|Melophagus ovinus illustration from British Entomology|
Melophagus ovinus, or the sheep ked, is a brown, hairy fly that resembles a tick. This wingless fly is about 4 to 6 mm long and has a small head, is a fly from the family Hippoboscidae. They are blood-feeding parasites of sheep. The legs of the sheep ked are very strong and are tipped with claws. Sheep ked lives their whole lives in the wool of sheep. Sheep ked are most commonly found on the neck, shoulders and underbelly of the host animal.
Native to most of Europe including Iceland, and the Faroe Islands, as well as North West Africa, Mongolia, and North India. Introduced and established in Kenya, South Africa, Japan, Australia, New Zealand, most of North America, and many parts of South America including Tristan da Cunha and the Falkland Islands.
Sheep ked lives for typically four to six months, in this time they may produce from 10 to 20 larvae. The female fly will produce a single larva at a time, retaining the larva internally until it is ready to pupate. The larva feeds on the secretions of a milk gland in the uterus of the female. After three larval instars, a white pre-pupa which immediately forms a hard dark puparium. This is deposited on the wool of the sheep and are attached with a glue-like material. The larva immediately hardens and becomes a darker color forming a puparium, which will contain the pupa. This pupal stage lasts for 19 to 23 days in the summer and 20 to 36 days in the winter. Pupal stages are not susceptible to insecticides. If removed from the host, the adult lives for 7–10 days.
It has been indicated by experiments that the sheep ked is capable of transmitting bluetongue virus in sheep, though there is little evidence that they are bluetongue disease vectors in nature. In lambs the sheep ked may cause anemia and reduce weight gain. The sheep ked feeds on the blood of its host and therefore causes irritation to the sheep, leading it to rub, producing both loss and damage of the wool. It also makes firm, hard nodules that develops on the skin called a cockle, this will reduce the value of the hide. The ked feces also stains the sheep's wool reducing its value. They also transmit Trypanosoma melophagium nonpathogenic protozoan parasite of sheep.
- Maa,T. C. (1969). "A Revised Checklist and Concise Host Index of Hippoboscidae (Diptera)". Pacific Insects Monograph (Honolulu: Bishop Museum, Honolulu, Hawaii) 20: 261–299.
- Stacy McDermit, Angela Stephan, Anna Bennett (2003). "Sheep Ked Melophagus ovinus". West Lafayette, IN, USA: Purdue University Animal Science Sheep Research and Education Center.
- Larroza, Marcela (16 January 2013). "Caracterización de la melofagosis en ovinos en la región patagónica: ciclo biológico, dinámica poblacional y distribución". Doctoral Thesis. p. 125. Retrieved 16 April 2014.
- A. J. Luedke, M. M. Jochim, and J. G. Bowne (1965). "Preliminary Bluetongue Transmissions with the Sheep Ked Melophagus Ovinus (L.)". Canadian Journal of Comparative Medicine and Veterinary Science (Ottawa, Canada: Canadian Veterinary Medical Association) 29 (9): 229–231. PMC 1494446. PMID 4221988.
- "Sheep Keds". Merck & Co. 2008. p. 1.