Decrypting the Genetic Mysteries of Hornets: The Secret to their Achievements in Invading the World

Scientists from UCL have sequenced the genomes of two hornet species, the European hornet and the Asian hornet, for the first time. The researchers compared these genomes to the previously sequenced genome of the giant northern hornet and found clues to explain why hornets are such effective invasive species, adapted to new environments and prey. The study discovered rapid genome evolution, with many duplicated or mutated genes, particularly those related to communication and olfaction. Understanding these genomes may support the management of hornet populations, mitigating their ecological impact in invaded regions while supporting their pest control role in native ecosystems.

Hornets, the largest of the social wasps, play a vital ecological role as top predators of other insects. In their native regions, they help to regulate the populations of insects such as flies, beetles, caterpillars, and other types of wasps. However, hornets can become established as invasive species in areas they are not native to, potentially causing significant damage to ecosystems and economies by hunting important pollinators, such as honeybees, wild bees, and hoverflies.

The international team of scientists investigated the genomes of three types of hornets, including the Asian hornet, a species of hornet native to Southeast Asia that is an invasive species in many parts of Europe and has also been spotted in some parts of North America. The researchers sequenced the genomes of the native European hornet, Vespa crabro, and the invasive yellow-legged Asian hornet, Vespa velutina, comparing these with the genome of the giant northern hornet, Vespa mandarinia.

The study identified genes that have been rapidly evolving since the species differentiated themselves from other wasps and from one another, particularly relating to communication and olfaction. Co-author Dr Alessandro Cini stated that "These findings are exciting, as they may help explain why hornets have been so successful in establishing new populations in non-native regions." Understanding these genomes may provide insights into the biology of hornets, their behaviour, evolution, and how they interact with the environment, supporting the management of hornet populations around the world while promoting healthy, functional ecosystems and agriculture.

“Hornets are carried to different parts of the world accidentally by humans. All that is needed is a small number of mated queens to be transported, hidden in cargo perhaps. The genomes suggest that hornets have lots of genes involved in detecting and responding to chemical cues – these may make them especially good at adapting to hunt different types of prey in non-native regions.”

Senior author Professor Seirian Sumner (UCL Centre for Biodiversity & Environment) said: “These hornet genomes are just the beginning. The genomes of more than 3,000 insect species have now been sequenced by efforts around the world, but wasps are under-represented among these.

“Genomes tell us about aspects of the ecology and evolution that other methods cannot. Evolution has equipped these insects with an incredible genetic toolbox with which to exploit their environment and hunt their prey.”

Armed with these new genomes, the scientists hope to help improve the management of hornet populations, both for their ecosystem services as pest controllers in native zones, and as ecological threats in regions where they are invasive.