ESTIMATING POLYANDRY OF WILD MOSQUITOES IN SINGAPORE

Abstract

Aedes aegypti and Ae. albopictus are major global mosquito vectors of deadly pathogens. In Singapore, Wolbachia-infected males have suppressed Ae. aegypti by inducing cytoplasmic incompatibility in wild females. However, the native and more environmentally resilient Ae. albopictus may take over the ecological niche. It is therefore important to consider the prominence of polyandry in local populations, which can lead to wild females producing viable offspring despite mating with infected males. Surprisingly, despite highly conservative approaches, I report one of the highest polyandry estimates to date: 83.9% for Ae. albopictus and 95% for Ae. aegypti. Results suggest strong fecundity selection driving female-biased sexual size dimorphism in Ae. albopictus, where female body size strongly predicts female re-mating. However, there is no evidence of strong postcopulatory selection for sperm length in males. This study provides a first look at polyandry and the mating system in local mosquitoes using polymorphic and highly optimized microsatellites.