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HYMENOPTERA, Heloridae (Proctotrupoidea) -- <Images>
& <Juveniles>, [formerly
Mesoserphidae < -- <Images>
& <Juveniles>] Please refer also
to the following link for details on this group: Heloridae = Link
1 Description & Statistics Heloridae. -- There is
but one North American species, Helorus paradixus (Provancher), a
black insect about 4.5 mm long with a more or less complete venation in the
front wings. This species is a Parasite of the larvae of chrysopid
lacewings. Adults emerge from the
host's cocoon. Helorus paradoxus Prov.
was studied by Don Clancy (Clausen 1940).
This species is mostly restricted to Chrysopa majescula
Banks, though several other species of the genus occur in the same habitat. Females have a preoviposition period of
2-8 days, after which host larvae are attacked in any stage of
development. The abdomen is brought
forward beneath the body, and the ovipositor is inserted into the lateral or
lateroventral region of the host body, usually the abdomen. After insertion, the female folds her legs
and may be dragged for a time by the excited host. Only a single egg is laid at each insertion, and adult life may
extend to 4-6 weeks. During this time
ca. 50 eggs are laid, usually 1-2 per day. The egg is free floating in the host body fluids, where it increases
much in size during incubation. The
embryo lies curled within the shell with the head at the micropylar end
(Clausen 1940/1962). Hatching occurs
in a minimum of 2 days after deposition.
Duration of the larval period, in particular the 1st instar, is
variable, for the first molt does not occur until the host cocoon is spun and
the prepupal stage attained. In hosts
that carry over until the second year, the parasitoid persists in the first
stage through that extended period.
When oviposition is in nearly mature host larvae and under summer
conditions, the stage lasts only 3-6 days.
Soon after the first molt, the host body fluids become filled with
opaque white spherical bodies. As
these increase in number there is a corresponding decrease in the fat bodies
and softer tissues. It seems that the
parasitoid larva has to secrete an enzyme which is necessary for the
breakdown of the host tissues. All
host movement ceases about the middle of the parasitoid's 2nd larval stadium,
and death occurs coincident with the second molt. The 2nd instar lasts 2.5-3 days. Feeding is very extensive after the second molt, and the body
contents of the host are completely devoured within 2 days. The parasitoid orients its body in reverse
to that of the host. After remaining
in the empty skin for several days, the larva emerges from a point near the
posterior end, and only the last 4-5 segments remain embedded in the
wound. Another resting period follows
before pupation takes place. The tip
of the pupal abdomen retains a light attachment to the host remains, and the
body is greatly curved to fit the outline of the host cocoon. The larval meconium is not voided until
after adult emergence. The pupal
stage is completed in 8-12 days, giving 22-40 days for the complete cycle
from egg laying to emergence (average of 30 days). Several generations are produced yearly, and hibernation is as
the 1st instar larva within the host larva in its cocoon. This is a small family. The hosts seem limited to Chrysopidae, and
parasitoids are internal on lacewing larvae, with adult emergence being from
the cocoon. The body is only about
6.5 mm. long, stout, and mostly black.
The sickle-shaped mandibles are long and cross over in the shape of a
scissors. The labrum is long and
narrow and usually not exposed. The
flagellum has a ringed article between the pedicel and segment 1. The forewing has 5 closed cells including
a subtriangular first medial cell.
Tarsal claws are pectinate.
Metasomal segment 1 is distinctly elongated (petiolate). The etasomal terga 2-4 are fused into a
syntergite (Masner 1993). All species are solitary endoparasitoids in larvae of
Chrysopidae (Neuroptera), and the dults emerge from the host cocoon. For detailed descriptions of immature stages, please
see Clausen (1940/62). References:
Please refer to <biology.ref.htm>, [Additional references may be found
at: MELVYL Library ] Kozlov, M. A.
1978/1987. Family Heloridae
(Helorids). In: G. S. Medvedev
(ed.) 1987, Keys to the Insects of the European Part of the USSR. Vol. 3
Hymenoptera, Pt. 2. Akad. Nauk., Zool. Inst., Leningrad, SSSR. (trans. fr. Russian,
Amerind. Publ. Co., Pvt. Ltd., New Delhi).
1341 p. |