1
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Golian MJ, Friedman DA, Harrison M, McMahon DP, Buellesbach J. Chemical and transcriptomic diversity do not correlate with ascending levels of social complexity in the insect order Blattodea. Ecol Evol 2024; 14:e70063. [PMID: 39091327 PMCID: PMC11289792 DOI: 10.1002/ece3.70063] [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: 01/25/2024] [Revised: 06/21/2024] [Accepted: 07/11/2024] [Indexed: 08/04/2024] Open
Abstract
Eusocial insects, such as ants and termites, are characterized by high levels of coordinated social organization. This is contrasted by solitary insects that display more limited forms of collective behavior. It has been hypothesized that this gradient in sociobehavioral sophistication is positively correlated with chemical profile complexity, due to a potentially increased demand for diversity in chemical communication mechanisms in insects with higher levels of social complexity. However, this claim has rarely been assessed empirically. Here, we compare different levels of chemical and transcriptomic complexity in selected species of the order Blattodea that represent different levels of social organization, from solitary to eusocial. We primarily focus on cuticular hydrocarbon (CHC) complexity, since it has repeatedly been demonstrated that CHCs are key signaling molecules conveying a wide variety of chemical information in solitary as well as eusocial insects. We assessed CHC complexity and divergence between our studied taxa of different social complexity levels as well as the differentiation of their respective repertoires of CHC biosynthesis gene transcripts. Surprisingly, we did not find any consistent pattern of chemical complexity correlating with social complexity, nor did the overall chemical divergence or transcriptomic repertoire of CHC biosynthesis genes reflect on the levels of social organization. Our results challenge the assumption that increasing social complexity is generally reflected in more complex chemical profiles and point toward the need for a more cautious and differentiated view on correlating complexity on a chemical, genetic, and social level.
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Affiliation(s)
- Marek J. Golian
- Institute for Evolution & BiodiversityUniversity of MünsterMünsterGermany
| | - Daniel A. Friedman
- Department of Entomology & NematologyUniversity of California – DavisDavisCaliforniaUSA
| | - Mark Harrison
- Institute for Evolution & BiodiversityUniversity of MünsterMünsterGermany
| | - Dino P. McMahon
- Institute of Biology – Zoology, Freie Universität BerlinBerlinGermany
- Department for Materials and EnvironmentBAM Federal Institute for Materials Research and TestingBerlinGermany
| | - Jan Buellesbach
- Institute for Evolution & BiodiversityUniversity of MünsterMünsterGermany
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2
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Buellesbach J, Holze H, Schrader L, Liebig J, Schmitt T, Gadau J, Niehuis O. Genetic and genomic architecture of species-specific cuticular hydrocarbon variation in parasitoid wasps. Proc Biol Sci 2022; 289:20220336. [PMID: 35673870 PMCID: PMC9174729 DOI: 10.1098/rspb.2022.0336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cuticular hydrocarbons (CHCs) serve two fundamental functions in insects: protection against desiccation and chemical signalling. How the interaction of genes shapes CHC profiles, which are essential for insect survival, adaptation and reproductive success, is still poorly understood. Here we investigate the genetic and genomic basis of CHC biosynthesis and variation in parasitoid wasps of the genus Nasonia. We mapped 91 quantitative trait loci (QTL) explaining the variation of a total of 43 CHCs in F2 hybrid males from interspecific crosses between three Nasonia species. To identify candidate genes, we localized orthologues of CHC biosynthesis-related genes in the Nasonia genomes. We discovered multiple genomic regions where the location of QTL coincides with the location of CHC biosynthesis-related candidate genes. Most conspicuously, on a region close to the centromere of chromosome 1, multiple CHC biosynthesis-related candidate genes co-localize with several QTL explaining variation in methyl-branched alkanes. The genetic underpinnings behind this compound class are not well understood so far, despite their high potential for encoding chemical information as well as their prevalence in hymenopteran CHC profiles. Our study considerably extends our knowledge on the genetic architecture governing this important compound class, establishing a model for methyl-branched alkane genetics in the Hymenoptera in general.
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Affiliation(s)
- Jan Buellesbach
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149 Münster, Germany
| | - Henrietta Holze
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149 Münster, Germany
| | - Lukas Schrader
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149 Münster, Germany
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, PO Box 874701, Tempe, AZ 85287-4501, USA
| | - Thomas Schmitt
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Juergen Gadau
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149 Münster, Germany
| | - Oliver Niehuis
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), Albert Ludwig University of Freiburg, Hauptstr. 1, 79104 Freiburg, Germany
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3
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Wang Y, Sun W, Fleischmann S, Millar JG, Ruther J, Verhulst EC. Silencing Doublesex expression triggers three-level pheromonal feminization in Nasonia vitripennis males. Proc Biol Sci 2022; 289:20212002. [PMID: 35078369 PMCID: PMC8790373 DOI: 10.1098/rspb.2021.2002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/21/2021] [Indexed: 01/28/2023] Open
Abstract
Doublesex (Dsx) has a conserved function in controlling sexual morphological differences in insects, but our knowledge of its role in regulating sexual behaviour is primarily limited to Drosophila. Here, we show with the parasitoid wasp Nasonia vitripennis that males whose Dsx gene had been silenced (NvDsx-i) underwent a three-level pheromonal feminization: (i) NvDsx-i males were no longer able to attract females from a distance, owing to drastically reduced titres of the long-range sex pheromone; (ii) NvDsx-i males were courted by wild-type males as though they were females, which correlated with a lower abundance of alkenes in their cuticular hydrocarbon (CHC) profiles. Supplementation with realistic amounts of synthetic (Z)-9-hentriacontene (Z9C31), the most significantly reduced alkene in NvDsx-i males, to NvDsx-i males interrupted courtship by wild-type conspecific males. Supplementation of female CHC profiles with Z9C31 reduced courtship and mating attempts by wild-type males. These results prove that Z9C31 is crucial for sex discrimination in N. vitripennis; and (iii) Nvdsx-i males were hampered in eliciting female receptivity and thus experienced severely reduced mating success, suggesting that they are unable to produce the to-date unidentified oral aphrodisiac pheromone reported in N. vitripennis males. We conclude that Dsx is a multi-level key regulator of pheromone-mediated sexual communication in N. vitripennis.
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Affiliation(s)
- Yidong Wang
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, Building 107, 6708 PB Wageningen, Netherlands
| | - Weizhao Sun
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, Building 107, 6708 PB Wageningen, Netherlands
| | | | - Jocelyn G. Millar
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | - Joachim Ruther
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Eveline C. Verhulst
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, Building 107, 6708 PB Wageningen, Netherlands
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4
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Legan AW, Jernigan CM, Miller SE, Fuchs MF, Sheehan MJ. Expansion and Accelerated Evolution of 9-Exon Odorant Receptors in Polistes Paper Wasps. Mol Biol Evol 2021; 38:3832-3846. [PMID: 34151983 PMCID: PMC8383895 DOI: 10.1093/molbev/msab023] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Independent origins of sociality in bees and ants are associated with independent expansions of particular odorant receptor (OR) gene subfamilies. In ants, one clade within the OR gene family, the 9-exon subfamily, has dramatically expanded. These receptors detect cuticular hydrocarbons (CHCs), key social signaling molecules in insects. It is unclear to what extent 9-exon OR subfamily expansion is associated with the independent evolution of sociality across Hymenoptera, warranting studies of taxa with independently derived social behavior. Here, we describe OR gene family evolution in the northern paper wasp, Polistes fuscatus, and compare it to four additional paper wasp species spanning ∼40 million years of evolutionary divergence. We find 200 putatively functional OR genes in P. fuscatus, matching predictions from neuroanatomy, and more than half of these are in the 9-exon subfamily. Most OR gene expansions are tandemly arrayed at orthologous loci in Polistes genomes, and microsynteny analysis shows species-specific gain and loss of 9-exon ORs within tandem arrays. There is evidence of episodic positive diversifying selection shaping ORs in expanded subfamilies. Values of omega (dN/dS) are higher among 9-exon ORs compared to other OR subfamilies. Within the Polistes OR gene tree, branches in the 9-exon OR clade experience relaxed negative (relaxed purifying) selection relative to other branches in the tree. Patterns of OR evolution within Polistes are consistent with 9-exon OR function in CHC perception by combinatorial coding, with both natural selection and neutral drift contributing to interspecies differences in gene copy number and sequence.
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Affiliation(s)
- Andrew W Legan
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Christopher M Jernigan
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Sara E Miller
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Matthieu F Fuchs
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Michael J Sheehan
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
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5
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Holze H, Schrader L, Buellesbach J. Advances in deciphering the genetic basis of insect cuticular hydrocarbon biosynthesis and variation. Heredity (Edinb) 2021; 126:219-234. [PMID: 33139902 PMCID: PMC8027674 DOI: 10.1038/s41437-020-00380-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 02/01/2023] Open
Abstract
Cuticular hydrocarbons (CHCs) have two fundamental functions in insects. They protect terrestrial insects against desiccation and serve as signaling molecules in a wide variety of chemical communication systems. It has been hypothesized that these pivotal dual traits for adaptation to both desiccation and signaling have contributed to the considerable evolutionary success of insects. CHCs have been extensively studied concerning their variation, behavioral impact, physiological properties, and chemical compositions. However, our understanding of the genetic underpinnings of CHC biosynthesis has remained limited and mostly biased towards one particular model organism (Drosophila). This rather narrow focus has hampered the establishment of a comprehensive view of CHC genetics across wider phylogenetic boundaries. This review attempts to integrate new insights and recent knowledge gained in the genetics of CHC biosynthesis, which is just beginning to incorporate work on more insect taxa beyond Drosophila. It is intended to provide a stepping stone towards a wider and more general understanding of the genetic mechanisms that gave rise to the astonishing diversity of CHC compounds across different insect taxa. Further research in this field is encouraged to aim at better discriminating conserved versus taxon-specific genetic elements underlying CHC variation. This will be instrumental in greatly expanding our knowledge of the origins and variation of genes governing the biosynthesis of these crucial phenotypic traits that have greatly impacted insect behavior, physiology, and evolution.
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Affiliation(s)
- Henrietta Holze
- Molecular Evolution and Sociobiology Group, Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149, Münster, Germany
| | - Lukas Schrader
- Molecular Evolution and Sociobiology Group, Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149, Münster, Germany
| | - Jan Buellesbach
- Molecular Evolution and Sociobiology Group, Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, DE-48149, Münster, Germany.
- Department of Environmental Science, Policy, and Management, University of California-Berkeley, 130 Mulford Hall #3114, Berkeley, CA, 94720-3114, USA.
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6
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Byers KJRP, Darragh K, Fernanda Garza S, Abondano Almeida D, Warren IA, Rastas PMA, Merrill RM, Schulz S, McMillan WO, Jiggins CD. Clustering of loci controlling species differences in male chemical bouquets of sympatric Heliconius butterflies. Ecol Evol 2021; 11:89-107. [PMID: 33437416 PMCID: PMC7790645 DOI: 10.1002/ece3.6947] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/23/2022] Open
Abstract
The degree to which loci promoting reproductive isolation cluster in the genome-that is, the genetic architecture of reproductive isolation-can influence the tempo and mode of speciation. Tight linkage between these loci can facilitate speciation in the face of gene flow. Pheromones play a role in reproductive isolation in many Lepidoptera species, and the role of endogenously produced compounds as secondary metabolites decreases the likelihood of pleiotropy associated with many barrier loci. Heliconius butterflies use male sex pheromones to both court females (aphrodisiac wing pheromones) and ward off male courtship (male-transferred antiaphrodisiac genital pheromones), and it is likely that these compounds play a role in reproductive isolation between Heliconius species. Using a set of backcross hybrids between H. melpomene and H. cydno, we investigated the genetic architecture of putative male pheromone compound production. We found a set of 40 significant quantitative trait loci (QTL) representing 33 potential pheromone compounds. QTL clustered significantly on two chromosomes, chromosome 8 for genital compounds and chromosome 20 for wing compounds, and chromosome 20 was enriched for potential pheromone biosynthesis genes. There was minimal overlap between pheromone QTL and known QTL for mate choice and color pattern. Nonetheless, we did detect linkage between a QTL for wing androconial area and optix, a color pattern locus known to play a role in reproductive isolation in these species. This tight clustering of putative pheromone loci might contribute to coincident reproductive isolating barriers, facilitating speciation despite ongoing gene flow.
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Affiliation(s)
- Kelsey J. R. P. Byers
- Department of ZoologyUniversity of CambridgeCambridgeUK
- Smithsonian Tropical Research InstitutePanamaPanama
- Present address:
Department of Cell and Developmental BiologyJohn Innes CentreNorwichUK
| | - Kathy Darragh
- Department of ZoologyUniversity of CambridgeCambridgeUK
- Smithsonian Tropical Research InstitutePanamaPanama
- Present address:
Department of Evolution and EcologyUniversity of California DavisDavisCAUSA
| | - Sylvia Fernanda Garza
- Smithsonian Tropical Research InstitutePanamaPanama
- Present address:
Department of Collective BehaviourMax Planck Institute of Animal BehaviourKonstanzGermany
| | - Diana Abondano Almeida
- Smithsonian Tropical Research InstitutePanamaPanama
- Present address:
Institute for Ecology, Evolution and DiversityGoethe UniversitätFrankfurtGermany
| | - Ian A. Warren
- Department of ZoologyUniversity of CambridgeCambridgeUK
| | | | - Richard M. Merrill
- Smithsonian Tropical Research InstitutePanamaPanama
- Division of Evolutionary BiologyLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Stefan Schulz
- Institute of Organic ChemistryDepartment of Life SciencesTechnische Universität BraunschweigBraunschweigGermany
| | | | - Chris D. Jiggins
- Department of ZoologyUniversity of CambridgeCambridgeUK
- Smithsonian Tropical Research InstitutePanamaPanama
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7
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Walsh J, Pontieri L, d'Ettorre P, Linksvayer TA. Ant cuticular hydrocarbons are heritable and associated with variation in colony productivity. Proc Biol Sci 2020; 287:20201029. [PMID: 32517627 DOI: 10.1098/rspb.2020.1029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In social insects, cuticular hydrocarbons function in nest-mate recognition and also provide a waxy barrier against desiccation, but basic evolutionary features, including the heritability of hydrocarbon profiles and how they are shaped by natural selection are largely unknown. We used a new pharaoh ant (Monomorium pharaonis) laboratory mapping population to estimate the heritability of individual cuticular hydrocarbons, genetic correlations between hydrocarbons, and fitness consequences of phenotypic variation in the hydrocarbons. Individual hydrocarbons had low to moderate estimated heritability, indicating that some compounds provide more information about genetic relatedness and can also better respond to natural selection. Strong genetic correlations between compounds are likely to constrain independent evolutionary trajectories, which is expected, given that many hydrocarbons share biosynthetic pathways. Variation in cuticular hydrocarbons was associated with variation in colony productivity, with some hydrocarbons experiencing strong directional selection. Altogether, this study builds on our knowledge of the genetic architecture of the social insect hydrocarbon profile and indicates that hydrocarbon variation is shaped by natural selection.
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Affiliation(s)
- Justin Walsh
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Luigi Pontieri
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology (LEEC), University of Paris 13, Sorbonne Paris Cité, France
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8
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Wang GH, Berdy BM, Velasquez O, Jovanovic N, Alkhalifa S, Minbiole KPC, Brucker RM. Changes in Microbiome Confer Multigenerational Host Resistance after Sub-toxic Pesticide Exposure. Cell Host Microbe 2020; 27:213-224.e7. [PMID: 32023487 DOI: 10.1016/j.chom.2020.01.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/26/2019] [Accepted: 01/15/2020] [Indexed: 01/04/2023]
Abstract
The gut is a first point of contact with ingested xenobiotics, where chemicals are metabolized directly by the host or microbiota. Atrazine is a widely used pesticide, but the role of the microbiome metabolism of this xenobiotic and the impact on host responses is unclear. We exposed successive generations of the wasp Nasonia vitripennis to subtoxic levels of atrazine and observed changes in the structure and function of the gut microbiome that conveyed atrazine resistance. This microbiome-mediated resistance was maternally inherited and increased over successive generations, while also heightening the rate of host genome selection. The rare gut bacteria Serratia marcescens and Pseudomonas protegens contributed to atrazine metabolism. Both of these bacteria contain genes that are linked to atrazine degradation and were sufficient to confer resistance in experimental wasp populations. Thus, pesticide exposure causes functional, inherited changes in the microbiome that should be considered when assessing xenobiotic exposure and as potential countermeasures to toxicity.
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Affiliation(s)
- Guan-Hong Wang
- Rowland Institute at Harvard University, Cambridge, MA 02142, USA
| | - Brittany M Berdy
- Rowland Institute at Harvard University, Cambridge, MA 02142, USA
| | - Olivia Velasquez
- Rowland Institute at Harvard University, Cambridge, MA 02142, USA
| | - Nikola Jovanovic
- Rowland Institute at Harvard University, Cambridge, MA 02142, USA
| | - Saleh Alkhalifa
- Department of Chemistry, Villanova University, Villanova, PA 19085, USA
| | | | - Robert M Brucker
- Rowland Institute at Harvard University, Cambridge, MA 02142, USA.
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9
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Distinct Roles of Cuticular Aldehydes as Pheromonal Cues in Two Cotesia Parasitoids. J Chem Ecol 2020; 46:128-137. [PMID: 31907752 DOI: 10.1007/s10886-019-01142-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/04/2019] [Accepted: 12/20/2019] [Indexed: 10/25/2022]
Abstract
Cuticular compounds (CCs) that cover the surface of insects primarily serve as protection against entomopathogens, harmful substances, and desiccation. However, CCs may also have secondary signaling functions. By studying the role of CCs in intraspecific interactions, we may advance our understanding of the evolution of pheromonal communication in insects. We previously found that the gregarious parasitoid, Cotesia glomerata (L.), uses heptanal as a repellent pheromone to help avoid mate competition among sibling males, whereas another cuticular aldehyde, nonanal, is part of the female-produced attractive sex pheromone. Here, we show that the same aldehydes have different pheromonal functions in a related solitary parasitoid, Cotesia marginiventris (Cresson). Heptanal enhances the attractiveness of the female's sex pheromone, whereas nonanal does not affect a female's attractiveness. Hence, these common aldehydes are differentially used by the two Cotesia species to mediate, synergistically, the attractiveness of the main constituents of their respective sex pheromones. The specificity of the complete sex pheromone blend is apparently regulated by two specific, less volatile compounds, which evoke strong electroantennographic (EAG) responses. This is the first demonstration that volatile CCs have evolved distinct pheromonal functions to aid divergent mating strategies in closely related species. We discuss the possibility that additional compounds are involved in attraction and that, like the aldehydes, they are likely oxidative products of unsaturated cuticular hydrocarbons.
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10
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Mair MM, Ruther J. Chemical Ecology of the Parasitoid Wasp Genus Nasonia (Hymenoptera, Pteromalidae). Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00184] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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11
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Semmelmann F, Kabeya N, Malcicka M, Bruckmann A, Broschwitz B, Straub K, Merkl R, Monroig O, Sterner R, Ruther J, Ellers J. Functional characterisation of two Δ12-desaturases demonstrates targeted production of linoleic acid as pheromone precursor in Nasonia. ACTA ACUST UNITED AC 2019; 222:jeb.201038. [PMID: 31019064 DOI: 10.1242/jeb.201038] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/18/2019] [Indexed: 01/08/2023]
Abstract
Insect pheromones are often derived from fatty acid metabolism. Fatty acid desaturases, enzymes introducing double bonds into fatty acids, are crucial for the biosynthesis of these chemical signals. Δ12-desaturases catalyse the biosynthesis of linoleic acid by introducing a second double bond into oleic acid, but have been identified in only a few animal species. Here, we report the functional characterisation of two Δ12-desaturases, Nvit_D12a and Nvit_D12b, from the parasitic wasp Nasonia vitripennis. We demonstrate that Nvit_D12a is expressed in the rectal vesicle of males where they produce a linoleic acid-derived sex pheromone to attract virgin females. 13C-labelling experiments with Urolepis rufipes, a closely related species belonging to the 'Nasonia group', revealed that females, but not males, are able to synthesise linoleic acid. U. rufipes males produce an isoprenoid sex pheromone in the same gland and do not depend on linoleic acid for pheromone production. This suggests that Δ12-desaturases are common in the 'Nasonia group', but acquired a specialised function in chemical communication of those species that use linoleic acid as a pheromone precursor. Phylogenetic analysis suggests that insect Δ12-desaturases have evolved repeatedly from Δ9-desaturases in different insect taxa. Hence, insects have developed a way to produce linoleic acid independent of the omega desaturase subfamily which harbours all of the eukaryotic Δ12-desaturases known so far.
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Affiliation(s)
- Florian Semmelmann
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Naoki Kabeya
- Department of Aquatic Bioscience, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, 113-8657 Tokyo, Japan
| | - Miriama Malcicka
- Department of Ecological Sciences, Vrije Universiteit, Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Astrid Bruckmann
- Institute of Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Bastian Broschwitz
- Institute of Zoology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Kristina Straub
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Rainer Merkl
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Oscar Monroig
- Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes 12595, Spain
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Joachim Ruther
- Institute of Zoology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Jacintha Ellers
- Department of Ecological Sciences, Vrije Universiteit, Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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12
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Bien T, Gadau J, Schnapp A, Yew JY, Sievert C, Dreisewerd K. Detection of very long-chain hydrocarbons by laser mass spectrometry reveals novel species-, sex-, and age-dependent differences in the cuticular profiles of three Nasonia species. Anal Bioanal Chem 2019; 411:2981-2993. [PMID: 30957203 DOI: 10.1007/s00216-019-01736-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/22/2019] [Accepted: 03/01/2019] [Indexed: 12/27/2022]
Abstract
Long-chain cuticular hydrocarbons (CHC) are key components of chemical communication in many insects. The parasitoid jewel wasps from the genus Nasonia use their CHC profile as sex pheromone and for species recognition. The standard analytical tool to analyze CHC is gas chromatography coupled with mass spectrometric detection (GC/MS). This method reliably identifies short- to long-chain alkanes and alkenes, but CHC with more than 40 carbon atoms are usually not detected. Here, we applied two laser mass spectrometry (MS) techniques, namely direct laser desorption/ionization (d)LDI and silver-assisted (Ag-)LDI MS, respectively, to analyze CHC profiles of N. vitripennis, N. giraulti, and N. longicornis directly from the cuticle or extracts. Furthermore, we applied direct analysis in real-time (DART) MS as another orthogonal technique for extracts. The three methods corroborated previous results based on GC/MS, i.e., the production of CHC with carbon numbers between C25 and C40. However, we discovered a novel series of long-chain CHC ranging from C41 to C51/C52. Additionally, several previously unreported singly and doubly unsaturated alkenes in the C31-C39 range were found. Use of principal component analysis (PCA) revealed that the composition of the newly discovered CHC varies significantly between species, sex, and age of the animals. Our study adds to the growing literature on the presence of very long-chain CHC in insects and hints at putative roles in insect communication. Graphical abstract.
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Affiliation(s)
- Tanja Bien
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149, Münster, Germany.,Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Jürgen Gadau
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, 48149, Münster, Germany.
| | - Andreas Schnapp
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149, Münster, Germany
| | - Joanne Y Yew
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, 1993 East-West Road, Honolulu, HI, 96822, USA
| | - Christian Sievert
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, 48149, Münster, Germany
| | - Klaus Dreisewerd
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149, Münster, Germany. .,Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany.
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The Genetics of Mating Song Evolution Underlying Rapid Speciation: Linking Quantitative Variation to Candidate Genes for Behavioral Isolation. Genetics 2019; 211:1089-1104. [PMID: 30647070 DOI: 10.1534/genetics.118.301706] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/11/2019] [Indexed: 02/07/2023] Open
Abstract
Differences in mating behaviors evolve early during speciation, eventually contributing to reproductive barriers between species. Knowledge of the genetic and genomic basis of these behaviors is therefore integral to a causal understanding of speciation. Acoustic behaviors are often part of the mating ritual in animal species. The temporal rhythms of mating songs are notably species-specific in many vertebrates and arthropods and often underlie assortative mating. Despite discoveries of mutations that disrupt the temporal rhythm of these songs, we know surprisingly little about genes affecting naturally occurring variation in the temporal pattern of singing behavior. In the rapidly speciating Hawaiian cricket genus Laupala, the striking species variation in song rhythms constitutes a behavioral barrier to reproduction between species. Here, we mapped the largest-effect locus underlying interspecific variation in song rhythm between two Laupala species to a narrow genomic region, wherein we find no known candidate genes affecting song temporal rhythm in Drosophila Whole-genome sequencing, gene prediction, and functional annotation of this region reveal an exciting and promising candidate gene, the putative cyclic nucleotide-gated ion channel-like gene, for natural variation in mating behavior. Identification and molecular characterization of the candidate gene reveals a nonsynonymous mutation in a conserved binding domain, suggesting that ion channels are important targets of selection on rhythmic signaling during establishment of behavioral isolation and rapid speciation.
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14
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Xue HJ, Segraves KA, Wei J, Zhang B, Nie RE, Li WZ, Yang XK. Chemically mediated sexual signals restrict hybrid speciation in a flea beetle. Behav Ecol 2018. [DOI: 10.1093/beheco/ary105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Huai-Jun Xue
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Kari A Segraves
- Department of Biology, Syracuse University, Syracuse, NY, USA
- Archbold Biological Station, Venus, FL, USA
| | - Jing Wei
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bin Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Rui-E Nie
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Wen-Zhu Li
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xing-Ke Yang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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15
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Buellesbach J, Vetter SG, Schmitt T. Differences in the reliance on cuticular hydrocarbons as sexual signaling and species discrimination cues in parasitoid wasps. Front Zool 2018; 15:22. [PMID: 29760760 PMCID: PMC5946414 DOI: 10.1186/s12983-018-0263-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 04/04/2018] [Indexed: 01/02/2023] Open
Abstract
Background Cuticular hydrocarbons (CHC) have been documented to play crucial roles as species- and sex-specific cues in the chemical communication systems of a wide variety of insects. However, whether they are sufficient by themselves as the sole cue triggering sexual behavior as well as preference of con- over heterospecific mating partners is rarely assessed. We conducted behavioral assays in three representative species of parasitoid wasps (Hymenoptera: Pteromalidae) to determine their reliance on CHC as species-specific sexual signaling cues. Results We found a surprising degree of either unspecific or insufficient sexual signaling when CHC are singled out as recognition cues. Most strikingly, the cosmopolitan species Nasonia vitripennis, expected to experience enhanced selection pressure to discriminate against other co-occurring parasitoids, did not discriminate against CHC of a partially sympatric species from another genus, Trichomalopsis sarcophagae. Focusing on the latter species, in turn, it became apparent that CHC are even insufficient as the sole cue triggering conspecific sexual behavior, hinting at the requirement of additional, synergistic sexual cues particularly important in this species. Finally, in the phylogenetically and chemically most divergent species Muscidifurax uniraptor, we intriguingly found both CHC-based sexual signaling as well as species discrimination behavior intact although this species is naturally parthenogenetic with sexual reproduction only occurring under laboratory conditions. Conclusions Our findings implicate a discrepancy in the reliance on and specificity of CHC as sexual cues in our tested parasitioid wasps. CHC profiles were not sufficient for unambiguous discrimination and preference behavior, as demonstrated by clear cross-attraction between some of our tested wasp genera. Moreover, we could show that only in T. sarcophagae, additional behavioral cues need to be present for triggering natural mating behavior, hinting at an interesting shift in signaling hierarchy in this particular species. This demonstrates the importance of integrating multiple, potentially complementary signaling modalities in future studies for a better understanding of their individual contributions to natural sexual communication behavior. Electronic supplementary material The online version of this article (10.1186/s12983-018-0263-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jan Buellesbach
- 1Department of Science, Policy, & Management, University of California, 130 Mulford Hall, Berkeley, CA 94720-3114 USA.,4Department of Evolutionary Biology and Animal Ecology, Faculty of Biology, University of Freiburg, Hauptstr. 1, D-79104 Freiburg, Germany.,5Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Albertstr. 19 A, D-79104 Freiburg, Germany
| | - Sebastian G Vetter
- 2Research Institute of Wildlife Ecology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstr. 1, A-1160 Vienna, Austria.,4Department of Evolutionary Biology and Animal Ecology, Faculty of Biology, University of Freiburg, Hauptstr. 1, D-79104 Freiburg, Germany
| | - Thomas Schmitt
- 3Department of Animal Ecology and Tropical Biology, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.,4Department of Evolutionary Biology and Animal Ecology, Faculty of Biology, University of Freiburg, Hauptstr. 1, D-79104 Freiburg, Germany.,5Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Albertstr. 19 A, D-79104 Freiburg, Germany
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16
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Quantitative Trait Locus Analysis of Mating Behavior and Male Sex Pheromones in Nasonia Wasps. G3-GENES GENOMES GENETICS 2016; 6:1549-62. [PMID: 27172207 PMCID: PMC4889652 DOI: 10.1534/g3.116.029074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A major focus in speciation genetics is to identify the chromosomal regions and genes that reduce hybridization and gene flow. We investigated the genetic architecture of mating behavior in the parasitoid wasp species pair Nasonia giraulti and Nasonia oneida that exhibit strong prezygotic isolation. Behavioral analysis showed that N. oneida females had consistently higher latency times, and broke off the mating sequence more often in the mounting stage when confronted with N. giraulti males compared with males of their own species. N. oneida males produce a lower quantity of the long-range male sex pheromone (4R,5S)-5-hydroxy-4-decanolide (RS-HDL). Crosses between the two species yielded hybrid males with various pheromone quantities, and these males were used in mating trials with females of either species to measure female mate discrimination rates. A quantitative trait locus (QTL) analysis involving 475 recombinant hybrid males (F2), 2148 reciprocally backcrossed females (F3), and a linkage map of 52 equally spaced neutral single nucleotide polymorphism (SNP) markers plus SNPs in 40 candidate mating behavior genes revealed four QTL for male pheromone amount, depending on partner species. Our results demonstrate that the RS-HDL pheromone plays a role in the mating system of N. giraulti and N. oneida, but also that additional communication cues are involved in mate choice. No QTL were found for female mate discrimination, which points at a polygenic architecture of female choice with strong environmental influences.
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17
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Pascoal S, Mendrok M, Mitchell C, Wilson AJ, Hunt J, Bailey NW. Sexual selection and population divergence I: The influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oceanicus). Evolution 2016; 70:82-97. [PMID: 26678168 DOI: 10.1111/evo.12839] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/20/2015] [Accepted: 11/21/2015] [Indexed: 11/29/2022]
Abstract
Debates about how coevolution of sexual traits and preferences might promote evolutionary diversification have permeated speciation research for over a century. Recent work demonstrates that the expression of such traits can be sensitive to variation in the social environment. Here, we examined social flexibility in a sexually selected male trait-cuticular hydrocarbon (CHC) profiles-in the field cricket Teleogryllus oceanicus and tested whether population genetic divergence predicts the extent or direction of social flexibility in allopatric populations. We manipulated male crickets' social environments during rearing and then characterized CHC profiles. CHC signatures varied considerably across populations and also in response to the social environment, but our prediction that increased social flexibility would be selected in more recently founded populations exposed to fluctuating demographic environments was unsupported. Furthermore, models examining the influence of drift and selection failed to support a role of sexual selection in driving population divergence in CHC profiles. Variation in social environments might alter the dynamics of sexual selection, but our results align with theoretical predictions that the role social flexibility plays in modulating evolutionary divergence depends critically on whether responses to variation in the social environment are homogeneous across populations, or whether gene by social environment interactions occur.
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Affiliation(s)
- Sonia Pascoal
- Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, United Kingdom
| | - Magdalena Mendrok
- Institute of Environmental Sciences, Jagellonian University, Gronostajova 7, Kraków, 30-387, Poland
| | - Christopher Mitchell
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW, 2751, Australia.,Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Cornwall, TR10 9EZ, United Kingdom
| | - Alastair J Wilson
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Cornwall, TR10 9EZ, United Kingdom
| | - John Hunt
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Cornwall, TR10 9EZ, United Kingdom
| | - Nathan W Bailey
- Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, United Kingdom.
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18
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Xue HJ, Wei JN, Magalhães S, Zhang B, Song KQ, Liu J, Li WZ, Yang XK. Contact pheromones of 2 sympatric beetles are modified by the host plant and affect mate choice. Behav Ecol 2016. [DOI: 10.1093/beheco/arv238] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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19
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Insect Cuticular Hydrocarbons as Dynamic Traits in Sexual Communication. INSECTS 2015; 6:732-42. [PMID: 26463413 PMCID: PMC4598662 DOI: 10.3390/insects6030732] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/10/2015] [Accepted: 07/29/2015] [Indexed: 11/17/2022]
Abstract
Recent research has demonstrated extensive within-species variation in pheromone expression in insect species, contrary to the view that pheromones are largely invariant within species. In fact, many studies on insect cuticular hydrocarbons (CHCs) show that pheromones can be highly dynamic traits that can express significant short-term plasticity across both abiotic and social environments. It is likely that this variability in CHC expression contributes to their important role in sexual signaling and mate choice. In this review, I discuss CHC plasticity and how this might influence sexual communication. I also highlight two important avenues for future research: examining plasticity in how individuals respond to CHC signals, and testing how sexual communication varies across abiotic and social environments.
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20
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Blaul B, Steinbauer R, Merkl P, Merkl R, Tschochner H, Ruther J. Oleic acid is a precursor of linoleic acid and the male sex pheromone in Nasonia vitripennis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 51:33-40. [PMID: 24874439 DOI: 10.1016/j.ibmb.2014.05.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/16/2014] [Accepted: 05/17/2014] [Indexed: 06/03/2023]
Abstract
Linoleic acid (C18:2(Δ9,12), LA) is crucial for many cell functions in organisms. It has long been a paradigm that animals are unable to synthesize LA from oleic acid (C18:1(Δ9), OA) because they were thought to miss Δ(12)-desaturases for inserting a double bound at the Δ(12)-position. Today it is clear that this is not true for all animals because some insects and other invertebrates have been demonstrated to synthesize LA. However, the ability to synthesize LA is known in only five insect orders and no examples have been reported so far in the Hymenoptera. LA plays a particular role in the parasitic wasp Nasonia vitripennis, because it is the precursor of the male sex pheromone consisting of (4R,5R)- and (4R,5S)-5-hydroxy-4-decanolides. Here we demonstrate by stable isotope labeling that N. vitripennis is able to incorporate externally applied fully (13)C-labeled OA into the male sex pheromone suggesting that they convert initially OA into LA. To verify this assumption, we produced fly hosts (Lucilia caesar) which were experimentally enriched in (13)C-labeled OA and reared male parasitoids on these hosts. Chemical analysis of transesterified lipid raw extracts from hosts and parasitoids revealed that N. vitripennis but not L. caesar contained (13)C-labeled LA methyl ester. Furthermore, male wasps from the manipulated hosts produced significant amounts of (13)C-labeled sex pheromone. These results suggest that N. vitripennis possesses a Δ(12)-desaturase. The additional fitness relevant function as pheromone precursor might have favored the evolution of LA biosynthesis in N. vitripennis to make the wasps independent of the formerly essential nutrient.
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Affiliation(s)
- Birgit Blaul
- University of Regensburg, Institute of Zoology, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - Robert Steinbauer
- University of Regensburg, Institute of Biochemistry, Genetic & Microbiology, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - Philipp Merkl
- University of Regensburg, Institute of Biochemistry, Genetic & Microbiology, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - Rainer Merkl
- University of Regensburg, Institute of Biophysics & Physical Biochemistry, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - Herbert Tschochner
- University of Regensburg, Institute of Biochemistry, Genetic & Microbiology, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - Joachim Ruther
- University of Regensburg, Institute of Zoology, Universitätsstraße 31, 93053 Regensburg, Germany.
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21
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Buellesbach J, Gadau J, Beukeboom LW, Echinger F, Raychoudhury R, Werren JH, Schmitt T. Cuticular hydrocarbon divergence in the jewel wasp Nasonia: evolutionary shifts in chemical communication channels? J Evol Biol 2013; 26:2467-78. [PMID: 24118588 DOI: 10.1111/jeb.12242] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 12/29/2022]
Abstract
The evolution and maintenance of intraspecific communication channels constitute a key feature of chemical signalling and sexual communication. However, how divergent chemical communication channels evolve while maintaining their integrity for both sender and receiver is poorly understood. In this study, we compare male and female cuticular hydrocarbon (CHC) profiles in the jewel wasp genus Nasonia, analyse their chemical divergence and investigate their role as species-specific sexual signalling cues. Males and females of all four Nasonia species showed unique, nonoverlapping CHC profiles unambiguously separating them. Surprisingly, male and female phylogenies based on the chemical distances between their CHC profiles differed dramatically, where only male CHC divergence parallels the molecular phylogeny of Nasonia. In particular, N. giraulti female CHC profiles were the most divergent from all other species and very different from its most closely related sibling species N. oneida. Furthermore, although our behavioural assays indicate that female CHC profiles can generally be perceived as sexual cues attracting males in Nasonia, this function has apparently been lost in the highly divergent female N. giraulti CHC profiles. Curiously, N. giraulti males are still attracted to heterospecific, but not to conspecific female CHC profiles. We suggest that this striking discrepancy has been caused by an extensive evolutionary shift in female N. giraulti CHC profiles, which are no longer used as conspecific recognition cues. Our study constitutes the first report of an apparent abandonment of a sexual recognition cue that the receiver did not adapt to.
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Affiliation(s)
- J Buellesbach
- Department of Evolutionary Biology and Animal Ecology, Faculty of Biology, University of Freiburg, Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
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22
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Brucker RM, Bordenstein SR. The hologenomic basis of speciation: gut bacteria cause hybrid lethality in the genus Nasonia. Science 2013; 341:667-9. [PMID: 23868918 DOI: 10.1126/science.1240659] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Although the gut microbiome influences numerous aspects of organismal fitness, its role in animal evolution and the origin of new species is largely unknown. Here we present evidence that beneficial bacterial communities in the guts of closely related species of the genus Nasonia form species-specific phylosymbiotic assemblages that cause lethality in interspecific hybrids. Bacterial constituents and abundance are irregular in hybrids relative to parental controls, and antibiotic curing of the gut bacteria significantly rescues hybrid survival. Moreover, feeding bacteria to germ-free hybrids reinstates lethality and recapitulates the expression of innate immune genes observed in conventionally reared hybrids. We conclude that in this animal complex, the gut microbiome and host genome represent a coadapted "hologenome" that breaks down during hybridization, promoting hybrid lethality and assisting speciation.
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Affiliation(s)
- Robert M Brucker
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.
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23
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Niehuis O, Buellesbach J, Gibson JD, Pothmann D, Hanner C, Mutti NS, Judson AK, Gadau J, Ruther J, Schmitt T. Behavioural and genetic analyses of Nasonia shed light on the evolution of sex pheromones. Nature 2013; 494:345-8. [PMID: 23407492 DOI: 10.1038/nature11838] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 12/12/2012] [Indexed: 01/28/2023]
Abstract
Sex pheromones play a pivotal role in the communication of many sexually reproducing organisms. Accordingly, speciation is often accompanied by pheromone diversification enabling proper mate finding and recognition. Current theory implies that chemical signals are under stabilizing selection by the receivers who thereby maintain the integrity of the signals. How the tremendous diversity of sex pheromones seen today evolved is poorly understood. Here we unravel the genetics of a newly evolved pheromone phenotype in wasps and present results from behavioural experiments indicating how the evolution of a new pheromone component occurred in an established sender-receiver system. We show that male Nasonia vitripennis evolved an additional pheromone compound differing only in its stereochemistry from a pre-existing one. Comparative behavioural studies show that conspecific females responded neutrally to the new pheromone phenotype when it evolved. Genetic mapping and gene knockdown show that a cluster of three closely linked genes accounts for the ability to produce this new pheromone phenotype. Our data suggest that new pheromone compounds can persist in a sender's population, without being selected against by the receiver and without the receiver having a pre-existing preference for the new pheromone phenotype, by initially remaining unperceived. Our results thus contribute valuable new insights into the evolutionary mechanisms underlying the diversification of sex pheromones. Furthermore, they indicate that the genetic basis of new pheromone compounds can be simple, allowing them to persist long enough in a population for receivers to evolve chemosensory adaptations for their exploitation.
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Affiliation(s)
- Oliver Niehuis
- Centre for Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, 53113 Bonn, Germany.
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24
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Fine-scale mapping of the Nasonia genome to chromosomes using a high-density genotyping microarray. G3-GENES GENOMES GENETICS 2013; 3:205-15. [PMID: 23390597 PMCID: PMC3564981 DOI: 10.1534/g3.112.004739] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 11/30/2012] [Indexed: 01/16/2023]
Abstract
Nasonia, a genus of four closely related parasitoid insect species, is a model system for genetic research. Their haplodiploid genetics (haploid males and diploid females) and interfertile species are advantageous for the genetic analysis of complex traits and the genetic basis of species differences. A fine-scale genomic map is an important tool for advancing genetic studies in this system. We developed and used a hybrid genotyping microarray to generate a high-resolution genetic map that covers 79% of the sequenced genome of Nasonia vitripennis. The microarray is based on differential hybridization of species-specific oligos between N. vitripennis and Nasonia giraulti at more than 20,000 markers spanning the Nasonia genome. The map places 729 scaffolds onto the five linkage groups of Nasonia, including locating many smaller scaffolds that would be difficult to map by other means. The microarray was used to characterize 26 segmental introgression lines containing chromosomal regions from one species in the genetic background of another. These segmental introgression lines have been used for rapid screening and mapping of quantitative trait loci involved in species differences. Finally, the microarray is extended to bulk-segregant analysis and genotyping of other Nasonia species combinations. These resources should further expand the usefulness of Nasonia for studies of the genetic basis and architecture of complex traits and speciation.
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25
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Brucker RM, Funkhouser LJ, Setia S, Pauly R, Bordenstein SR. Insect Innate Immunity Database (IIID): an annotation tool for identifying immune genes in insect genomes. PLoS One 2012; 7:e45125. [PMID: 22984621 PMCID: PMC3440344 DOI: 10.1371/journal.pone.0045125] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/14/2012] [Indexed: 01/07/2023] Open
Abstract
The innate immune system is an ancient component of host defense. Since innate immunity pathways are well conserved throughout many eukaryotes, immune genes in model animals can be used to putatively identify homologous genes in newly sequenced genomes of non-model organisms. With the initiation of the “i5k” project, which aims to sequence 5,000 insect genomes by 2016, many novel insect genomes will soon become publicly available, yet few annotation resources are currently available for insects. Thus, we developed an online tool called the Insect Innate Immunity Database (IIID) to provide an open access resource for insect immunity and comparative biology research (http://www.vanderbilt.edu/IIID). The database provides users with simple exploratory tools to search the immune repertoires of five insect models (including Nasonia), spanning three orders, for specific immunity genes or genes within a particular immunity pathway. As a proof of principle, we used an initial database with only four insect models to annotate potential immune genes in the parasitoid wasp genus Nasonia. Results specify 306 putative immune genes in the genomes of N. vitripennis and its two sister species N. giraulti and N. longicornis. Of these genes, 146 were not found in previous annotations of Nasonia immunity genes. Combining these newly identified immune genes with those in previous annotations, Nasonia possess 489 putative immunity genes, the largest immune repertoire found in insects to date. While these computational predictions need to be complemented with functional studies, the IIID database can help initiate and augment annotations of the immune system in the plethora of insect genomes that will soon become available.
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Affiliation(s)
- Robert M Brucker
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.
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26
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Cooperation, Conflict, and the Evolution of Queen Pheromones. J Chem Ecol 2011; 37:1263-75. [DOI: 10.1007/s10886-011-0036-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 10/16/2011] [Accepted: 10/28/2011] [Indexed: 01/08/2023]
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