Butterflies of
Europe
Chestnut Heath
Coenonympha
glycerion
BORKHAUSEN, 1788
Family - NYMPHALIDAE
subfamily -
SATYRINAE
Tribe - SATYRINI
subtribe -
COENONYMPHINA
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Coenonympha
glycerion, Jadovno, Velebit mountains, Croatia
© Peter Bruce-Jones |
Introduction
The genus
Coenonympha comprises 39 known species, found variously in
North America, Europe, north Africa and temperate areas of Asia.
There are 14 species in Europe.
Coenonympha
glycerion is found across much of Europe from northern
Portugal to Russia, but is absent from many areas including Britain,
Sweden, Norway, Finland, southern Spain and western France. Beyond
Europe it's range extends to Siberia, Mongolia and Japan.
The size and number of ocelli on
the underside wings varies considerably according to locality. In
the Spanish subspecies C. glycerion iphioides
they are particularly prominent. In examples from cooler areas the
ocelli are often entirely absent. The white markings on the
hindwings also vary greatly, some examples having just one or two
small white patches, while in others these are linked to form a
prominent white post-median band.
Coenonympha
glycerion, Jadovno, Velebit mountains, Croatia
© Peter
Bruce-Jones
Habitats
Coenonympha glycerion is found in
sheltered grassy habitats including sub-alpine hay meadows,
woodland clearings and scrubby grassland, at elevations between
about 300-1800 metres.
Lifecycle
The butterflies
emerge from early June to late August according to locality and
lay their eggs singly on grass blades, usually close to bushes.
The caterpillar
when fully grown is pale green, with a prominent white stripe
below the spiracles, and a series of thin faint whitish stripes
along the back. It feeds nocturnally on grasses including
Brachypodium sylvaticum,
Cynosurus cristatus,
Briza media,
Melica ciliata and Bromus erectus.
The chrysalis is
of the usual Satyrine shape, pale green in colour, with a
peppering of tiny white dots. The inner margins of the wing cases
are white, edged with black. It is suspended by the cremaster from
a stem or leaf.
Adult behaviour
Both sexes
commonly nectar
at a wide range of flowers including ox-eye daisy, heather,
scabious, thyme, vetches and umbellifers.
The butterflies
are active on warm sunny days but tend to hide among bushes in hot
weather. On overcast days, and when roosting overnight, they
usually sit at the top of dead flower heads, most commonly on
plantains.
Coenonympha
glycerion ambushed by crab spider Thomisus onustus
© Peter
Bruce-Jones
The butterfly depicted above has been ambushed by a crab
spider Thomisus onustus ( Thomisidae ).
This remarkable spider has a chameleon-like ability to change colour
to match it's surroundings, so it can be white, yellow, pink or
variegated in appearance. The change of colour takes about 2 or 3
days to complete however, so it is common to find a spider on the
"wrong colour" of flower.
Crab spiders often spend several
days motionless on a flower head, waiting for their next meal to fly
in. They have excellent forward vision, and move immediately and
stealthily towards any bee or butterfly which settles on the flower.
In contrast, their peripheral vision is poor, so much so that it is
possible for a butterfly to settle alongside the spider without
being attacked. If on the other hand it is unfortunate enough to
walk across the spider's field of vision, the powerful pincer-like
forelegs immediately seize the butterfly. The spider then bites it
on the neck, injecting it with a paralysing venom which incorporates
enzymes that liquefy the butterfly's internal tissues.
Thomisus onustus then sucks out the
body contents of the butterfly, discarding the chitinous exoskeleton
and wings.
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