Warble fly

Specific Classification Kingdom : Animalia Phylum : Arthropoda Class : Insecta Order : Diptera Family : Oestridae Subfamily : Hypodermatinae Genus : Hypoderma

Warble fly is a name given to the genus Hypoderma. Large flies which are parasitic on cattle and deer. Other names include "heel flies", "bomb flies", and "gad flies", while their larvae are often called "cattle grubs" or "wolves.“ Common species of warble fly include Hypoderma lineatum (horse), Hypoderm bovis (cattle) and Hypoderma tarandi (reindeer) . Morphology The adult fly is 12 to 14 mm long has black banded with yellowish and orange hair, leg well covered with black and orange hair, wings with black veins.

Hypoderma lineatum Female flies attach their eggs (up to 500) to hairs around the hocks and on the lower parts of the body. 1st-stage larvae hatch within a few days, burrow into the skin and begin their migration towards their winter "resting sites", i.e. the submucosa of the esophagus. After a period of several months and a molt, the L2s migrate to the subcutaneous tissue of the back where they molt to L3s.These can be palpated as distinct swellings "warbles". After 5-11 weeks the mature larvae emerge through the skin and drop to the ground. In California, warbles of H . lineatum begin to appear in mid-November, reaching a peak in January to February. The mature larvae pupate in the soil, and adults emerge in 1-3 months.  During laying Egg by H . Lineatum(Oxwarble fly ) Young Warbles

Harms The warble flies cause a great annoyance to the host as the approches to lay eggs. The fly will lay eggs on the foreleg of the affected cattle. These will be ingested by licking, and be swallowed. Internal cycle involves the passing oesophagus muscles and spinal cord before subcutaneous re-emerging. When they re-emerge, the larvae cause many swellings "warbles" under the skin, causing some harm to animals, but not as a general disease. It doesn't burrow into the flesh, but stays under the skin (hence, its scientific name Hypoderma ). when accidentally destroyed by pressure, the larvae can cause large purulent (discharging pus) swellings. The warble flies cause a great economic loss to man. Larvae of hypoferma may attack humans. However, they remain confined to skin only, causing ‘migrating lumps’.

Control ( Management ) The larvae maybe squeezed out from the warbles to lessen the animals suffering. Insecticide named trichlorphon given in food or applied to legd and abdomen in proper doses given good relief from the infection of warble flies. Warble fly has been eradicated in many countries, beginning from Denmark and Western Germany, in the 1960s. The method was the pour-on application of an organophosphorus compound.

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