Bee pollination biology: buzzing, behavior, and biomechanics

Abstract

For millions of years, flowering plants have relied on animals to transfer pollen among flowers; this leads to fertilization, seed set, and ultimately the passing of genetic information to the next generation. The relationships among pollinators and plants are complex. Pollinators generally visit flowers to collect food rewards. Plants have evolved a variety of mechanisms that manipulate pollinator behavior and increase the probability of successful fertilization. Plants can influence the evolution of pollinators, and pollinators can influence the evolution of plants. In this work, I characterize some of the relationships between plants and pollinators. First, I focus on buzz pollination (or floral sonication). When a bee performs this behavior, it usually grasps the anthers of the flower and, using its flight muscles, vibrates. When the vibration is transferred to the flower, pollen is released. This behavior is particularly useful when bees collect pollen from plants that have poricidal anthers that release pollen only from small pores. When bees vibrate these anthers, pollen is released, like salt coming out of a saltshaker. Buzz pollination is important for a variety of human foods (e.g. tomatoes). Honeybees, notably, cannot perform buzz pollination, and thus other pollinators, like bumblebees, are more effective at pollinating some plant species. I answer the following questions about buzz pollination: How do bumblebees change their buzz pollination behavior in different environmental conditions and on different species of plants? How do different species of bees perform buzz pollination differently? How does marking bees with bee tags affect their ability to perform buzz pollination? How does consuming a pesticide affect bees’ ability and likelihood to perform buzz pollination? Last, I investigate pollination from the plant’s perspective. I characterize the explosive pollination mechanism of the mountain laurel. I describe how the catapult mechanism of the mountain laurel may act as a pollen dispensing system – similar to poricidal anthers, the catapult may dispense pollen only to the subset of floral visitors that are likely to successfully transfer the pollen.