On the Evidence of the European Bee-Eater (Merops apiaster) as a Predator of the Yellow-Legged Hornet (Vespa velutina) and Its Possible Contribution as a Biocontrol Agent

SIMPLE SUMMARY: The Yellow-legged Hornet is an exotic and invasive insect which, having entered Europe through France in 2004, has now spread across many countries of the continent. It is a threat to biodiversity and causes significant damage to beekeeping. Control measures have not been able to stop the expansion of this hornet, so all means of fight are important, including natural predators. We studied the diet of the European Bee-eater to understand its role and predation intensity on the Yellow-legged Hornet. We found several hornet remains in some locations of Central Portugal. Although the importance of this predation remains to be determined, Bee-eater could be one more agent in the fight against the biological control of this pest, even though the two species do not coexist in much of the Iberian Peninsula. However, in a large area of the rest of Europe, it is predictable that the distribution range of the two species will overlap to a greater extent and the Bee-eater may play a greater role as a biological control agent. ABSTRACT: The Yellow-legged Hornet (Vespa velutina nigrithorax) (YLH) is an invasive insect that arrived in Europe in 2004 and is now spread across nine countries. It is a threat to the native entomofauna and harmful to beekeeping and agriculture, as it is a ravenous predator of the European Honey Bee (Apis mellifera) and other pollinating species. Its expansion has been unstoppable and all resources are needed to fight against it, including native vertebrate predators. Among these, the European Bee-eater (Merops apiaster) (EBE) is a potential one, but little is known about its predation on YLH. In a study carried out in Portugal, remains of YHL were detected in EBE nesting sites, which, to the best of our knowledge, is the first such report. This means that this bird could be one more agent in the biological control of this pest (although research on predation intensity is still needed), in conjunction with other natural predators and other strategies. In the Iberian Peninsula, both species are allopatric in vast regions, so the role of EBE may be more limited. However, in the rest of Europe, at a country or continent scale, the scenario may be different and sympatry may occur to a greater extent.