Tamarisk wasp butterfly nests on West Coast

The tamarisk wasp butterfly is mainly found in more southern and warmer parts of Europe. The chance that the species occurred with us therefore seemed small. Twenty percent of the 25 wasp butterfly species have only been discovered recently (since 2015). The fact that many of these species are true heat enthusiasts may play a role.

Harmless

As the name suggests, the tamarisk wasp butterfly also closely resembles a wasp. However, it is a sophisticated form of imitation, called mimicry, which is intended to mislead enemies. Hoverflies and beetles use a similar disguise. The wasp butterfly is completely harmless.

At the end of 2021, the first caterpillars of the Tamariskwesp butterfly were found on the Belgian West Coast. After intensive monitoring during the following year, it appeared that the species only occurs there for the time being, albeit very numerous. The caterpillars develop just under the bark of the planted tamarisks, with a preference for the slightly thicker specimens. With a bit of luck, passers-by can see newly hatched butterflies resting on the trunks in the late morning from June to early September. The rest of the year, the round holes through which the butterflies leave the tree trunk are reminders of the presence of the wasp butterfly.

“The species feels very much at home on the West Coast,” says Ruben Meert of the Insect Working Group Voelspriet. “A very large population was found in the past two years. And the formerly frequently planted avenue tamarisks, which are resistant to drought and sea wind, certainly have something to do with that.”