Seasonal trends in honey bee pollen foraging revealed through DNA barcoding of bee-collected pollen

Abstract

Recent declines in the abundance and diversity of wild bee species have made it important to understand how introduced species such as honey bees contribute to pollinating native plants. In this study, we decoded the waggle dances of Apis mellifera pollen foragers and used DNA barcoding of bee-collected pollen over 17 months to characterize spatio-temporal patterns in recruitment behavior and dietary breadth in a diverse yet fragmented Mediterranean scrub environment. Foragers danced for small, nearby patches of pollen resources during the cool dormant season but danced for 1.6-2.7-fold more distant and more widely dispersed resources during the hot dry season, a time of seasonal drought and floral dearth. Individual foragers collected pollen from a wide variety of species, but colonies focused recruitment on a small subset of common species in flower during each season: 2.7, 6.3, and 10% of all species in bloom during the dormant, growth, and dry seasons, respectively. Pollen foragers danced almost exclusively for cold-adapted native species during the dormant season, equally for native and nonnative plants during the short growth season, and primarily for non-native ornamental species during the dry season. Our results suggest that honey bee recruitment behavior and dietary breadth may be influenced by seasonal changes in pollen resources. Furthermore, they indicate that honey bees may be useful in pollinating common native plants, and that non-native ornamental species can provide a major source of colony protein during a seasonal dearth of flowering native species.

Quantitative multi‐locus metabarcoding and waggle dance interpretation reveal honey bee spring foraging patterns in Midwest agroecosystems

“…In conducting a waggle dance analysis study in tandem with our pollen metabarcoding approach, we were able to relate the taxonomic composition of our samples to observed spatial patterns of honey bee foraging, as in previous studies (Garbuzov, Couvillon, Schürch, Ratnieks, ; Danner, Keller, Härtel, & Steffan‐Dewenter, ; Park & Nieh, ; Sponsler, Matcham, Lin, Lanterman, & Johnson, ). In conducting these analyses together, our broad goal was to understand not only what plant taxa were being foraged upon most heavily but to also infer where in the landscape these taxa were most likely growing.…”

Adaptive evolution of honeybee dance dialects

“…[31]; circuit duration, e.g. [22,[32][33][34]). We decided to infer foraging distance from dances' circuit durations because this is much more time efficient: to determine a dance's average circuit duration, one needs to make a single time measurement of a counted number of consecutive circuits.…”

Combined nutritional stress and a new systemic pesticide (flupyradifurone, Sivanto®) reduce bee survival, food consumption, flight success, and thermoregulation

“…We therefore tested field-realistic situations exposing bees to these environmental stresses throughout the year. We categorized our study period into two seasons, winter (September to February) and summer (March to August), to respectively reflect the cool and wet dormant season, and warm and dry growth season that are relevant to bees in our local ecosystem (Park and Nieh, 2017).…”

“…Hesselbach and Scheiner (2019) also observed variations in the effects of FPF depending on the season the bees were collected. Honey bees can adapt to seasonal changes and food scarcity by modifying their foraging range (Schneider and McNally, 1993) and recruitment strategies (Park and Nieh, 2017). Bees are differentially affected by pesticides according to season: following pesticide treatment, winter bees showed higher mortality than summer bees (Decourtye et al, 2003).…”