Drosophila subobscura
Drosophila subobscura | |
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Five anatomical images of a Drosophila subobscura (male) on a rotting squash, located near Christchurch Park, Ipswich | |
Scientific classification | |
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Species group: | obscura
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Species: | D. subobscura
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Binomial name | |
Drosophila subobscura Collin, 1936
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Drosophila subobscura is a species of fruit fly in the family
Description
Both wild type and laboratory-reared individuals of D. subobscura are brown, with clear wings, yellow
Head
The arista (bristles arising from the antennae) of D. subobscura contain 6-8 branches, with 1-2 of those branches below the terminal fork. The species has a brown antenna with grey pollinosity that is approximately the same color as the rest of the head-capsule. The front of the antenna is dark brown and matte, without any pollinosity except on the frontal triangle and fronto-orbital plates, both of which are shiny and slightly pollinose. The carina (tracheal cartilage that divides the two bronchi) of the fly is rounded, widening below, and the face is a paler brown color with grey pollinosoty. The genae is brown with heavy, grey pollinosity. The ocelli (small or 'simple' eyes of an insect) are the same color as the eyes.[1]
Body
The
The legs of D. subobscura are a yellowish color. The combs of the teeth are each aligned on the longitudinal axis of the first and second tarsal segments of the fore legs. The proximal comb, identified as the comb of the first segment, has 7-12 teeth and is about half as long as the segment itself. Teeth on the distal end of the segment are slightly longer than the segment. The first tarsal segment is slightly longer than both the second and third segments, but shorter than their combined length. The abdomen has tergites that are uniformly dark brown, but shiny in some lights. Other lights reveal a grey pollinosity appearance.[1]
Bristles
The upper
Distinction from other species of Drosophila
D. subobscura are found to be unusual among the Drosophila genus, because they are monandrous (females only mate one at a time).[3][4] Additionally, unlike the rest of the Drosophila genus, D. subobscura do not mate in the absence of light[5][6] nor do they produce courtship songs by wing vibration.[7] A study published in 2017 revealed that the difference in courtship behavior between D. subobscura and D. melanogaster (in particular, the D. subobscura's nuptial gift transfer behavior) could be potentially due to the optogenetic activation of a distinct neural circuit that differs in both flies.[8]
Taxonomy
In 1933, A. H. Sturtevant captured a species of Drosophila in England. When Sturtevant submitted the captured specimens to J. E. Collin of Newmarket, Collin initially misidentified the species as D. obscura. Three years later, the first description of D. subobscura appeared in an addendum to Gordon's paper through a short note written by Collin. In the note, Collin compared both sexes of D. subobscura and differentiated them as a separate species from D. obscura, their nearest related species. Collin's description, considered incomplete but necessary to validate the D. subobscura name, was followed up with a more complete description by Dr. James Smart.[9][10][1]
In 1942,
In experimental trials, D. subobscura does not breed with any other species of obscura, except D. madeirensis, a species also in the subobscura subgroup. When crossed, sterile males and fertile female hybrids are formed.[13] As of March 2019, the first long-read sequencing of D. subobscura's genome has been presented, showing that evolution of its genome structure is indirectly driven by the effects of suppressing recombination of genetic inversions. This suppressive effect maintains various sets of adaptive alleles together in the midst of gene flow.[14]
When Collin identified Sturtevant's captured species as D. subobscura in 1933, the name was coined as a manuscript name. The species was then bred at the Department of Biometry in University College in London to be genetically experimented on. Here, one paper that resulted from this experimental work in London referred to the tested species as Collin's coined manuscript name, D. subobscura, and was referred to as such moving forward. During this time, involved parties knew that D. subobscura was simply a manuscript name, thus creating anticipation that Collin would publish a description of the species and consequently validate the name. Although Collin did not publish the anticipated description of the species, in 1936, he contributed a note in the addendum of a paper published by Gordon that same year. The note outlines a diagnosis of the sexes and differentiation of the species from D. obscura and attributes the D. subobscura name to Collin. Thus, the name “D. subobscura Collin” dates from 1936, because none of the papers that come before it include a description of the given species that would have satisfied nomenclature rules. Therefore, prior to the addendum in Gordon's paper in 1936, the D. subobscura name used in published works must be regarded as a manuscript name. In 1938, two years after Gordon's paper, Dr. Eugéne Séguy had discovered a new species of Drosophila in Kenya, naming it D. subobscura. Though this D. subobscura was recorded in the 1938 Zoological Record, the “D. subobscura Collin” name has not appeared in the Zoological Record as a new species, yet.[1][15][16][17]
Distribution
D. subobscura is widely distributed in Europe, from Scandinavia south to the Mediterranean, and in North Africa and the Middle East as far east as Iran.[18] Its distribution spans over thirty latitudinal degrees, with its most dense populations residing in the western Palaeartic realm.[19] Introduced populations of D. subobscura are found in the west coasts of Canada, the United States, and Chile.[20]
D. subobscura was first discovered in the Americas (southern Chile) in February 1978.
There has been recent speculation about D. subobscura colonization in western North America being a more modern-event. The origin of the North and South America colonizers remains unknown, but evidence reveals that they derive from the original, Palearctic populations.[20]
Habitat
D. subobscura is mainly found in open fields or forest fringes.[24] Decreases in light and temperature induce locomotion activity in D. subobscura towards areas outside of the forest.[25] The genome of some Greek populations of D. subobscura has shown evidence of microgeographic variation, prompting a possibility that the species exhibits habitat choice.[26]
However, no evidence has been found to show that D. subobscura exhibits individual habitat choice, aligning with the fact that its well-studied inversion polymorphism is relatively inflexible and slow to respond to the environment. Additionally, individuals do not exhibit much preference for different times of the day; even then, there remains some evidence to suggest that the species displays feeding and breeding site fidelity, as individuals were shown to return to familiar baits.[27]
Mating
D. subobscura is
Although males always extend their own proboscis, this activity within the female varies greatly. Activities among three consecutive male-female courtships showed three different female behaviors: 1) no protrusion of the proboscis, 2) continued extension of the proboscis for several seconds after mounting had occurred, and 3) repeated protrusion and withdrawal of the proboscis before the male mounted.[29] The tips of the male and female probosces can be observed to be brought into contact, where they alternate with back and forth motions.[33]
Sexual selection
D. subobscura practice
It has been shown that males that are in good condition produce more nutritional gifts, thereby increasing their mating success. Additionally, starved females show preference for well-fed males as a way to increase the female's fecundity – this preference is speculated to be the case due to the greater quantity of drops that well-fed males produce.[36] If larger males, carrying bigger nutritional gifts, are prevented from producing their gifts, then small males are more successful in female courtship, due to better tracking of the female during the courtship dance. Larger males are seen to have slower acceleration and deceleration speeds.[37]
Inbred male behavior
Reported observations of mating behavior in inbred males reveal that in most cases, active courtships were seen, but mating did not normally follow. However, prolonged dances were rare. In some instances, the male directly approaches the female, in which the female steps sideways several times in front of the stationary male, before ultimately turning away. Occasionally, the male attempts to follow the sidestep movements of the female but would often lag behind and struggle to consistently face the female. In the incident that the female stands still and extends her proboscis, the male usually would attempt to mount. More often than not, the inbred male would fall on his back, or land too far forward or too far back on the female. In the case of the latter, the female normally stands still with her wings partially extended before eventually kicking off the male. Inbred males who have continuously but unsuccessfully attempted to court a female may approach the female from the side or behind and attempt to directly mount, a behavior described as “desperation” to some scientists. These mating attempts remain unsuccessful. The observed lower mating success in inbred males has been thought to be due to lower athletic ability via physiologically-efficient muscles, sense organs, and neuromuscular coordination, rather than lower intensity of courtship.[29]
Influence of gut microbiota on mating behavior
A study has displayed that the condition of D. subobscura's gut microbiota can have an effect on its mating behavior.
Genetics
Analysis of D. subobscura's
D. subobscura is frequently used in evolutionary-biological studies.[45][46][47][48][49] As D. subobscura, among others within its species group, has been reputed as a model organism for evolutionary-biological studies, its genetics and ecology have been scrutinized for more than forty years.[50] These flies have served as favorable models ever since Theodosius Dobzhansky and his colleagues published their influential works in the 1930s.[51][52] From the species' discovery in the Palearctic realm to its colonization of North and South America, it has attracted the interests of both European and American scientists as experimental material in evolution, biology, and ecology.[53]
Significance in tracking climate change
The D. subobscura genome has been used to track global climate change by measuring the magnitude and direction of shifts in chromosome inversion frequencies in comparison to ambient temperatures at selected European, North American. and South American sites.[54] In 21 of 22 populations of D. subobscura, genotypes seen in warm climates increased in frequency. It was shown that genetic changes in D. subobscura at these sites can be used as a possible tool to track global climate warming.[54]
References
- ^ a b c d e f g h "Smart, J. 1945. Drosophila subobscura Collin: descriptive notes on the species with comments on its nomenclatorial status (Diptera). Proc. R. Entomol. Soc. Lond. Ser. B. Taxon, 14:53-56" (PDF). Retrieved 24 September 2019.
- S2CID 30655586.
- S2CID 43641513.
- PMID 23885723.
- S2CID 29557017.
- S2CID 33047873.
- ISSN 0005-7959.
- PMID 29109241.
- ^ Gordon, C (1936). "The frequency of heterozygous in free-living populations of Drosophila melanogaster and Drosophila subobscura". J. Genet.: 25–33.
- ^ Collin, J. E. (1936). "Note Drosophila subobscura sp.n. male, female. Addendum to Gordon". J. Genet.: 60.
- ^ "A. H. Sturtevant 1942. The classification of the genus Drosophila with the description of nine new species. Univ Texas Publ 4213:5–51" (PDF). Retrieved 24 September 2019.
- ^ Therese A. Markow; Patrick M. O'Grady (2005). Drosophila: A guide to species identification and use. London: Elsevier. ISBN 978-0-12-473052-6. Retrieved 24 September 2019.
- PMID 1917545.
- PMID 30885123.
- ^ Drosophila Information Service (1939–43). Nos. 11–17. Reports from Biometry Department, University College, London.
- ^ Séguy, Drosophila subobscura, 1938, Mem. Mjs. Hist. nat. Paris (n.s.) 8:352.
- ^ Séguy, Drosophila subobscura, 1939, Zool. Rec. 75 (Pt. 12):384.
- ^ "Bächli, G. "Quantitative methods for population analysis applied to a Drosophila (Diptera, Drosophilidae) collection." Aquilo (Zool) 20 (1979): 33-40".
{{cite journal}}
: Cite journal requires|journal=
(help) - ISBN 9780120176076. Retrieved 24 September 2019.
- ^ S2CID 55247939.
- S2CID 84917494.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ISBN 978-3-642-74527-0.
- JSTOR 2425832.
- ^ "Burla, H.: Systematik, Verbreitung und Ökologie der Drosophila-Arten der Schweiz. Rev. suisse Zool. 58, 23–175 (1951)".
{{cite journal}}
: Cite journal requires|journal=
(help) - S2CID 12730201.
- ^ Krimbas, C.B.; Alevizos, V. (1973). "The genetics of Drosophila subobscura populations. IV. Further data on inversion polymorphism in Greece—Evidence of microdifferentiation". Egypt. J. Genet. Cytol. 2 (12): 1–132.
- .
- S2CID 12804737.
- ^ S2CID 43641513.
- S2CID 33047873.
- .
- ^ "Osservazioni comparativo ed esperimenti sulle modalita del corteg-giamento nelle cinque species europes del gruppo "obscura"".
{{cite journal}}
: Cite journal requires|journal=
(help) - hdl:2246/934.
- S2CID 53156432. Retrieved 24 September 2019.
- S2CID 53155030. Retrieved 24 September 2019.
- .
- S2CID 54361166.
- ^ .
- )
- ^ "Mainx F, Koske T, Smital E. Untersuchungen über dier chromosomale Struktur europaischer Vertreter der Drosophila obscura Gruppe. Z Indukt Abstamm Vererbungsl. 1953;85:354–72".
{{cite journal}}
: Cite journal requires|journal=
(help) - PMID 112146.
- PMID 535729. Retrieved 24 September 2019.
- )
- ^ Powell JR. Progress and prospects in evolutionary biology: the Drosophila model. New York: Oxford University Press; 1997.
- S2CID 16488003.
- PMID 15341152.
- S2CID 11927366.
- PMID 21931524.
- PMID 21108788.
- ^ Krimbas, C.B. & Loukas,M.(1980) Inversion Polymorphism of Drosophila subobscura Evol.Biol.12,163-234.
- ISBN 9781461571483.
- ^ Powell JR. Progress and Prospects in Evolutionary Biology: The Drosophila Model. 1997, New York: Oxford Univ Press.
- ^ Powell JR & Krimbas, C.B., Drosophila Inversion Polymorphism / Edition 1.
- ^ S2CID 7525234.
External links
- Bioimages images of Drosophila subobscura