Checklist of UK Recorded Ceraphronidae

Ceraphronoidea

Alekseev (1978/1987), as translated from the Russian, noted that "This superfamily includes two inadequately studied families of small and very minute parasitic hymenopterans; body length 0.5-4.5 mm. Body color black, rarely chocolate-brown to rusty or yellow. Color usually lightens toward posterior end of body. Difference in color of macropterous and micropterous forms typical-- latter always lighter in tone. Antennae geniculate, with 7-11 segments (in European species with 9-11 segments), and attached slightly above clypeus. Basal antennal segment almost always the longest segment. Sides of pronotum reach tegulae. Mesonotum with transverse groove along posterior margin, and often one median groove, and two parapsidal grooves; or only with median groove; sometimes only with one transverse groove. Axillae very well developed, separated from shield by V-shaped suture, the frenum. Fore tibiae with two spurs. Venation of wings simple. Fore wings with fused costal and subcostal veins, behind which either large pterostigma located distally after transverse interstice, or marginal and postmarginal veins (the so-called linear pterostigma). The vein originating from the pterostigma on the alar plane is called the radial vein. Hind wings veinless and without anal lappet (in very rare cases anal lappet retained in form of trace). Forms with reduced wings are rather common, especially among females. Abdomen with roundish sides. Longest abdominal tergites and sternites-- the 1st tergite and 1st sternite. In the family Ceraphronidae the Waterston organ is located on the anterior middle part of the 4th abdominal tergite, and partially on the posterior part of the 3rd tergite. This is a small dense structure with unique reticulate sculpture (the Waterston organ may not be visible in elongated abdominal tergites). Ovipositor extends beyond tip of abdomen and is usually concealed during repose."

Primary and secondary parasitoids. major hosts: braconids infesting aphids (secondary parasitism), Neuroptera, predatory gall midges, coccids, Mecoptera, gall wasps and ladybirds."

"More than 20 genera known in world fauna." Alekseev (1978/1987) provided a key with 12 genera and about 100 species.

Ceraphronidae

This is a moderately sized cosmopolitan family with cairca 615 species known as of 1993. Important morphological characters include antennae geniculate, 10-11 segmented in male, 9-10 segmented in female; forewing when present with a large stigma; scutellum large, subconvex-convex; metathorax short, rounded behind. The pronotum is visible as a short transverse line dorsally; mandible is bidentate; postmarginal vein is absent; apical tibial spur formula is 2.1.2, sensory area (Waterson's organ) occurs medially on the 6th abdominal tergum.

Most Ceraphronidae are hyperparasitoids of aphids and scale insects, through various braconid and chalcidoid primary parasitoids. A few species are endoparasitoids of dipterous larvae. Most species are solitary, external larval parasitoids (hyperparasitoids; ectoparasitoids of internal hosts). Because of their hyperparasitic habits, they have not been used in biological control.

Masner (1993) reported that in this family the body is 1-3 mm long, usually black or brown but sometimes yellow, orange or reddish. They are macropterous, brachypterous or almost apterous. If winged then the forewing has a narrow linear stigma and metasoma with a wide base. Female antennae have 7-8 flagellar segments, males 8-9.

The hosts and habits of members of this family are little known, but some species have been reared as endoparasitoids of Cecidomyiidae (Diptera), Thysanoptera, Neuroptera, Lepidoptera and puparia of higher Diptera. Some are hyperparasitoids from braconid cocoons. Species are frequently encountered in soil; some are associated with Formicidae but with no direct integration (Masner 1993). There are circa 360 identified species worldwide (1,000 estimated).

Alekseev (1978/1987), as translated from the Russian, that "Antennae of males with one more segment than antennae of females. Depression above antennal sockets always well defined. Pterostigma linear; radial vein sometimes short. Mesonotum with only median groove or without grooves; parapsidal grooves exceptionally present in one species. Abdominal petiole visible in dorsal view; abdomen relatively laterally compressed. Male genitalia with fused volsellae and parameres. Europe, five genera. Mainly parasitoids of gall midges (Cecidomyiidae), but some are parasitoids of Neuroptera and Hymenoptera."

Immature Stages of Ceraphronidae (= Calliceratidae)

Clausen (1940) noted the family Ceraphronidae as Calliceratidae. The egg and larval instars of several species of Lygocerus and Conostigmus in the Cephronidae have been observed and described. In Lygocerus, four larval instars are recorded for L. cameroni, L. niger and Lygocerus sp. from Japan, with some evidence presented that an additional instar may intervene between those described as the first and second. Kamal, however, found only three instars in C. zaglouli and C. timberlakei.

The egg of L. cameroni is elliptical in form, 0.25 mm. in length, and white in color, with a minute protuberance at one end, and the chorion bears minute longitudinal striations. That of Lygocerus sp. (Fig. 36A) is similar, though the nipple‑like protuberance at the posterior end is considerably narrowed. In L. niger, there is a similar protuberance at the anterior pole, also.

The first‑instar larvae of L. cameroni and Lygocerus sp. (Fig. 36B) are similar in form and have relatively large, rounded heads, followed by 12 body segments, with the greatest width occurring in the anterior abdominal region. The mandibles are minute and slender and are adapted for penetrating only a delicate host skin. The integument bears no sensory setae or cuticular spines. There arc two pairs of spiracles, one situated on the intersegmental membrane separating the first two thoracic segments, or at the anterior margin of the second, and another on the first abdominal segment. The larva of C. timberlakei is distinguished by the size and form of the last abdominal segment, which equals the four preceding segments in length and is deflected ventrad. No mention is made of the respiratory system.

The second‑instar larva of L. cameroni is distinguished from the first by the posses­sion of an additional body segment and four pairs of spiracles, these being situated at the anterior margin of the second thoracic and on the third thoracic and the first two abdominal segments.

The third‑instar larva of L. cameroni is more robust than the second, being somewhat globose, with the head markedly ventral in position. There are seven pairs of spiracles, the first being situated at the posterior margin of the first thoracic segment and the following ones on the third thoracic and first five abdominal segments. Spi­racular branches may also be found in the second thoracic and the sixth abdominal segments. The third‑instar larva of Lygocerus sp. (Fig. 36C) differs from the above in the more elongated form of the body and the presence of transverse rows of conical protuberances dorsally and laterally upon all body segments except the last. The caudal segment is somewhat irregularly bilobed transversely.

The mature larvae of L. cameroni, L. niger and Lygocerus sp. (Fig. 36D) are similar in all principal characters. The body is robust, broadest in the thoracic region, and curved or straight according to the cell that it occupies. The head is relatively small, with simple mandibles. In all these species, the last abdominal segment is transversely bilobed, the dorsal lobe being distinctly conical in form. The thoracic and all abdominal segments except the last bear conical papillae or tubercles on the dorsum and sides, which are arranged in transverse rows in L. niger and Lygo­cerus sp, and are scattered in L. cameroni. In the latter species, they occur also upon the conical process of the last abdominal segment. There are seven pairs of spiracles, situated at the posterior margin of the first thoracic segment and on the third thoracic and first five abdominal segments. In Lygocerus sp., these are markedly dorsal in position, and the pair on the third thoracic segment is much the largest.

The mature larva of Conostigmus, which is stated by Kamal to be the third instar, lacks the principal characters that readily distinguish Lygocerus. The conical inte­gumentary papillae and the conical process on the last abdominal segment are lacking. The head is exceptionally large and hemispherical, and the last abdominal segment is longer than those preceding it and smoothly rounded. In C. zaglouli, each abdominal segment, except the last, bears a sclerotized ring, which is much heavier ventrally than on the dorsum. There are eight pairs of large spiracles, whereas C. timberlakei has only six, situated on the first thoracic and the first five abdominal segments.