With further climate change still expected, it is predicted to increase the frequency with plants will be water stressed, which subsequently influences phytophagous insects, particularly Lepidoptera with limited mobility of larvae. Previous studies have indicated that oviposition preference and offspring performance of Lepidoptera insects are sensitive to drought separately. However, the integration of their two properties is not always seen. Here, we evaluated changes in oviposition selection and offspring fitness of a Lepidoptera insect under three water-stressed treatments using a model agroecosystem consisting of maize Zea mays, and Asian corn borer Ostrinia furnacalis. Results found that female O. furnacalis preferred to laying their eggs on well-watered maize, and then their offspring tended to survive better, attained bigger larvae mass, and developed more pupae and adults on the preferred maize. Oviposition selection of O. furnacalis positively correlated with height and leaf traits of maize, and offspring fitness positively related with water content and phytochemical traits of hosts. Overall, these results suggest that oviposition choice performed by O. furnacalis reflects the maximization of offspring fitness, supporting preference–performance hypothesis. This finding further highlights that the importance of simultaneous evaluation of performance and performance for water driving forces should be involved, in order to accurately predict population size of O. furnacalis under altered precipitation pattern.

No abstract

Entomopathogenic fungi (EPF), often considered as a bioinsecticide, are also able to colonize and establish a symbiotic relationship with plants as an endophyte. Recent studies demonstrated that endophytic EPF can enhance plant growth and are antagonistic to fungal pathogens. These newly emerging, but not yet fully understood, ecological roles suggest the possibility that EPF may further mediate oviposition preferences and offspring performance of an herbivorous insect. However, such EPF-mediated effects and underlying mechanisms are largely unexplored. Here, we examined the hypothesis that the endophytic EPF Beauveria bassiana can modulate oviposition behavior of the Asian corn borer Ostrinia furnacalis. We observed that O. furnacalis females preferred to lay eggs on B. bassiana inoculated maize plants. This is likely attributed to the net effects of plant volatile profiles induced by B. bassiana, with an increase in emitted amount of insect-attractive compounds 2-ethyl-1-hexanol and 3-hexen-1-ol and a decrease in insect-repellent compounds β-caryophyllene, naphthalene, and α-pinene. This finding provides an example of EPF-induced plant volatile-mediated interaction between plants and insects. However, fewer O. furnacalis larvae, pupae, and adults survived on the oviposition-preferred maize possibly due to lower plant nitrogen content. These results indicated that oviposition selection by O. furnacalis did not reflect the maximization of offspring fitness following B. bassiana inoculation. We suggest that fitness consequences of oviposition preferences should be considered when incorporating EPF as a biopesticide and as a potential biofertilizer within an integrated pest management programs.