Plasticity in mating behaviour drives asymmetric reproductive interference in whiteflies

Reproductive interference between species with incomplete mate recognition can disrupt the process of mate acquisition. Accordingly, reproductive interference can reduce female and male fitness and lead to sexual exclusion. Here, we tested the hypothesis that flexible mating behaviours could mitigate the fitness-reducing effects of reproductive interference between reproductively incompatible biotypes of the haplodiploid whitefly Bemisia tabaci. We show that females of the globally distributed and invasive B biotype respond to reproductive interference from the Q biotype by increasing their acceptance of copulation attempts from B males. This behavioural plasticity increases the ability of B females to mate successfully and maintain a constant sex ratio in their offspring despite reproductive interference. In contrast, females of competing biotypes have invariant behaviour and produce fewer female offspring because of reproductive interference from the B biotype. Heuristic simulation models incorporating data on behavioural and life history traits of the B and Q biotypes obtained here, and published data on other biotypes, show that this plasticity in mating behaviour of B females could contribute to sexual exclusion of closely related biotypes. Our results demonstrate a powerful link between mating behaviour, reproductive interference and sexual exclusion, suggesting that variation in mating behaviour could determine the effects of reproductive interference and drive sexual exclusion among closely related species or among biotypes of a species.