Strategies for
Survival
PAGE 6
PAGE 1 - MATE RECOGNITION
PAGE 2 - CAMOUFLAGE and
DISGUISE
PAGE 3 - APOSEMATIC
COLOURATION
PAGE 4
- MIMICRY
PAGE 5
- SEXUAL DIMORPHISM
PAGE 6 - ROOSTING BEHAVIOUR
PAGE 7 - SEASONAL DIMORPHISM
In cool or rainy weather butterflies are
inactive, and thus particularly vulnerable to attack by birds and
small mammals.
In tropical areas many species hide away
beneath leaves, even when sunny, and only come into the open to
undertake specific tasks such as feeding or reproducing. This
behaviour is very widespread amongst the metalmarks ( Riodinidae )
and Spreadwing skippers ( Pyrginae ).
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Eurybia
molochina, ( Riodinidae ) hiding
beneath a leaf in the Peruvian rainforest |
In temperate zones members of the Papilionidae
and Pieridae normally roost beneath the leaves of herbaceous
plants. Species which hibernate as adults need a particularly
effective disguise, as they have to avoid being seen for many
months. The Brimstone
Gonepteryx rhamni
for example is superbly camouflaged as it hangs beneath the leaves
of bramble or ivy during the winter months. The wings are
leaf-like in shape and colour, and even have raised venation to
simulate the veins of leaves.
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Gonepteryx rhamni,
( Pieridae ) hibernating beneath a bramble leaf, West Sussex,
England |
In contrast many members of the Nymphalinae
roost hanging beneath tree branches, where their underside
patterns offer an effective dead-leaf disguise.
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Polygonia c-album,
( Nymphalinae ) hibernating beneath a branch, West Sussex, England |
Pyrgines such as the Grizzled Skipper
Pyrgus
malvae usually roost at the top of dead flower-heads. The Dingy
Skipper
Erynnis tages behaves similarly, but takes things a stage
further by wrapping it's wings tightly around dead knapweed
flowers, where it is almost impossible to see
( unless you are a
very determined entomologist ! ).
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Erynnis tages,
( Pyrginae ) roosting on a dead knapweed flower, Hampshire,
England |
Polyommatines ( Blues ) normally roost at the
top of grass heads, assuming a head-downwards position. Satyrines
such as Small Heath, Marbled White and Meadow Brown nearly always
roost on grass heads or flower heads. Checkerspots and small
Fritillaries ( Melitaeinae ) adopt a similar tactic, often
roosting on the flowers of rushes. Such strategies at first seem a
little difficult to
understand, as the butterflies are easily spotted. The probable
explanation is that they are choosing sites where they are out of
reach of nocturnal predators such as mice.
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Mellicta athalia,
( Nymphalinae : Melitaeini ) roosting on a rush flower, Kent,
England |
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