Honeybee cognitive ecology in agricultural settings

FARINA WALTER M.

Washington DC

Workshop; Janelia Farm Conference: Learning and Memory: A Synthesis of Flies and Honeybees; 2014

Howard Hugh Medical Institute

Agricultural scenarios that require insect pollinators provide an opportunity to study how changing environments influence the way the honeybees perceive, learn, discriminate, and use odor resource information along successive flowering events. It is well-known that floral constancy displayed by honeybees promotes a biased preference for specific resources, and sets this insect in a central role as pollen vector in commercial crops that require cross pollination. We evaluated their behavior in different crops that require them as essential pollinators. One of them is the sunflower (Hellianthus annuus) plants used to produce hybrid seeds. In this agricultural ecosystem, honeybees have to transfer pollen from the male fertile or pollen parent inflorescences to the male sterile or seed parent inflorescences. How bees behave in these crops which exhibit a noticeable dimorphism between cultivars is an open question. We then described their foraging performance in different hybrid crop fields that presented different dimorphism between cultivars, and also estimated their efficiency in the transfer of pollen between cultivars. Additionally, their behavioral plasticity was evaluated according to environmental changes, an issue that has been extensively studied in the laboratory but seldom along temporal variation in natural resources. To study this topic, we worked in mixed agricultural settings of apple (Malus domesticus) and pear (Pyrus communis) trees, in which their blooming periods were shifted slightly. Individual preferences correlated with variations in the type of resources collected at the colony level according to changes in the floral market. Proboscis extension response (PER) to pear and apple floral scents of bees captured at the hives located within the crops fluctuated according to changes in floral availability too. The capability of the PER-trained honeybees to discriminate between both floral scents at the beginning or at the end of the flowering period was also found, although bees lose this ability when both flowers were fully available. These response patterns suggest that olfactory information experienced on flowers were recalled to predict reward yet susceptible of being reversed when the floral scents were no longer available in the orchard. Combining behavioral assays and field observations, we provide examples here examples of how honeybees process floral odor information to make decisions about resources in complex environments.