2.8. Statistics
In the microcosm experiments, we compared the change in the number of A. aphidimyza and
C. carnea before and after exposure to H. axyridis using a 2-sample t-test. A repeated-measures mixed model analyses of variance(ANOVA) was used to compare differences in aphid abun-dance between microcosm treatments.
Block was included as a random effects factor and treatment, time, and their interaction as fixed effects factors.
Differences in aphid and
predator abundance between treatments were assessed by
comparing least squares means. Aphid counts were square-
root transformed prior to analysis to meet the assumptions
of the model.