Inferring the foraging ranges of social bees from sibling genotypes sampled across discrete locations

Abstract

A knowledge of the distances regularly travelled by foraging bees is essential to understanding the movement of pollen across landscapes, and has implications for the conservation of both pollinators and plants. Unfortunately, the movements of bees are difficult to measure directly at ecologically relevant scales. A common strategy for quantifying the foraging ranges of social bees is to sample the genotypes of foragers across a landscape. Individual foragers can be assigned to colonies with polymorphic genetic markers, and the dispersion of siblings in space can be used to make inference about colony locations and foraging movements. Several previous studies have sampled sibling genotypes at discrete locations (for example, at regular points along a transect), rather than in continuous space. Restricting the collection of bees to discrete locations presents a number of considerations for sampling design and data analysis. In this paper, we develop a spatially-explicit, model-based framework for the simulation and estimation of foraging ranges. Using these tools, we simulated experiments to characterise the efficacy of different sampling strategies, and provide an example with actual data that demonstrates the advantages of our method over an approach based on regression.