Natural skip oviposition of the mosquito Aedes aegypti indicated by codominant genetic markers.

Abstract

This study examines the use of codominant restriction fragment length polymorphism (RFLP) markers to estimate the number of sibling families found within and among oviposition sites used by the mosquito Aedes aegypti (L) (Diptera: Culicidae). Estimates were made using pairwise relatedness (rxy) calculations based on alleles shared between individuals. Genotypes for eight laboratory mosquito families were determined at six RFLP loci and the observed allele frequencies were used to generate simulated distributions of rxy from full-sibling and unrelated pairs of individuals. The midpoint (mp) between the means of the pairwise rxy distributions was used to discriminate full-sibling families from unrelated families. Clusters of individuals with rxy values higher than the mp value were grouped as putative sibling families. This method was tested by calculating actual rxy for all pairwise comparisons of the known laboratory full-sibling and paternal half-sibling families, followed by upgma cluster analysis to group sibling families. The technique was then used for sibling estimations on wild caught mosquitoes collected at three locations in Trinidad, West Indies. From field populations, 35 families were estimated among 122 individuals tested with an average of 6.2 families per container. Members of 19 predicted families clustered as groups across multiple containers, providing molecular evidence for skip-oviposition behaviour in Ae. aegypti females, whereby individual females oviposit in more than one container.