Orussidae
Encyclopedia
The family Orussidae 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 beetle
s (or horntail
s), but very little else is known of the life cycle other than that they are parasitoid
s. 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 wasp
s. They are generally rarely-encountered, but can be locally abundant, as in the mountain ranges of Southern California
.
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
, 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
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...
, as they are often considered to be the sister taxon to the Apocrita
Apocrita
Apocrita is a suborder of insects in the order Hymenoptera.Apocrita includes wasps, bees and ants, and consists of many families. It includes the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" formed between the first two segments of the actual abdomen; the...
. They possess a number of bizarre anatomical features not shared by any other living Hymenoptera, including an ovipositor
Ovipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...
that is folded over and looped around the gut internally, extending into the thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
, 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
Insect flight
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...
.
Orussids lay their eggs in trees, attacking the larvae of wood-boring beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s (or horntail
Horntail
Horntail or wood wasp is the common name for any of the 100 non-social species of the family Siricidae, of the order Hymenoptera, a type of xylophagous sawfly...
s), but very little else is known of the life cycle other than that they are parasitoid
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
s. 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 wasp
Cuckoo wasp
Commonly known as cuckoo wasps, the Hymenopteran family Chrysididae is a very large cosmopolitan group of parasitoid or cleptoparasitic wasps, often highly sculptured, with brilliantly colored metallic-like bodies...
s. They are generally rarely-encountered, but can be locally abundant, as in the mountain ranges of Southern California
Southern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...
.
External links
- Waspweb Excellent photographs of several Chalinus species.