Preference-performance in polyphagous Copitarsia decolora and Peridroma saucia: Are mothers or larvae right?

The preference-performance hypothesis predicts that herbivores oviposit where the larval performance is optimal. Although evidence supports this hypothesis, a recent analysis has shown that host selection by adults in terms of larval performance is influenced by the number of potential hosts. In the case of polyphagous species, females not always oviposit where the larval performance is ideal, suggesting that larvae of these insects should have an active role in host selection. In this work, we evaluated if C. decolora and P. saucia larvae, two polyphagous species of economic importance, have a better host choose than their mothers in terms of larval performance. In laboratory and greenhouse assays with eight species of cultivated plants, we tested adults and larval preference in terms of oviposition, larval initial orientation and larval settling. To evaluate the larval performance we registered the consumption, survival, longevity and pupal weight. We found that larvae and females of both species actively choose their host and that the larval orientation towards a specific plant is strongly related with the females’ preference, suggesting that stimuli that rule the host selection, act in a similar way in both stages. However, the females and neonates selection did not match with the best larvae development, indicating that the performance do not influence directly in the preference. These results suggest that other selection pressures should influence the choice of the host plant in these two species.