Big session looking for eggs and larvae in Savernake Forest yesterday, conducting an initial assessment of the 2026 'egg lay' (= number of eggs laid) and of larval survival in the heatwave. A gang of four searched one of the main breeding grounds (ground searching + shepherd's crooks, aiming to follow the larvae through).
Goodish news:-
1 The 'egg lay' looks good, though it is almost certainly lower than last year (an annus mirabilis in which the Purple Emperor won BC Wiltshire's Butterfly of the Year).
2 Larval survival seems to be OK-ish (judged by the number of finds of egg case bases + 1st instar silk pads and feeding, minus any live larva). Last year, we lost a lot of baby larvae to heat desiccation, and some eggs 'boiled in the bag'. This year, the females seem to have laid more in heavy shade, sensibly.
We found six 2nd instar larvae, 10 1st instar larvae; only one egg (about to hatch); one dead egg (predated by a sucking bug)) and five 'L1 Fails' (egg case base + pad & feeding - larva [egg case base is abbreviated to ECB, though that also stands for England & Wales Cricket Board; and about to hatch is abbreviated to ATH]). That's good.
Best, sallow foliage condition was Good to Very Good - heat and drought haven't adversely affected sallow foliage, though a few early-leafing sallows (males mainly) have gone through the phase of being suitable for young larvae.
Here's yesterday's best photo, of a late L1 larva (1st instar) next to an early L2 (2nd instar) -
Silver-washed Fritillary and Purple Hairstreak seemed to be over in the forest - imagine that, paphia and quercus gone by the end of July...
At present, it seems that the final 2026 sighting of Apatura iris in England was of a female seen by Toby Ludlow in Lincs on Fri July 25th (July 26th used to be National Purple Emperor Day - peak season...) - unless is double-broods...
No comments:
Post a Comment