The 'Strepsiptera' (occasionally known as ''twisted-winged parasites'') are an order of
insects with nine families making up about 610 species. They are
parasitoids
on other insects; their hosts include
bees,
wasps,
leafhoppers,
silverfish, and
cockroaches.
Male Strepsiptera have
wings,
legs,
eyes, and
antennae, and look like flies, though they generally have no useful
mouthparts. Females, in all families except the Mengenillidae, never leave their host and are
neotenic in form, lacking wings and legs. Males have a very short adult lifetime (usually less than five hours) and do not feed as adults. They search for and mate with a female (whose anterior region extrudes through the host's body). Sperm passes through an opening in the head of the female and from there directly into the body cavity (
haemocoel).
Strepsiptera enter their insect hosts as
larvae. They undergo
hypermetamorphosis and become a less mobile larval form. In this stage they feed within the host's body cavity. The colour and shape of the host's abdomen may be changed and the host usually becomes sterile. The parasites then undergoes
holometabolous metamorphosis to become adults. Adult males emerge out of the host body while females stay on inside.
Male Strepsiptera have eyes unlike those of any other
insect, resembling the schizochroal eyes found in the
trilobite group known as
Phacopida. Instead of
compound eyes consisting of hundreds of
ommatidia, each of which sees one pixel, the strepsipteran eyes consist of a few dozen lenses, each with its own individual
retina.
The order, named by
William Kirby in 1813, is named for the
hind wings (twisted wing), which are held at a twisted angle when at rest. The forewings are reduced to
halteres.
Strepsiptera are an enigma to taxonomists. Some believe they are the sister group to the beetle families
Meloidae and
Rhipiphoridae, which have similar parasitic development and forewing reduction; some say they are the sister group to the
beetles; some say they are the sister group to the
flies, which have hindwings modified into halteres. The earliest strepsipteran is the highly primitive ''
Cretostylops engeli'' in middle Cretaceous amber from Myanmar.
References
★
Evolution of the Insects, Grimaldi, D. and Engel, M.S., , , Cambridge University Press, 2005, ISBN 0-521-82149-5
External links
★ http://tolweb.org/tree?group=Strepsiptera
★ http://www.strepsiptera.uni-rostock.de/
★
Survey of Modern Counterparts of Schizochroal Trilobite Eyes: Structural and Functional Similarities and Differences