''Bombylius canescens,'' (commonly known as the Western bee-fly) is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of bee-fly belonging to the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Bombyliidae The Bombyliidae are a family of flies, commonly known as bee flies. Adults generally feed on nectar and pollen, some being important pollinators. Larvae are mostly parasitoids of other insects. Overview The Bombyliidae are a large family of fl ...

. ''Bombylius canescens'' is a Palearctic species with limited distribution in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

, usually found in

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...

to semi-arid habitats.

Taxonomy

''Bombylius canescens'' is in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

'' Bombylius'', which belongs to the subfamily Bombyliinae of family Bombyliidae''.'' ''Bombylius fugax'', ''Bombylius cinerascens'' and ''Bombylius minor'' are sometimes considered synonyms of ''B.canescens,'' rather than distinct species.

Description

Adult flies in the family Bombyliidae may have short or long proboscides. Variation in proboscides length is often seen at the subfamily level. ''B.canescens'' is a Bombyliid fly of the long-proboscis variety. Specimens collected in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

had proboscis of lengths within the range of 7-9 mm. The proboscis of Bombyliid flies are not retractable. The species has pale tawny hairs, and has wings with the base and foremargin that are light brown. Black hair protrudes from the sides of the face and a cross-band under the antenna. The head possesses numerous long black hairs behind the eyes. The

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...

does not have any black hairs between the humeri and the base of the wings. The

femora The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with t ...

is mainly black".

Distribution

A general description of the range of ''B.canescens'' from 1796 includes countries across the Southern belt of

Western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...

, Central and

Eastern Eastern may refer to: Transportation *China Eastern Airlines, a current Chinese airline based in Shanghai *Eastern Air, former name of Zambia Skyways *Eastern Air Lines, a defunct American airline that operated from 1926 to 1991 *Eastern Air Li ...

Europe. Further sources include observe the fly in

Malta Malta ( , , ), officially the Republic of Malta ( mt, Repubblika ta' Malta ), is an island country in the Mediterranean Sea. It consists of an archipelago, between Italy and Libya, and is often considered a part of Southern Europe. It lies ...

Jordan Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

, Italy,

Wales Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...

, and

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

Life history

'' Bombylius'' fly larvae are ectoparasitoids that parasitise other insect larvae. ''B.canescens'' larvae parasitise the larvae of ground-nesting bees. Adult ''B.canescens'' are more commonly observed in the early spring, when adult activity coincides with nest initiation of host species.

Food resources

In contrast to the parasitic larvae, adult ''B. canescens'' are anthophilic and only feed on flowers. Adult ''B. canescens'' are capable of digesting pollen as well as nectar. The larval stage is the only point at which

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

aceous feeding occurs, where the larvae parasitize/predate larval bees. In Spain, adults have been observed visiting and pollinating ''Petrocoptis grandiflora''. Currently, researchers have been unable to isolate a specific type of flower or plant that is exclusively pollinated by bee-flies; however, observations of ''B.canescens'' from Central Europe and Italy recorded visits by adults to the following flowers: * Family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

**''

Arnica montana ''Arnica montana'', also known as wolf's bane, leopard's bane, mountain tobacco and mountain arnica, is a moderately toxic European flowering plant in the daisy family Asteraceae. It is noted for its large yellow flower head. The names "wolf's ...

'' **'' Hieracium pilosella'' * Family

Crassulaceae The Crassulaceae (from Latin ''crassus'', thick), also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a unique form of photosynthesis, known as Crass ...

**''

Sempervivum arachnoideum ''Sempervivum arachnoideum'', the cobweb house-leek, is a species of flowering plant in the family Crassulaceae, native to European mountains, in the Alps, Apennines and Carpathians. Growing to tall by wide, it is a rosette-forming succulent p ...

'' * Family

Caprifoliaceae The Caprifoliaceae or honeysuckle family is a clade of dicotyledonous flowering plants consisting of about 860 species, in 33, to 42 genera, with a nearly cosmopolitan distribution. Centres of diversity are found in eastern North America an ...

**'' Knautia drymeia'' * Family

Hypericaceae Hypericaceae is a plant family in the order Malpighiales, comprising six to nine genera and up to 700 species, and commonly known as the St. John's wort family. Members are found throughout the world apart from extremely cold or dry habitats. '' ...

**''

Hypericum perforatum ''Hypericum perforatum'', known as St. John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus '' Hypericum''. Possibly a hybrid between '' H. maculatum'' and '' H. attenuatum'', the species can be found ...

'' * Family

Primulaceae The Primulaceae , commonly known as the primrose family (but not related to the evening primrose family), are a family of herbaceous and woody flowering plants including some favourite garden plants and wildflowers. Most are perennial though som ...

**'' Primula farinosa'' * Family

Scrophulariaceae The Scrophulariaceae are a family of flowering plants, commonly known as the figwort family. The plants are annual and perennial herbs, as well as shrubs. Flowers have bilateral (zygomorphic) or rarely radial (actinomorphic) symmetry. The Scr ...

**''

Euphrasia officinalis ''Euphrasia rostkoviana'' (synonym ''Euphrasia officinalis''),
in BoDD – Botanical Dermatology Database also ...

'' **''Veronica saxatilis''

Parental care

Dissection studies have revealed that females with mature oocytes in their ovaries and females with oocytes in the stage of

vitellogenesis Vitellogenesis is the process of yolk protein formation in the oocytes of non mammalian vertebrates during sexual maturation. The term ''vitellogenesis'' comes from the Latin ''vitellus'' ("egg yolk"). Yolk proteins, such as Lipovitellin and P ...

have strongly dilated crops. Adult ''B.canescens'' are found among parasitic guilds, which include other Bombyliidae flies at aggregations of bee nests. The flies hover over bee nests to position themselves for oviposition. Females achieve oviposition into bee nests by a sudden jerk or flick of the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

. The mobile parasitic larvae that are oviposited into the nest initially feed on provisions meant for bee larvae, then

hypermetamorphosis Hypermetamorphosis, or heteromorphosis,P.J. Gullan & P.S. Cranston. 2010. The Insects: An Outline of Entomology, 4th Edition. Wiley-Blackwell. is a term used in entomology that refers to a class of variants of holometabolism, that is to say, com ...

e into

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other s ...

Interactions with other species

''Bombylius canescens'' have been observed targeting bees as host species across the ''

Lasioglossum The sweat bee genus ''Lasioglossum'' is the largest of all bee genera, containing over 1700 species in numerous subgenera worldwide.Gibbs, J., et al. (2012)Phylogeny of halictine bees supports a shared origin of eusociality for ''Halictus'' and ...

'', ''

Andrena ''Andrena'' is a genus of bees in the family Andrenidae. With over 1,500 species, it is one of the largest genera of animals. It is a strongly monophyletic group that is difficult to split into more manageable divisions; currently, ''Andrena'' is ...

'', ''

Halictus The genus ''Halictus'' is a large assemblage of bee species in the family Halictidae. The genus is divided into 15 subgenera, some of dubious monophyly, containing over 200 species, primarily in the Northern Hemisphere (a few species occur in So ...

'' and '' Odynerus'' genera. Adults have also been observed searching for nests of '' Panurgus banksianus'', a potential host species.

Physiology

''Bombylius canescens'' specimens were studied in a study of cranial

physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...

done on

Brachycera The Brachycera are a suborder of the order Diptera. It is a major suborder consisting of around 120 families. Their most distinguishing characteristic is reduced antenna segmentation. Description A summary of the main physical characteristics i ...

flies. Observations from the specimen guided the conclusion that the mushroom body calyx is well developed in flies of the order Bombyliidae.

Conservation

''Bombylius canescens'' has not been assigned a threat rating by the IUCN.

References

Bombyliidae Insects described in 1796 Asilomorph flies of Europe {{Bombyliidae-stub