Investigating Honey Bee Pollen Foraging Patterns Across a Season Using DNA Metabarcoding

Abstract

The western honey bee, or Apis mellifera, is a vital pollinator, essential for both ecosystems and agriculture worldwide. As human influences on these bees become more pronounced, understanding their pollen foraging behavior is increasingly important. Pollen provides crucial nutrients for A. mellifera such as protein and lipids that are necessary for hive health and prosperity. Pollen DNA metabarcoding allows for the longitudinal analysis of the floral sources of corbicular (bee-collected) pollen. In this study we employ the use of metabarcoding and Oxford Nanopore Sequencing technology to analyze the floral composition of pollen samples collected on a weekly basis from two closely related hives. In total, we identified 74 distinct plant taxa (at the genus level) between the two hives. Although both hives had equivalent values of taxonomic richness and diversity, the majority of taxa identified were unique to the individual hives. This indicates a large degree of variation in pollen foraging despite the hives relative proximity. In addition to this interhive analysis, we also analyzed changes in pollen origin of a single hive across the course of five months. We identified 59 distinct plant taxa within samples from this hive whose presence and relative abundance differ drastically on a weekly basis with no taxa being present in all samples across the observed time period. In addition, even though there was a median of 8 to 9 taxa detected in each sample, each sample was composed primarily of 1 to 2 taxa indicating a degree of foraging preference that changes on a regular basis. Further quantitative and qualitative comparisons completed in this study demonstrate the degree of variation in pollen foraging patterns both throughout the season and between hives.