European Yellowjacket Wasp Control in Bosque Pehuén

Better known as the yellow jacket, the Vespula germanica, is an invasive exotic species that is extremely important to control in conservation areas in Chile, as it constitutes a threat to biodiversity.

Main Characteristics of the European Yellowjacket Wasp and Their Food Habits

The european yellowjacket (Vespula germanica) is a species of wasp native to Europe, Northern Africa and Asia, which allegedly arrived in Chile through commercial traffic in the late 1960s. The size of this insect fluctuates between 12 and 16 millimeters long. It is black with yellow stripes and has characteristic black antennae, unlike the paper wasp (Polistes dominulus), which has yellow antennae.

Another big difference between the european yellowjacket wasp and the paper wasp, is that the former builds its nests underground, while the latter always does so at height. In addition, the first of these has a stinger with attached glands, which can inject a compound that can cause allergies. Unlike bees, a european yellowjackets can also sting more than once, with its stinger, without dying.

Yellowjacket colonies have three castes: workers, drones (males), and the queen. The first of these transport food to the nest, which is usually made up of other insects, carrion from dead animals, nectar and fruits, among other things.

How the Presence of Yellowjackets Affects an Environment when not in their Natural Habitat
This invasive exotic species is voracious and aggressive, thus affecting the balance reached by the native species where they invade. Its main ecological effects include: competition for resources with other native species, and the predation of insects and arthropods to feed their larvae. Yellowjackets have also been recorded attacking and feeding on newborn chicks.

Fortunately, some native species have already learned to coexist with the european yellowjacket and recognize them as a resource on which to prey. Some vertebrates that have been recorded feeding on yellowjackets are the chestnut hued hued (Pteroptochus castaneus), the Diucon (Xolmis pyrope) and the tenuous lizard (Liolaemus tenuis).

The Importance Behind Controlling Invasive Species in Areas of Conservation
Invasive alien species constitute a threat to biodiversity, since their aggressiveness and velocity of propagation attempts to displace and/or alter populations of native species. That is why controlling yellowjackets and other invasive species constitutes a very relevant challenge in areas dedicated to conservation.

In particular, the european yellowjacket–a particularly aggressive species–is attracted to the food that visitors bring to natural spaces, which becomes a real problem for tourism in those areas. Thus, the management of this wasp is essential to ensure ones experience in nature is satisfactory and safe.

This wasp is considered to have one of the highest economic impacts for the country, causing annual losses close to 21 million dollars. In this sense, the contribution that a protected area can have by controlling the populations of Vespula germanica transcends the benefits that this can have for local biodiversity.

Control of Yellowjackets in Bosque Pehuén
In Bosque Pehuén we have decided to do a thorough and early control of the yellowjacket. Between October and December we set 30 traps for queen wasps, which consist of bottles with a mixture of 50% apple cider vinegar and 50% water.

To date we have captured 2 queen wasps and some workers. At the end of December we added 17 traps for yellowjacket workers, following the Clarillo method developed by CONAF (More information here). This method mainly consists in the use of toxic bait composed of chicken corduroy with Fipronil (Regent 250), which is transported by the workers to the nests, thus eliminating the entire colony.

Additionally, to see the effect of the method, every three weeks we are monitoring the yellowjacket populations by observing large portions of corduroy for 10 minutes and counting the number of wasps that come to forage.