The effects of larval nutrition on reproductive performance in a food-limited adult environment

Abstract

It is often assumed that larval food stress reduces lifetime fitness regardless of the conditions subsequently faced by adults. However, according to the environment-matching hypothesis, a plastic developmental response to poor nutrition results in an adult phenotype that is better adapted to restricted food conditions than one having developed in high food conditions. Such a strategy might evolve when current conditions are a reliable predictor of future conditions. To test this hypothesis, we assessed the effects of larval food conditions (low, improving and high food) on reproductive fitness in both low and high food adults environments. Contrary to this hypothesis, we found no evidence that food restriction in larval ladybird beetles produced adults that were better suited to continuing food stress. In fact, reproductive rate was invariably lower in females that were reared at low food, regardless of whether adults were well fed or food stressed. Juveniles that encountered improving conditions during the larval stage compensated for delayed growth by accelerating subsequent growth, and thus showed no evidence of a reduced reproductive rate. However, these same individuals lost more mass during the period of starvation in adults, which indicates that accelerated growth results in an increased risk of starvation during subsequent periods of food stress.

Figure 1. Mass (circles) and pronotum width (square symbols) at eclosion for each larval feeding treatment.

Error bars represent 1 SE from the mean and if not visible are smaller than the symbols.

Figure 2. Mass gained or lost (as percentage of initial mass) in response to adult feeding treatment for first week after eclosion.

As sexes did not differ, data from males and females are combined. Error bars one standard error from the mean.

Figure 3. Effect of larval and adult food treatment on reproductive traits in female ladybird beetles.

(A) Total number of eggs produced during the first month post-eclosion. (B) Time to first clutch. Error bars represent one standard error from the mean.