Many insects and arachnids engage in same-sex sexual behaviors. But they’re not gay, say a pair of researchers from Israel and Switzerland. It's just a case of mistaken identity — and high sex drives.
Bugs often engage in what appears to be homosexual behavior, like courting and mating attempts with members of the same sex. Unlike vertebrates, however, this can’t be easily explained. Same-sex sexual behaviors in birds and mammals are often understood as “practice” for young adults and as a way to maintain group alliances.
This doesn’t apply to bugs, however. For them, these efforts are incredibly risky and pointless; not only is it dangerous, it takes time and energy — and for no apparent evolutionary or procreative advantage. Indeed, bugs typically mate in a “quick and dirty” way, says Tel Aviv University’s Inon Scharf, a co-author of the new study. “The cost of taking the time to identify the gender of mates or the cost of hesitation appears to be greater than the cost of making some mistakes.”
Sharf, along with Oliver Martin of ETH Zurich, recently looked at the males of over 110 species of bugs and insects to see if they could find some sensical reasons for same-sex behavior. They looked at males because same-sex behavior among insects and arachnids is almost exclusive to them.
But they found nothing.
Instead, the researchers suggest these creatures simply haven’t evolved the capacity to be more discriminating in their mating choices. They point to other examples of mating “confusion” among insectoid males, like attempts to procreate with inanimate objects such as beer bottles. Or males laces with female pheromones. Many species also try to mate with related species — another case of mistaken identification.
“[Same-sex sexual] behavior in arthropods is predominantly based on mistaken identification and is probably maintained because the cost of rejecting a valid opportunity to mate with a female is greater than that of mistakenly mating with a male,” conclude the researches in the study.
“Homosexual behavior may be genomically linked to being more active, a better forager, or a better competitor,” they note. “So even though misidentifying mates isn’t a desirable trait, it’s part of a package of traits that leaves the insect better adapted overall.”
Read the entire study at Behavioral Ecology and Sociobiology: “Same-sex sexual behavior in insects and arachnids: prevalence, causes, and consequences.”