9403318 Garrigan The metabolic load (ML) hypothesis suggests that quantitative differences between specialist and generalist insect herbivores are responsible for the evolution of dietary specialization. This hypothesis is underpinned by two critical assumptions: that the capability to detoxify plant secondary compounds is physiologically costly to insects and that specialists have a detoxification advantage relative to generalists. Rigorous evaluation of the ML hypothesis will only be possible when reliable data are collected in a consistent fashion for several specialist and polyphagous herbivore. Bomb calorimetry and newly - developed flow through respirometry will be employed to calculate growth and metabolic efficiency for 12 Lepidopteran herbivore (six generalist and six specialist) species being fed six different plant - derived toxins; cost and efficiency estimates will be in comparable energetic units. %%% This research addresses the topic of host specialization in plant / insect interactions. Within the past five to ten years, the scientific community has come to recognize that a treasure trove of biologically active chemical compounds exists within the natural world. The most intelligent way to understand this complexity is by ascertaining how it evolves over ecological / evolutionary time. One of the most elegant ways of accomplishing this goal is by "assaying" coevolved ecological relationships using a battery of extractive and quantitative chemical methods of analysis. Results of such studies can then be adapted for pharmacological purposes. ***
