Infertile egg production in the lady beetle Eriopis connexa

Oogenesis and egg development are metabolic process with a high energy cost for females. This suggests that most developing eggs should yield viable offspring. Females of Eriopis connexa (Germar) (Coleoptera Coccinellidae) lay infertile eggs even when continuously paired with fertile males and have access to an abundance of food. We studied the production of infertile eggs and the role of egg consumption by unrelated females in this species, based on the hypothesis that production of infertile eggs varies as a function of pesticide resistance in E. connexa females given the reproductive costs imposed by the resistance trait. Further, we also hypothesize that prey shortage provides a cue to produce more infertile eggs as food for newly hatched larvae. Under these conditions, egg cannibalism and egg intraguild predation should improve the reproductive performance of E. connexa females. Contrary to our hypothesis, the egg infertility rates of E. connexa were similar between susceptible- and insecticide-resistance phenotypes. The number of infertile eggs per egg batch correlated with the number of eggs laid, with percentages of infertile eggs ranging from 21.8 and 34.8%, irrespective of egg batch size. Periods of prey deprivation significantly reduced E. connexa fecundity but did not stimulate females to produce more infertile eggs as food for newly hatched larvae. Moreover, cannibalism and intraguild predation did not enhance reproduction. However, life-history traits were improved when larvae and adults engaged in egg cannibalism or intraguild predation if combined with a standard prey diet. In conclusion, we rejected the proposed hypotheses on the role of infertile egg production by E. connexa, even though egg cannibalism and intraguild predation were significant food sources for E. connexa.