|Common Nettle and Small Nettle.
Betony , Bramble, Dandelion, Devil's-bit Scabious,
Field Scabious, Greater Stitchwort, Hawkweeds,
Heather, Knapweeds, Marjoram, Primrose , Privet,
Ragwort, Thistles, Thyme and Water Mint.
Male: 45 - 55 mm.
52 - 62 mm.
Any time of the year, even on the last days of
December or first days of January if the temperature
is high enough to wake them from hibernation.
However, adults normally emerge from hibernation
at the end of March and start of April.
There are typically 2 broods each year, except in the
north, where there is usually only a single brood.
This butterfly has always fluctuated in numbers,
but the cause of the most-recent decline is not yet
known, although various theories have been proposed.
One is the increasing presence of a particular parasitic fly,
Sturmia bella.The fly lays its eggs on leaves of the foodplant,
close to where larvae are feeding. The tiny eggs are then eaten
whole by the larvae and the grubs that emerge feed on the
insides of their host, avoiding the vital organs.
A fly grub eventually kills its host and emerges from
either the fully-grown larva or pupa before itself pupating.