Identifying North American moths - there are rather a lot

Have managed to borrow a moth book - the moth book in fact, for the western states of the USA - and will be using it to help name and inform my moth observations from this and previous visits to the U.S.A.

Moths of Western North America by Jerry A. Powell and Paul A. Opler, University of California Press, 2009

It is a very fine and serious hardback book, large format with 370 pages of text and 64 colour photographic plates showing traditionally spread specimens. There are about 2500 species illustrated and described. Prior to the arrival of this work last year the published information available on Western North American moths was either obscure and scattered or else superficial.

However, the diversity of the region's lepidoptera is so great - this work is not a compendium of the fauna or a guide to it but a detailed overview representing about 25% of the species in each of the native families (all of which are treated). It comes as a bit of a shock for someone from a small 'biologically depauperate' European island to think that this hefty and definitive looking book therefore will not cover, say, 75% of the Noctuid species flying around out there (in fact it is likely to describe most of what a casual observer will encounter because the species were selected based on being widespread, well known, more easily identifiable or of some other notable interest). The authors estimate that there are about 8000 named species of moth in the western states and provinces and at least another 3000 species for which specimens have been collected but not yet described. Worldwide there are 160,000 - 180,000 named species in the Lepidoptera and the real total could easily be more than double this.

Makes a dilettante moth-er think, but since arriving here the nights have mostly been chilly and there appear to be very few moths flying yet.

Behrensia conchiformis (Noctuidae) - Lake Forest Park 25/4/2010 found by outside light. Its local foodplant is likely to be Snowberry (Symphoricarpos albus) which I have now seen for the first time as part of a natural plant community. I wonder what, if any, insects feed on the extensive gamebird cover and garden populations of this plant back home.

Larva of Silver-Spotted Tiger Moth - Lophocampa argentata (Arctiidae) - Lake Forest Park 25/4/2010 found on fallen Douglas Fir (the foodplant) branch. Other individuals also seen on wall, apparently attracted to light, and Vine Maple (Acer circinatum) foliage, presumably dropped from fir canopy above.


This is Xanthorhoe labradorensis (Geometridae) - which I suppose would be the 'Labrador Carpet', Lake Forest Park - attracted to outside light 26/4/2010. I must say, it looks a lot like a European Flame Carpet to me, and apparently some authorities have indeed classed it as a subsp. of X. designata.

Sabulodes aegrotata (Geometridae) - Omnivorous Looper, Lake Forest Park, 24/4/2010, perched on outside wall by light for at least 3 days but has now gone.