Tuesday, 3 June 2014

Speckled Wood life-cycle

A butterfly fluttering around its larval foodplant is always worth watching to see if it is a female looking to lay eggs. At Mowsbury Hill LNR on 26th April a female Speckled Wood (with larger light patches than males) was hopping from plant to plant at ground level. After she moved off one patch of grass I looked for an egg and it was easy to find on a blade of grass. It appeared to the eye rather whiter than it appears in this photo. About the size of a grain of salt it's amazing to think this was manufactured inside a butterfly and will itself become a butterfly in a few months, the second of probably three broods this year.

On 5th May this was the newly-hatched 1st instar larva, about 3mm long:

On 7th May it is now a 2nd instar larva and about 1mm longer:

Having now travelled to Dorest and back with me(!) it has surprised me by pupating overnight (23rd-24th May). The caterpillar seemed much too small and the pupa is tiny, only 12mm from end to end! I have my fears that it may have been infected by something - time will tell. Here's the newly formed pupa with two white features of "something" inside.

Much to my surprise the pupa seems to have progressed normally and is nearly ready to emerge (3rd June):

And the final product, released at Mowsbury Hill (3rd June) within a few metres of where the egg was laid 38 days earlier. I'm astonished that a normal-sized speckled wood could emerge from a pupa that seemed about the right size for a small heath, and that it could transform from a caterpillar to a butterfly in only 11 days. I'm glad that I still find some things wonderful!

1 comment:

Darren said...

Fabulous, thank you Keith - very educational. Atb, Darren