Quicksilver

Silver-washed Fritillery (Argynnis paphia) with Peacock (Aglais io) in the background

On a whirlwind afternoon last month, we recorded three new species of butterfly for the property. They were part of a big influx that occurred over several days, pushed in our direction by warm southerly winds and enticed to the garden by a plethora of blooming Buddleia bushes. Among the multitude of Peacocks, Red Admirals and Small Tortoiseshells that were sprinkled across the flower spikes, we spotted a suspiciously orange flash, which resolved itself into this slightly battered but still handsome male Silver-washed Fritillery (Argynnis paphis) – a rare visitor to our corner of England. You can tell he's a male by the long dark streaks on his forewing; these are his "sex brands". When he's courting a female, he dazzles her with his acrobatics, flying loops above, in front of, and under her as she continues to fly in a straight line. If she's impressed enough to land, he shakes loose a shower of scented scales from those sex brands to further convince her of his desirability. At first glance it seems odd to call this butterfly "silver-washed", given that it's orange and black. The steaks which give it its common name are actually on the underside of its hindwing, and are only visible when the butterfly folds its wings.

This isn't a common species in our part of England. Typically, it's found in the southern and western corners of Britain, with only the occasional strays making it futher north and east. It's primarily a woodland species, breeding in shadier parts of the forest, but moving to more open areas to feed. Adults fly from mid-June through August. Once she's mated, a female will lay her eggs in moss or bark crevices near colonies of Common Dog-violet (Viola riviniana). Though they hatch in the fall, the larvae immediately go into hibernation. The following spring, they'll emerge to feed on the newly-flowering violets. The species underwent a big population decline in the 1900s, but in recent decades have started to expand their range again. Here's hoping they become more common again in our part of the country!