Chalcidids, like leucospids, are fairly robust wasps with
enlarged hind femora. The group has received considerable taxonomic attention,
especially in the Old World, but recently much has been published in the
New World (e.g., Delvare 1992, Boucek 1992). Boucek (1988:37) summarized
the more comprehensive literature for the Old World and gave keys to
subfamilies (5) and genera (31) of the Australasian fauna. He also
provided keys to the New World genera (Boucek 1992). Boucek and Halstead
(in Gibson, et al. 1997) treated the Nearctic genera. Three subfamilies
are found in the Nearctic:
Haltichellinae: 7 genera, 22 species. This is a poorly
known group with few revisions or keys. Halstead (1990) revised the 5 Nearctic
species of Haltichella and discussed the Holarctic genus Belaspidia
(1988a). Grissell and Schauff (1981) provided a key to the 3 species of
Invreia (now Psilochalcis), but many more are now known to
be present.
Dirhininae: 1 genus, 3 species. The Nearctic species were
revised by Burks (1936, 1947).
Chalcidinae: 8 genera, 118 species. There are three
tribes in this subfamily: Chalcidini, Phasgonophorini, and
Brachmeriiini. Until recently Chalcidini and Brachymerini were each
treated as subfamilies, but Boucek (1988) reduced them to tribes. The
Nearctic genera and species of Chalcidini were treated in part by Burks
(1940), but recently Delvare (1992) made many changes in the
classification of this tribe and provided a key to New World genera and
species groups. Much work remains to be to be done on the speciose
genus Conura (once called Spilochalcis). Moitoza
(1994) revised one species group of Conura. Burks (1968a) revised
Ceratosmicra (now a subgenus of Conura). The genus
Melanosmicra (as Platychalcis) was recently reported
in the Nearctic (Halstead 1988b). In Phasgonophorini, the genus
Trigonura was revised by Burks (1959), and in Brachymerini, the
genus Brachymeria was revised by Burks (1960).
In addition to the above, 2 Old World subfamilies are known. The
Epitraninae with 1 genus and about 50 species (Boucek 1988) has had 3
species reported from the Neotropics but Boucek (1988, 1992) believes
these to be doubtful records or possible introductions. The
Smicromorphinae with 1 genus and about 5 species (Boucek 1988) is known
only from Africa, South Asia, and Australasia.
STATISTICS: Number of world species: about 1500 (about
100 Nearctic); number of world genera: about 90 (11 Nearctic).
BIOLOGY: All chalcidids are parasitic. Most attack pupae
of Lepidoptera and Diptera, but some parasitize other Hymenoptera or beetles.
Parasites of Lepidoptera usually attack young pupae, while those of Diptera
attack mature larvae (Clausen 1940).
Haltichelline genera mostly parasitize lepidopterous pupae. A few species
are known to attack solitary bees which nest in hollow twigs, the larvae
of ant lions, and coleopterous larvae or pupae. The ant lion parasite (Lasiochalcidia
igiliensis) actually provokes the host into grabbing the parasite's
legs in its mandibles, at which time the parasite oviposits into the membrane
between the larva's head and thorax. The enlarged hindlegs of chalcidids
have been shown to aid females in back to back fighting (Cowan 1979) and
presumably function similarly in other families (e.g. Podagrion males,
Grissell and Goodpasture 1981).
The species of Dirhininae, where known, attack the pupal stage of
Tephritidae and synanthropic flies.
The life histories of genera of Chalcidinae are variable. Chalcis
attacks pupae of Stratiomyiidae associated with boggy or marshy areas
(fresh and salt water). The only known species of Metadontia
parasitizes lycaenid larvae. The majority of Conura attack
Lepidoptera pupae, but a few are known from Coleoptera (Chrysomelidae,
Curculionidae), Diptera (Syrphidae), and as secondary parasites of
Ichneumonidae and Braconidae.
Among Brachymerini, Brachymeria are mostly primary parasites of Lepidoptera
but a few attack muscoid Diptera as well as acting as secondary parasites
attacking tachinid and sarcophagid Diptera in Lepidoptera and Orthoptera.
In Phasgonophorini, Trigonura and Phasgonophora both attack
buprestids and the former genus also attacks scolytid beetles.
Little is known about the biology of the non-Nearctic subfamilies Epitraninae
and Smicromorphinae. Riek (1970) reported a species of Epitraninae from
Lepidoptera and Boucek (1988) listed small moths of Pyralidae and Tineidae
as hosts. The Smicromorphinae are suspected ant parasites but no records
have been confirmed (Boucek 1988).
DISTINGUISHING CHARACTERS: The species of chalcidids are
generally robust, with enlarged hindfemora and arched tibiae. Colors range
from black (sometimes with white or yellow marks) to yellow. The characters
that separate this family from others with an enlarged hindfemur
are: 1) forewing flat (not folded); 2) ovipositor horizontal (not
vertical or produced over the metasoma as in
Leucospidae); 3) prepectus barely visible or fused with the mesosoma
and not visible, 4) the pronotum separated from the tegula by the side
lobe of the scutum, and 5) the rounded (not elongate) tegula. The wing
veins are variable with the submarginal and marginal veins always
present; the postmarginal may be longer or shorter than the stigmal
vein, which may be reduced to a stub.
COLLECTING: Chalcidids are often swept from small flowers
(especially Asteraceae, Umbelliferae, Fabaceae), generally during warm times
of the year (late summer and fall in the North). They can become quite numerous
at times. They may be reared by collecting lepidopterous and dipterous pupae.
DISTRIBUTION: Largely tropical with only about 200 (of
1400) species occurring in the Northern Hemisphere. While the Nearctic count
for chalcidids is about 100 species, the poorly known Neotropical region
has over 200 described species. Brachymeria (ca. 250 species) is
fairly well spread over the world. Conura (200 species) is
largely confined to the Neotropical Region with a few species in the Nearctic
and even fewer in the Old World (Schmitz 1946). Dirhinus, though
few in number of species, may be found throughout the world. The Haltichellinae
are apparently well represented in the Southern Hemisphere. The Epitraninae
and Smicromorphinae, though few in numbers, appear to be limited to the
Old World.
