Silk-button causer/gall

Description:

The Silk button Gall ----is abundant on the underside of the oak leaf and can reach 3mm across. This gall holds the agamic generation and looks like a thick, rolled edge disk with a deep central pit and gold hairs, there is no mark on the top of the leaf. It is a single cell gall holding one wasp and can be seen from august to october, until the leaves fall in autumn. The wasp larva will mature in august but remain in the gall on the ground throughout the winter, emerging the following year from february to april. The agamic generation wasp is winged and measures in at approxiamtly 2.5mm in length. The head is small and pointed, black and granulated, with medium sized pale brown eyes and pale straw ocelli. The antennae are dark brown with a large rounded pedicel, and consists of 15 segments. The black thorax has pale hairs and short notaulices at the back. The tegulae are pale. The long clear wings have dark brown viens and hairs. The dark coxae and femora gradually lightening over the rest of the legs with pale joints. The trapezoid, segmented, bulky (from the side) gaster is dark neutral brown and shiney, but paler underneath and along the ploughshare. The back end is hairy. ( http://hedgerowmobile.com/Neurtoterusnum... )

Habitat:

====Physical appearance=== -----Galls This Silk button spangle gall has a cover of golden hairs that give the impression of silk thread. The 0.3 cm button-shaped galls have a pronounced concavity and sit tightly against the leaf lamina. ----The similar gall wasp N. albipes Blister galls are about 0.3 cm in diameter and green or greyish in colour; well camouflaged with the leaf lamina. The gall has narrow ridges running downwards on all sides from a central papilla on the upper surface and sometimes on the lower surface as well. Both galls are both unilocular and unilarval. -----Gall wasp The female wasp of the bisexual generation is about 1.8–2.4 mm in length; largely brown in colour with clear wings and hairy legs. The male is also winged and slightly shorter than the female. The agamic generation consists of only female wasps which measure approximately 2.5 mm in length. The pointed head is black, with pale brown eyes and long clear wings are present with dark brown veins and hairs

Notes:

Neuroterus numismalis is a gall wasp that forms chemically induced leaf galls on oak trees. It has both bisexual and agamic (parthenogenetic) generations and forms two distinct galls on oak leaves, the Silk button gall and Blister gall. The galls can be very numerous with more than a thousand per leaf (wikipedia) ( http://www.soortenbank.nl/soorten.php?so... )