Friday, 21 May 2010

More critical timings

The larvae of the Orange Tip butterfly eat only the seedpods of their host plants (Cardamine pratensis on my patch), so they need to hatch just after the seedpod has formed. This Orange Tip egg has been laid on the foodplant at exactly the right time, just as the flower is about to open:

Hatching will take place about a week from now, by which time the embryonic seedpod will be formed. (Gestation is around 10 days, but the egg is now orange, which means it was laid 2-3 days ago.)

A few insects are dependent on Buttercups, and the first local flower opened today. The larger insect in the following shot is the hoverfly Cheilosia albitarsis, which feeds as a larva on the rootstock of Creeping Buttercup. The smaller creatures are the micromoth Micropterix calthella:

The larvae of Micropterix calthella are unknown, but given the fact that they appear on the same day as the flowers open (and then stay very close to the same flowers for the next couple of months), then I'm sure there is a very tight relationship between the moth and the plant. This mating couple was photographed on the tendrils of Bush Vetch, so you can get an idea of scale:

Another Micropterix species is the wonderful Micropterix aureatella:

This little beauty is only 6mm. long, but is as beautiful as any other species on the planet. Again, the larval stage is unknown, but it is believed to live on Bilberry which is certainly close by.

1 comment:

The Weaver of Grass said...

Fascinating photos Stuart. The orange tip is possibly my favourite butterfly and we get them a lot on the farm here in Wensleydale.
I would like to contact you by e mail so that I can send you a photograph, but don't quite know how to find your e mail address.
I have just returned from the Isle of Elba and took a photograph of some kind of organism which fringed the sea edge. Locals said it was akind of algae - it looks like a single celled thing - bright blue and absolutely fascinating - I thought you might like to see the photo and tell me a bit about it. How can I get in touch?