Thursday, 23 October 2008

City butterflies: the Comma

11 September 2006, comma basking on clematis
I have recorded 18 species of butterflies since 2003 in the city of Hull. Four of these I see occasionally, or I have seen just once (White Letter Hairstreak, Brimstone, Orange Tip or Small Copper), species that are more at ease in the countryside. This leaves 14 species that are common enough in the city streets, parks and gardens. One of the most obvious October butterflies is the Comma, Polygonia c-album. This species is recognized by their bright orange background with dark marks and an unique ragged edge-looking wings. Its underside is quite dark in the overwintering generation, with a clear white 'c' in the hind wing: once it closes its wings, it looks like a withered old leaf. Its legs have elegant white stockings. I find the comma difficult to tell apart in flight from the Small Tortoiseshell.
10th October 2008, Comma basking on apple tree
 There are not many sources of nectar around in October; I have recorded commas feeding on Ivy, Buddleia and Cherry Laurel this autumn. In her treasure trove Butterfly Garden webpage, the late Linda Walls also cites Verbena, which flowers in October. The butterflies around this month are the overintering generation. They still fly on sunny days on the look out for nectar sources in preparation for winter. Although the odd individual interrupts overwintering on sunny winter days, they should wake up again at the end of March, ready to mate and lay their eggs.
25th September 2008, Comma feeding on cherry laurel 
The photos above show individuals from the overwintering generation. The one below is the only one I've got from a summer generation ('hutchinsoni'), taken on 8/07/07. Note that its underwings are much paler than the overwintering form.

The following graph shows my sightings for a OS grid square in Hull. it shows the butterfly overwinters from October to late March - frost season here - and the hibernating generation mates and dies off during april. No adults are seen in May and June, but the 'hutchinsoni' or summer generation emerges lays eggs and dies off in July. Finally, September sees a new generation of commas, which are non-reproducing and will overwinter.


3 comments:

Jane said...

I found your site via your comment on mine, and I'm so glad I've visited. Some great facts and figures for an "insect geek" like me. We had comma's coming out of our ears this autumn (not literally, you know what I mean!). All landing on the fallen apples, along with a horde of red admirals. I bet they have disappeared now! I wonder what the collective noun for butterflies is? a fluttering maybe? I'll have to look it up... Jane

Blackbird said...

Thanks for your comments Jane! I haven't visited my blog in days, even a resistant garden spider has disappeared now, I have to turn to birds until the spring.

Jane said...

I know what you mean. The only things I've blogged about are Bats and Woodpeckers. Still... they fill the time until the bugs appear again!