Abstract: It is unknown what mechanism bees use to adjust their foraging behavior during floral turnover. Optimal foraging theorem suggests bees need to balance efficient resource collection with reducing the costs of switching between plant species as floral abundance shifts. Most organisms maximize behavior based on memory, or number of past experiences used, and learning, or how much a past experience influences foraging behavior. There are two extremes of memory and learning: organisms in variable environments tend to have shorter memories and determine foraging behavior based on newer experiences versus older memories, while organisms in stable environments have longer memories and determine foraging behavior based on both older and newer experiences. Our objective is to determine how a generalist bee, Bombus impatiens, uses memory and learning to adjust its foraging behavior to a quickly-changing floral environment.
We investigated memory and learning using a field study to inform a matching computer simulation. In a meshed hoop house, we used 44 potted plants to simulate gradual floral turnover from Trifolium pratense to Monarda fistulosa over a series of 10 environmental trials. No preference was shown between the two plant species, and relearning cost was only observed when switching from M. fistulosa to T. pratense. The results of field study suggests B. impatiens is adapted to a moderately variable environment, with foraging behavior adjusting slowly to changing floral abundance.
The simulation is still being adjusted, using existing theories with knowledge of floral environments to build certain hypothesis. Floral environments change in floral abundance daily and in floral type on a longer time scale. Therefore, B. impatiens may be adapting both on a daily scale and a longer-term scale. This could be done by valuing newer experiences than older experiences, likely on a daily time-frame. Additionally, its memory could be long in order to slow the adjustment of foraging behavior to a slowly-changing floral environment. By doing this, B. impatiens may adjust quickly to abundance, but slowly to new plant species.
Our completed simulation will further our understanding of memory and learning, allowing us to construct environments that target specific bee behavior. This could be used to direct bees to visit plants in need of conservation in restored habitats, to increase crop pollination during crucial bloom periods, or to move further from areas treated with chemicals at specific times of the year.
