What is an electric harp for the control of the Asian horned warbler?
An electric harp is basically a square window into which wires are stretched. These wires have a mesh size of about 18 - 20 mm which allows bees to pass through, but not Asian hornets. These threads are energized and give a shock to the Asian hornet. This has the effect that the Asian hornet falls down dazed or even dies on the spot. It is similar to an electronic fly swatter. In addition, at that moment, the Asian hornbug releases a pheromone that will deter other hornets. This pheromone signals danger and warns others not to come near. It remains present for a short period of time.
The electric harp is especially effective at times when the Asian hornet needs a lot of protein, which is often the case at the height of brood nest development August - October. They will then hunt solitary bees and other insects, as well as a lot of hives, which serve as a kind of snack bar for the Asian hornet. By placing electric harps in a certain way, many hornets can be caught. They then fall to the ground or into a water tank and drown, lowering the predation pressure on the hives.
Harps are placed so that they are perpendicular to the hives, with two at the end and one in the middle of a row of hives, to catch Asian hornets. These get a shock as they fly from hive to hive, which bees do less or not at all. There are also beekeepers who put bait at e harps to attract the Asian hornet and make them fly through.
The electronic harp consists of two parts: the harp itself and a device that generates the power. There are versions that are mains-powered or solar-powered, and you can add a battery for days with less sun. There are also accessories such as a water tank in which stunned hornets can drown. The harp is widely used in Portugal, Spain and France and is also gaining popularity in the rest of Europe. There are also other solutions, such as trapping hornets with traps or locating nests and exterminating them. When working with hornets do use proper protection. Hornets are very different from wasps or bees and require special suits and personal protection.
When a hive is attacked by Asian hornets, they will initially capture the worker bees from the air or from the flight board. If this continues, the hive will retreat and mount defense, trying to kill any invading hornets. This interferes with the food supply for the hive. Indeed, they no longer fly out to forage, which may eventually lead to the demise of the hive. Harps help reduce predation pressure. In the final months of the season, a large hive can sometimes resist Asian hornets, but they too can suffer by not getting enough nutritious pollen, for example, which threatens the survival of the hive in winter. After all, healthy well-fed winter bees are not produced.