Ottawa (Dunrobin), ON Canada

25 May 2004   1:26PM EST  (top)  (male)
21 June 2004   9:10PM EST  (center left)  (female)
8 June 2003   10:19PM EST  (center right)  (male)
21 June 2004   9:10PM EST  (bottom)  (female)
The specimen in the photo at top was found resting near my light early in the morning, and stayed in the same place all day.  The photos at center left and bottom show the same female specimen.

Automeris io, commonly called the Io Moth, is one of about 10 species of Saturniidae recorded from the Ottawa area (J.D. Lafontaine, pers. comm., 2001).  The Saturniidae, variously termed the Giant Silkworm or Royal Moths include our largest and some of our most spectacular moths.

Automeris io is sexually dimorphic.  In the male, the forewing is yellow, with lines and spots variably evident in shades of brownish to purplish gray.  In the female, the forewing is heavily shaded with reddish, purplish, brownish and/or grayish colors, and the lines are mainly evidenced by alterations in the color from base, to median, to submedian, to terminal area, the terminal area generally being pale and yellowish.  In both sexes, the yellow hindwing is marked with a startling, staring round black and blue "eye" with a white center.  A fine curved black line parallels the outer curve of the "eye" a short distance outward, followed by a curved reddish line that meets a streak of dark pinkish red along the inner margin.  Covell (1984) indicates a wingspan ranging from 5 to 8 cm.

According to Handfield (1999), the larvae of Automeris io feed on many different trees, shrubs and other plants, but principally on birch and basswood.  The caterpillars have sharp stinging hairs that irritate the skin, and should not be handled.  He indicates an adult flight season from late May to early August for my general area.

My records to date for Automeris io (each date representing "the night of") are in the table below: