Ottawa (Dunrobin), ON Canada
11 August 2005 9:10PM EST (top left and top
8 August 2004 9:36PM EST (top right)
4 June 2005 9:42PM EST (bottom left and bottom right)
The pairs of "same date" photos are of single specimens photographed
from two angles.
My thanks to Dr. Jean-François Landry of Agriculture Canada for
identifying a number of my specimens of Swammerdamia caesiella.
For further information, I have relied on Internet resources, mainly related to
the incidence of this species in Europe, but also including images from the All
Leps: Barcode of Life web site.
Swammerdamia caesiella has mottled gray forewings that
remind me of the pattern of fish scales. A slightly darker band, most
noticeable at the inner margin, usually crosses the wing about 1/3 of the way
from the base. There is a hint of white at the inner margin near the anal
angle; photographs of spread specimens also show a white mark at the costa near
the apex. The head and thorax are white in all the specimens I've seen at
my location, but a some Internet illustrations show a grayish thorax. The
hindwing is grayish.
In my experience, the dark fringe of the forewing sometimes
shows a slight orange-brown reflection from the flash, suggesting on the basis
of written descriptions that this could be the very similar species Swammerdamia
pyrella. The latter, however, has not been recorded from the Ottawa
area, and all of the specimens submitted from my locations for expert
examination have been identified as Swammerdamia caesiella.
According to Internet sources, the larva of Swammerdamia
caesiella feeds on birch. My observation records appear to suggest two
generations per year in my area.
My records to date for Swammerdamia caesiella (each date
representing "the night of") are in the table below: