Chalcidoid Main | Chalcid Literature | Chalcid Collecting | Chalcid Forum


habitus illustration: female of Eupelmidae

Female of Eupelmidae

This family, the Tanaostigmatidae, and the Encyrtidae (also some aphelinids) are distinct among chalcidoids (at least in females) in the absence of a mesopleural depression for the reception of the midfemora. Instead this area is bulging or convex in females of these families (Gibson 1986b refers to this area as the acropleuron, but we use "mesopleuron" since it is the term that is most often encountered in previously published keys or other literature). Males do not always show this character, and some eupelmid males are not so easily distinguished from some pteromalid males. Riek (1970) placed eupelmids (and Aphelinidae) as a subfamily of Encyrtidae, but this does not seem any more reasonable than placing them all in the Pteromalidae. Burks (1979) placed Eupelmidae as a separate family. It seems best that all should share equal rank in the same family, or all should be families, but to place some apparent equal ranking taxa as families and others as subfamilies seems capricious. The only Nearctic key since Ashmead (1896) is the key to genera by Gibson (in Gibson, et al. 1997). The world genera of Calosotinae and Neanastatinae are treated by Gibson (1989) and the Eupelminae by Gibson (1995).

The Eupelmidae may be divided into 3 subfamilies as follows:

Calosotinae: 19 species in 5 genera. Gibson (1989) lists 8 genera of calosotines for the world (four of which he described as new). Four genera of calosotines are known from the Nearctic (Archaeopelma, Licrooides, Eusandalum, and Calosota). The genus Calosota (5 species) was revised by Burks (1973).

Eupelminae: Gibson (1995) in his world revision of the subfamily lists 86 Nearctic species in 14 genera. There are about 71 Neotropical species in 15 genera. The only useful revisions of genera for the group are for Macroneura (now a subgenus of Eupelmus) (Gibson, 1990), Arachnophaga (10 spp; Gahan 1943), Anastatus (14 spp; Burks 1967), and Lecaniobius (3 spp.; Compere 1939).

Neanastatinae: Only 2 genera are included in this subfamily which was revised by Gibson (1989, as Metapelminae) who described 2 new genera. Lambdobregma and Metapelma occur in the Nearctic.
STATISTICS: Number of world species: 850 (110 Nearctic); number of world genera: 45 (20 Nearctic).

BIOLOGY: The calosotines apparently attack insects in plant stems or wood and may be primary or perhaps facultative secondary parasites. For example Calosota metallica has been reared as a primary of both hymenopterous (Tetramesa: Eurytomidae) and dipterous (Mayetiola: Cecidomyiidae) gall-formers on grass as well as a secondary on torymid and eurytomid parasites of the gall-formers (Burks 1973). Eusandalum seems to mostly attack wood-boring beetles.

Eupelminae are known to be fairly variable in their various modes of existence even within species. In the Nearctic, Anastatus are all egg parasites of various insects including Lepidoptera, Orthoptera (roaches, mantids), and Heteroptera. However several of these species are also known to attack Apanteles and thus are secondary parasites. Species of Eupelmus attack cynipid gall-formers, Coleoptera and Diptera in plant stems and flower heads, Lepidoptera, and Orthoptera eggs. They are also facultatively secondary and attack parasites of the above-mentioned hosts. The genus Arachnophaga attacks Lepidoptera or their parasites, as well as spider egg sacs. One species is a secondary on Chrysopa. The genus Lecanobius parasitizes Coccidae (Ceroplastes, Saissetia) and apparently the parasites of these coccids (e.g. Scutellista: Pteromalidae).

Genera of Neanastatinae exhibit different biologies. Metapelma species are parasites of wood-boring insects, probably mostly in the families Buprestidae and Cerambycidae. Neanastatus are primary or secondary parasites of Cecidomyiidae and Lamdobregma schwarzi was reared from a cricket egg.

DISTINGUISHING CHARACTERS: As previously mentioned, eupelmids, tanaostigmatids, and encyrtids are separated from all other chalcidoids (at least in females) by the convex mesopleuron which does not have a groove for the reception of the midfemur. Also the midtibial spur is fairly thick, long (subequal to basitarsus), and distinct, appearing more like an appendage than a seta or spine. Eupelmids are distinguished from encyrtids by several fairly distinct characters: the scutum of female eupelmids is flat or concave, at least in part (entirely convex in encyrtids, tanaostigmatids and also many male eupelmines), the axillae (both sexes) do not meet medially, or if so, they are at least as long as wide and do not appear to be transverse (in encyrtids and tanaostigmatids nearly always meeting medially and/or transverse), and the midcoxae (both sexes) are several times their own diameter removed from the forecoxae (in encyrtids nearly contiguous with forecoxae). In general, male Eupelminae, Calosotinae, Tanaostigmatidae, and Encyrtidae have the scutum flat to convex, but Eupelminae and Tanaostigmatidae males have the mesopleuron concave. Encyrtids and Calosotinae have the mesopleuron convex; this combined with the axillae and coxal characters should help to separate males of the families that might be confused. However, male eupelmines will key to Pteromalidae Subfamilies may be separated by characters given in the key.

COLLECTING: Eupelmids are not frequently collected by general sweeping, although they often are found in Malaise trap samples. Occasionally large numbers of a single species may be taken when sweeping grasses in disturbed places (riverbanks, road grades). It is generally not too difficult to rear them from cynipid galls if a fair number of galls are collected. Dead twigs with evidence of borers (e.g. exit holes, frass) may also produce eupelmids.

DISTRIBUTION: Eupelmids are fairly well distributed throughout the world.

Chalcidoid Main | Chalcid Literature | Chalcid Collecting | Chalcid Forum