Saddleback Journal of Biology - Saddleback College

Fall 2009 Biology 3B Paper
The Effects of Temperature on Rates of Metamorphosis in Vanessa cardui
Rose Park and Laura Chan
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
The objective of this study was to determine if environmental temperatures could
potentially be a contributing factor in the rate of metamorphosis in Vanessa cardui,
commonly known as the Painted Lady butterfly. The researchers did this by testing the
length of time in days each subject took to progress from the larval stage to the pupa
stage as a chrysalis in two groups incubated at different temperatures. The reasoning
for this study was that if the subjects incubated at the higher temperature, 27.7C,
progressed to the pupa stage at a significantly greater rate than those incubated at the
lower temperature, 22.2C, temperature could be a contributing factor to the rate of
metamorphosis. The investigators hypothesized the higher temperature of incubation
would yield a greater rate of metamorphosis in V. cardui than the lower temperature.
The hypothesis was tested by recording the number of days for each caterpillar in each
test group it took to progress from the larva to pupa stage. The mean number of days it
took for the higher temperature group was 11.450.65 days (S.E.M., N=20), while the
mean number of days for the lower temperature group was 15.570.16 days (S.E.M.,
N=24). An unpaired, one-tailed t-test was used and the result suggests that there is a
significant difference in metamorphic rate between subject groups (p