Cycle of the Gatekeeper
The almost spherical egg is flattened at top and base and
pale yellow with orange mottling. It is c.0.6 mm tall.
The eggs are laid singly on blades and stems of grass in July and
August, hatching in c.20 days.
The rather stout adult larva is between 23-26 mm in length and
tapers towards the rear. There are two colour
forms. One with the body a light green with a darker green
mediodorsal line, the other pale ochreous with a
dark brown mediodorsal line. Both have a dark-edged white band
extending along both sides below the level
of the spiracles. The head is bilobed and always
pink-ochreous. The short anal points are ochreous.
The newly hatched larva eats its eggshell and after feeds by day on
various species of grass until October,
when it enters hibernation. It overwinters
low down among the grasses until the spring when it resumes
feeding and maturation. After overwintering, the larva
feeds this time by night and is fully fed by early July.
Pupation takes place aroung the end of June or early July when a
silk pad is spun by the larva on vegetation
close to the ground. Cremasteral hooks are absent but the pupa is
suspended from the pad by prong-tipped hairs
arising from the cast larval skin which remains attached to the lower
abdomen. This stage lasts c.3 weeks.
The adult emerges and is on the wing from late July to early
September. Many species of flowers are visited
for nectar, especially brambles (Rubus spp.).