Warble fly
Encyclopedia
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
), Hypoderma bovis (cattle
) and Hypoderma tarandi (reindeer
) .
Adult warble flies are large, hairy and bee-like; brown, orange or yellow in color. The adults have vestigial mouthparts and so do not feed during their short lifespan, which can be as little as five days.
They are found in all continents of the northern hemisphere, principally between 25 and 60 degrees latitude.
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). Nevertheless, when accidentally destroyed by pressure, the larvae can cause large purulent swellings.
From the subcutaneous swelling, the warble will puncture the skin when coming out of the bovine. From those numerous holes, the hide is rendered valueless.
The migrating larvae can cause damage to meat as the tunnels they make fill with a substance known as butcher's jelly. Growing livestock may have a lower daily weight gain. Milk yields may also suffer, but in adult cows, the infestation is generally limited, due to immunisation following the first infestation, as a calf.
Warble fly has been eradicated in many countries, beginning from Denmark
and Western Germany
, in the 1960s. They have also been eradicated from the United Kingdom, as well as from Belgium
. The method was the pour-on application of an organophosphorus
compound.
From the 1980s, the preventive treatment is easier, by subcutaneous use of Ivermectin, but the warble fly remains present in North Africa
.
, a firm specialising in building car bodies for Rolls-Royce
, reported that 40% of the (on average) seven hides per car needed to make leather car seats had to be thrown away on account of blemishes caused by warble flies and barbed wire while the cattle involved were still alive.
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
which are parasitic on cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
and deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
. 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
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
), Hypoderma bovis (cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
) and Hypoderma tarandi (reindeer
Reindeer
The reindeer , also known as the caribou in North America, is a deer from the Arctic and Subarctic, including both resident and migratory populations. While overall widespread and numerous, some of its subspecies are rare and one has already gone extinct.Reindeer vary considerably in color and size...
) .
Adult warble flies are large, hairy and bee-like; brown, orange or yellow in color. The adults have vestigial mouthparts and so do not feed during their short lifespan, which can be as little as five days.
They are found in all continents of the northern hemisphere, principally between 25 and 60 degrees latitude.
Infestations
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 cordSpinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
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). Nevertheless, when accidentally destroyed by pressure, the larvae can cause large purulent swellings.
From the subcutaneous swelling, the warble will puncture the skin when coming out of the bovine. From those numerous holes, the hide is rendered valueless.
The migrating larvae can cause damage to meat as the tunnels they make fill with a substance known as butcher's jelly. Growing livestock may have a lower daily weight gain. Milk yields may also suffer, but in adult cows, the infestation is generally limited, due to immunisation following the first infestation, as a calf.
Warble fly has been eradicated in many countries, beginning from Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
and Western Germany
Western Germany
The geographic term Western Germany is used to describe a region in the west of Germany. The exact area defined by the term is not constant, but it usually includes, but does not have the borders of, North Rhine-Westphalia and Hesse...
, in the 1960s. They have also been eradicated from the United Kingdom, as well as from Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
. The method was the pour-on application of an organophosphorus
Organophosphorus
Organophosphorus compounds are degradable organic compounds containing carbon–phosphorus bonds , used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment...
compound.
From the 1980s, the preventive treatment is easier, by subcutaneous use of Ivermectin, but the warble fly remains present in North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
.
Rolls-Royce
In 1969 Mulliner Park WardMulliner Park Ward
Mulliner Park Ward was a bespoke coachbuilder in Hythe Road, Willesden, London UK.Mulliner now is the personal commissioning department for Bentley....
, a firm specialising in building car bodies for Rolls-Royce
Rolls-Royce Limited
Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....
, reported that 40% of the (on average) seven hides per car needed to make leather car seats had to be thrown away on account of blemishes caused by warble flies and barbed wire while the cattle involved were still alive.
External links
- common cattle grub on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
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