The ecological function of insect egg micropyles

Insect egg micropyles are openings through the chorion allowing sperm entry for fertilisation. Micropyles are diverse structures showing remarkable variation in number, spatial arrangement and physical structure across extant insect orders. Despite being almost ubiquitous across insects, they have received little attention. As key morphological features of an immobile life stage, it is plausible that part of the diversity exihibited by micropyles is adaptive supporting other egg structures during embryo development. So whilst egg fertilization is the primary function of micropyles, they could aid embryo development and be shaped by natural, as well as sexual selection. Here I first used ancestral reconstruction to investigate micropyle presence, number and variation in primitive insects. Then, I used phylogenetic comparative analyses to explore the ecological function of micropyle number. I hypothesised that micropyle number correlated with: (i) aeropyle presence facilitating oxygen exc...