EASTBIO Bees and buzz pollination in crops: Evaluating the potential for matching bee vibrations and buzz-pollinated crops to improve fruit yield

Bee pollination is an ecological interaction with enormous importance across diverse natural environments and in many agricultural crops. A particularly intriguing type of interaction between bees and flowers is buzz pollination, which involves specialised flowers and vibration-producing bees. This interaction requires a specialised type of bee behaviour: the production of powerful thoracic vibrations applied to pollen-carrying structures in flowers. This behaviour has evolved in some bees (e.g. bumblebees) but not others (e.g., honeybees). Among plants, thousands of species have evolved flowers that require vibrations to be fully pollinated. Buzz-pollinated flowers usually keep pollen inside tubular structures (anthers or corolla tubes), which restrict pollen access and removal. Buzz-pollinated plants include important food crops such as tomato, blueberries, and kiwi. Buzz-pollinated crops grown in greenhouses or outdoor settings often require supplemental pollination to achieve full fruit set and to improve fruit quality. This supplemental pollination is often provided using mechanical shakers, or additional pollinators such as honeybees or bumblebees. However, the effectiveness of these treatments is enormously varied even within the same crop species. This diversity of outcomes could be explained by variation at the plant, bee or environmental levels. Previous work has shown that buzz-pollinating bees differ widely in the type of vibrations they can produce, and that the type of vibration applied to a flower determines pollen release, and potentially fruit quality. Moreover, environmental variables such as temperature and humidity may influence both the likelihood of bees producing vibrations or the effectiveness of these vibrations to release pollen from different types of flowers. The main goal of this project is to investigate what type of supplemental pollination is more effective at maximising fruit yield in buzz-pollinated soft fruits including blueberries. In this project, we will use laboratory and field experiments to address three questions: (1) What is the relationship between vibration properties (amplitude, frequency and duration) and pollen release and fruit quality across different varieties of blueberries? (2) What are the properties of the vibrations used by buzz-pollinating bees while visiting experimental plots of different varieties of blueberries? (3) What is the effect of increased temperature and humidity on the capacity of buzz-pollinating bees to release pollen from flowers? Our experimental approach will include laboratory experiments investigating the biomechanical properties of buzz pollination using bees, accelerometers, mechanical shakers, particle counters, and laser vibrometers. The biomechanical component of the study will involve regular work with the Centre for Ultrasonic Engineering at the University of Strathclyde. Glasshouse and field trials of bee vibrations, pollen removal and fruit set will be carried out at both the University of Stirling and The James Hutton Institute, which hosts a large live collection of blueberry cultivars and has extensive experience with the pollination of food crops. Experiments of buzz-pollination under varying temperatures and humidity conditions will be carried out at the Controlled Environment Facilities at the University of Stirling. The results of this project are of great relevance for food security in the context of declining populations of bee pollinators and will offer insights into the effects of increases in temperature associated with climate change on the pollination effectiveness of buzz-pollinating insects.

This is a full-time opportunity