Oak Marble Gall Wasp

The male wasp is very dark brown to black on the head has a hunched thorax with a black abdomen.

Oak marble gall wasp. The oak marble gall wasp arrived too late to make as great a contribution to our written heritage as other gall wasps. These growths typically emerge at bud break in the early spring. Identify oak galls on your trees. Oak apple or oak gall is the common name for a large round vaguely apple like gall commonly found on many species of oak oak apples range in size from 2 to 4 centimetres 1 to 2 in in diameter and are caused by chemicals injected by the larva of certain kinds of gall wasp in the family cynipidae.

A developing gall typically looks like either a big seedpod or a small tumor like growth on the. The marble gall is found on pendunculate oaks. Length 1 5 to 2mm. The alternate generation causes rather small and insignificant galls in buds of turkey oak quercus cerris.

Oak marble gall wasp andricus kollari. When the wasp emerges they can be male or female leaving a small hole in the gall. Oak marble galls are caused by another gall wasp this time andricus kollari. Oak marble gall description.

Clusters of oak marble galls also known as oak nuts can be found on oak twigs. Nonetheless this species has a place in our history as an example of entrepreneurship during victorian times when the natural world was seen as a source of novelty wealth and progress. The adult female wasp lays single eggs in developing leaf buds. The empty gall is left on the twig.

Marble galls are initially green but later become brown and can persist for several years. Synonyms for the species include cynips kollari andricus quercusgemmae a. Oak marble gall wasp andricus kollari causes hard woody spherical galls up to 25mm in diameter on the stems. Oak marble galls are frequently mistaken for oak apple due to their superficial resemblance they develop as a chemically induced distortion of leaf buds on pedunculate and sessile oak caused by the parthenogenetic gall wasp andricus kollari laying eggs within leaf buds the turkey oak introduced to britain in 1735 is required for the completion of the life cycle of the gall.

They turn brown as they mature and emergence holes from which the asexual adults have escaped can be seen from autumn onwards. Andricus kollari also known as the marble gall is a parthenogenetic species of wasp which causes the formation of marble galls on oak trees. Marble galls only contain the larvae of one female wasp which then lays its eggs in the buds of the turkey oak. Click here to support naturespot by making a donation small or large your gift is very much appreciated.

Confusingly the term marble gall is used to describe both the species of wasp and the gall it causes.