Vespa velutina, new sightings: why it is so dangerous

It must first be remembered that the wasp velutina is not native to our continent. It is in fact called an 'alien species' or Chinese wasp, and its appearance in Europe has not gone unnoticed. This Asian hornet, or Asian killer hornet, originates from south-east Asia, specifically India, Indochina, Java and China. In Europe it was first sighted in 2004 in France, near Bordeaux. It appears to have been introduced with a cargo of ornamental plants from China. From there, it quickly spread to the rest of France, encroaching on Spain, Portugal, Belgium and, in 2012, also to Italy. In our country, it is found in Liguria and the Cuneo area, with a few findings also in the Rovigo area. What is most frightening about this insect is its danger not only to humans, but also to bees.

Essential for proper surveillance is knowing how to recognise the wasp velutina, without confusing it with its European 'relative', the wasp crabro, our hornet. The velutina species introduced into Europe is called nigrothorax and this name already gives valuable indications of its characteristic traits. The body is in fact of dark colour and the abdomen has a thin yellow band near the junction of the thorax. The fourth tergite, on the other hand, is completely yellow with a black triangle inside. The end of the abdomen, on the other hand, is reddish-brown. The head, on the other hand, is yellow-reddish at the front, and brown at the top. The antennae are also black, changing to a browner colour in the lower part. Another characteristic feature are the legs, which are yellow at the end. The wasp velutina ranges in size from 19 to 29 mm.

Knowing the biological cycle of these insects is extremely important in order to understand how to operate in order to limit the damage they could create in the apiary (and beyond). New colony creation: in February, the fertilised bees overwinter look for a place to establish their new colony. Once they find a suitable place, they build the so-called primary nest, composed of cellulose mixed with their saliva. That of the wasp velutina is smaller than that of the hornet, and the cells are not visible from the outside. The secondary nest: as the family grows, it becomes necessary to change nests. At this point, the sterile workers will build a secondary nest. These nests are generally found in trees, at a height of about 10 metres.

The hunting period: in the period from July to October, velvet wasps engage in 'hunting'. The adults obtain sugars for themselves from plants and fruits, but in order for the larvae to develop properly, they must be fed with protein. To procure this source of nourishment, Asian bumblebees lurk in front of the hive entrance, where they await the return of the foraging bees. The problem, however, is not only related to the killing of bees. The hive is literally under siege and the bees take refuge in the hive, ceasing to procure the food necessary for the family's survival. In Liguria, they have observed that 3-5 velutine bees can catch a bee every 10 seconds. Wintering: the velvet wasp's life cycle ends in November.

The need to fight these Asian hornets is clear, especially bearing in mind that our honey bees have not developed any defence mechanism against them. In South-East Asia, on the other hand, the native bees mass on the intruder, which is literally overheated and killed by heat shock. The fight against this insect focuses mainly against queen wasps, which are the easiest targets. Specifically, the most important actions can be taken in the autumn, when the queen wasp hatches, or in the spring, when the fertile queens establish their new colonies. One way to monitor the insect's presence near the hive is to construct classic traps consisting of a plastic bottle into which sugary substances and clear beer are poured.

The scientific community, on the other hand, is focusing on the possibility of implementing biological control techniques, basically by introducing parasites or pathogens of the wasp velutina, which would in some way counteract its development. This route, however, is very delicate because the introduction of other, allogenic species could cause enormous problems for the native species. Currently, a reporting network of the presence of the wasp velutina is active throughout Italy. The importance of monitoring and containment of the presence of this hornet is essential to prevent it from spreading like wildfire throughout the territory.

However, it is also important to monitor one's own hives. Proper control of the health and development of one's colonies is essential to ensure their survival and production levels. By using a remote monitoring system, even the most distant and hard-to-reach apiaries can be kept under control. The balance 3Bee allows data to be collected on the main biological parameters of the hive: weight, internal and external temperature, sound and humidity. This data is then sent to the cloud and you can view it directly on your smartphone and better manage your activity, planning trips and targeted interventions.