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Möllerke A, Brasse G, Bello J, Vidal DM, Dettner K, Zettel J, Berg MP, Scheu S, Leinaas HP, Schulz S. The unique epicuticular chemistry of Collembola - A cross-species analysis. iScience 2024; 27:110416. [PMID: 39139403 PMCID: PMC11321324 DOI: 10.1016/j.isci.2024.110416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/04/2024] [Accepted: 06/27/2024] [Indexed: 08/15/2024] Open
Abstract
Springtails (Collembola), tiny hexapod arthropods, are abundant in the soil of most ecosystems, but our knowledge of their secondary metabolites is limited, in contrast to that of insects. In insects, the outer cuticle is usually covered by mixtures of long-chain hydrocarbons serving different functions, such as water regulation or chemical communication. In contrast, the knowledge of the epicuticular chemistry of springtails is scarce. We analyzed the cuticular lipids of 23 species covering different lineages. The often complicated structures were elucidated using gas chromatography/mass spectrometry, microderivatization, and synthesis. In contrast to insects, the terpene biosynthetic pathway is used for many of these lipids, producing unprecedented higher terpenes. In addition, evidence for de novo cholesterol biosynthesis in springtails was found, which is absent in insects. Finally, diverse non-insect linear compounds originating from the fatty acid biosynthetic pathway were identified. Our comparative analysis showed clear differences compared to insects and shed light on phylogenetic relationships.
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Affiliation(s)
- Anton Möllerke
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany
| | - Gregor Brasse
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany
| | - Jan Bello
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany
| | - Diogo Montes Vidal
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany
| | - Konrad Dettner
- Universität Bayreuth, Lehrstuhl für Tierökologie 2, Universitätsstraße 30, 95440 Bayreuth, Germany
| | - Jürg Zettel
- Speichergasse 8, 3150 Schwarzenburg, Switzerland
| | - Matty P. Berg
- Vrije Universiteit Amsterdam, Institute of Life and Environment, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Stefan Scheu
- University of Göttingen, JFB Institute of Zoology and Anthropology, 37073 Göttingen, Germany
- University of Göttingen, Centre for Biodiversity and Sustainable Land Use, 37077 Göttingen, Germany
| | - Hans Petter Leinaas
- University of Oslo, Department of Bioscience University of Oslo, P.O.Box 1066 Blindern, 0316 Oslo, Norway
| | - Stefan Schulz
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany
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Adams SA, Gurajapu A, Qiang A, Gerbaulet M, Schulz S, Tsutsui ND, Ramirez SR, Gillespie RG. Chemical species recognition in an adaptive radiation of Hawaiian Tetragnatha spiders (Araneae: Tetragnathidae). Proc Biol Sci 2024; 291:20232340. [PMID: 38593845 PMCID: PMC11003775 DOI: 10.1098/rspb.2023.2340] [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: 10/16/2023] [Accepted: 03/05/2024] [Indexed: 04/11/2024] Open
Abstract
Studies of adaptive radiations have played a central role in our understanding of reproductive isolation. Yet the focus has been on human-biased visual and auditory signals, leaving gaps in our knowledge of other modalities. To date, studies on chemical signals in adaptive radiations have focused on systems with multimodal signalling, making it difficult to isolate the role chemicals play in reproductive isolation. In this study we examine the use of chemical signals in the species recognition and adaptive radiation of Hawaiian Tetragnatha spiders by focusing on entire communities of co-occurring species, and conducting behavioural assays in conjunction with chemical analysis of their silks using gas chromatography-mass spectrometry. Male spiders significantly preferred the silk extracts of conspecific mates over those of sympatric heterospecifics. The compounds found in the silk extracts, long chain alkyl methyl ethers, were remarkably species-specific in the combination and quantity. The differences in the profile were greatest between co-occurring species and between closely related sibling species. Lastly, there were significant differences in the chemical profile between two populations of a particular species. These findings provide key insights into the role chemical signals play in the attainment and maintenance of reproductive barriers between closely related co-occurring species.
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Affiliation(s)
- Seira A. Adams
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, #3114, Berkeley, CA 94720, USA
- Center for Population Biology, University of California, 2320 Storer Hall, Davis, CA 95616, USA
- Department of Evolution and Ecology, University of California, 2320 Storer Hall, Davis, CA 95616, USA
| | - Anjali Gurajapu
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, #3114, Berkeley, CA 94720, USA
| | - Albert Qiang
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, #3114, Berkeley, CA 94720, USA
| | - Moritz Gerbaulet
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, Braunschweig 38106, Germany
| | - Stefan Schulz
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, Braunschweig 38106, Germany
| | - Neil D. Tsutsui
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, #3114, Berkeley, CA 94720, USA
| | - Santiago R. Ramirez
- Center for Population Biology, University of California, 2320 Storer Hall, Davis, CA 95616, USA
- Department of Evolution and Ecology, University of California, 2320 Storer Hall, Davis, CA 95616, USA
| | - Rosemary G. Gillespie
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, #3114, Berkeley, CA 94720, USA
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Dorsey OC, Rosenthal GG. A taste for the familiar: explaining the inbreeding paradox. Trends Ecol Evol 2023; 38:132-142. [PMID: 36241551 DOI: 10.1016/j.tree.2022.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 09/04/2022] [Accepted: 09/12/2022] [Indexed: 11/06/2022]
Abstract
The negative consequences of inbreeding have led animal biologists to assume that mate choice is generally biased against relatives. However, inbreeding avoidance is highly variable and by no means the rule across animal taxa. Even when inbreeding is costly, there are numerous examples of animals failing to avoid inbreeding or even preferring to mate with close kin. We argue that selective and mechanistic constraints interact to limit the evolution of inbreeding avoidance, notably when there is a risk of mating with heterospecifics and losing fitness through hybridization. Further, balancing inbreeding avoidance with conspecific mate preference may drive the evolution of multivariate sexual communication. Studying different social and sexual decisions within the same species can illuminate trade-offs among mate-choice mechanisms.
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Affiliation(s)
- Owen C Dorsey
- Program in Ecology and Evolutionary Biology and Department of Biology, Texas A&M University, TX, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca", Calnali, Hidalgo, Mexico.
| | - Gil G Rosenthal
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", Calnali, Hidalgo, Mexico; Department of Biology, University of Padua, Padua, Italy
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Kennedy SR, Ying Lim J, Ashley Adams S, Krehenwinkel H, Gillespie RG. What is adaptive radiation? Many manifestations of the phenomenon in an iconic lineage of Hawaiian spiders. Mol Phylogenet Evol 2022; 175:107564. [PMID: 35787456 DOI: 10.1016/j.ympev.2022.107564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/27/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022]
Abstract
Adaptive radiation provides the ideal context for identifying and testing the processes that drive evolutionary diversification. However, different adaptive radiations show a variety of different patterns, making it difficult to come up with universal rules that characterize all such systems. Diversification may occur via several mechanisms including non-adaptive divergence, adaptation to novel environments, or character displacement driven by competition. Here, we characterize the ways these different drivers contribute to present-day diversity patterns, using the exemplary adaptive radiation of Hawaiian long-jawed orbweaver (Tetragnatha) spiders. We present the most taxonomically comprehensive phylogenetic hypothesis to date for this group, using 10 molecular markers and representatives from every known species across the archipelago. Among the lineages that make up this remarkable radiation, we find evidence for multiple diversification modalities. Several clades appear to have diversified in allopatry under a narrow range of ecological conditions, highlighting the role of niche conservatism in speciation. Others have shifted into new environments and evolved traits that appear to be adaptive in those environments. Still others show evidence for character displacement by close relatives, often resulting in convergent evolution of stereotyped ecomorphs. All of the above mechanisms seem to have played a role in giving rise to the exceptional diversity of morphological, ecological and behavioral traits represented among the many species of Hawaiian Tetragnatha. Taking all these processes into account, and testing how they operate in different systems, may allow us to identify universal principles underlying adaptive radiation.
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Affiliation(s)
| | - Jun Ying Lim
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Seira Ashley Adams
- Department of Environmental Science, Policy and Management, University of California Berkeley, USA
| | | | - Rosemary G Gillespie
- Department of Environmental Science, Policy and Management, University of California Berkeley, USA
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Identification of Cuticular and Web Lipids of the Spider Argiope bruennichi. J Chem Ecol 2022; 48:244-262. [PMID: 35006525 PMCID: PMC8934766 DOI: 10.1007/s10886-021-01338-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 10/25/2022]
Abstract
Emerging evidence shows that the cuticular and silk lipids of spiders are structurally more diverse than those of insects, although only a relatively low number of species have been investigated so far. As in insects, such lipids might play a role as signals in various contexts. The wasp spider Argiope bruennichi has probably the best investigated chemical communication system within spiders, including the known structure of the female sex pheromone. Recently we showed that kin-recognition in A. bruennichi could be mediated through the cuticular compounds consisting of hydrocarbons and, to a much larger proportion, of wax esters. By use of mass spectrometry and various derivatization methods, these were identified as esters of 2,4-dimethylalkanoic acids and 1-alkanols of varying chain lengths, such as tetradecyl 2,4-dimethylheptadecanoate. A representative enantioselective synthesis of this compound was performed which proved the identifications and allowed us to postulate that the natural enantiomer likely has the (2R,4R)-configuration. Chemical profiles of the silk and cuticular lipids of females were similar, while male cuticular profiles differed from those of females. Major components of the male cuticular lipids were tridecyl 2,4-dimethyl-C17-19 alkanoates, whereas those of females were slightly longer, comprising tridecyl 2,4-dimethyl-C19-21 alkanoates. In addition, minor female-specific 4-methylalkyl esters were detected.
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Pheromone communication among sexes of the garden cross spider Araneus diadematus. Naturwissenschaften 2021; 108:38. [PMID: 34448943 PMCID: PMC8397638 DOI: 10.1007/s00114-021-01747-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/19/2021] [Accepted: 08/09/2021] [Indexed: 11/10/2022]
Abstract
Chemical communication plays a fundamental role in many aspects of an animal’s life from assessing habitat quality to finding mating partners. Behavioural observations show that chemical communication likewise plays an important role in spiders, but the contexts and the substances involved are little explored. Here, we investigate the chemical communication in the garden cross spider Araneus diadematus (Clerck, 1757) between and within the sexes. Using choice trials, we demonstrate that males are attracted to odours of adult females, but not to those of subadult females. Our data further suggest that adult females avoid odours of conspecific adult females, possibly in order to reduce reproductive competition with other females. Cuticle and silk extracts as well as headspace samples of subadult and adult virgin females were analysed via GC–MS. Available candidate compounds for the female sex pheromone were tested via electroantennography on palps (electropalpography) of adult virgin females and on females in behavioural trials. We propose sulcatone (6-methyl-5-hepten-2-one) as a candidate substance for the female volatile pheromone and several long-chained alkanes and alcohols as candidates for contact pheromones. Apart from demonstrating that attraction of males to females depends on the latter’s developmental stage, our study suggests that pheromones can also play an important role between females, an aspect that requires further attention.
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