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Order
- STREPSIPTERA
(Greek, strepsis = twisting; pteron = wing)
Common Name: stylops
Distribution: Cosmopolitan
Description
Members of the order Strepsiptera are highly specialised parasites of
other insects. For some time they were considered to be modified beetles,
however this is no longer believed. However, the strepsipterans are
probably closely related to Coleoptera (beetles) or
Diptera (flies). The
species within this order show an extreme form of sexual dimorphism: the
adult male is a free-living winged insect, while the adult female is a
"maggot-like" organism within the body of the host (endoparasite).
Adult males have bulging compound eyes with a few facets - there are no
simple eyes (ocelli). Mandibles are present but small. The forewings are
reduced to stubs but the hind wings are broad with a few veins. Males live
for only a few hours after leaving their hosts and probably do not feed -
their only activity is to find females for reproduction. Males are quite
small (less than 5 mm long) and are probably not rare but their small size
and short life spans means that they are not often encountered. Females
remain within the body of the host insect.
Larva
Eggs hatch within the female strepsipteran and the juveniles travel out of
the female's brood passage to the surface of the host. Juveniles leave
while the host is visiting a flower. The larvae are 6-legged and have
compound eyes but lack antennae and mandibles. They attach themselves to
an insect visiting the flower on which they have alighted. The parasite
absorbs nutrients directly through its skin. Females never develop any
further than an advanced "maggot" form and protrude their
forepart through the host cuticle when involved in fertilisation. Males
pupate in the host and then emerge by pushing off a small cuticle cap
which protrudes from the host's body. Females attract males by scent
(pheromones).
Members
Stylops - most representatives are not commonly known.
Food
Strepsipterans feed on the body of other insects. Hosts include bees,
wasps or other members of the Order
Hymenoptera.
Importance
The importance of strepsipterans is unknown at present. |