Specialist and generalist oviposition strategies in butterflies: maternal care or precocious young?

ABSTRACT

Herbivorous insects specialized on a narrow set of plants are believed to be better adapted to their specific hosts. This hypothesis is supported by observations of herbivorous insect species with a broader diet breadth which seemingly pay a cost through decreased oviposition accuracy. Despite many studies investigating female oviposition behavior, there is a lack of knowledge on how larvae cope behaviorally with their mothers' egg-laying strategies. We have examined a unique system of five nymphalid butterfly species with different host plant ranges that all feed on the same host plant. The study of this system allowed us to compare at the species level how oviposition preference is related to neonate larval responses in several disadvantageous situations. We found a general co-adaptation between female and larval abilities, where species with more discriminating females had larvae that were less able to deal with a suboptimal initial feeding site. Conversely, relatively indiscriminate females had more precocious larvae with better abilities to cope with suboptimal sites. Despite similarities between the tested species with similar host ranges, there were also striking differences. Generalist and specialist species can be found side by side in many clades, with each clade having a specific evolutionary history. Such clade-specific, phylogenetically determined preconditions apparently have affected how precisely a broad or narrow diet breadth can be realized.