| Populations are a fundamental unit of ecological diversity that provide essential goods and services to humanity and are the basis of functioning ecosystems. Understanding the structure of populations and their sensitivity to change is therefore critical. The dynamics of any population depend on how and when it interacts with populations of other species. In the case of herbivorous insects, an interaction with plants can strongly influence the abundance and characteristics of insects through time. To better understand how hostplant interactions affect insect populations, I studied the influence of hostplant quality on a butterfly population. I examined how larval survivorship of the Bay checkerspot (Euphydryas editha bayensis) is affected by variation in the seasonal decline of its hosts. This collection of studies explores this insect's resources, its performance on and use of various host species, and its dynamics and sensitivity to change. The work expands our knowledge of insect-plant dynamics in general and improves our understanding of how environmental variation affects the checkerspot-hostplant interaction in particular. It also suggests approaches for conserving insect populations. |
