Oak/Northern Eggar moths (1 Viewer)

[RJElse]

Hi
I found this moth at South Stack, Anglesey. I think it's a Northern Eggar, but how do you split this species from Oak Eggar (if they are seperate species)? Whereabouts do their ranges meet?

Thanks, RJElse

 

[Angus T]

Hi
I found this moth at South Stack, Anglesey. I think it's a Northern Eggar, but how do you split this species from Oak Eggar (if they are seperate species)? Whereabouts do their ranges meet?

Thanks, RJElse

I raised this question on another forum a few days back. And Ian Rippey replied with this

There are supposed to be 2 sub-species (not species), Lasiocampa quercus quercus (Oak Eggar) and Lasiocampa quercus callunae (Northern Eggar), found respectively mainly in Southern England (woods, commons, etc) and in the North and West (bogs and moorlands) and the former is supposed to have a one year cycle from egg to adult and to fly in July and August and the latter a 2 year cycle, flying in May and June.

However in my experience the "Northern Eggar" flies from about mid or late June to mid-July (although in the Burren it seems to regularly fly in early August); I have never seen it in May. Although perhaps mostly a moth of bogs and moorland it can be found (in the adult and larval stage) on sand dunes, around woods, hedges and rough grassland (eg at several places around North Armagh), etc (as well as heather larvae can be found on Birch, Bramble, etc). Volume 7 Part 2 in the series Moths and Butterflies of Great Britain and Ireland discusses the 2 sub-species at some length, and though it is too long (ie I am too lazy!) to reproduce this here, the conclusion is "Hence the validity of the concept of two sub-species is questionable because of the lack of correlation between imaginal (ie adult, not imaginary) features and the length of life cycle, just as in Trichiura crataegi (Linnaeus) [ie the Pale Eggar] and its so-called subsp. ariae Hubner." It also states calls it "An extremely variable species" and says that "broods of larvae from the midlands and Wales will segregate into 2 groups, with one- and two- year life cycles."

IAN RIPPEY 30.7.2005


I should add that all my records(4th season) of adults are between mid-July and mid August

 

[harry eales]

Hi
I found this moth at South Stack, Anglesey. I think it's a Northern Eggar, but how do you split this species from Oak Eggar (if they are seperate species)? Whereabouts do their ranges meet?

Thanks, RJElse

I would say it's a Norther Eggar based on my own experience of this species.
In the male Oak Eggar the yellow band across the forewing is quite sharply defined whereas in the Northern Eggar it tends to be less well defined and the yellow on the outer edge of the band bleeds into the areas between the wing veins towards the outer edge of the wing.


Having bred several hundred specimens over the years I cannot recollect any male Northern Eggar having a sharply defined yellow band.

Harry