“Pollinator size and its consequences” - Predictive allometry for pollinating insects: An R package

Abstract

Allometric scaling laws have key implications for the conservation and management of pollinating insects in both managed and unmanaged ecosystems. Body size (BS) can predict influential traits such as foraging distance (FD) yet available predictive models for both body size and foraging distance are outdated, rely upon geographically restricted sampling and have limited applicability for non-bee taxa. More accurate predictions of pollinator body size and related foraging distance require models that consider biogeography, ecological traits (eg. sociality and nesting strategies), intraspecific variation and phylogenetic relatedness. Here we present the results of an international collaboration that catalogued existing predictive allometries for pollinating insects (Hymenoptera (BS: 38, FD: 6), Diptera (BS: 26, FD: 0) and Lepidoptera (BS: 21, FD: 1) and improved upon pre-existing equations for estimating body size and foraging distance in key pollinating taxa (bees and hoverflies). We measured dry weight, intertegular span and body length of bees and hoverflies from Australia (n = 900), Europe (n = 1000) and USA (n = 650) and constructed region-specific predictive equations for estimating pollinator body size. We re-examined bee and hoverfly body size:foraging distance relationships using pre-existing and new data. These models, to be released as an R package in late 2018, will be a useful resource in the conservation management of both wild and managed pollinators globally.