A truly awful day in Savernake..., just about my bleakest day caterpillaring. On my last visit, on Easter Monday, I had 18 larvae there. The tally is now down to eight. This is probably in part due to the habit iris larvae have moving from shady places to positions in full sun after they change into the fourth instar. However, some of the missing larvae were already in sunny situations and I strongly suspect that larvae are still being heavily predated. One may well have been accidentally eaten by a deer (I've recorded pre-hibernation larvae succumbing to deer browsing before).
Of course, I may well have missed one or two, as spotting larvae in windy weather is particularly difficult. I doubt I'll see three of the eight again as they're about to change skins and are likely to wander up-tree when they've changed - final instar larvae are amazingly mobile and sun loving.
For the record, one advanced larva was changing into the fifth and final instar - now that's early -; two others will change into the fifth instar soon, three are in the mid-4th instar, one in the early-4th and one retard is just changing into the 4th instar now. My captive ones range from early-4th to early-5th instar.
Three cool and wet weeks have slowed larval progress down but the return of good weather this week will enable them to race ahead of schedule again. An early flight season is still on the cards: the butterfly could well be on the wing by mid-June this year - watch this space...
Here's No 213, changing skin for the final time (hand-held, of necessity, in a raging gale) -