The first specimens of the Asian wasp Vespa velutina detected in Europe were located near Bordeaux (France) in 2004, most likely arriving accidentally in a shipment of ceramic and gardening material. Two decades later, this wasp specialized in capturing honey bees (which is sometimes called the 'murder wasp') has spread throughout France and large areas of Spain, Portugal, Belgium, Holland, Germany, Italy, United Kingdom and Ireland.
The main problem caused by this invasive species is damage to the hives, both due to the number of bees (Apis melifera) that they devour and due to the paralysis of the activity of these pollinating insects, which do not dare to go out in search of food when The wasps fly before the hives.
During recent years, various beekeepers and specialists have designed and tested numerous systems to combat the velutina wasp. Specifically, many of these methods attempt to eliminate wasps that approach the hives and, in this way, facilitate the activity and survival of the honey producers. There are also a multitude of traps and products to combat velutinas in their nests or while they fly away from the hives.
"Everything has been tried, from chemicals to electric harps, but now we are verifying that to protect the hives the most effective method is Koldo traps," explain Núria Roura, researcher, together with Josep Maria Bas, both in the Group. of Animal Biology Research at the University of Girona (UdG). This type of trap to catch velutinas has been designed and named in honor of Koldo Belasko, a Basque beekeeper who has been concerned about the damage caused by these wasps for years.
The UdG experts have tested the effectiveness of this type of traps with controlled trials in areas with the presence of velutinas, for example in Garrotxa and Baix Empordà, and have introduced small technical changes to improve their effectiveness in beekeeping farms. in Catalonia. "The results are very positive. Last year, for example, in an apiary with 40 boxes located in Garrotxa we captured 8,132 velutine wasps," explains Núria Roura.
The team led by Josep Maria Bas and Núria Roura highlights that Koldo traps, in addition to being effective in protecting hives, "are a very interesting proposal because they combat the problem without the need to use chemicals." In addition to scientifically testing and improving the design of these traps, UdG experts make the information available to interested beekeepers, including a video that shows in detail how they can be built and how the traps work. adapted Koldo traps.
"It all started simply by observing how these bugs fly and how they hunt," explains Koldo Belasko to La Vanguardia. "These wasps fly one meter from the entrance to the hives, waiting for the bees to leave or return to the nest, a moment they take advantage of to hunt them on the fly," details this beekeeper from Laukiz (Basque Country). After each attack, the wasps make a lifting flight and retreat to their nests with the prey or try again if they have failed.
The Koldo trap is made up of a tubular structure built with a grid through whose grids bees can pass but not wasps (which are larger). This tube is placed horizontally in front of the line of hives, with an opening at the entrance to each of them. In the mesh or grid that forms the tube, some windows are cut out at the height at which the wasps fly. At the ends of the tubular structure, other mesh tubes are installed in a vertical position and at the top of these chimneys a type of funnel is placed through which the wasps can enter but do not know how to get out.
The final part of the traps, in the chimneys, the funnels in which the wasps are trapped, "is based on the design of the pots that fishermen use to catch lobsters or crabs, in this case it is the wasps that They come in and can't get out," explains Koldo Belasko to La Vanguardia.
"The wasps see the bees coming in and out and, like sharks going for sardines, they enter through the windows of the trap, move along the tube chasing the bees and, after attacking, end up getting into the chimneys." and the funnels from which they no longer know how to get out and die," explains Koldo Belasko. Due to the flight and hunting system, wasps generally do not know how to find the windows through which they have entered and fly laterally towards the chimneys, explains this ingenious Basque beekeeper.
The UdG experts have introduced small changes to the original design, using slightly wider grids, to facilitate the passage of bees with pollen, but without allowing wasps to pass through. In addition, they slightly separate the trap link from the entrance to the hive, also to facilitate access for the bees.
The UdG experts highlight that Koldo traps, by not using chemical products, are an ideal alternative to avoid damage to other species and consider that it is a proposal that should be taken into account by beekeepers and administrations. This team from the Animal Biology Research Group has received collaboration and aid from institutions such as the Generalitat of Catalonia and the Provincial Council of Girona and hopes to continue advancing with a project, currently in process, that could be financed by the Ministry of Ecological Transition.
The results of the work of this group of researchers from the UdG will be presented at the technical conference Situation and management of the Asian wasp in apiaries that will be held online on April 5.
