Predation risk makes bees reject rewarding flowers and reduce foraging activity
- 613 Downloads
In the absence of predators, pollinators can often maximize their foraging success by visiting the most rewarding flowers. However, if predators use those highly rewarding flowers to locate their prey, pollinators may benefit from changing their foraging preferences to accept less rewarding flowers. Previous studies have shown that some predators, such as crab spiders, indeed hunt preferentially on the most pollinator-attractive flowers. In order to determine whether predation risk can alter pollinator preferences, we conducted laboratory experiments on the foraging behavior of bumble bees (Bombus impatiens) when predation risk was associated with a particular reward level (measured here as sugar concentration). Bees foraged in arenas containing a choice of a high-reward and a low-reward artificial flower. On a bee’s first foraging trip, it was either lightly squeezed with forceps, to simulate a crab spider attack, or was allowed to forage safely. The foragers’ subsequent visits were recorded for between 1 and 4 h without any further simulated attacks. Compared to bees that foraged safely, bees that experienced a simulated attack on a low-reward artificial flower had reduced foraging activity. However, bees attacked on a high-reward artificial flower were more likely to visit low-reward artificial flowers on subsequent foraging trips. Forager body size, which is thought to affect vulnerability to capture by predators, did not have an effect on response to an attack. Predation risk can thus alter pollinator foraging behavior in ways that influence the number and reward level of flowers that are visited.
KeywordsBombus impatiens Bumble bees Foraging Non-consumptive effects Pollination Predation risk
We thank Josefa Bleu and Julia Olszewski for their enthusiastic assistance with preliminary experiments, the members of the Bronstein and Dornhaus labs, and two anonymous reviewers for helpful comments on the manuscript, the Department of Ecology and Evolutionary Biology at the University of Arizona for funding the experiments, and funding for EIJ from NSF DMS 0540524 to R. Gomulkiewicz.
- Bachman WW, Waller GD (1977) Honeybee responses to sugar solutions of different compositions. J Apic Res 16:165–169Google Scholar
- Bednekoff PA (2007) Foraging in the face of danger. In: Stephens DW, Brown JS, Ydenberg RC (eds) Foraging: behavior and ecology. The University of Chicago Press, Chicago, pp 305–329Google Scholar
- Brown JS, Kotler BP (2007) Foraging and the ecology of fear. In: Stephens DW, Brown JS, Ydenberg RC (eds) Foraging: behavior and ecology. The University of Chicago Press, Chicago, pp 437–480Google Scholar
- Chien SA, Morse DH (1998) The roles of prey and flower quality in the choice of hunting sites by adult male crab spiders Misumena vatia (Araneae, Thomisidae). J Archnol 26:238–243Google Scholar
- Cruden RW, Hermann SM, Peterson S (1983) Patterns of nectar production and plant–pollinator coevolution. In: Bentley B, Elias T (eds) The biology of nectaries. Columbia University Press, New YorkGoogle Scholar
- Heiling AM, Herberstein ME (2004) Floral quality signals lure pollinators and their predators. Ann Zool Fenn 41:421–428Google Scholar
- Hugie DM, Dill LM (1994) Fish and game—a game-theoretic approach to habitat selection by predators and prey. J Fish Biol 45:151–169Google Scholar
- Morse DH (2007) Predator upon a flower: life history and fitness in a crab spider. Harvard University Press, CambridgeGoogle Scholar
- Sih A (1998) Game theory and predator–prey response races. In: Dugatkin LA, Reeve HK (eds) Game theory and animal behavior. Oxford University Press, Oxford, pp 221–238Google Scholar