Cycle of the
The glossy pale yellow eggs are c.0.8 mm high and flattened
at the base. They are laid singly on the blades of
a wide range of grasses in April or May and again in the
summer. Hatching occurs between 8-23 days,
depending on the temperature.
On emerging, the larvae do not always eat the eggshell but remain close
to it on the leaf.
They feed inwards from the margins of the leaf to the
The first brood larvae feed by day and night and are fully grown in
25-30 days when they enter pupation.
The larvae of the late summer brood are unusual in that they either
hibernate as larvae or pupate before
hibernating and therefore can be found overwintering
in either state.
It has been found that when the autumn is cool, larvae emerging from
eggs as early as mid-August remain
in the larval stage and overwinter in this state. While in warmer
temperatures larvae emerging as late as
the end of September develop rapidly enough to pupate in November
and overwinter in this state. These
pupae hatch the following spring producing butterflies as early as March
but more usually in April and
May. While the overwintering larvae do not produce larvae until
later in spring. This larval stage lasting
at least 7 months.
The duration of the pupal stage is variable and dependant on temperature
and time of year. In summer it may
be as short as 10 days, but in the overwintering
pupal stage it can last roughly from November to April.
The pupa is attached by cremasteral spines to a silken pad spun on the
underside of leaves of the foodplant
or adjacent vegetation. The cast larval skin is always
attached to the pupa.
Adults can emerge continuously from April to mid-October. There
tends to be an overlap among different
generations and in warm summers there may be three broods with old worn
specimens still on the wing
Both sexes feed on the honeydew of ash, oak and birch or nectar from
ragwort. Mating and ovipositing
take place from April onwards.
© DHardiman 2004
© DHardiman 2002
outer margins of the females wings are more rounded and the creamy-yellow
patches usually larger
than the males althought there is a marked seasonal variation in bothe sexes.
oblique band of blackish androconial scales in the centre of the male
forewings are difficult to see.