Larval nutrition-induced plasticity affects reproduction and gene expression of the ladybeetle, Cryptolaemus montrouzieri

Abstract

Background: Organisms may develop into multiple phenotypes under different nutritional environments by developmental plasticity, whereas the potential costs and mechanisms of such plasticity are poorly understood. Here we examined the fitness and gene expression of nutrition-induced phenotypes in the ladybeetle, Cryptolaemus montrouzieri after having experienced varying larval food regimes.

Results: We found that C. montrouzieri adults undergoing a variable larval food regime achieved a similar developmental time, survival, body mass and egg production as those undergoing a high larval food regime. The survival, developmental time, body mass and fecundity of the adults from a restricted larval food regime were inferior to those from the high and variable larval food regimes. However, the adults from this restricted larval food regime had a higher expression level of genes encoding immune- and antioxidant-related enzymes than those from the high and variable larval food regimes when exposed to starvation and pesticide conditions in adult life.

Conclusions: These results suggest that larval food availability in C. montrouzieri not only triggers adult phenotypic differences but also affects reproduction and expression level of genes in adult life, indicating that the larval nutritional conditions can affect adult fitness and resistance to stressful conditions through developmental plasticity.

Fig. 1

Effects of larval food regimes (high, variable and restricted) on development of C. montrouzieri. a Body mass of male and female adults at emergence; b, Larval and pupal developmental time; c, Survival from egg hatch to adult emergence. Asterisks (*) indicate significant differences. Error bars represent 1 SE value

Fig. 2

Reproductive performance of adult phenotypes resulting form high, variable and restricted larval food regimes. a Pre-oviposition period; b, Egg production; c, Egg hatch. Asterisks (*) indicate significant differences. Error bars represent 1 SE value

Fig. 3

Resistance of adult phynotypes resulting from high, variable and restricted larval food regimes to a 5-day starvation period in the adult stage. a Body mass changes after having experienced the starvation period versus ad libitum food in the early adult stage; b, Survival curves of reproductively active adult phenotypes subjected to food starvation; c, Mean survival time from the start of food deprivation to death. Error bars represent 1 SE value

Fig. 4

Expression of genes encoding immune-related and antioxidant-related enzymes in adult phenotypes resulting from high, variable and restricted larval food regimes after having been subjected to a 24 h starvation period or pesticide treatment in the adult stage. a Lysozyme; b, Acid phosphatase; c, Phenol oxidase; d, Carboxylesterase; e, HSP60; f, Peroxidase. Different letters within each treatment indicate significant differences. Error bars represent 1 SE value