Wednesday, June 24, 2009

A spangle of fritillaries

While surveying breeding birds last Saturday in the outback of Morgan County, I was struck by the numbers of butterflies coursing about. I saw many species, but it was the following two that really grabbed my eye, is it was the most I had ever seen of either in one day.

A Mourning Cloak, wings up and looking much like a blackened leaf. They really blend well when in this position. I saw dozens; seemed like every fifty feet I’d flush one from the back country gravel roads.

When a Mourning Cloak flashes its wings to the open position, they transform into a thing of great beauty. The dominant dorsal color is a rich velvety purple-black, trimmed with gilt and dotted with blue flecks of the richest azure. No wonder the Brits refer to Mourning Cloaks as “Camberwell Beauties”. They get around; it’s got one of the widest distributions in the butterfly world, occurring throughout North America as well as in Europe and Eurasia.

Their host plants include elms, willows, and some of the poplars, all of which are common in Ohio. They must have had a recent hatch, as all of the cloaks that I saw were stunning in their freshness. Mourning Cloaks last a while, too – they overwinter as adults and can sometimes be seen flying about and shaking off the dust in warm sunny mid-winter days.

It was the Great Spangled Fritillaries that really grabbed my eye, though. They were everywhere. The most I’ve ever seen in a single day. This is a fresh male, and nearly all that I saw were boys, as they emerge prior to the females.

This is a female Great Frit, one of relatively few I saw that day. Note how it is darker above, and when seen with the males they are noticeably larger.

The ventral, or underside, of the wings may be more striking than the upper surface. Dotted with shining silvery chevrons, it’s as if the butterflies have been draped in exotic bling. Fritillaries employ a rather bizarre reproductive strategy. Females lay eggs near, but not often on, the host plants, which are violets of many species. The larvae winter over in leaf litter without feeding, then come spring must locate violets to feed upon. Although it seems a scattershot way of doing business, it obviously has worked well with Great Spangled Fritillaries in Morgan County.

The video above shows a small patch of Canada Thistle, Cirsium arvense, that is being swarmed by a feeding frenzy of frits. In general, Canada Thistle is a despicable non-native invader, but these butterflies are obviously intoxicated by its nectar. There were dozens of butterflies on this thistle patch, and all were males with the exception of one early to emerge female.

1 comment:

dAwN said...

Love your spangle of Fritillaries! Great post and info as always..I will get there all have such amazing flowers and fauna there!