Asymmetrical reproductive interference between Aedes aegypti and Aedes albopictus: Implications for coexistence

Background & objectives: Aedes aegypti and Ae. albopictus are two sympatric mosquito species that compete with each other for resources when their breeding habitats overlap. This study examines what happens when sympatric Ae. aegypti and Ae. albopictus mosquitoes’ mate with each other and other species by looking at insemination rates, fecundity, and hatchability rate. Methods: We performed controlled mating experiments in laboratory settings, assessing both conspecific and interspecific crosses. We measured insemination rates, egg numbers, and hatching success to examine the reproductive interference dynamics between these two distinct mosquito species. Results: In the context of conspecific mating, it was observed that both female Ae. aegypti and Ae. albopictus exhibited high insemination rates, with percentages 98% and 94%, respectively. However, interspecific mating exhibited interesting asymmetries as Ae. albopictus males achieved a notable insemination success rate of 28% when mating with Ae. aegypti females, while Ae. aegypti males achieved only an 8% insemination success with Ae. albopictus females. Additionally, females that mated with interspecific males had reduced production of viable eggs compared to conspecific mating. Most notably, interspecific mating resulted in the production of infertile eggs, while conspecific mating led to successful hatching. Interpretation & conclusion: The study reveals that Ae. aegypti and Ae. albopictus can asymmetrically interfere with each other’s reproduction, causing a ‘satyr’ effect. This understanding of interspecific competition and reproductive interference in these mosquito species could impact their coexistence in shared breeding habitats.