Effect of climatic and biotic factors on summer diapause incidence along a geographical gradient over two consecutive years

This dataset contains field data collected in 2022 and 2023 to assess the incidence of summer diapause in cereal aphid parasitoids along a longitudinal climatic gradient across Europe, spanning from western France to the Czech Republic (~1200 km). Mummies parasitizing cereal aphids were sampled in wheat fields at multiple sites during late spring and subsequently reared under controlled laboratory conditions to determine diapause incidence, adult emergence rates, and mortality. In addition, a range of ecological and climatic variables were recorded at each site, including aphid infestation levels, species abundances, parasitism and hyperparasitism rates, as well as local climatic indices. These data provide a unique opportunity to investigate how both abiotic and biotic factors shape the expression of summer diapause in cereal aphid parasitoids along a large-scale environmental gradient. An accompanying R script allows users to reproduce the main analyses, including the description of the climatic gradient and the evaluation of the direct and indirect effects of climate and biotic parameters on diapause incidence. All variables included in the dataset are fully described and documented within the R script (https://github.com/lenajego/IRP-GRADIENTS/blob/main/IRPGRADIENTS_Summer_Diapause_Biot_Abiot_2023_LJ_V6.R).