|
Ichneumon wasps are important internal parasites of other insects. Common
hosts are larvae and pupae of Coleoptera, Hymenoptera, and Lepidoptera.
There are Approximately 3,000 species in North America - more than any
other Hymenoptera family. They differ from the wasps
that sting (Scolioidea, Vespoidea and Sphecoidea) in that the antennae
are longer, usually with 16 or more segments. Female ichneumons
frequently exhibit an ovipositor longer than their body. Ovipositors and
stingers are analogous structures; some Ichneumons inject venom along
with the egg, but they do not use the ovipositor as a stinger, per se.
Stingers are used exclusively for defense; they cannot be used as
egg-laying equipment. Males wasps do not have stingers or ovipositors.
Ichneumon wasps of both sexes will wander over the surface of logs,
tree trunks, and even grass stems tapping with their antennae. Each sex
does so for a different reason; females are 'listening' for wood boring
larvae of the horntail wasps (hymenopteran family Siricidae) upon which
to lay eggs, males are listening for newly emerging females with which
to mate. Upon sensing the vibrations emitted by such a wood-boring
insect larvae, the female wasp will drill her ovipositor into the
substrate until it reaches the cavity wherein lies the larva. She then
injects an egg through the hollow tube into the poor unfortunate's home.
There the egg will hatch and the resulting larva will devour its host
before emergence. Some species of ichneumon wasps lay their eggs in the
ground, some even inject them directly into a host's body. If you happen
across one at work, approach slowly and carefully. You're in for a treat
watching this fascinating process.
You can view a series of large closeup pictures of the giant ichneumon
wasp Megarhyssa
drilling into a log and laying her eggs HERE.
|
