|
Strange but true !
Page
4 of
4
<< Previous |
Next >>
Vampire moths !
The
vampire moth Calyptra thalictri is a
native of Malaysia, the Urals and southern Europe but has recently been recorded
in Sweden, and could soon find its way to Britain.
Like other lepidoptera its proboscis is constructed from 2 hollow tubes. The
proboscis of the Vampire moth is sharp enough to pierce human skin, and the moth
is able to drill its proboscis into the skin by rocking its head from side to
side. There is no known health risk to humans, but the wound can remain sore for
a couple of hours. It is likely that the vampire habit evolved from an ancestral
ability to pierce fruit, or possibly arose 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 !
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,
typically feeding on mites, insect eggs and young larvae, but
don't in any way
harm the butterflies. They simply hitch a lift on butterflies and
other insects, using them as transportation to enable them to
disperse to new
habitats.
One tactic they use is to ambush a fully grown
caterpillar, grabbing its spines or head horns with their powerful
pincers. When the pincers "bite", the pseudoscorpion becomes quiescent.
After a few hours the caterpillar pupates, and 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 onto the butterfly, grabbing hold of its antennae or
legs. This causes the butterfly to take flight. Sometime later,
when the butterfly lands in a suitable place, the
pseudoscorpion drops off, and colonises it's new found habitat.
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 ( family Cosmopterigidae ) have been found to be able to complete their entire larval
period either on land or beneath water. The caterpillars are found only on
Hawaii. They are capable of living 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 caterpillars 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
caterpillars of several species of Blues and Hairstreaks ( Lycaenidae ) for
example feed on ant grubs or aphids, and the larvae of many species including
the Orange tip Anthocharis cardamines ( Pieridae )
are cannibalistic.
Hyposmocoma moths
and larval cases
( image supplied )
|
