Data for: Beyond latitude: Temperature, productivity, and thermal niche conservatism drive global body size variation in Odonata

Aim: So far, latitudinal body size-clines have been primarily discussed in the context of thermoregulation, sensu Bergmann. However, body size patterns are ambiguous in ectotherms and this heterogeneity remains poorly understood. We tested whether Bergmann’s rule and the resource availability rule which states that energetic requirements determine species’ body size, apply to damselflies and dragonflies (Odonata). Furthermore, we hypothesised that the contrasting effects of thermoregulation and resource availability (e.g. productivity) can obscure the overall gradient in body size variation.
Location: Global
Time period: Contemporary
Major taxa studied: Odonata
Methods: Using data for 43% of all odonate species described so far, we tested our hypotheses in phylogenetically and spatially comparative analyses at assemblage and species level. For the distribution data, we integrated expert range maps and ecoregional ranges based on all available occurrence records. To distinguish between l..., For our main analysis, we combined three types of information.
1) Body size
We compiled body size data from measurements of museum specimens and from the literature for 2,802 odonate species worldwide. For the main analyses, we used only data of body length for adult male individuals but mobilized other proxies of body size if available for imputation of the body length and supplementary analysis of body shape differences between Anisoptera and Zygoptera. Specifically, we measured the body and hindwing length (excluding terminal appendages) from images of 724 individuals of African odonates provided by the Naturalis Biodiversity Center (RHNM, Leiden, The Netherlands) and 487 specimens of African species from the Senckenberg Natural History Museum (SNHM, Frankfurt, Germany). For the images of African species from the Naturalis Biodiversity Center, European species from Dijkstra and Lewington (2006), and North American species from Needham et al. (2000), we calculated the body length, hin...,