''Rabdophaga rosaria'' is a

gall midge Cecidomyiidae is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small insects us ...

which forms ''Camellia'' galls or terminal rosette gall on

willow Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...

species.Darlington, page 169.Stubbs, page 61. It was first described by

Hermann Loew Friedrich Hermann Loew (19 July 1807 – 21 April 1879) was a German entomologist who specialised in the study of Diptera, an order of insects including flies, mosquitoes, gnats and midges. He described many world species and was the first specia ...

in 1850.

Description

Willows are extremely susceptible to gall induction and growth manipulation and ''Salix'' is one of the plant genera with the highest known numbers of associated galler species. ''Rabdophaga rosaria'' is probably a group of closely related, unnamed species, possibly each restricted to one species of willow. Galls should be recorded as ''R rosaria'' and the host plant should also be recorded. The gall consists of from thirty to sixty leaves, shortened and crowded together in rosettes on

white willow ''Salix alba'', the white willow, is a species of willow native to Europe and western and central Asia.Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. .Rushforth, K. (1999). ''Trees of Britain an ...

(''S. alba''),

crack willow Crack frequently refers to: * Crack, a fracture in a body * Crack, a fracture (geology) in a rock * Crack, short for crack cocaine Crack may also refer to: Art, entertainment, and media * ''Cracks'' (film), a 2009 independent thriller * Crac ...

(''S. fragilis''),

goat willow ''Salix caprea'', known as goat willow, pussy willow or great sallow, is a common species of willow native to Europe and western and central Asia.Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook 4. . Des ...

(''S. caprea'') and purple willow (''S. purpurea'') willows as well as the eared sallow (''S. aurita'') and

grey sallow ''Salix cinerea'' (common sallow, grey sallow, grey willow, grey-leaved sallow, large grey willow, pussy willow, rusty sallow) is a species of willow native to Europe and western Asia.Meikle, R. D. (1984). ''Willows and Poplars of Great Britain ...

(''S. cinerea''). The oviposition of this species results in a chemical interaction that halts the lengthwise growth of infected willow shoots, the leaves however continue to develop and thus the characteristic "rose" forms at the tip of the affected shoot.

Characteristics

''Rabdophaga rosaria'' is found on willow branches and the gall diameter depends upon the species, being larger on ''

Salix caprea ''Salix caprea'', known as goat willow, pussy willow or great sallow, is a common species of willow native to Europe and western and central Asia.Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook 4. . Des ...

'' at than on ''

Salix alba ''Salix alba'', the white willow, is a species of willow native to Europe and western and central Asia.Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. .Rushforth, K. (1999). ''Trees of Britain an ...

'' at . The development in the United Kingdom begins in May / June with leaf expansion and reaches maturity in August / September while the leaves are still green. The gall becomes brown and remains on the tree over winter until it is forced off by new growth in spring.

Causer, inquiline and associations

Each rosette contains a single pinkish-coloured larva which, unusually, pupates within the gall. ''Rabdophaga strobilina'' is closely related and is an

inquiline In zoology, an inquiline (from Latin ''inquilinus'', "lodger" or "tenant") is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms such as insects may live in the h ...

of ''R. rosaria''. One or more larva live under the modified leaves of the rosette and depending on the number of ''strobilina'' they can change the shape of the gall from a rosette to a 30–40 mm long cone-shaped artichoke. A common

is another gall midge, '' Perrisia iteophila'' and the

gall mite Eriophyidae is a family of more than 200 genera of mites, which live as plant parasites, commonly causing galls or other damage to the plant tissues and hence known as gall mites. About 3,600 species have been described, but this is probably ...

'' Eriophyes marginatus'' often appears on ''Camellia'' galls.

Phylogeny

A 2020 study which analysed the ''COI'' gene of mitochondrial DNA extracted from ''Rabdophaga'' larvae that induce rosette galls on ''Salix'' in the

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical region ...

Region showed that ''R. rosaria'' could be divided into 2 clades, 1 and 2, and the latter further divided into subclades 2A and 2B. Clade 1 consists of populations on ''Salix'' species of section ''Cinerella'' in subgenus ''Vetrix'' in Georgia and the UK, subclade 2A contains populations on ''Salix alba'' (section ''Salix'', subgenus ''Salix'') in The Netherlands and the UK, and subclade 2B consists of populations on section ''Helix'' in Poland, ''Phylicifoliae'' in Alaska, and ''Salix'' species in the Eastern Palaearctic Region.

Distribution

''Rabdophaga rosaria'' is widely distributed throughout the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

and is locally common. It is abundant in Finland.

Notes

Sources

* Darlington, Arnold (1975) The Pocket Encyclopaedia of Plant Galls in Colour. Pub. Blandford Press. Poole. . * Stubbs, F. B. Edit. (1986) ''Provisional Keys to British Plant Galls''. Pub. Brit Plant Gall Soc. .

External links

Plant Parasites of Europe
{{Taxonbar, from=Q7319994 rosaria Diptera of Europe Gall-inducing insects Insects described in 1850 Taxa named by Hermann Loew Willow galls