger-Hall KF, Sander Lower SE, Lindberg L, Hopkins A, Pallansch J, Hall DW. The evolution of sexual signal modes and associated sensor morphology in fireflies (Lampyridae, Coleoptera). Proc Biol Sci 2019; 285:rspb.2017.2384. [PMID: 29343601 DOI: 10.1098/rspb.2017.2384] [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] [Received: 11/01/2017] [Accepted: 12/11/2017] [Indexed: 11/12/2022] Open
Abstract
Animals employ different sexual signal modes (e.g. visual, acoustic, chemical) in different environments and behavioural contexts. If sensory structures are costly, then evolutionary shifts in primary signal mode should be associated with changes in sensor morphology. Further, sex differences are expected if male and female signalling behaviours differ. Fireflies are known for their light displays, but many species communicate exclusively with pheromones, including species that recently lost their light signals. We performed phylogenetically controlled analyses of male eye and antenna size in 46 North American taxa, and found that light signals are associated with larger eyes and shorter antennae. In addition, following a transition from nocturnal light displays to diurnal pheromones, eye size reductions occur more rapidly than antenna size increases. In agreement with the North American taxa, across 101 worldwide firefly taxa in 32 genera, we found light displays are associated with larger eye and smaller antenna sizes in both males and females. For those taxa with both male and female data, we found sex differences in eye size and, for diurnal species, in antenna size.
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Affiliation(s)
| | | | - Lauri Lindberg
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - Andrew Hopkins
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - Jenna Pallansch
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - David W Hall
- Department of Genetics, University of Georgia, Athens, GA, USA
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Tiede Y, Hemp C, Schmidt A, Nauss T, Farwig N, Brandl R. Beyond body size: consistent decrease of traits within orthopteran assemblages with elevation. Ecology 2018; 99:2090-2102. [PMID: 29944730 DOI: 10.1002/ecy.2436] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/03/2018] [Accepted: 06/11/2018] [Indexed: 12/18/2022]
Abstract
Morphological traits provide the interface between species and their environment. For example, body size affects the fitness of individuals in various ways. Yet especially for ectotherms, the applicability of general rules of interspecific clines of body size and even more so of other morphological traits is still under debate. Here we tested relationships between elevation (as a proxy for temperature) and productivity with four ecologically relevant morphological traits of orthopteran assemblages that are related to fecundity (body size), dispersal (wing length), jumping ability (hind femur length), and predator detection (eye size). We measured traits of 160 orthopteran species that were sampled along an extensive environmental gradient at Mt. Kilimanjaro (Tanzania), spanning elevations from 790 to 4,410 m above sea level (a.s.l.) with different levels of plant productivity. For traits other than body size, we calculated the residuals from a regression on body length to estimate the variation of traits irrespective of body size. Bayesian analyses revealed that mean body size of assemblages, as well as the means of relative wing length, hind femur length, and eye size, decreased with increasing elevation. Body size and relative eye size also decreased with increasing productivity. Both phylogenetic relationships, as well as species-specific adaptations, contributed to these patterns. Our results suggest that orthopteran assemblages had higher fecundity and better dispersal and escape abilities, as well as better predator detection at higher temperatures (low elevations) than at low temperatures (high elevations). Large body sizes might be advantageous in habitats with low productivity because of a reduced risk of starvation. Likewise, large eye size might be advantageous because of the ability to detect predators in habitats with low vegetation cover, where hiding possibilities are scarce. Our study highlights that changes in temperature and productivity not only lead to interspecific changes in body size but are also related to independent changes of other morphological traits that influence the ecological fit of organisms in their environment.
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Affiliation(s)
- Yvonne Tiede
- Faculty of Biology, Conservation Ecology, Philipps-Universität Marburg, Karl-von-Frisch-Straße 8, Marburg, 35043, Germany
| | - Claudia Hemp
- Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, Frankfurt (Main), 60325, Germany
| | - Antje Schmidt
- Faculty of Biology, Department of Ecology, Animal Ecology, Philipps-Universität Marburg, Karl-von-Frisch-Straße 8, Marburg, 35043, Germany
| | - Thomas Nauss
- Faculty of Geography, Department of Geoinformatics, Philipps-Universität Marburg, Deutschhausstraße 10, Marburg, 35032, Germany
| | - Nina Farwig
- Faculty of Biology, Conservation Ecology, Philipps-Universität Marburg, Karl-von-Frisch-Straße 8, Marburg, 35043, Germany
| | - Roland Brandl
- Faculty of Biology, Department of Ecology, Animal Ecology, Philipps-Universität Marburg, Karl-von-Frisch-Straße 8, Marburg, 35043, Germany
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Catalán A, Macias-Muñoz A, Briscoe AD. Evolution of Sex-Biased Gene Expression and Dosage Compensation in the Eye and Brain of Heliconius Butterflies. Mol Biol Evol 2018; 35:2120-2134. [DOI: 10.1093/molbev/msy111] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Ana Catalán
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA
- Section of Evolutionary Biology, Department of Biology II, Ludwig Maximilians Universität, Planegg-Martinsried, Germany
| | - Aide Macias-Muñoz
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA
| | - Adriana D Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA
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Seymoure BM. Enlightening Butterfly Conservation Efforts: The Importance of Natural Lighting for Butterfly Behavioral Ecology and Conservation. INSECTS 2018; 9:E22. [PMID: 29439549 PMCID: PMC5872287 DOI: 10.3390/insects9010022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 01/29/2018] [Accepted: 02/06/2018] [Indexed: 11/16/2022]
Abstract
Light is arguably the most important abiotic factor for living organisms. Organisms evolved under specific lighting conditions and their behavior, physiology, and ecology are inexorably linked to light. Understanding light effects on biology could not be more important as present anthropogenic effects are greatly changing the light environments in which animals exist. The two biggest anthropogenic contributors changing light environments are: (1) anthropogenic lighting at night (i.e., light pollution); and (2) deforestation and the built environment. I highlight light importance for butterfly behavior, physiology, and ecology and stress the importance of including light as a conservation factor for conserving butterfly biodiversity. This review focuses on four parts: (1) Introducing the nature and extent of light. (2) Visual and non-visual light reception in butterflies. (3) Implications of unnatural lighting for butterflies across several different behavioral and ecological contexts. (4). Future directions for quantifying the threat of unnatural lighting on butterflies and simple approaches to mitigate unnatural light impacts on butterflies. I urge future research to include light as a factor and end with the hopeful thought that controlling many unnatural light conditions is simply done by flipping a switch.
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Affiliation(s)
- Brett M Seymoure
- Department of Biology and Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA.
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Corral-López A, Garate-Olaizola M, Buechel SD, Kolm N, Kotrschal A. On the role of body size, brain size, and eye size in visual acuity. Behav Ecol Sociobiol 2017; 71:179. [PMID: 29213179 PMCID: PMC5705735 DOI: 10.1007/s00265-017-2408-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/11/2017] [Accepted: 11/16/2017] [Indexed: 10/25/2022]
Abstract
Abstract The visual system is highly variable across species, and such variability is a key factor influencing animal behavior. Variation in the visual system, for instance, can influence the outcome of learning tasks when visual stimuli are used. We illustrate this issue in guppies (Poecilia reticulata) artificially selected for large and small relative brain size with pronounced behavioral differences in learning experiments and mate choice tests. We performed a study of the visual system by quantifying eye size and optomotor response of large-brained and small-brained guppies. This represents the first experimental test of the link between brain size evolution and visual acuity. We found that female guppies have larger eyes than male guppies, both in absolute terms and in relation to their body size. Likewise, individuals selected for larger brains had slightly larger eyes but not better visual acuity than small-brained guppies. However, body size was positively associated with visual acuity. We discuss our findings in relation to previous macroevolutionary studies on the evolution of brain morphology, eye morphology, visual acuity, and ecological variables, while stressing the importance of accounting for sensory abilities in behavioral studies. Significance statement Pre-existing perceptual biases can be keys for the development of specific behavioral patterns. Hence, potential differences in sensory systems need to be taken into account in the study of animal behavior. We highlight this necessity concentrating on the visual domain and using experimental data on brain size-selected guppies in which we assessed eye size and visual acuity. Behavioral differences between large-brained and small-brained guppies in learning and mate choice predominantly relied on tests using visual cues. Analyses of visual capabilities in this system are therefore necessary. Furthermore, this system offers the unprecedented opportunity to experimentally test the relationship between brain size, eye morphology, and visual capabilities. Our results show similar visual acuities between large-brained and small-brained guppies. However, the differences observed in eye area between the sexes, together with the observed positive relationship between body size and visual acuity, highlight the need to incorporate perceptive differences in the study of animal behavior.
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Affiliation(s)
- Alberto Corral-López
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691 Stockholm, Sweden
| | - Maddi Garate-Olaizola
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691 Stockholm, Sweden
| | - Severine D Buechel
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691 Stockholm, Sweden
| | - Niclas Kolm
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691 Stockholm, Sweden
| | - Alexander Kotrschal
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691 Stockholm, Sweden
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Somanathan H, Borges RM, Warrant EJ, Kelber A. Visual Adaptations for Mate Detection in the Male Carpenter Bee Xylocopa tenuiscapa. PLoS One 2017; 12:e0168452. [PMID: 28107354 PMCID: PMC5249068 DOI: 10.1371/journal.pone.0168452] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/01/2016] [Indexed: 11/18/2022] Open
Abstract
Sexual dimorphism in eye structure is attributed to sexual selection in animals that employ vision for locating mates. In many male insects, large eyes and eye regions of higher acuity are believed to facilitate the location of females. Here, we compare various features of male and female eyes in three sympatric carpenter bee species, which include two diurnal species (Xylocopa tenuiscapa and X. leucothorax) as well as a nocturnal species (X. tranquebarica). In X. tenuiscapa, males have larger eyes than females, while in the nocturnal X. tranquebarica, males have slightly smaller eyes and in X. leucothorax, the eyes are of similar size in both sexes. X. tenuiscapa males detect females by perching near nest sites (resource defence) or along fly-ways and other open areas with good visibility. Males of the other two species search for females by patrolling. We postulate that the larger eyes of male X. tenuiscapa are beneficial to their mode of mate detection since perching males may benefit from a larger visual area of high resolution detecting moving stimuli across the sky, and which may be germane to the more social and gregarious nesting behaviour of this species, compared to the other solitary bees. We tested the performance of the eyes of male X. tenuiscapa behaviourally and find that a perching male can detect a flying female at a distance of 20 m, which darkens the visual field of a single ommatidium by just 2%. This, together with the bee's high spatial resolution permits detection of moving stimuli at least as well or even better than achieved by honey bee drones.
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Affiliation(s)
- Hema Somanathan
- IISER TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, India
- * E-mail:
| | - Renee Maria Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
| | - Eric J. Warrant
- Lund Vision Group, Department for Biology, Lund University, Lund, Sweden
| | - Almut Kelber
- Lund Vision Group, Department for Biology, Lund University, Lund, Sweden
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Li L, Ma H, Niu L, Han D, Zhang F, Chen J, Fu Y. Evaluation of chromatic cues for trapping Bactrocera tau. PEST MANAGEMENT SCIENCE 2017; 73:217-222. [PMID: 27060360 DOI: 10.1002/ps.4288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/26/2016] [Accepted: 04/04/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND Trapping technology based on chromatic cues is an important strategy in controlling Tephritidae (fruit flies). The objectives of this present study were to evaluate the preference of Bactrocera tau for different chromatic cues, and to explore an easy method to print and reproduce coloured paper. RESULTS Chromatic cues significantly affected the preference of adult B. tau. Wavelengths in the 515-604 nm range were the suitable wavelengths for trapping B. tau. Different-day-old B. tau had different colour preferences. Virtual wavelengths of 595 nm (yellow) and 568 nm (yellowish green) were the optimum wavelengths for trapping 5-7-day-old B. tau and 30-32-day-old B. tau respectively. The trap type and height significantly influenced B. tau attraction efficiency. The number of B. tau on coloured traps hung perpendicular to plant rows was not significantly higher than the number on traps hung parallel to plant rows. CONCLUSION The quantisation of colour on the basis of Bruton's wavelength to RGB function can serve as an alternative method for printing and reproducing coloured paper, but a corrected equation should be established between the theoretical wavelength and actual wavelength of coloured paper. Results show that a compound paper coloured yellow (595 nm) and yellowish green (568 nm) installed at 60 and 90 cm above the ground shows the maximum effect for trapping B. tau. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Lei Li
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, China
| | - Huabo Ma
- College of Environment and Plant Protection, Hainan University, China
| | - Liming Niu
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, China
| | - Dongyin Han
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, China
| | - Fangping Zhang
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, China
| | - Junyu Chen
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, China
| | - Yueguan Fu
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, China
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33
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Developmental lead exposure has mixed effects on butterfly cognitive processes. Anim Cogn 2016; 20:87-96. [DOI: 10.1007/s10071-016-1029-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
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Swanson EM, Espeset A, Mikati I, Bolduc I, Kulhanek R, White WA, Kenzie S, Snell-Rood EC. Nutrition shapes life-history evolution across species. Proc Biol Sci 2016; 283:20152764. [PMID: 27412282 PMCID: PMC4947880 DOI: 10.1098/rspb.2015.2764] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 06/20/2016] [Indexed: 11/12/2022] Open
Abstract
Nutrition is a key component of life-history theory, yet we know little about how diet quality shapes life-history evolution across species. Here, we test whether quantitative measures of nutrition are linked to life-history evolution across 96 species of butterflies representing over 50 independent diet shifts. We find that butterflies feeding on high nitrogen host plants as larvae are more fecund, but their eggs are smaller relative to their body size. Nitrogen and sodium content of host plants are also both positively related to eye size. Some of these relationships show pronounced lineage-specific effects. Testis size is not related to nutrition. Additionally, the evolutionary timing of diet shifts is not important, suggesting that nutrition affects life histories regardless of the length of time a species has been adapting to its diet. Our results suggest that, at least for some lineages, species with higher nutrient diets can invest in a range of fitness-related traits like fecundity and eye size while allocating less to each egg as offspring have access to a richer diet. These results have important implications for the evolution of life histories in the face of anthropogenic changes in nutrient availability.
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Affiliation(s)
- Eli M Swanson
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
| | - Anne Espeset
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA Department of Biology, University of Nevada-Reno, Reno, NV 89509, USA
| | - Ihab Mikati
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
| | - Isaac Bolduc
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
| | - Robert Kulhanek
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
| | - William A White
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
| | - Susan Kenzie
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
| | - Emilie C Snell-Rood
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, St Paul, MN 55108, USA
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Flight Morphology, Compound Eye Structure and Dispersal in the Bog and the Cranberry Fritillary Butterflies: An Inter- and Intraspecific Comparison. PLoS One 2016; 11:e0158073. [PMID: 27336590 PMCID: PMC4919012 DOI: 10.1371/journal.pone.0158073] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 06/09/2016] [Indexed: 11/24/2022] Open
Abstract
Understanding dispersal is of prime importance in conservation and population biology. Individual traits related to motion and navigation during dispersal may differ: (1) among species differing in habitat distribution, which in turn, may lead to interspecific differences in the potential for and costs of dispersal, (2) among populations of a species that experiences different levels of habitat fragmentation; (3) among individuals differing in their dispersal strategy and (4) between the sexes due to sexual differences in behaviour and dispersal tendencies. In butterflies, the visual system plays a central role in dispersal, but exactly how the visual system is related to dispersal has received far less attention than flight morphology. We studied two butterfly species to explore the relationships between flight and eye morphology, and dispersal. We predicted interspecific, intraspecific and intersexual differences for both flight and eye morphology relative to i) species-specific habitat distribution, ii) variation in dispersal strategy within each species and iii) behavioural differences between sexes. However, we did not investigate for potential population differences. We found: (1) sexual differences that presumably reflect different demands on both male and female visual and flight systems, (2) a higher wing loading (i.e. a proxy for flight performance), larger eyes and larger facet sizes in the frontal and lateral region of the eye (i.e. better navigation capacities) in the species inhabiting naturally fragmented habitat compared to the species inhabiting rather continuous habitat, and (3) larger facets in the frontal region in dispersers compared to residents within a species. Hence, dispersers may have similar locomotory capacity but potentially better navigation capacity. Dispersal ecology and evolution have attracted much attention, but there are still significant gaps in our understanding of the mechanisms of dispersal. Unfortunately, for many species we lack detailed information on the role of behavioural, morphological and physiological traits for dispersal. Our novel study supports the existence of inter- and intra-specific evolutionary responses in both motion and navigation capacities (i.e. flight and eye morphology) linked to dispersal.
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Shiel BP, Sherman CDH, Elgar MA, Johnson TL, Symonds MRE. Investment in sensory structures, testis size, and wing coloration in males of a diurnal moth species: trade-offs or correlated growth? Ecol Evol 2015; 5:1601-8. [PMID: 25937904 PMCID: PMC4409409 DOI: 10.1002/ece3.1459] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 02/10/2015] [Accepted: 02/16/2015] [Indexed: 11/17/2022] Open
Abstract
For dioecious animals, reproductive success typically involves an exchange between the sexes of signals that provide information about mate location and quality. Typically, the elaborate, secondary sexual ornaments of males signal their quality, while females may signal their location and receptivity. In theory, the receptor structures that receive the latter signals may also become elaborate or enlarged in a way that ultimately functions to enhance mating success through improved mate location. The large, elaborate antennae of many male moths are one such sensory structure, and eye size may also be important in diurnal moths. Investment in these traits may be costly, resulting in trade-offs among different traits associated with mate location. For polyandrous species, such trade-offs may also include traits associated with paternity success, such as larger testes. Conversely, we would not expect this to be the case for monandrous species, where sperm competition is unlikely. We investigated these ideas by evaluating the relationship between investment in sensory structures (antennae, eye), testis, and a putative warning signal (orange hindwing patch) in field-caught males of the monandrous diurnal painted apple moth Teia anartoides (Lepidoptera: Lymantriidae) in southeastern Australia. As predicted for a monandrous species, we found no evidence that male moths with larger sensory structures had reduced investment in testis size. However, contrary to expectation, investment in sensory structures was correlated: males with relatively larger antennae also had relatively larger eyes. Intriguingly, also, the size of male orange hindwing patches was positively correlated with testis size.
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Affiliation(s)
- Brett P Shiel
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University 221 Burwood Highway, Burwood, Melbourne, Victoria, 3125, Australia
| | - Craig D H Sherman
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University Pigdons Road, Waurn Ponds, Victoria, 3217, Australia
| | - Mark A Elgar
- School of BioSciences, University of Melbourne Melbourne, Victoria, 3010, Australia
| | - Tamara L Johnson
- School of BioSciences, University of Melbourne Melbourne, Victoria, 3010, Australia
| | - Matthew R E Symonds
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University 221 Burwood Highway, Burwood, Melbourne, Victoria, 3125, Australia
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Linking eye design with host symbiont relationships in pontoniine shrimps (Crustacea, Decapoda, Palaemonidae). PLoS One 2014; 9:e99505. [PMID: 24950292 PMCID: PMC4064969 DOI: 10.1371/journal.pone.0099505] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/15/2014] [Indexed: 11/19/2022] Open
Abstract
Symbiosis is prevalent in the marine environment with many studies examining the effects of such interactions between host and symbiont. Pontoniine shrimps are a group whose ecology is characterised by symbiotic interactions. This investigation examines the gross morphology of Pontoniinae compound eyes and superficial optical parameters with reference to their symbiotic relationship or lifestyle category; free-living, ectosymbiont, endosymbiont (bivalves) or endosymbiont (non-bivalves). The eye morphologies of free-living and ectosymbiotic species are very similar, yet differ from both forms of endosymbiotic species. Endosymbionts have significantly smaller and simpler eyes with larger facets and bigger interommatidial angles and eye parameters for increased sensitivity levels. However bivalve endosymbionts form an intermediary group between non-bivalve endosymbionts and ectosymbionts as a result of their more active lifestyle. The accessory eye or “nebenauge”, although of uncertain function, commonly occurs in free-living Pontoniinae species but rarely in endosymbionts apart from in more primitive species. The variation in morphology reflects tensions between functional requirements and ecological pressures that have strongly influenced eye design in Pontoniinae.
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Anthropogenic changes in sodium affect neural and muscle development in butterflies. Proc Natl Acad Sci U S A 2014; 111:10221-6. [PMID: 24927579 DOI: 10.1073/pnas.1323607111] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5-30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates.
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Ecological constraints on sensory systems: compound eye size in Daphnia is reduced by resource limitation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:749-58. [DOI: 10.1007/s00359-014-0918-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/07/2014] [Indexed: 10/25/2022]
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Everett A, Tong X, Briscoe AD, Monteiro A. Phenotypic plasticity in opsin expression in a butterfly compound eye complements sex role reversal. BMC Evol Biol 2012. [PMID: 23194112 PMCID: PMC3549281 DOI: 10.1186/1471-2148-12-232] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Background Animals often display phenotypic plasticity in morphologies and behaviors that result in distinct adaptations to fluctuating seasonal environments. The butterfly Bicyclus anynana has two seasonal forms, wet and dry, that vary in wing ornament brightness and in the identity of the sex that performs the most courting and choosing. Rearing temperature is the cue for producing these alternative seasonal forms. We hypothesized that, barring any developmental constraints, vision should be enhanced in the choosy individuals but diminished in the non-choosy individuals due to physiological costs. As a proxy of visual performance we measured eye size, facet lens size, and sensitivity to light, e.g., the expression levels of all opsins, in males and females of both seasonal forms. Results We found that B. anynana eyes displayed significant sexual dimorphism and phenotypic plasticity for both morphology and opsin expression levels, but not all results conformed to our prediction. Males had larger eyes than females across rearing temperatures, and increases in temperature produced larger eyes in both sexes, mostly via increases in facet number. Ommatidia were larger in the choosy dry season (DS) males and transcript levels for all three opsins were significantly lower in the less choosy DS females. Conclusions Opsin level plasticity in females, and ommatidia size plasticity in males supported our visual plasticity hypothesis but males appear to maintain high visual function across both seasons. We discuss our results in the context of distinct sexual and natural selection pressures that may be facing each sex in the wild in each season.
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Affiliation(s)
- Andrew Everett
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA.
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Merry JW, Kemp DJ, Rutowski RL. Variation in compound eye structure: effects of diet and family. Evolution 2011; 65:2098-110. [PMID: 21729063 DOI: 10.1111/j.1558-5646.2011.01285.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Studies of compound eyes have revealed that variation in eye structure can substantially affect visual performance. Here, we investigate the degree to which a stressful rearing environment, which decreases body size, affects the eye phenotype. Full siblings of the Orange Sulphur butterfly, Colias eurytheme, were collected from known parents and split within families among two diet treatments that varied in quality. In both sexes, individuals reared on the high-quality diet had larger eye height and anterior facet diameter, and therefore, by inference, superior vision. However, relative to their reduced body size, individuals reared on low-quality diet had proportionally larger eyes and facets than individuals reared on high-quality diet. We interpret this finding as evidence that butterflies encountering nutritional stress increased proportional investment in eye development to reduce loss of visual performance. We also found significant broad-sense genetic variation underlying eye structure in both males and females, and report novel heritability estimates for eye height and facet diameter. Surprisingly, there was greater genetic variation in eye height among males than among females, despite apparently stronger directional selection on male vision. We discuss the implications of these data for our understanding of eye development and evolution.
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Affiliation(s)
- Justin W Merry
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4601, USA.
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Allen CE, Zwaan BJ, Brakefield PM. Evolution of sexual dimorphism in the Lepidoptera. ANNUAL REVIEW OF ENTOMOLOGY 2011; 56:445-464. [PMID: 20822452 DOI: 10.1146/annurev-ento-120709-144828] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Among the animals, the Lepidoptera (moths and butterflies) are second only to beetles in number of described species and are known for their striking intra- and interspecific diversity. Within species, sexual dimorphism is a source of variation in life history (e.g., sexual size dimorphism and protandry), morphology (e.g., wing shape and color pattern), and behavior (e.g., chemical and visual signaling). Sexual selection and mating systems have been considered the primary forces driving the evolution of sexual dimorphism in the Lepidoptera, and alternative hypotheses have been neglected. Here, we examine opportunities for sexual selection, natural selection, and the interplay between the two forces in the evolution of sexual differences in the moths and butterflies. Our primary goal is to identify mechanisms that either facilitate or constrain the evolution of sexual dimorphism, rather than to resolve any perceived controversy between hypotheses that may not be mutually exclusive.
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Affiliation(s)
- Cerisse E Allen
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA.
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Differences in mate location behaviours between residents and nonresidents in a territorial butterfly. Anim Behav 2009. [DOI: 10.1016/j.anbehav.2009.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Rutowski RL, Gislén L, Warrant EJ. Visual acuity and sensitivity increase allometrically with body size in butterflies. ARTHROPOD STRUCTURE & DEVELOPMENT 2009; 38:91-100. [PMID: 18809509 DOI: 10.1016/j.asd.2008.08.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 06/19/2008] [Accepted: 08/11/2008] [Indexed: 05/26/2023]
Abstract
In insects, the surface area of the compound eye increases with body size both within and between species with only a slight negative allometry. This increase in surface area permits changes in eye structure that affect the eye's acuity and sensitivity, two features of eye performance that cannot be simultaneously maximized. Hence, as eye size varies within a lineage, so will the compromises between features that maximize acuity and those that maximize sensitivity. We examined these compromises in four species of nymphalid butterflies that varied in body mass over almost two orders of magnitude. The largest of these species was crepuscular and so additionally may indicate the potential effect of life style on eye structure. Across these species, as body size increased, facet diameters increased while interommatidial angles decreased. Finally, the eye parameter was fairly constant across species except in the crepuscular species in which some notably large values were observed in the frontal visual field. Based on our measurements, large butterflies have more acute and more sensitive vision than smaller butterflies. However, full understanding of the behavioral implications of this relationship awaits information on the temporal resolution of their eyes because typical flight velocities also increase with body size.
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Affiliation(s)
- R L Rutowski
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-1501, USA.
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Bergman M, Gotthard K, Berger D, Olofsson M, Kemp DJ, Wiklund C. Mating success of resident versus non-resident males in a territorial butterfly. Proc Biol Sci 2008; 274:1659-65. [PMID: 17472909 PMCID: PMC1914333 DOI: 10.1098/rspb.2007.0311] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Male–male competition over territorial ownership suggests that winning is associated with considerable benefits. In the speckled wood butterfly, Pararge aegeria, males fight over sunspot territories on the forest floor; winners gain sole residency of a sunspot, whereas losers patrol the forest in search of females. It is currently not known whether residents experience greater mating success than non-residents, or whether mating success is contingent on environmental conditions. Here we performed an experiment in which virgin females of P. aegeria were allowed to choose between a resident and a non-resident male in a large enclosure containing one territorial sunspot. Resident males achieved approximately twice as many matings as non-residents, primarily because matings were most often preceded by a female being discovered when flying through a sunspot. There was no evidence that territorial residents were more attractive per se, with females seen to reject them as often as non-residents. Furthermore, in the cases where females were discovered outside of the sunspot, they were just as likely to mate with non-residents as residents. We hypothesize that the proximate advantage of territory ownership is that light conditions in a large sunspot greatly increase the male's ability to detect and intercept passing receptive females.
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Affiliation(s)
- Martin Bergman
- Department of Zoology, Stockholm University, Stockholm, Sweden.
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Eberhard WG. Miniaturized orb-weaving spiders: behavioural precision is not limited by small size. Proc Biol Sci 2007; 274:2203-9. [PMID: 17609181 PMCID: PMC2706203 DOI: 10.1098/rspb.2007.0675] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The special problems confronted by very small animals in nervous system design that may impose limitations on their behaviour and evolution are reviewed. Previous attempts to test for such behavioural limitations have suffered from lack of detail in behavioural observations of tiny species and unsatisfactory measurements of their behavioural capacities. This study presents partial solutions to both problems. The orb-web construction behaviour of spiders provided data on the comparative behavioural capabilities of tiny animals in heretofore unparalleled detail; species ranged about five orders of magnitude in weight, from approximately 50-100mg down to some of the smallest spiders known (less than 0.005mg), whose small size is a derived trait. Previous attempts to quantify the 'complexity' of behaviour were abandoned in favour of using comparisons of behavioural imprecision in performing the same task. The prediction of the size limitation hypothesis that very small spiders would have a reduced ability to repeat one particular behaviour pattern precisely was not confirmed. The anatomical and physiological mechanisms by which these tiny animals achieve this precision and the possibility that they are more limited in the performance of higher-order behaviour patterns await further investigation.
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Affiliation(s)
- William G Eberhard
- Smithsonian Tropical Research Institute, and Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica.
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Merry JW, Morehouse NI, Yturralde K, Rutowski RL. The eyes of a patrolling butterfly: visual field and eye structure in the Orange Sulphur, Colias eurytheme (Lepidoptera, Pieridae). JOURNAL OF INSECT PHYSIOLOGY 2006; 52:240-8. [PMID: 16360167 DOI: 10.1016/j.jinsphys.2005.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 11/07/2005] [Accepted: 11/09/2005] [Indexed: 05/05/2023]
Abstract
Sensory information plays a critical role in determining an animal's behavior on both proximate and evolutionary timescales. Butterflies, like many other insects, use vision extensively over their lifetimes, and yet relatively little work has been published to date on their visual capabilities. We describe the visual system of a pierid butterfly, Colias eurytheme, with the ultimate goal of better understanding its role in shaping the behavior of this animal. We made several measurements: visual field dimensions, eye surface area, interommatidial angle (Deltaphi), facet diameter (D), and eye parameter (p). C. eurytheme had a large visual field and considerable regional variation in visual acuity, as inferred by Deltaphi and D. When compared to females, males had larger eye surface areas, smaller Deltaphi, and larger D in all regions except ventrally. Both sexes had proportionally large eye surface areas compared to other butterflies. Minimum p in males was small, indicating that some regions of their eyes may operate close to the diffraction limit. Finally, we found that both eye surface area and D scaled positively, but with negative allometry to body size. We discuss the relevance of these visual characteristics to the biology and behavior of C. eurytheme.
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Affiliation(s)
- Justin W Merry
- School of Life Sciences, Arizona State University, P.O. Box 874601, Tempe, AZ 85287-4601, USA.
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Werner YL, Seifan T. Eye size in geckos: Asymmetry, allometry, sexual dimorphism, and behavioral correlates. J Morphol 2006; 267:1486-500. [PMID: 17117406 DOI: 10.1002/jmor.10499] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The function of the vertebrate eye depends on its absolute size, and the size is presumably adapted to specific needs. We studied the variation of eye size at all levels, from intra-individual to inter-specific, in lid- less, spectacled, gecko lizards (Gekkonomorpha). We mea sured 1,408 museum specimens of 62 species, representing subfamilies Diplodactylinae, Gekkoninae, and Sphaerodactylinae. Intra-individually, eye size showed significant directional asymmetry in Stenodactylus sthenodactylus. A latitudinal study of six species confirmed that during postnatal ontogeny eye size undergoes conventional negative allometry; the slope is steeper among adults than among juveniles, expressing the need of juveniles for relatively larger eyes. Within species with sexual size dimorphism, commonly the larger sex possessed larger eyes in absolute terms but not relative to head-and-body length. Interspecifically, eye size showed negative allometry, with slope significantly steeper than those of intraspecific ontogenetic allometry, again expressing the need of juveniles for relatively larger eyes and showing that eye-size differences among species do not merely result from body-size differences. Finally, adult eye size varied interspecifically in correlation with parameters of behavioral ecology: eyes were significantly larger in nocturnal than in diurnal species, and significantly larger in cursorial than in scansorial species.
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Affiliation(s)
- Yehudah L Werner
- Department of Evolution, Systematics, and Ecology, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
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Soutar AR, Fullard JH. Nocturnal anti-predator adaptations in eared and earless Nearctic Lepidoptera. Behav Ecol 2004. [DOI: 10.1093/beheco/arh103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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