When does temperature limit bee flight? Identifying the missing pieces of the puzzle

Bees are the most important insect pollinators, and nearly all bee-mediated pollination depends on flight. In this review, we identify five key gaps that limit our ability to predict how abiotic factors shape bee flight performance and ecology. First, while clade strongly influences endothermy and flight temperature limits, we still know little about how phylogeny, body size, and ecological traits shape thermal biology across the full diversity of bee species - most data come from temperate, northern hemisphere  Apinae. Second, because the mechanisms of thermal balance during flight have only been studied in a handful of species, and these vary, we clearly lack a predictive understanding of when bees will be physiologically stressed by temperature during flight. Third, although some studies suggest desiccation may limit flight more than overheating, the links between thermal balance and water regulation remain poorly understood. Fourth, we know very little about bees’ capacity to r..., The table-1 presents clade-level variation in the thermal biology of bees, which was created by searching scholar.google.com and Web of Science using relevant keywords such as: bees, temperature, thermal, flight, activity, foraging, CTmax, and thermal limit. Many of the references were not found through web searches, but rather by investigating the bibliographies of in-hand papers. We are sure that additional relevant papers exist, but feel that it is very likely that the papers found and used will provide representative numbers for each parameter. Clades were based on Henriquez-Piskulich et al. 2024. To indicate the approximate number of species per clade, we relied on Danforth et al. 2019. To indicate the number of species in the clade whose flight thermal biology has been studied, we summed the number of species whose data contributed to Table 1. The endothermic index (thorax temperature – operative temperature) was taken from papers that directly measured minimal air and thorax temp..., # When does temperature limit bee flight? Identifying the missing pieces of the puzzle

Dataset DOI: [10.5061/dryad.4qrfj6qpt](10.5061/dryad.4qrfj6qpt)

## Description of the data and file structure

This review is organized around specific ‘missing pieces’ of information needed to build predictive models of how environmental temperature affects bee flight. Ecological and morphological differences affect flight energetics and thermoregulation. Therefore, the following data consist of physiological (e.g., CO~2~ production and O~2~ consumption rates, *CT*~max~, and other metrics of thermoregulation and performance), morphological (e.g., pubescence, reflectance, emissivity, body size, and body mass), and behavioral measurements (e.g., activity time, thermal thresholds for flight, etc.). These data are either original to this study or are from the primary literature. Here, we consider phylogenetic contexts and ecological niches when interpreting patterns of thermal performance across clade...,