Meeting Abstract
Behavior may vary from being completely pre-programmed, to being readily and extensively modified by experience. When learning has costs, we expect that congenital expression of behavior will be favored. Foraging behavior is one essential activity where the costs of learning could impact the degree of pre-programming. While the majority of angiosperms offer two nutritionally complementary rewards to bees, pollen and nectar, most studies have focused on nectar foraging. Floral morphologies vary considerably and complex designs that offer nectar can require extensive learning. Little is known about costs of pollen foraging however, even though it is the sole protein source for larval and adult growth, and thus essential for survival. Six-8% of angiosperms offer only pollen, concealed in specialized poricidal anthers. Only bees that are able to vibrate the anthers and thus shake the pollen out (a complex behavior termed floral sonication) can access this essential nutrient. While we know a great deal about the function of sonication, the degree to which learning plays a role in shaping this behavior is an open question. In the Eastern Bumble Bee (Bombus impatiens) we find that the sonication motor routine is strongly congenitally expressed. Sonication behavior is rapidly released upon discovery of the androecium and is mediated by chemical cues from the anthers. We show evidence that a decrease in latency to sonicate with experience is likely a result of priming or imprinting, involving a heightening of responses to releaser stimuli. While anther cues appear to release sonication innately, petal cues release landing behavior innately. However, with experience, anther cues also promote landing.
