Early Thorn Geometridae

Selenia dentaria (Fabricius, 1775)

Description: Wingspan spring brood 46-51mm summer brood 40-44. Adults are extremely variable in colour. There is a lot of variation between individuals. This is especially noticeable when specimens from different regions are compared. Adults of the spring brood are generally more numerous, larger, and more richly marked than those of the second generation. The wings are scalloped and there are 3 crosslines on the forewings. There is also a dark patch at the apex of the forewing.

Key Identification Features:

Sets:  male upperside

Flight Period: There are two generations per year. Adults from the spring brood have been recorded from mid-February to the end of May, although some individuals occasionally persist into early June. The second generation appears usually from mid-July to early September.

Status: Common and widespread throughout its range in N. Ireland. Most frequently encountered in southern counties.

Ecology: A distinctive species found in a wide variety of habitats including woodland, heathland, bogs and suburban gardens. Adults appear frequently at light usually in good numbers, especially in early spring. They are occasionally found by day resting among the leaves on branches or among the leaf litter. The larvae can be found during May and June and again in September on a variety of trees including Hawthorn Crataegus monogyna, birch Betula spp., Alder Alnus glutinosa, willow Salix spp. and Blackthorn Prunus spinosa. It overwinters in the pupal stage.

World Distribution: Across Europe to eastern Siberia.

Bradley & Fletcher number: 1917 Agassiz number: 70.237

Additional information:

UK Moths account


 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland