Pollinators Use Multiple Cues to Identify Flowers Across Continents

Although at least 75% of our crop species depend on the activities of wild pollinators, little is known about their flower preferences. As global populations of domestic bee pollinators decline, it is of utmost importance for us to understand what factors attract wild pollinators such as hoverflies to flowers, and how these preferences differ in the face of environmental change. Now, a team of scientists from Uppsala University in Sweden and Flinders University in Australia, and the National Centre for Biological Sciences (NCBS) in India have discovered that hoverflies, a group of generalist pollinators, use a combination of cues such as color, shape, and scent to identify flowers. You and I live in a sensory world--sight, sound, touch, and taste blend to give us a sense of our surroundings. However, imagine perceiving the world as a fly, with a brain the size of a pinhead. Yet many insects with miniscule brains manage to do exactly what we do--identify objects like a flower, or a plant. Dr. Karin Nordström's group from the University of Uppsala, Sweden, and Flinders University, Australia, and Dr. Shannon Olsson's team from the NCBS in Bangalore, India, have long been interested in how insects, with their "teeny-tiny" brains can recognize objects such as flowers. Now, through their collaborative work on hoverflies, the two teams have found an answer. These insects use a multimodal sensory mechanism--in other words, hoverflies require a combination of clues including shape, size, color, and scent--to recognize flowers in different environments across the world. The teams' results are especially important with respect to our scarce knowledge of what attracts wild insect pollinators to flowers. Although at least 75% of our crop species depend on the activities of wild pollinators, little is known about their flower preferences. As global populations of domestic bee pollinators decline, it is of utmost importance for us to understand the factors that attract wild pollinators such as hoverflies to flowers, and how these preferences differ in the face of environmental change.