The ecological function of insect egg micropyles

Insect egg micropyles are openings through the chorion allowing sperm entry for fertilisation. Micropyles diverse structures showing remarkable variation in number, spatial arrangement and physical structure across extant insect orders. Despite being almost ubiquitous insects, they have received little attention. As key morphological features of an immobile life stage, it is plausible that part diversity exhibited by adaptive, supporting other during embryo development. So, while fertilization primary function micropyles, could aid development be shaped natural, as well sexual selection. Here I first used ancestral reconstruction to investigate micropyle presence, number primitive insects. Then, phylogenetic comparative analyses explore ecological number. hypothesised correlated with (1) aeropyle presence facilitating oxygen exchange; (2) aquatic oviposition water influenced (3) critical bioclimatic variables. Across 24 hexapod orders, most likely state was one or two interspecific high intraspecific low. Mean ranged from zero Entognatha, Strepsiptera Thysanoptera 120 Panstrongylus geniculatus, Hemiptera, over 100 on average Apidae, Hymenoptera. Micropyle strongly positively related size, larger eggs having more micropyles; aeropyles; annual precipitation, developing habitats low precipitation exhibiting fewer (4) negatively width, numerous smaller ones. However, did not affect Overall these findings point adaptive addition their fertilisation function. This consistent hypothesis survival, so this almost-ubiquitous trait insects natural selection pressures stage. Read free Plain Language Summary article Journal blog.