TY  - JOUR
A1  - Koussoroplis, Apostolos-Manuel
A1  - Wacker, Alexander
T1  - Covariance modulates the effect of joint temperature and food variance
on ectotherm life-history traits
JF  - Ecology letters
N2  - Understanding animal performance in heterogeneous or variable environments is a central question in ecology. We combine modelling and experiments to test how temperature and food availability variance jointly affect life-history traits of ectotherms. The model predicts that as mean temperatures move away from the ectotherm's thermal optimum, the effect size of joint thermal and food variance should become increasingly sensitive to their covariance. Below the thermal optimum, performance should be positively correlated with food–temperature covariance and the opposite is predicted above it. At lower temperatures, covariance should determine whether food and temperature variance increases or decreases performance compared to constant conditions. Somewhat stronger than predicted, the covariance effect below the thermal optimum was confirmed experimentally on an aquatic ectotherm (Daphnia magna) exposed to diurnal food and temperature variance with different amounts of covariance. Our findings have important implications for understanding ectotherm responses to climate-driven alterations of thermal mean and variance.
KW  - Biotic interactions
KW  - co-limitation
KW  - Daphnia
KW  - environmental fluctuations
KW  - heterogeneity
KW  - variability
KW  - vertical migration
KW  - zooplankton
Y1  - 2016
U6  - https://doi.org/10.1111/ele.12546
SN  - 1461-023X
SN  - 1461-0248
VL  - 19
SP  - 143
EP  - 152
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -