The family Tachinidae is
considered the largest amongst all the
diverse families of Diptera (two-winged true
flies). Recent science shows approximately
8,200 species worldwide. Adult tachinid
flies are diverse in appearance, but they
are generally known for their bristly
facies. Archytas (fig. 1) exhibits
prototypical tachinid features, including a
large, metallic-colored abdomen covered with
bristles. Many other tachinids, however, are
sparsely bristled and exhibit very pale
coloration. All Tachinids share the
parasitoid habit, and almost all of them are
endoparasites of of other insects; in spite
of their varied appearance all species of
Tachinidae are alike in this characteristic.
Insects most commonly parasitized by the
tachinids are the larvae of the Lepidoptera
(butterflies and moths) and the adults and
larval form of the beetles, or Coleoptera.
Other tachinids attack true bugs of the
Hemiptera (Heteroptera), larva of
Hymenoptera (bees, wasps, ants, sawflies),
or adults of Orthoptera (grasshoppers,
katydids, crickets and their kin). Rarely do
Tachinidae parasitize other Diptera or any
other groups of arthropods, however, some of
these flies are known to attack woodlice
(Isopoda).
Few tachinids are known to be host-specific,
although some species of the genus Phasiinae
are limited to a few Hemiptera hosts. Many
tachinids will attack insect hosts in 2 or
more different orders. Many tachinids
parasitize major agricultural pests of food
or timber crops, and have potential for use
as biological control agents, but most
attempts at using them in such wise have
been dismal failures.
Among the methods tachinids use to infect
their subjects are the oviparous
species that place large, macrotype eggs
directly on the body of the host, the
micro-oviparous, which place tiny,
microtype eggs on foliage or other
foodstuffs being consumed by the host, or
the larviparous, which retain their
eggs until maturity; these eggs hatch
immediately upon being laid on or near the
target. Some female tachinidae that attack
bugs or beetles have piercing ovipositors
much like wasps in the
Hymenoptera family
Ichneumonidae.
Adult flies can be found almost anywhere. I
usually see them feeding at flowers or
amongst low vegetation. Females frequently
fly in search of host candidates.
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