Detailed closeup on the Migrant hoverfly, Eupeodes corollae sitting on a green leaf

Migrant hoverflies, scientifically known as Eupeodes corollae, are fascinating insects with completely different but equally interesting ecology as juveniles and adults. These agile fliers are widespread across temperate regions, migrating with the changing seasons to maintain their populations. Particularly common in the UK, migrant hoverflies are frequently spotted in parks and gardens across Europe. Remarkably adaptable, they also thrive in various subtropical environments, including the Mediterranean and parts of North America. When they migrate, it appears that females arrive at the new location first. However, it is not yet known if this is because they leave earlier to find better resources for egg-laying or because they are just better fliers.

Hoverflies provide both pest control and pollination services, making them particularly interesting. As juveniles, migrant hoverflies are voracious predators of aphids, which are considered pests due to their destructive impact on plants. When they mature, adult hoverflies feed on nectar from flowers, simultaneously pollinating them. In a world where effective pest control and pollination are ongoing challenges, insects like hoverflies are indispensable.

Macro shot of a migrant hoverfly on siberian chive flowersOne particularly fascinating trait of hoverflies is their mimicry of bees and wasps. Their black and yellow bodies resemble these stinging insects, which helps deter predators such as birds and other insects such as dragonflies. However, hoverflies are harmless and stingless. This mimicry is a form of protective adaptation, as hoverflies belong to a completely different order of insects than bees and wasps.

Another intriguing aspect of hoverflies is the sexual dimorphism in their body symmetry. The yellow markings on males often merge, while females have narrower, distinct markings. Additionally, in males, the eyes will often meet in the centre to form a single, large, joined eye rather than two separate ones. These compound eyes are composed of many tiny components called ommatidia, providing them with excellent vision.

At the Natural Resources Institute (NRI), researchers are engaged in various studies related to migrant hoverflies. Our focus includes identifying floral compounds that attract hoverflies, understanding their responses to pesticides and pathogens, and exploring how they learn and respond to volatile compounds that might help them locate flowers or egg-laying sites.

A new area of our research investigates whether we can train hoverflies to respond to specific cues. By exposing them to certain stimuli along with sugar water, a reliable cue, we examine whether their memory can be enhanced using caffeine and assess the impact of pathogen exposure on their learning and memory. This research holds significant potential for improving pollination efficiency and revealing whether certain pest control methods, which do not kill hoverflies outright, might still impair their pollination abilities.