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<rhagioni.htm> [For
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DIPTERA, Rhagionidae (= Leptidae) -- <Images>
& <Juveniles> Rhagionidae or "snipe flies" includes two groups that
have sometimes been assigned to the families Xylophagidae and
Coienomyidae. They are predaceous in
both the adult and larval stages.
Adults are consistently predaceous, their prey being principally
adults of other Diptera, and several species have been reported to have
developed bloodsucking behavior. Most
are abundant only in very moist habitats, but some occur under arid
conditions. The larvae are usually
predaceous, preying on a variety of insects and smaller animals (Clausen
1940/62). The two genera, Lampromyia
and Vermileo have been thoroughly
studied in Europe. Vermileo vermileo L. was investigated very early in the history of
entomology by DeReaumur (1753) and Degeer (1776). Larvae of this and species of similar behavior are called
"worm lions" to distinguish them from ant lions of the Neuroptera,
with which they have some similarity.
Larvae construct pits in the dust and sand at the bases of cliffs and
other similar locations. These pits
are conically shaped, and the Vermileo
larva lies on its dorsum at the bottom of the pit where it encircles any
suitable prey that falls within reach, dragging it underneath the sand. Ants are one of the principal foods. The behavior of V. comstocki Wheeler
was discussed by Wheeler (1930). This
species inhabits glacial silt and dust in the mountains of western North
America. Eggs are laid in masses of
50 or more, adhering together in rows in the dust or silt. They hatch in ca. 8 days. Young larvae are gregarious, but later
instars are solitary. The larva lies
in the inverted position in the pit, with its anterior end across the bottom. Prey consists principally of a common ant
species, Formica fusca L. Engle (1929) reported on behavior in Lampromyia sericea
Westw. and Wheeler (1930) on several species of Lampromyia. Larvae of
African L. pallida Macq. differs in behavior from others of the genus and
from Vermileo by holding its body
in a vertical position, with the anterior end coiled at the bottom of the pit
where it awaits its prey. Species of the genus Chrysopilus
that have been studied are quite different in their larval habits and host
preferences from those previously discussed.
Chrysopilus nubeculus Macq. is predaceous in the
egg capsules of Algerian locusts, and C.
ferruginosus Wied. lives in
decaying plant roots or tissues in the East Indies and Philippines. The latter species is a predator on the
larvae of the banana weevil, Cosmopolites
sordidus Germ., and the sugarcane
beetle borer, Rhobdocnemis obscura Bsd.. it was introduced into several areas in
efforts at biological control.
Froggatt (1928) reported that the eggs were deposited in clusters of
16-60 in the borer holes in slightly decayed stem tissue. Young larvae found in decaying stems that
contained no weevil larvae were believed to be phytophagous. In North America Atherix
variegata Wlk. is an aquatic species
of considerable abundance. Large egg
masses and the remains of many flies have found on the underside of a
Connecticut bridge by Britton (1936).
The largest of the masses covered an area of ca. 50 sq-ft., and was at
least one-half inch deep. Eggs hatch
in ca. 6 days, and young larvae drop into water, where they feed on various
soft bodied insects and other organisms.
Some species of Symphoromyia
also have aquatic larvae (Clausen 1940/62). References: Please refer to <biology.ref.htm>, [Additional references
may be found at: MELVYL
Library] |