Research Grant Title:               Prey Spectrum of Asian Hornets

Research Grant Period:           September 2020 to December 2022

Grantee:                                     University of Exeter
Prof J.L. Osborne, Prof C.R. Tyler, Dr P.J. Kennedy, Dr J. Poidatz

1st quarter Report

The Asian hornet (Vespa velutina nigrothorax) is an invasive non-native predator, of bees and others insects, that is rapidly spreading across parts of Europe since its accidental introduction into south-west France in or before 2004.  In France, beekeepers estimate they have lost 5-80% of honeybee colonies (average 30%) in areas where Asian hornets have become well established.  This compares to the scale of losses that have resulted from the spread of the non-native Varroa destructor mites across Europe in the 1990s, and it is consequently anticipated that an establishment of the Asian hornet in the UK will adversely impact on the viability of our beekeeping and honey industry.  Of additional and immediate concern is that the Asian hornet preys opportunistically on a range of wild insects, and damage to pollinator communities and pollination services could be extensive but is so far poorly quantified.

This BBKA funding enables us to augment the current BBSRC-funded project on “Asian hornets: measuring and modelling the new emerging threat to managed and wild pollinators”.  In particular, we will be able to extend the number of samples collected from Asian hornet nests that we will be able to analyse, using molecular techniques, to determine the prevalence of different insect species in the Asian hornet diet.  Understanding of invertebrate diets has improved enormously in recent years via the application of molecular methods that allow the sequencing of prey DNA in either regurgitates, gut contents or faeces of predators.  As these methods analyse fresh material from live individuals, the samples provide a snapshot of recently-consumed prey, based on DNA still present in the samples.

In 2020, due partly to the assistance of colleagues and volunteers in the Aquitaine region of France and on Jersey, we were able to collect fresh material from 44 nests at various stages of development (23 nests from Jersey and 21 nests from France).  The nests were chosen to represent a range of habitats where Asian hornets may be foraging and thereby consider the broad range of prey Asian hornets may feed on.  Nest samples are being processed in our laboratory on the Cornwall campus before being transferred to the Exeter campus for molecular analysis in Prof Charles Tyler’s laboratory.  Prof Tyler is physiologist and environmental biologist with vast experience of applying genetic and genomic techniques to understand the basis of physiological processes.  Although slightly delayed due to the current pandemic, we are currently advertising for a research assistant to work with Prof Charles Tyler’s team and conduct the molecular analysis of the collected samples.  We are hoping to further augment these samples with additional material from France, Jersey and UK, as well as northern Spain, in 2021.  We are also reviewing what is known from published literature and unpublished data about the range of invertebrate species documented as attacked or preyed upon by Asian hornets (or similar generalist predatory Vespa species).  Key taxonomic groups will be searched in the BOLD (Barcode Of Life Data) database to identify prey groups/species for which DNA data may be lacking.  During 2021, we aim to collect voucher specimens to fill these gaps in the database.