Preference and performance of the generalist aphid Myzus persicae on closely and distantly related plant species

Abstract

AbstractThe ability of herbivorous insects to discriminate suitable host plants for the development of their progeny is not homogenous. Herbivores with broader diets show weaker correlation between oviposition preference and offspring performance in comparison with specialist insects. The neural constraints hypothesis postulates that due to neural limitation, generalist insects would have greater difficulty in processing a large number of stimuli from diverse host plants. Under this framework, it is expected that generalists would be more efficient in discriminating suitable plants when faced with more similar stimuli from closely related plants (simplified environment), and less efficient when faced with more diverse stimuli from unrelated plants (complex environment). In this study, we evaluated this in the generalist aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae). Preference was evaluated as the aphid's ability to discriminate between congeneric plant species or between plants from different families. The congeneric host plants were the cultivated potato, Solanum tuberosum L., the wild potato, Solanum commersonii Dunal, tomato, Solanum lycopersicum L., and eggplant, Solanum melongena L. (Solanaceae). The plant species of different families used were spinach, Spinacia oleracea L. (Amaranthaceae), squash, Cucurbita maxima Duchesne (Cucurbitaceae), and basil, Ocimum basilicum L. (Lamiaceae). Performance was evaluated as the population growth in one generation on whole‐plant conditions and on excised leaves. The results showed positive correlations between settlement and larviposition preferences and the performance of M. persicae for all comparisons between unrelated plant species. Positive correlations between preference and performance were also observed for two of the three comparisons between congeneric plants. These results indicate that M. persicae can efficiently discriminate between suitable plants for their progeny regardless of the degree of relatedness of the plants, which is at odds with the neural constraints hypothesis. The results contribute to the knowledge of host selection mechanisms in generalist herbivores, particularly in an underrepresented insect group.