Nymphalid Immune Response and Infection: Mechanisms Facilitating Host Plant Range Expansion

Abstract

The relationship dynamics among host plant phytochemistry, herbivore fitness, and herbivore immune defense has been the focus of recent studies in ecoimmunology. However, there are few studies connecting all three of the aforementioned to diet breadth expansion. I used the common buckeye (Junonia coenia) (Lepidoptera: Nymphalidae) to investigate the mechanisms behind how the introduced host incorporation event had first occurred from an ecoimmunological perspective. The yellow monkeyflower (Mimulus guttatus) is the native host and narrowleaf plantain (Plantago lanceolata) is a recent introduced host that has been incorporated into buckeye diet. In the wild, insects encounter many pathogens and to simulate this natural event, the Junonia ceonia densovirus (JcDNV) was used to provide a natural immune challenge. In this work, I revealed that the neurohormone octopamine plays a role in oviposition behavior and provide evidence that the introduced host is a good quality host that buckeyes will continue to utilize.