Engrailed Geometridae

Maps updated: April 2008

Ectropis bistortata (Goeze, 1781)

Description: Wingspan 38-45mm. A variable species with different melanic forms, ranging from pale to ochreous brown; the degree of mottling varies considerably between individuals with some more heavily marked than others.

Similar Species: Similar to the Small Engrailed E. crepuscularia which generally flies later. Both species are almost impossible to tell apart visually, however the date of capture is an important factor in determining identification.

Key Identification Features:

Sets:  male upperside

Flight Period: From early March to the beginning of May.

Status: Scarce, and only confirmed with certainty in 1999 from Lackan Bog, Castlewellan and Rostrevor in Down and Crom, Fermanagh. These are the first genuine records, which confirm its existence as a resident species in N. Ireland. Verification of the specimens where confirmed by two leading British Moth experts. Its early flight period has no doubt allowed it to remain undetected in some localities until recently.

Ecology: A problematical species found mainly in damper parts of woodlands and bogs. This species has for some time caused confusion with the closely related Small Engrailed. The Small Engrailed is single-brooded and flies slightly later and is not normally encountered before the end of April. Despite extensive trapping on two of the above named sites, no evidence of a second generation has been found. In southern Ireland the only confirmed records are from western counties, where in 1994 a specimen was taken in Co. Galway during August confirming a second generation. Adults come frequently to light and may occasionally be found at rest on the trunks of trees. The larvae can be found in May and June on birch Betula spp, oak Quercus spp., willow Salix spp. and broom. It overwinters in the pupal stage.

World Distribution: Across central Europe east to Siberia and Japan.

Caterpillar: 

 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland
http://www.ulstermuseum.org.uk/lepidoptera/species.asp?item=6039

[Home]