Abstract

Organisms must continually adapt to changing environmental conditions to survive. We focused on caterpillars because they are very sensitive to temperature and play an important role in many food webs.  We hoped to determine if size or phylogeny affect thermal tolerance. We hypothesized that caterpillars with lower masses would have higher thermal tolerance because past studies found smaller organisms had higher thermal tolerances. We also hypothesized that caterpillar species with similar evolutionary histories would have similar thermal tolerances. We collected 156 caterpillars and exposed the caterpillars to extreme high and low temperatures and recorded the temperatures at which they lost motor control (critical thermal minimum and maximum).  Our results do not show significant correlations between thermal tolerance and evolutionary history or caterpillar size. It is possible that other factors such as season or symbiotic relationships affect thermal tolerance.