Biology subjects

Lapeyre, B.

Publications and source records attributed to Lapeyre, B..

7 recordsLinked to original sources

bioRxiv2026

Scents for safe sex: a volatile sex pheromone promotes outbreeding in a parasitoid wasp with severe genetic load

When mating among genetically related individuals results in inbreeding depression, various behaviors and life-history traits evolve to favor outbreeding. Long-range sexual communication following natal dispersal is one such adaptation. In parasitoid wasps with single-locus complementary sex determination (sl-CSD), inbreeding increases the production of unviable or sterile diploid males. Mastrus ridens is such a species, with a genetic load underpinned by sl-CSD, combined with a high potential for sibmating because siblings emerge in close proximity from the same host and become sexually active shortly after emergence. With this context in mind, we investigated the mate-finding strategy of M. ridens using complementary behavioral, chemical, and electrophysiological approaches. Wind-tunnel bioassays and field experiments showed that males orient toward virgin females and, to a lesser extent, mated females. This attraction from a distance appeared to be the sole form of conspecific attraction. Chemical analyses using static and dynamic headspace sampling and solvent extracts, followed by GC-MS, revealed several potential pheromonal candidates, including methyl 6-methylsalicylate. This compound elicited reproducible antennal responses in males in GC-EAD recordings. Altogether, our results suggest that mate finding in M. ridens is guided by a volatile sex pheromone emitted by females, with methyl 6-methylsalicylate as one putative component. Such mate-finding mechanisms promote outbreeding and may explain the low proportion of unfit diploid males observed in natural populations. Surprisingly, chemical analyses suggested that males also emit this compound, whereas neither males nor females showed behavioral responses to males. This apparent discrepancy suggests that attraction may depend on a more complex pheromonal signal and opens further avenues for investigation.

ecology↗

bioRxiv2026

Pollinator specificity among three co-flowering Mediterranean Aristolochia species pollinated by Diptera

Attracting specific pollinators can be favoured by natural selection to avoid reproductive interference between sympatric plant species. However, the ways in which fine differences in floral traits lead to the attraction of specific pollinators are diverse and unknown in many pollination interactions. We surveyed pollinators on three sympatric Aristolochia species (A. clematitis, A. pistolochia and A. rotunda) pollinated by Diptera to investigate if specific pollination occurs. To decipher if specific pollination may be mediated by different floral odours, we characterized the volatile organic compounds (VOCs) emitted by flowers and highlighted those VOCs electrophysiologically detected by pollinators in A. rotunda and A. pistolochia. Among the most abundant pollinators, Forcipomyia monilicornis was a specific pollinator of A. pistolochia while two Dasyhelea species were specific pollinators of A. clematitis. Forcipomyia aristolochiae and T. ruficeps were non-specific pollinators of A. rotunda, although they were more frequently found in A. rotunda flowers. The floral odours of A. rotunda and A. pistolochia differed significantly from each other and elicited specific electrophysiological responses in their respective pollinators. Although several pollinator species visit more than one Aristolochia species, those pollinators are preferentially found in one Aristolochia species. Selective attraction is likely mediated by specific VOCs.

ecology↗

bioRxiv2025

Pollinator abundance shapes sexual selection in an angiosperm

Sexual selection is a cornerstone of evolutionary biology potentially operating in all sexually-reproducing organisms. Modern developments in the field revealed that this selective force extends beyond Darwins initial focus on access to mates in terms of competition for access to gametes of the other sex. Despite its presumed universality, sexual selection theory remains largely untested in plants compared to animals. This gap may partly stem from challenges in quantifying sexual selection using approaches that account for a critical plant-specific factor: the reliance on pollinators as third-party agents for accessing mates. Here, we quantified sexual selection along consecutive episodes of selection in the hermaphroditic plant Brassica rapa by integrating the monitoring of pollinator movements with genetic paternity analyses in experimental populations. Our approach identifies pollen competition for ovules as the primary arena for sexual selection in B. rapa. Darwinian competition for access to mates constitutes a secondary force, and was stronger in the male compared to the female sex function, as predicted by classic theory. Importantly, experimentally induced variation in pollinator abundance modulated the balance between pre- and post-pollination sexual selection. Under reduced pollinator abundance, the opportunity for selection on mate acquisition increased. Crucially, we demonstrate that ignoring pollinator movements among plants leads to erroneous quantification of pre-pollination sexual selection. We argue that a unifying theory of sexual selection requires a more comprehensive quantification of pre- and post-pollination episodes of selection, taking into account the specificities of gamete transfer in plants.

evolutionary biology↗

bioRxiv2025

Major transitions in early coral development: novel insights enabled by visualisation of a comprehensive transcriptomic dataset for Acropora millepora

BackgroundGiven the ecological importance of reef-building corals (Scleractinia), it is perhaps surprising that the molecular mechanisms underlying many of the morphological and metabolic changes during their development remain unclear. In part, this is due to the lack of a comprehensive transcriptomic dataset for any coral. A second challenge in the analysis of such non-model developmental datasets is that the volume of data often complicates its interpretation. ResultsTo overcome these limitations, we profiled gene expression in Acropora millepora across 26 life stages from unfertilised eggs to juvenile polyps and developed an interactive online tool based on the R-application Shiny to simultaneously visualise changes in the expression of large numbers of genes. As expected, major transcriptomic changes (transitions) occurred during gastrulation and the acquisition of competence. Surprisingly, however, settlement triggered by using the natural inducer CCA did not immediately lead to major changes in gene expression, but a major transition involving many genes was observed 3 - 6 hours after settlement induction. ConclusionsWe hope that providing access to this extensive developmental transcriptome dataset and software to facilitate its analysis will expedite a better understanding of the changes that occur during coral development. The online tool is available at https://amil-deview.mmb.group.

developmental biology↗

bioRxiv2020

No evidence for long-range male sex pheromones in two malaria mosquitoes

AO_SCPLOWBSTRACTC_SCPLOWCues involved in mate seeking and recognition prevent hybridization and can be involved in speciation processes. In malaria mosquitoes, females of the two sibling species Anopheles gambiae s.s. and An. coluzzii mate in monospecific male swarms and hybrids are rare. Long-range sex pheromones driving this behavior have been debated in literature but to date, no study has proven their existence or their absence. Here, we attempted to bring to light their existence. To put all the odds in our favor, we used different chemical ecology methods such as behavioral and electrophysiological assays as well chemical analyses, and we worked with mosquitoes at their optimal physiological mating state i.e. with swarming males during their natural swarming windows. Despite all our efforts, our results support the absence of long-range sex pheromones involved in swarm detection and recognition by females. We briefly discuss the implications of this finding in ecology, evolution and for control strategies.

ecology↗

bioRxiv2018

Identifying conserved molecular mechanisms of thermo-acclimation in symbiotic organisms

Seawater temperature rise in French Polynesia has repeatedly resulted in symbiosis breakdown between giant clam (Tridacna maxima) and dinoflagellates (Symbiodinium spp.), particularly in small individuals. Herein, we explored the physiological and gene expression responses of the clam hosts and their photosynthetically active symbionts over a 65-day experiment in which clams were exposed to either normal or environmentally relevant elevated seawater temperatures. These data were combined with publicly available data for both free-living Symbiodinium (clades C1 and F) and Symbiodinium spp. in hospite with the coral Pocillopora damicornis. Gene module preservation analysis revealed that the function of the symbionts photosystem II was impaired at high temperatures, and this response was conserved across all holobionts and Symbiodinium clades examined. Similarly, activation of the phytohormone abscisic acid signaling and epigenetics modulation appeared to be a key response mechanisms for symbionts in hospite with giant clams exposed to high temperatures and also distinguish thermo-tolerant from thermo-sensitive Symbiodinium C1 phenotypes.

genomics↗

bioRxiv2017

Symbiodinium genomes reveal adaptive evolution of functions related to symbiosis

Symbiosis between dinoflagellates of the genus Symbiodinium and reef-building corals forms the trophic foundation of the worlds coral reef ecosystems. Here we present the first draft genome of Symbiodinium goreaui (Clade C, type C1: 1.03 Gbp), one of the most ubiquitous endosymbionts associated with corals, and an improved draft genome of Symbiodinium kawagutii (Clade F, strain CS-156: 1.05 Gbp), previously sequenced as strain CCMP2468, to further elucidate genomic signatures of this symbiosis. Comparative analysis of four available Symbiodinium genomes against other dinoflagellate genomes led to the identification of 2460 nuclear gene families that show evidence of positive selection, including genes involved in photosynthesis, transmembrane ion transport, synthesis and modification of amino acids and glycoproteins, and stress response. Further, we identified extensive sets of genes for meiosis and response to light stress. These draft genomes provide a foundational resource for advancing our understanding Symbiodinium biology and the coral-algal symbiosis.

genomics↗