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HYMENOPTERA, Trichogrammatidae (Westwood 1833)-(Chalcidoidea)-<Images> & <Juveniles> Trichogrammatidae. -- Trichogrammatids
are tiny insects, 0.3-1.1 mm long,.
The three-segmented tarsi, and the microscopic hairs of the wings that
are usually arranged in rows, distinguish them and the rather short head that
is somewhat concave posteriorly. The members of this group are parasitoids
attacking eggs of their hosts. Some species have been reared in large numbers
to aid in the control of orchard pests. Trichogrammatidae are
tiny parasitic wasps with most species having adults less than 1.2 mm in
length. They parasitize the eggs of many orders of insects and have been
regarded as important biological control agents, attacking many pest insects
particularly Lepidoptera. These wasps are weak
fliers and they may be dispersed by wind action. Their forewings are usually
stubby, with a fringe of hinged setae around the outer margin to increase the
surface area during the downstroke. The males of some species are apterous,
and they may mate with their sisters inside the host egg
john.heraty@ucr.eduThis, dying without ever leaving the host egg. They are parasitic on the eggs of
other insects. In order to complete development their adult size is
never larger than a single host egg, and often multiple individuals will
develop in a single egg making the emerging adults smaller than the host
egg. The size varies from 0.22 – 1.55 mm. Some such as Trichogramma are known to
parasitize eggs of several insect orders, while other genera may be
restricted to a single host order. The eggs of Hemiptera are
parasitized by the largest number of genera (e.g. Aphelinoidea,
Paracentrobia, and Ufens), though Coleoptera and Lepidoptera
eggs are also utilized by some genera. Most species parasitize eggs
placed in or on plant tissues. Several genera ( e.g. Hydrophylita,
Lathromeroidea and Prestwichia) parasitize eggs of aquatic
insects and have been reported to swim underwater in search of hosts. Some genera of Trichogrammatidae have been deployed in
biological control. Trichogramma spp. have received the most
attention because they are parasitoids of pest Lepidoptera and can be mass
propagated and released into the environment. Trichogramma has
been widely used in augmentative biological control, and although the
effectiveness of this technique has been documented in some European
glasshouse experiments, convincing data is lacking as to its practicality for
controlling pest insects in the open agroecosystem. There are ca. 842 species in 84 genera worldwide.
Species occur in all vegetated terrestrial habitats. Only two genera, Ittysella and Brachyufens,
may be restricted to the Nearctic region. Six genera are found only in
America (Brachista, Lathrogramma, Pintoa, Trichogrammatomyia, Xenufens, and
Zagella). The family as been poorly sampled
throughout the world and collections for comprehensive taxonomic studies are
absent. = = = = = = = = = = = = = = = References: Please refer to <biology.ref.htm>, [Additional references
may be found at: MELVYL
Library] Clausen, C. P. 1940. Entomophagous Insects. McGraw-Hill, NY. 688 p. Doutt, R. L. & G.
Viggiani. 1968. The classification of the
Trichogrammatidae (Hymenoptera: Chalcidoidea). Proc. Calif. Acad. Sci. 35:
477-586. Hayat, M. & B. R.
Subba-Rao. 1988. Family Trichogrammatidae. In: B. R. Subba-Rao, & M. Hayat (eds.),
Oriental Insects, Vol. 19. Association
For The Study of Oriental. Insects, Gainesville, FL. 329 p. Kryger, J. P. 1918.
Ent. Med. 12: 257-354. Nagaraja, H. & S.
Nagarkatti. 1973. A key to some New World species of Trichogramma (Hymenoptera:
Trichogrammatidae) with descriptions of four new species. Proc. Ent. Soc. Wash. 75(3): 288-97. Nagarkatti, S. & H.
Nagaraja. 1971. Redescriptions of some known species of Trichogramma (Hym.,
Trichogrammatidae) showing the importance of the male genitalia as a
diagnostic character. Bull. Ent. Res.
61: 13-31. Nikol'skaya, M. N. & V.
A. Trjapitcyn. 1978/1987. Family Trichogrammatidae
(Trichogrammatids). 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. Pinto, J. D., G. R. Platner
& E. R. Oatman. 1978. Clarification of the identity of several
common species of North American Trichogramma
(Hymenoptera: Trichogrammatidae). Ann. Ent. Soc. Amer. 71:
169-80. Prinsloo, G. L. 1980.
An illustrated guide to the families of African Chalcidoidea (Insecta:
Hymenoptera). Rep. So. Africa, Dept.
Agr. & Fisheries Sci. Bull. 395. 66 p. Viggiani, G.
1971. Ricerche sugli:
Hymenoptera Chalcidoidea XXVIII.
Studio morfologico comparativo dell'armatura genitale esterna Maschile
dei Trichogrammatidea. Boll. Lab. Ent. Agr. Filippo
Silvestri 29: 181-222. Yoshimoto, C. M. 1984.
The Insects and Arachnids of Canada. Part 12. The Families and Subfamilies of Canadian
Chalcidoid Wasps, Hymenoptera: Chalcidoidea.
Biosystematics Res. Inst., Ottawa, Ontario, Res. Br. Agr. Canada Publ. 1760.
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