My captive breed iris larvae are showing a remarkable variation in development progress. The larvae emerged from hibernation in March with a length of 10mm, give or take a millimetre. A couple of the larvae have hardly moved on from their hibernation state. They have not fully greened up and are no more than 12mm in length. Compare this with the most advanced larvae that are up to 23mm in length and a verdant green colour, picture below. If I had a way of accurately measuring the diffence in weights, without disturbing the larvae, then the difference would be even more remarkable. The larvae lengths today, in millimetres, were as follows: 23, 22, 22, 18, 15, 14, 13, 12, 12.
I think the fine weather in March induced some of the larvae to come out of hibernation early and begin feeding agressively. These cats have continued to develop quickly. The less developed larvae have effectivly become trapped in a partial state of hibernation due to the cold and damp weather since the end of March.
Pure speculation on my part but if this pattern is being repeated in the wild population then I suspect we will get a very protracted emergence season this year.