When pollinators are also herbivores: do you get an arms race in hawkmoths and evening primroses? 2019
Chicago Botanic Garden

Ecology, Population Biology, Reproductive Biology

The evening primrose family, Onagraceae, includes many species that are nocturnally pollinated by hawkmoths. Many different hawkmoth species are known to pollinate Onagrads but only one species, Hyles lineata, uses plants as both a nectar source (adults, act as pollinators) and larval host (caterpillars, act as herbivores). Female H. lineata moths oviposit on plants when nectaring and the caterpillars feed on leaf tissue, flower buds and flowers. In some species, herbivory by H. lineata caterpillars can dramatically reduce plant fitness (fruit set) if damage to flowers diminishes the reproductive potential. To reduce herbivory, plants have evolved defensive traits (trichomes, secondary compounds) and/or can upregulate the expression of such traits. The extent to which these defensive traits are expressed is largely a result of past selective pressures imposed by herbivores. Given this, species that have a lot of herbivory may be better defended than those that do not. This project will test the hypothesis that Oenothera species that have experienced a lot of herbivory will be better defended than those that experience little-to-no herbivory. The REU student will conduct a series of trials with living caterpillars and 9 different taxa with in Oenothera section Pachylophus. Caterpillars fed plant materials (leaves, flower buds, flower petals) from well-defended plants are expected to perform poorly (lower weight gain, higher mortality). This work will contribute to a larger understanding of how plants navigate the dual needs of successful reproduction and minimizing the negative impacts of herbivory.

Intern(s)