What does oestrus mean?
An oestrus is a fly in the genus Oestrus, a group of botflies whose larvae develop within or on mammalian hosts. Different species are associated with particular animals: Oestrus ovis, commonly called the sheep bot fly, lays its eggs near a sheep’s nostrils, after which the larvae migrate into the nasal passages and sinuses. Other species affect various mammals, and larvae of Oestrus can occasionally infect humans. In zoological usage the genus name is capitalized, while the plural of the common noun is oestri. The term is chiefly technical, appearing in entomology, veterinary medicine and medical reports of infestation. Although the English “gadfly” ultimately comes from the same ancient Greek source, it is not a precise modern synonym for oestrus and is now used more broadly for irritating people or persistent nuisances.
nounA fly belonging to the genus Oestrus, whose larvae are internal parasites of mammals. The best-known member is the sheep bot fly, Oestrus ovis.
- A fly of the genus Oestrus, especially the sheep bot fly.
"The sheep bot fly, Oestrus ovis, lays its eggs near the nostrils of grazing sheep."
"Oestrus larvae can cause irritation and bleeding in sheep."
"The infestation was identified as being caused by a fly of the genus Oestrus."
The plural oestri refers to multiple flies of the genus Oestrus.
"The larvae of several oestri were found in the infected tissue."
The sheep bot fly, Oestrus ovis, can lay its eggs near a sheep’s nostrils, allowing the young larvae to enter the nasal passages and sinuses.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does oestrus come from?
The word comes through Latin from Ancient Greek oistros, meaning “gadfly,” an insect whose sting was believed to madden cattle; the Greek word could also convey restless excitement or frenzy. The modern zoological sense developed from this ancient term through the Linnaean naming of the genus Oestrus. Related English forms include gadfly, oestrous and oestriasis, the last denoting infestation by larvae of botflies.
Related word forms
How oestrus is actually used
The name is normally capitalized when it denotes the zoological genus. In general writing, a particular member may be called an oestrus, though the more familiar term is botfly.
Easily confused with oestrus
An oestrus is a botfly genus, whereas a gadfly may refer to a blood-feeding fly or, figuratively, to an irritating or restless person.