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.
