Symbiont-mediated shifts in cuticular hydrocarbon profiles reduce female attractiveness after mating
Males can influence future mating interactions of females after copulation by changing female signals that subsequent males will encounter. In insects, such effects commonly involve cuticular hydrocarbons (CHCs), but whether heritable microbial symbionts contribute to post-mating chemical signalling remains largely unknown. Kelly's citrus thrips, Pezothrips kellyanus, provides an ideal system to…
Males have the ability to impact the future mating choices of females after mating by altering the chemical signals that subsequent males will detect. In insects, this often involves cuticular hydrocarbons (CHCs), but the role of heritable microbial symbionts in post-mating chemical communication is not well understood. The citrus thrips, Pezothrips kellyanus, serves as an excellent model to investigate this phenomenon because reproductive compatibility is influenced by common arthropod endosymbionts.
In P. kellyanus populations, Cardinium is present in virtually all individuals, while Wolbachia varies in prevalence and spreads through cytoplasmic incompatibility (CI). However, females that are infected with only Cardinium avoid mating with males that carry both Cardinium and Wolbachia. This behavior is associated with the distinct CHC profile of males infected with both symbionts.
The researchers investigated whether the influence of these endosymbionts persists on females after copulation by modifying the female CHC profile and observing the subsequent mating behavior of males. Through behavioral assays and GC-MS-based CHC profiling, they discovered that females who were first mated with males infected with both Cardinium and Wolbachia received fewer antennal contacts and mating attempts from subsequent females infected only with Cardinium.
Additionally, mating with Wolbachia-infected males altered the female CHC profile, resulting in a unique post-mating chemical signature. The most significant finding was the presence of tridecane, a chemical compound previously found only in males infected with both symbionts, exclusively in females that had mated with such males.
These results demonstrate that endosymbionts can modify the CHCs of mated females and influence future sexual communication between males and females. This previously unknown post-mating pathway through which endosymbionts reshape sexual communication may have implications for reproductive compatibility and symbiont transmission dynamics.
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