Four-spotted Cave Ichneumon Wasp - Cave Animal of the Year 2017

Introduction

The Four-spotted Cave Ichneumon Wasp (Diphyus quadripunctorius), which belongs to the order of hymenopters, was first mentioned in 1776 by the Danish zoologist Otto Friedrich Müller. It is found under the name Ichneumon quadripunctorius in his book "Zoologiae Danicae Prodromus, seu Animalium Daniae et Norvegiae Indigenarum characteres, nomina, et synonyma imprimis popularium", the first compilation of the fauna of Denmark and Norway. It doesn’t seem to have a common name in English, Four-spotted Cave Ichneumon Wasp is a translation of the German common name, "Vierfleck-Höhlenschlupfwespe".

In natural caves, mining tunnels and rock cellars, these animals are overwintering in large numbers. For this reason, the Four-spotted Cave Ichneumon Wasp was elected as Cave Animal of The Year 2017. This Ichneumon Wasp represents a large number of species, which are depending on caves as sheltered and frost-free refuges.

The Verband der deutschen Höhlen- und Karstforscher e.V. (German Speleological Society)has chosen the Cave Animal of the Year to point out the immense deficiencies in the research of subterranean ecosystems and their associated faunas.

Description & Ecology

During spring and summer, the Four-spotted Cave Ichneumon Wasp is found in meadows and at the margins of forests. The females are not very choosy when it comes to deposit their eggs. A multitude of butterfly species are known as hosts, with noctuid or owlet moths being the most common. A single egg is injected into the caterpillar.These are pupating before the larva of the wasp starts feeding. The adult Ichneumon wasp is finally emerging from the pupa. The males of the Four-spotted Cave Ichneumon Wasp are found only in summer. They die after the copulation, only fertilised females are overwintering.

For overwintering, they are seeking out frost free localities, like caves, mine tunnels and rock cellars, but also cracks in the rock and cavities in old trees. Here they can be found as early as June, up to August often together with the males. In subterranean cavities, the females are often building large congregations of up to 100 animals,which are sitting tightly packed in cracks and niches. It is by far the most common species of Ichneumon wasps. The Four-spotted Cave Ichneumon Wasp is classified as subtroglophil, it penetrates caves down to the region of permanent darkness.

The female of this black and yellow Ichneumon Wasp is distinguished by a white ring on the long feelers, and yellow tights of the hind legs. On the black abdomen, four pale dots are found, from which the common name is derived. The males are lacking the white ring on the feelers, the tights of the hind legs are orange. The first segments of the abdomen are yellow in the males. The body length of this Ichneumon wasp measures 13 to 15 mm.

Distribution

The distribution range of the Four-spotted Cave Ichneumon Wasp extends from Northern Africa and Near East over the whole of Europa to the British Isles and Scandinavia. To the East, the range stretches to the European part of Russia. In Germany, the species is known from all cave areas, where they overwinter in large numbers.