“It’s now nesting season, not just for birds but also Potter Wasps (Vespidae: Eumininae) it seems. Perhaps it’s because of the latter and other insect births at this time, that the former is timed upon?
“I have been observing a Delta sp. wasp constructing its nest in my porch, comprising of cells or chambers resembling clay pots (above).
“Once the wasp (I read it is the female that constructs the nest) puts the finishing touches on the neck of a pot, she deposits her egg (I understand that she lays one egg in every pot). See video here:
“She then proceeds to bring back to the nest paralysed prey (in this case, Nolid moth caterpillars) which she catches, paralyses by injection of venom and seals them in with her eggs. When the wasp larvae emerge, they will have fresh meat to feed on.
“Peering into an open cell, one can just make out a few paralysed but twitching Nolid moth caterpillars (above).
“Within a few hours, more paralysed caterpillars are piled into the cell until it is full (above).
“This species of Nolid or ‘Big-head’ caterpillar has an enlarged green thorax which is thought to act as a deterrent to birds by resembling unripe berries (above).
“The adult wasp then starts sealing the open cell with more mud, by using her front pair of legs to pat down and shape the blob of wet mud which she has carried back to the nest (above).
“Video of wasp sealing the cell full of caterpillars and her eggs above.
“Just 3-4 mud-collecting trips in as many minutes, and the cell is completely sealed (above, below).
“The caterpillars are consumed alive when the larvae hatch. The larvae then proceed to pupate, and the adult wasp will break through the mud nest to begin its adult life.”
11th March 2016