Variability and inheritance of the chorionic tubercles on eggs of Listronotus oregonensis (Coleoptera: Curculionidae)

Abstract

AbstractThe tubercles present on the egg chorion of the carrot weevil, Listronotus oregonensis (LeConte), are described and their variability in density quantified between females. Tubercle density varied by a factor of six between females, from 19 000 to 115 000 tubercles per mm2. The average density of tubercles for a given female remained constant throughout its oviposition period. When isofemale lines were created, the average tubercle density remained constant from generation to generation, and crossing experiment suggested that tubercle density was transmitted by the female. Using isofemale lines with low and high densities of tubercles, no effect on egg survival in water or susceptibility to egg parasitism was found. Tubercle density and the heritability of this character suggest a probable reproductive advantage for females that produce eggs with this chorionic pattern even though the precise role of these traits remains to be determined.