Hippobosca equina, or the forest fly, is a fly

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...

 from the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Hippoboscidae

Hippoboscidae

Hippoboscidae, the louse flies or keds are obligate parasites of mammals and birds. In this family there are winged species which can fly at least reasonably well, as well as others with vestigial or no wings which are flightless and highly apomorphic...

. They are blood-feeding ectoparasite

Parasitism

Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...

s of 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...

s, and sometimes 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...

. It is a permanently fully winged fly, not shedding its wings on finding its host, as in some other Hippoboscidae. this means it may leave its host to deposit its larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e. They are good fliers.

Distribution

The primary distribution is in Europe and parts of Asia and Africa. It has been introduced to other locations, though in some cases latter eradicated by modern husbandry practices. In the United Kingdom they are known primarily from the New Forest

New Forest

The New Forest is an area of southern England which includes the largest remaining tracts of unenclosed pasture land, heathland and forest in the heavily-populated south east of England. It covers south-west Hampshire and extends into south-east Wiltshire....

 and increasingly from South Devon

Devon

Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...

. There are occasionally recorded from other part of the UK, though some reports as far north as the Scottish borders are considered dubious. In the United Kingdom, their flight period is from May to October, but peaking August and early September.

Hosts

Their primary host are equine

Equus (genus)

Equus is a genus of animals in the family Equidae that includes horses, donkeys, and zebras. Within Equidae, Equus is the only extant genus. Like Equidae more broadly, Equus has numerous extinct species known only from fossils. This article deals primarily with the extant species.The term equine...

s; they are often also frequently found 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...

 on which they are able to maintain a population. They have been known to bite a number of other mammals, including sheep, goats, and sometimes humans. Other mammals it may also live on are Red Deer

Red Deer

The red deer is one of the largest deer species. Depending on taxonomy, the red deer inhabits most of Europe, the Caucasus Mountains region, Asia Minor, parts of western Asia, and central Asia. It also inhabits the Atlas Mountains region between Morocco and Tunisia in northwestern Africa, being...

, camel

Camel

A camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...

, rabbit and on birds, the Grey Heron

Grey Heron

The Grey Heron , is a wading bird of the heron family Ardeidae, native throughout temperate Europe and Asia and also parts of Africa. It is resident in the milder south and west, but many birds retreat in winter from the ice in colder regions...

, and the Northern Goshawk. They have been fed and bred on guinea pig

Guinea pig

The guinea pig , also called the cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family, nor are they from Guinea...

s in the laboratory.