Defensive behaviour of Apis mellifera against Vespa velutina in France: Testing whether European honeybees can develop an effective collective defence against a new predator ★

• Since 2004 honeybees in France have to confront the invasive species Vespa velutina.
• Hornets predation is effective through “bee-hawking” and direct attack at colonies.
• Reduction of honeybees’ forage activity is still not so effective.
• During balling behaviour only a small number of honeybees engulfs hornets.
• Overall, the defence of the honeybees against the hornets is still inefficient.

We investigated the prey–predator interactions between the European honeybee, Apis mellifera, and the invasive yellow-legged hornet, Vespa velutina, which first invaded France in 2004 and thereafter spread to neighbouring European countries (Spain, Portugal and Italy). Our goal was to determine how successfully honeybees are able to defend their colonies against their new predator in Europe. Experiments were conducted in the southwest of France—the point of entry of the hornet in Europe—under natural and semi-controlled field conditions. We investigated a total of eight apiaries and 95 colonies subjected to either low or high levels of predation. We analyzed hornet predatory behaviour and collective response of colonies under attack. The results showed that A. mellifera in France exhibit an inefficient and unorganized defence against V. velutina, unlike in other regions of Europe and other areas around the globe where honeybees have co-evolved with their natural Vespa predators.