Brown Oak Tortrix (Archips xylosteana)
The Brown Oak Tortrix is another brown leaf-rolling moth, which is sometimes difficult to identify, for it is quite variable. Male and female differ considerably. The male is best identified by its wing-shaped grey markings on approximately one third of the wing. Just above this marking is a dark spot, sometimes resembling an eye. The grey marking looks like a Batman-logo. The females are much lighter and less well marked. The markings in the tips of the wings are quite meaningless in this case, for they are extremely variable. Males will reach a wingspan of some 18 to 20 mm., females are some 3 to 4 mm larger. In the pictures on this page is a male.
The caterpillar is glazy and brownish. It has a black head and the end of the body is black as well. Over the head runs a bright, yellowish small line. The larvae of Archips xylosteana usually are some 10 to 14 mm in length. Like many other Tortrix-larvae the eggs are laid in summer and hatch quickly. The small larvae live among the leaves of the tree, but don't eat very much and grow kind of slowly. In autumn the larvae make a small cocoon in which they overwinter. In spring they get out of their cocoon as soon as the leaves are growing, roll up a leaf and eat it. Now they eat a lot and grow very fast. This is the stage they do damage to many trees. And the larvae are not choosy at all. They are found on Oak, just like the name indicates, but like Birch as well. Damage is also done to a number of trees humans are interested in as well, such as Prunus species, Apple and Pear.
Adult Brown Oak Tortrixes fly in summer (in June and July mainly, but also in decreasing numbers in August). They usually fly by night, but sometimes are seen during daylight. The moth comes to light regularly, but not in very great numbers. A very common species, occurring all over Europe, including most of the British Isles, often appearing in very great numbers.
NB This species is also known as the Golden Tortrix or the Variegated Golden Tortrix Moth.