Courtship behavior confusion in two invasive subterranean termite species (Coptotermes)

Congeneric species that live in sympatry may have evolved various mechanisms that maintain reproductive isolation among species. However, with the spread of invasive organisms, some species that evolved in allopatry can now be found outside their native range and may have the opportunity to interact, without reproductive isolation mechanism. In South Florida, where the Asian subterranean termite (Coptotermes gestroi (Wamann)) and the Formosan subterranean termite (Coptotermes formosanus Shiraki) (Blattodea: Rhinotermitidae) are invasive, the two species can engage in heterospecific mating behavior as their distribution range and their dispersal flight season both overlap. Termites rely on semiochemicals to find a mate after a dispersal flight event. In this study, we showed that females of both species produce (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol (DTE) from their tergal glands as a shared sex pheromone. Both species primarily rely on an inundative dispersal flight strategy to find a mate, and DTE is functionally used as a  contact pheromone to initiate and maintain the tandem between males and females. The C. gestroi male preference for C. formosanus female during tandem resulted from the relatively high amount of DTE produced by C. formosanus female tergal glands, when compared with C. gestroi females. This results into mating confusion in the field during simultaneous dispersal flights, with a potential for hybridization consequences. Such observation implies that no prezygotic barriers emerged while the two species evolved in allopatry for ~18 Ma.