Checklist of UK Recorded Aulacidae, Evanoidea, Gasteruptiidae

Aulacidae (Evanioidea)

The habits of this family are relatively unknown, except that they are mainly parasitic on larvae of wood-boring Coleoptera, with a few species attacking the larvae of horntail wasps in the family Xiphydriidae (Clausen 1940/1962). Froggatt recorded up to 50 parchment-like cocoons of Aulacus apicalis Westw. which were matted together in the burrow of a Piesarthrius marginellus Hope larva (Clausen 1940/1962).

Mason (1993) noted that the body of species in this family is relatively slender. Female antennae have 12 flagellar segments, and males 11. The proplura is long and neck-like; the mesoscutum is often humped anteriorly; and the metasoma is attached high on the propodeum, but distinctly separated from the metanotum by a wide dorsal band of the propodeum. The medial (inner) side of the female metacoxa usually has a vertical or oblique groove; the metatibia is not thickened, and the ovipositor is long.

This is an ancient cosmopolitan family with circa 13 genera and 150 known species (many have not been described). Although there are relatively few extant species, extinct species are abundant in the fossil record and ar thought to have formed a major part of Hymenoptera in the Mesozoic era. Adults parasitize larvae of wood-boring Coleoptera. Some parasitize wood-boring sawfly larvae of the family Xiphydriidae. They are at times found in relative abundance following lumbering operations or forest fires, but they are usually scarce. In North America there are 28 species (20 in Canada), and are common in the boreal forest.

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Evaniidae (Evanioidea).

There are relatively few genera and species in this family, all of which are believed parasitic in the egg capsules of cockroaches (Clausen 1940/1962). Early researchers mistakenly believed that some species were parasitic on other stages of cockroaches. Biological studies on Zeuxevania splendidula Costa (Genieys 1924) developing in the egg capsules of Loboptera decepiens Germ. in Europe, revealed that the parasitoid egg was deposited within one of the eggs in the capsule before the covering was completely hardened. This is in accord with the habit of many other parasitoids of eggs contained within a capsule or covered with an appreciable quantity of mucilaginous material that hardens rapidly, as for example in the scelionid parasitoids of grasshopper and mantid eggs (Clausen 1940/1962).

Mason (1993) reported that in this family the body is short and stout, with a typical appearance. Antennae are elbowed with 11 (rarely 8) flagellar segments in both sexes. The legs are relatively long. The hind wing has the jugal lobe separated from the claval lobe by a deep incision. The metasoma is relatively small and compressed, attached high on the propodeum by a curved, tubular petiole. The ovipositor is short and mostly hidden.

There are circa 14 genera and 400 species, especially abundant in the tropics. In Europe one species ranges north to the Lapland tundra. A few species are cosmopolitan, living inside warehouses and other buildings with cockroaches. Adults seek ut and oviposit in the concealed egg cases of cockroaches (Dictuoptera: Blattodea). The larvae feed on the cockroach eggs and pupate inside the ootheca. Evaniids are usually considered predators. In North America there are 11 species (4 in southern Canada).

The egg is cylindrical in form, 1.0 mm in length, 0.25 mm in greatest width, slightly curved, and with one end markedly constricted and terminating in a broadly conical structure which bears a minute pedicel. First instar larvae are somewhat cylindrical in form with 13 distinct segments, simple but strongly extruded mandibles, and a complete internal tracheal system, but no spiracles. In this stage feeding is confined to the contents of the single egg, but following the first molt the neighboring eggs in the capsule come under attack. The first stage larva is therefore a true egg parasitoid, but it becomes an egg predator after the molt. The second instar larva is globular in form but otherwise closely resembles the preceding instar, the distinguishing characters being those of the head. The 3rd & last instar larvae are very robust, about twice as long as wide, with the head large and the mandibles still simple. There are no integumentary spines, sensory setae, or sculpturing upon the body. The tracheal system is now open, with nine pairs of spiracles located on the 1st and 3rd thoracic and the first seven abdominal segments. Each of the seven abdominal segments possesses an accessory ventral commissure in addition to the usual anterior and posterior commissures. Only a single individual is able to develop to maturity in each egg capsule. Winter is passed in the mature larval stage within the capsule, and adult emergence takes place in late spring or early summer (Clausen 1940/1962).

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Gasteruptiidae (Evanioidea)

This family is distributed worldwide and is represented by a considerable number of species. However little is known regarding them except that they are parasitic on solitary wasps and bees (Clausen 1940/1962). Hoppner (1904) gave a general account of the habits of Gasteruption assectator F. as a parasitoid of Prosopis spp. in Europe. Eggs are deposited externally upon the body of mature Prosopis larvae. It is not known whether this takes place before or after the cell is closed. After the host larva has been completely consumed, the Gasteruption larva gnaws its way into an adjoining cell and feeds on a second host before reaching maturity. The cocoon is formed within the cell of the host. Mature larvae of G. assectator are elongate and bear bands of stout, brownish setae, directed caudad, on the dorsum of the segments. A lesser number of these setae occur ventrally. There are nine pairs of spiracles which are located on the second thoracic and the first eight abdominal segments. Mandibles are tridentate (Clausen 1940/1962).

Mason (1993) noted that the body was slender in species of this family. The antenna has 12 flagellar segments in the female and 11 in the male. The propleura is long and neck-like, clearly separating the head from the pronotum. The metasoma is attached very high on the propodeum, so that it appears to touch the metanotum. The metatibia is strongly clavate in both sexes. The ovipositor is moderately to very long (except in Hyptiogaster).

Members of this family have a typical hovering flight with the swollen metatibiae hanging down so that the insect resembles a helicopter carrying a large load on a cable (Mason 1993). The biology of Nearctic species is unknown, but some European species were reared from nests of solitary bees or wasps in holes in wood where they are predators, feeding on one or more of the eggs and larvae found in the nests. The family contains circa 9 genera and 500 species worldwide, with more species in tropical than temperate areas. There are 15 species in North America (9 in Canada).

Kieffer (1912) revised and Hedicke (1939c) catalogued the world species. Crosskey (1951, 1962) revised the British species and reviewed the world genera. Pasteels (1958 and earlier) revised species of Gasteruption. Townes (1950) reviewed the North American genera and species. Oehlke (1984) revised the German species.

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