Orussidae
From Wikipedia, the free encyclopedia
| Orussidae | ||||||||||||||
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about 70 species in 16 genera |
The family Orussidae (the sole living member of the superfamily Orussoidea) is the only Symphytan group which is parasitic, thus giving them the common name parasitic wood wasps. They are an ancient group, well-represented in the fossil record, and are believed to represent a sort of "missing link" within the order Hymenoptera, as they are often considered to be the sister taxon to the Apocrita. They possess a number of bizarre anatomical features not shared by any other living Hymenoptera, including an ovipositor that is folded over and looped around the gut internally, extending into the thorax, eggs that are longer than the body itself and folded over within the ovarioles, and a unique method of jumping that has involved the loss of the dorsoventral flight muscles.
Orussids lay their eggs in trees, attacking the larvae of wood-boring beetles (or horntails), but very little else is known of the life cycle other than that they are parasitoids. The adults of many genera are often somewhat ant-like in appearance, and they crawl and hop fairly slowly. Others are somewhat larger and more active, with a type of "scurry and fly" search pattern very reminiscent of cuckoo wasps. They are generally rarely-encountered, but can be locally abundant, as in the mountain ranges of Southern California.
