Brimstone caterpillars usually take about a month to reach this stage, unusually this is at 17 days. Most of my initial theories are now in tatters, empiricism tends to do that. Observe, record, form theory. Repeat. Maintain, amend or discard theory. Or just ignore the science stuff, gather data, collate & theorise at a later date. And that's what I'm doing.
The larvae have stopped eating, their bodies thickening and legs shortening. Bottom image.
At the base of the tail is the cremaster, a sort of hook which is attached to a pad of silk woven on a twig or other suitable anchorage.
Unlike most butterflies which simply hang down from the tail as pupae, Brimstones spin a silken sling which supports the body. You can see the silk in the top pictures.
By now, things are happening inside the caterpillar. Enzymes and imaginal discs are active. The imaginal discs produce the cells which form butterfly parts in a way similar to stem cells in humans.
To be continued...
Doggie mummy living in ancient York, Yorkshire, England.
Joined 1st Jan 2018
1st Jan 2024 have achieved 196%
28 March 2024 200%
I take photos, am not a photographer.
Interested...
@kali66 I've learnt a tremenous amount about caterpillar/pupa/imago anatomy & physiology during my 2 seasons with Brimstones and there is still far more for me to learn. At the same time, I'm learning to use the reversed lens Canon more effectively and efficiently - but still turn to my trusty Pany most of the time.
Many thanks
j
@stownsend The outcome is not assured remember, but I have confidence we'll have butterflies even if we don't see the eclosion. Usual story, turn back on pupa, ooops there it is unfolding its crumpled wings!
j
Many thanks
j
j
jx
Thank you for your interest
j
j