Female resistance behaviour and progeny sex ratio in two Bradysia species (Diptera: Sciaridae) with paternal genome elimination

Abstract

The relationship between female mating preferences and sex allocation has received considerable theoretical and empirical support. Typically, choosier females adjust their progeny sex ratio towards sons, who inherit the attractive traits of their father. However, in species with paternal genome elimination, where male sperm do not contain the paternal genome, predictions for the direction of progeny sex ratio biases and their relationship with female choosiness are atypical. Paternal genome elimination also creates a potential for male-female conflict over sex allocation, and any influence of female mate choice on sex ratio outcomes have interesting implications for sexually antagonistic coevolution. Within the Sciaridae (Diptera) are species that produce single-sex progeny (monogenic species) and others in which progeny comprise both sexes (digenic species). Paternal genome elimination occurs in both species. We explore female mate resistance behaviour in a monogenic and digenic species of mushroom gnat from the genus Bradysia. Our experiments confirmed our theoretical predictions, revealing that in the monogenic and digenic species, females producing female-biased progeny were more likely to have resisted at least one mating attempt.