Family - LYCAENIDAE
subfamily - THECLINAE
Tribe - EUMAEINI
© Adrian Hoskins
are about 30 Callophrys species, of
which 10 are found in temperate Asia. Additionally there are 25
species in North America and one which is found only in Spain and
The Green Hairstreak never displays it's brown upperside except when
in flight. The green colour of the underside (
like the blues and coppers of other Lycaenids ) is produced
by light refracting and reflecting from a
microscopic lattice within translucent
wing scales. The iridescent colouring varies in
hue according to the directional qualities of the light
and the angle of view. The butterfly can thus appear to be
metallic apple-green, turquoise or emerald, when viewed from various
Some individuals known as form caecus
have plain undersides, but on others the wings are marked with a row
of white dots, often edged with reddish - these are called form
The sexes are almost identical, but the male has a small patch of
scent scales in the discal cell of the upperside forewing.
This is also visible in certain lighting conditions in the form of a
little raised pad in the cell on the underside.
is widely distributed in Europe and across temperate Asia to
This species can be found in a wide variety of habitats including
calcareous grassland, woodland clearings, heaths and moorland, sand
dunes, coastal habitats and mountainsides.
widely over their habitat, laying their eggs singly on the
leaves or flower buds of the various
foodplants, including bird's foot trefoil
Lotus corniculatus, common rockrose
Helianthemum chamaecistus, dogwood
Cornus sanguinea, buckthorn
Rhamnus catharticus, gorse
Ulex europaeus, and broom
Cytisus scoparius. On moorlands and
heaths the main foodplant is bilberry
Vaccinium myrtillus, and in woodlands bramble
Rubus fruticosus is commonly used.
Like other Lycaenid larvae, that of the Green Hairstreak is plump,
like a woodlouse. It is green, and marked with rows of yellow dots
on the back and sides. The larva feeds on the flower buds, flowers
or tender young leaves of common rockrose, gorse, bilberry, bird's
foot trefoil, dogwood, broom and various vetches.
At some sites the larvae feed on buckthorn berries, in which they
make a hole through which they extract the contents.
The larva leaves the foodplant to pupate just under the surface of
the ground, often where there are stones or fallen leaves.
The pupa has the
ability to produce a squeaking noise - this was once thought to be a
defence mechanism against ants and beetles, but research on other
Lycaenids that also share this behaviour suggest that the pupa is
actually "singing" to attract the attention of ants, which carry it
into their nests below the ground. The pupa secretes a sugary
coating which the ants drink, and in exchange the pupa gains
protection from other insects that would not dare enter the ants
and females behave quite differently. Males establish territories,
typically perching on gorse flowers, or on the foliage of hawthorn,
various other bushes,
often at the bottom of hills.
On sunny mornings they use these perches as vantage points from
up to intercept
small insects, including bees, flies, and various butterfly species,
as well as other Green Hairstreaks.
perching they regulate their body temperature by tilting their wings -
in cooler conditions they are angled to present the maximum wing area
to the sun but in hot conditions they are angled edge
on to minimise heat absorption. This lateral-basking
has the additional advantage that the wings cast no give-away shadows,
helping the already superbly camouflaged butterfly to
even more perfectly against its background and avoid being detected by
several males will have overlapping territories, so male-male
encounters are frequent.
they engage in a
zipping about in tight circles,
each trying to outwit and outmanoeuvre the other with constant changes
of direction. Each male changes his territory several times throughout
the day in response to the changing position of the sun which causes
each perch to become shaded at some stage. Thus the butterflies
frequently find themselves intruding into each other's territories and
often both males believe they have "ownership" of a particular spot.
At such times their battles can be protracted and intense. The pair
will commonly spiral rapidly to a height of about 4 metres, then break
away. Invariably however they soon meet again and continue the battle
which may last for several minutes. During this time they may chase
each other up to 4 or 5 metres horizontally from the point where the
conflict began. Eventually the weaker male gives up and leaves the
vicinity, and the victor returns to his original perch.
Females spend most of their time fluttering
the ground in search of egg-laying
sites, and are seen far less often than the males.
sexes nectar at a wide range of spring flowers including bird's
horseshoe vetch, common vetch,
holly, wayfaring tree, bluebells,
© Adrian Hoskins