Can critical temperatures be related to insect order

Abstract

Insect phenology models are widely used for decision support in pest management and more recently in risk assessments During the last two decades numerous linear and nonlinear models have been used to describe insect development rates and estimate various critical temperatures (CT) including optimal development temperature (T_opt) maximum development temperature (T_max) minimum development temperature (T_min) and thermal constant (K) (eg day degree requirements to complete development) Using a database comprising more than 600 species from laboratory and field experiments the relationship between CT for the six main insect orders Coleoptera Diptera Hymenoptera Lepidoptera Homoptera and Hemiptera was compared There were no significant differences (P>005) between T_opt and T_max for all orders but T_min and K showed significant (P<0001) differences between orders with Hemiptera and Coleoptera having the highest and Homoptera the lowest T_min for egg to adult development Conversely the thermal constant (K) for egg to adult development was highest for Lepidoptera and lowest for Hymenoptera A possible explanation for the observed differences in T_min and K may relate to trophic level within the insect kingdom The lack of significant variation of T_opt and T_max across orders may simply relate to the models used to calculate these variables with linear models sometimes fitted to nonlinear temperature dependent development patterns