Acronicta alni (Linnaeus, 1767)

Description: Wingspan 37-43 mm. Forewings mainly grey with a large darker dorsal streak and grey antemedian and post median lines. The latter is mostly obscured due to the darker dorsal colouring. The subterminal line is not clearly defined. There is also a long black tornal streak which is clearly visible. The stigmata is similar to ground colour and finely edged in black. Hindwings silky white with fine brown veining.

Key Identification Features:

• Dark-coloured dorsal streak
• Black tornal streak
• White hind wings

Sets:

Flight Period: Beginning of June to late July.

Status: Widespread but local, occurring in scattered localities across southern counties. The adults are never commonly encountered even in sites where they have been recorded before. It may be under recorded in some areas especially in the west where suitable habitat exsists.

Ecology: An attractive species found in the damper parts of well established woodlands. Although its name would suggest that it is restricted to Alder Alnus glutinosa, it can in fact be found on other broad-leaved trees. Adults are attracted to light, but are rarely encountered in more than ones and twos. Despite the conspicuous nature of the larvae they have seldom been found in N. Ireland. It has been stated that they prefer to rest and feed in the higher branches of trees, which might account for the lack of larval records. When fully mature they will rest and feed quite openly on the surface of the leaves. The larvae are best looked for during July and August. It overwinters as a pupa.

World Distribution: Local throughout western Europe, although it has been recorded from Portugal to Denmark.

Bradley & Fletcher number: 2281 Agassiz number: 73.036

Additional information:

UK Moths account

Caterpillar: