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Hymenopteran


Hymenopteran name for members of the order Hymenoptera that includes the familiar insects like hornets, sawflies, wasps, bees, ants and their relatives. There are more than 100,000 described species of Hymenoptera.

Hymenopterans are of exceeding importance to human beings. Although some species of sawflies, chalcids, and most cynipids feed on foliage of a wide variety of plants, numurous members of ichneumon flies, wasps, braconids etc are predatory or parasitic and constitute biological control agents of agricultural pests. Many hymenopterans including the honeybees assist in pollination of a wide variety of plants.

Hymenopterans are found in all continents of the world. They are, however, more common in tropical and subtropical countries. They have two pairs of transparent wings with conspicuous venation. Their mouthparts are lapping or chewing-lapping type.

Members of the suborder Apocrita have a constriction at the base of their abdomen. In all females a well-developed ovipositor is present, which may also function as a sting. Many hymenopterans including the ants and honeybees show highly developed social behaviour. [SM Humayun Kabir]

Parasitic hymenopteran Any of the hymenopteran insects having a parasitic mode of life. Usually they are parasitic at the larval stage and are free living at the adult stage. In most instances, they kill their hosts, but in certain cases, the host may live for some time before dying. Although the parasitic hymenopterans constitute one of the largest groups, it is assumed that at least 77% of them are still undescribed. The parasitic hymenopterans are classified under 48 families in 10 superfamilies. The superfamily Evanioidea contains three families with 1050 species. The members of the family Evaniidae (ensign wasps) are parasitic on egg capsules of cockroach with 14 genera, 400 species of which Evania appendigaster have been recorded from Bangladesh. The superfaniily Ceraphronoidea includes two families with over 800 species. In Bangladesh one species has been recorded from rice pest and one from cotton pest.

Members of the superfamily Proctotrupoidea are very small (nearly 3-6 mm) and are included in nine families with about 2,500 species; one species has been reported from mango orchards of Bangladesh. They are mainly parasitic on various beetles living in soil litter and rotten wood, but some are found in ant nests, and are parasitic on ants and flies. The superfamily Platygastroidea includes two families with about 4,000 species; in Bangladesh 11 species have been recorded from rice pests; one from the cotton pest and one from stored grain pest. The superfamily Cynipoidea includes six families with 3,000 species; one species has been recorded from mango orchards of Bangladesh. Members of superfamily Chalcidoidea are known as chalcid-flies. They are generally minute and are included in 20 families, with about 3,300 genera and 22,500 species. The smallest insect Megaphragma (Trichogrammatidae) of the world belongs to this group. The adult is only about 0.18 mm in length and is parasitic in the egg of thrips.

In Bangladesh more than 20 species of chalcid parasites were recorded from rice pests, six from jute pests, 18 from cotton pests, six from sugarcane pests, and 13 from stored grain pests. Ichneumonidae (superfamily Ichneumonoidea) is the largest family of Hymenoptera and are commonly known as ichneumon flies. This family consists of approximately 60,000 species worldwide of which about 20,000 species are distributed in the Indo-Australian region. Caterpillars are the common hosts of Ichneumonidae. In Bangladesh 14 species were recorded from rice pests, two from cotton pests, one from sugarcane pests, and three from stored grain pests.

The Braconidae, known as braconid-flies, is the second largest family of Hymenoptera, consisting of more than 40,000 species worldwide. In Bangladesh 14 species were recorded from rice pests, six from jute pests, 13 from cotton pests, and two from sugarcane pests. The superfamily Chrysidoidea known as cuckoo wasps are aculeate Hymenoptera with 4,899 recorded species, all parasitic on solitary wasps, solitary bees, sawflies, and on moths. In Bangladesh three species were recorded from rice pest, one from sugarcane pest and one from stored grain pest. Members of the five families of the superfamifly Vespoidea parasitize the larvae of soil-dwelling Coleoptera or soil-nesting wasps and bees. One species of pompilid and one species of sphecid have been recorded as larval parasites of sugarcane pests from Bangladesh. Gapud (1992) compiled a list of 182 species of parasitic hymenopterans from Bangladesh and neighbouring countries. In an annotated catalogue, Bhuiya (1999) included more than 300 species of parasitic hymenopterans from Bangladesh. [Md Ismail Mia]

Bibliography VP Gapud Insect and mite pests of plant crops in Bangladesh and their enemies: a compendium. USAID/ BARC/CHECCI and Co. Consulting Inc. pp. 265, 1992; BA Bhuiya (ed) An annotated catalogue of parasitic hymenoptera from Bangladesh. Green Leaf Publishers, London, 1999.