Genome sequencing reveals insights into the success of invasive hornet species

Scientists from UCL (University College London) has successfully sequenced the genomes of two hornet species for the first time, namely the European hornet and the Asian hornet (also known as the yellow-legged hornet). By comparing these genome sequences with that of the giant northern hornet, which was recently sequenced by another research group, the scientists have uncovered valuable insights into why hornets have been highly successful as invasive species worldwide. The findings of their study have been published in Scientific Reports.

Hornets are the largest social wasps and play a crucial ecological role as apex predators of other insects. In their native habitats, they act as natural pest controllers, regulating the populations of various insects like flies, beetles, caterpillars, and other wasp species. These services are essential for maintaining healthy ecosystems and supporting agriculture.

However, hornets have also demonstrated remarkable success as invasive species. They can establish themselves in non-native areas and pose significant threats to both ecosystems and economies by preying on important pollinators such as honey bees, wild bees, and hoverflies.

To gain a better understanding of how these hornet species have expanded their ranges so effectively, an international team of scientists analyzed the genomes of three different types of hornets.

The genome sequence represents the genetic code or set of instructions that defines a species. Comparing the genomes of different species allows scientists to gain insights into their biology, including their behavior, evolutionary history, and interactions with the environment.

In this study, the researchers sequenced the genomes of the European hornet (Vespa crabro), a native species that serves as a vital top predator and is protected in certain regions of Europe, and the invasive Asian hornet (Vespa velutina), commonly referred to as the yellow-legged hornet. The Asian hornet has established itself across much of Europe in the past two decades, posing a significant threat to native ecosystems, and has sporadically been observed in the UK. The scientists compared these genomes with that of the giant northern hornet (Vespa mandarinia), a species recognized for its role as a pest controller, pollinator, and food source in its native Asian range. The giant northern hornet has more recently appeared in North America, where it may endanger native fauna.

Through their analysis of the three closely related hornet species, the researchers discovered specific genes that have undergone rapid evolution since the species diverged from other wasps and from each other. Notably, they identified genes associated with communication and olfaction (smell) that have undergone significant changes.

Dr. Emeline Favreau, the study’s lead author from UCL Centre for Biodiversity & Environment, expressed excitement over the evidence of rapid genome evolution observed in these hornet genomes compared to other social insects. They found numerous genes that had been duplicated or mutated, including genes likely involved in communication and sensing the environment.

Genome evolution is instrumental in enabling organisms to adapt to their surroundings, allowing them to develop new behaviors and physiological traits.

Co-author Dr. Alessandro Cini, who conducted the research at UCL before relocating to the University of Pisa, highlighted the significance of these findings in explaining the successful establishment of hornets in non-native regions. Since hornets are inadvertently transported by humans to different parts of the world, a small number of mated queens hidden in cargo can lead to the establishment of new populations. The genomes suggest that hornets possess numerous genes associated with detecting and responding to chemical cues, potentially making them highly adept at adapting to hunt different prey species in non-native regions.

Senior author Professor Seirian Sumner from UCL Centre for Biodiversity & Environment emphasized that these hornet genomes represent only the beginning. While over 3,000 insect species have had their genomes sequenced worldwide, wasps are underrepresented in these efforts. Genomes provide insights into ecological and evolutionary aspects that other methods cannot uncover. These insects possess an extraordinary genetic toolkit enabling them to exploit their environment and prey effectively.

With the newly sequenced hornet genomes, the scientists aim to enhance hornet population management strategies. This knowledge can be used to maximize their ecosystem services as pest controllers in their native habitats and address the ecological threats posed by invasive populations in other regions.

Source: University College London

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