Sun Bathing Butterfly

Silver-washed Fritillary, Argynnis paphia

The sun has been in short supply in Ireland this year, and with September in full swing it looks (and feels) like we've had our, some may say inadequate, share for the year. These some would not include the Silver-washed Fritillary, Argynnis paphia. A large and attractive species native to Ireland that is common in woodlands, it has a yellow-orange upperwing marked with black that are similar to other Fritillary species, but is distinguished by the silvery sheen of the underwings (1). The adults are often found on their favourite food of brambles, basking in the sun. Here, they use their wings to absorb solar radiation and maintain their temperature above the ambient. By adjusting the angle of its wings at rest, it can absorb as much or as little sun as possible. Under artificial conditions, A. paphia was seen to adjust its wing position to maintain a thoracic temperature of 34±1.5 °C (3).

References:

1. Sterry, 2004. Collins Complete Guide to Irish Wildlife p. 106
2. Kammer and Brachi, 1973. Comparative Biochemistry and Physiology 45 pp. 1057-1063
3. Vielmetter, 1958. Journal of Insect Physiology 2 pp. 13-16