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Strange but true !
Vampire
moths !
Adult moths usually obtain their food from nectar and other sources
of proteins and minerals, but there is one species with a rather
gruesome habit: Calyptra thalictri is a
very ordinary-looking pale brown moth from the family Noctuidae. It
is a native of Malaysia, the Urals and southern Europe but has
recently been recorded in Finland and Sweden, and could soon find
its way to Britain. Like other moths it has a proboscis constructed
from 2 hollow tubes which are used like a straw to suck fluids.
Instead of feeding at nectar, the Vampire moth feeds on blood by
drilling its proboscis into the skin of mammals including humans!
There is no known health risk, but the wound can remain sore for a
couple of hours. The vampire habit probably evolved from an
ancestral ability to pierce fruit, but it could have arisen
accidentally when moths imbibed mammal sweat - in the tropics many
butterfly species and moths habitually obtain essential minerals by
imbibing human sweat.
The
chrysalis that sings !
The caterpillar of the Green Hairstreak
Callophrys rubi 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 substance which the ants drink. In
exchange the pupa gains protection from other insects that would not
dare enter the ants nest.
The Green Hairstreak
Callophrys rubi, has a chrysalis that
sings! ©
Adrian Hoskins
Hitch-hiking on butterflies !
Close
examination of recently emerged butterflies can sometimes reveal the
presence of very tiny scorpion-like creatures clinging by their
pincers to the legs or antennae. These "pseudoscorpions" are
carnivores. They normally feed on mites, insect eggs and young larvae.
They don't feed on the adult butterflies or harm them in any way -
they simply hitch a lift on them, using them as transport to enable
them to disperse to new habitats.
One
tactic they use is to ambush a fully grown larva, using their powerful
pincers to grab hold of it by its spines or head horns. When the
pincers bite, the pseudoscorpion becomes quiescent. After a few hours
the larva pupates. The pseudoscorpion remains attached to the shed
larval skin, which itself remains attached to the base of the pupa.
Eventually the butterfly emerges from the pupa and the pseudoscorpion
then scuttles onboard the butterfly, gripping hold of its antennae or
legs. The butterfly then flies off. Sometime later when it lands in a
suitable place, perhaps several kilometres away, the pseudoscorpion
drops off. Pseudoscorpions are related to spiders, mites, scorpions
and harvestmen. Their hitch-hiking behaviour is known as phoresy.
Amphibious, carnivorous caterpillars
!
Scientists have discovered the
first known truly amphibious insects - 4 species of moth in the
genus Hyposmocoma ( Cosmopterigidae )
are now known to be capable of completing their entire larval period
either on land or under water. The larvae are found only on Hawaii.
They normally live in damp habitats on land, but are equally at home
in fast running streams, at which time they breathe by direct
diffusion of oxygen through hydrophilic skin. They live within
conical or cylindrical cases, very similar to those used by caddis
fly larvae, and constructed by binding together tiny fragments of
wood or gravel with silk.
The feeding behaviour of the larvae
is unique among Lepidoptera - most of the 350 members of the genus
Hyposmocoma feed on plants, but these 4
species are carnivorous. They seize small snails and other molluscs,
bind them with silk to prevent them escaping, and then devour their
soft tissue!
Hyposmocoma
are the only known species to feed on molluscs, although various
other forms of carnivorous behaviour are found among certain
families of butterfly and moth. The larvae of many species of Blues
and Hairstreaks ( Lycaenidae ) for example feed on ant grubs or
aphids.
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