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Drosophila (), from Ancient Greek δρόσος ( drósos), meaning "dew", and φίλος ( phílos), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly.
One species of Drosophila in particular, Drosophila melanogaster, has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and " Drosophila" are often used synonymously with D. melanogaster in modern biological literature. The entire genus, however, contains more than 1,500 species and is very diverse in appearance, behavior, and breeding habitat.
Effective population size has been credibly suggested to positively correlate with the effect size of both negative and positive selection. Recombination is likely to be a significant source of diversity. There is evidence that crossover is positively correlated with polymorphism in D. populations.
The larvae of at least one species, D. suzukii, can also feed in fresh fruit and can sometimes be a pest. A few species have switched to being parasitism or . Many species can be attracted to baits of fermented or mushrooms, but others are not attracted to any kind of baits. Males may congregate at patches of suitable breeding substrate to compete for the females, or form leks, conducting courtship in an area separate from breeding sites.
Several Drosophila species, including Drosophila melanogaster, D. immigrans, and D. simulans, are closely associated with humans, and are often referred to as Domestication species. These and other species ( D. subobscura, and from a related genus Zaprionus indianus) have been accidentally introduced around the world by human activities such as fruit transports.
Drosophila species vary widely in their reproductive capacity. Those such as D. melanogaster that breed in large, relatively rare resources have ovaries that mature 10–20 eggs at a time, so that they can be laid together on one site. Others that breed in more-abundant but less nutritious substrates, such as leaves, may only lay one egg per day. The eggs have one or more respiratory filaments near the anterior end; the tips of these extend above the surface and allow oxygen to reach the embryo. Larvae feed not on the vegetable matter itself, but on the and present on the decaying breeding substrate. Development time varies widely between species (between 7 and more than 60 days) and depends on the environmental factors such as temperature, breeding substrate, and crowding.
Fruit flies lay eggs in response to environmental cycles. Eggs laid at a time (e.g., night) during which likelihood of survival is greater than in eggs laid at other times (e.g., day) yield more larvae than eggs that were laid at those times. Ceteris paribus, the habit of laying eggs at this 'advantageous' time would yield more surviving offspring, and more grandchildren, than the habit of laying eggs during other times. This differential reproductive success would cause D. melanogaster to adapt to environmental cycles, because this behavior has a major reproductive advantage.
Their median lifespan is 35–45 days.
Courtship behavior of male Drosophila is an attractive behaviour. Females respond via their perception of the behavior portrayed by the male. Male and female Drosophila use a variety of sensory cues to initiate and assess courtship readiness of a potential mate. The cues include the following behaviours: positioning, pheromone secretion, following females, making tapping sounds with legs, singing, wing spreading, creating wing vibrations, genitalia licking, bending the stomach, attempt to copulate, and the copulatory act itself. The songs of Drosophila melanogaster and Drosophila simulans have been studied extensively. These luring songs are sinusoidal in nature and vary within and between species.
The courtship behavior of Drosophila melanogaster has also been assessed for sex-related genes, which have been implicated in courtship behavior in both the male and female. Recent experiments explore the role of fruitless ( fru) and doublesex ( dsx), a group of sex-behaviour linked genes.
The fruitless ( fru) gene in Drosophila helps regulate the network for male courtship behavior; when a mutation to this gene occurs altered same sex sexual behavior in males is observed. Male Drosophila with the fru mutation direct their courtship towards other males as opposed to typical courtship, which would be directed towards females. Loss of the fru mutation leads back to the typical courtship behavior.
These lists are not inclusive. Polyandry among the Drosophila pseudoobscura in North America vary in their number of mating partners. There is a connection between the number of time females choose to mate and chromosomal variants of the third chromosome. It is believed that the presence of the inverted polymorphism is why re-mating by females occurs. The stability of these polymorphisms may be related to the sex-ratio meiotic drive.
However, for Drosophila subobscura, the main mating system is monandry, not normally seen in Drosophila.
However, some species of Drosophila are difficult to culture in the laboratory, often because they breed on a single specific host in the wild. For some, it can be done with particular recipes for rearing media, or by introducing chemicals such as sterols that are found in the natural host; for others, it is (so far) impossible. In some cases, the larvae can develop on normal Drosophila lab medium, but the female will not lay eggs; for these it is often simply a matter of putting in a small piece of the natural host to receive the eggs.
The Drosophila Species Stock Center located at Cornell University in Ithaca, New York, maintains cultures of hundreds of species for researchers.
Drosophila is a useful in vivo tool to analyze Alzheimer's disease. Rhomboid proteases were first detected in Drosophila but then found to be highly conserved across , mitochondrion, and bacteria. Melanin's ability to protect DNA against ionizing radiation has been most extensively demonstrated in Drosophila, including in the formative study by Hopwood et al. in 1985.
Drosophila species also harbour vertically transmitted endosymbionts, such as Wolbachia and Spiroplasma. These endosymbionts can act as reproductive manipulators, such as cytoplasmic incompatibility induced by Wolbachia or male-killing induced by the D. melanogaster Spiroplasma poulsonii (named MSRO). The male-killing factor of the D. melanogaster MSRO strain was discovered in 2018, solving a decades-old mystery of the cause of male-killing. This represents the first bacterial factor that affects eukaryotic cells in a sex-specific fashion, and is the first mechanism identified for male-killing phenotypes.
Alternatively, they may protect theirs hosts from infection. Drosophila Wolbachia can reduce viral loads upon infection, and is explored as a mechanism of controlling viral diseases ( e.g. Dengue fever) by transferring these Wolbachia to disease-vector mosquitoes. The S. poulsonii strain of Drosophila neotestacea protects its host from parasitic wasps and nematodes using toxins that preferentially attack the parasites instead of the host.
Since the Drosophila species is one of the most used model organisms, it was vastly used in genetics. However, the effect abiotic factors, such as temperature, has on the microbiome on Drosophila species has recently been of great interest. Certain variations in temperature have an impact on the microbiome. It was observed that higher temperatures (31 °C) lead to an increase of Acetobacter populations in the Gut microbiota of Drosophila melanogaster as compared to lower temperatures (13 °C). In low temperatures (13 °C), the flies were more cold resistant and also had the highest concentration of Wolbachia.
The microbiome in the gut can also be transplanted among organisms. It was found that Drosophila melanogaster became more cold-tolerant when the gut microbiota from Drosophila melanogaster that were reared at low temperatures. This depicted that the gut microbiome is correlated to physiological processes.
Moreover, the microbiome plays a role in aggression, immunity, egg-laying preferences, locomotion and metabolism. As for aggression, it plays a role to a certain degree during courtship. It was observed that germ-free flies were not as competitive compared to the wild-type males. Microbiome of the Drosophila species is also known to promote aggression by octopamine OA signalling. The microbiome has been shown to impact these fruit flies' social interactions, specifically aggressive behaviour that is seen during courtship and mating.
Glutamate can serve as an excitatory neurotransmitter, specifically at the neuromuscular junction in fruit flies. This differs from vertebrates, where acetylcholine is used at these junctions.
In Drosophila, histamine primarily functions as a neurotransmitter in the visual system. It is released by photoreceptor cells to transmit visual information from the eye to the brain, making it essential for vision.
As with many Eukaryotes, this genus is known to express SNAREs, and as with several others the components of the SNARE complex are known to be somewhat substitutable: Although the loss of SNAP-25 - a component of neuronal SNAREs - is lethal, SNAP-24 can fully replace it. For another example, an R-SNARE not normally found in can substitute for synaptobrevin.
The Hawaiian species of Drosophila (estimated to be more than 500, with roughly 380 species described) are sometimes recognized as a separate genus or subgenus, Idiomyia,
Evidence from phylogenetic studies suggests these genera arose from within the genus Drosophila:
Several of the subgeneric and generic names are based on anagrams of Drosophila, including Dorsilopha, Lordiphosa, Siphlodora, Phloridosa, and Psilodorha.
The data have been used for many purposes, including evolutionary genome comparisons. D. simulans and D. sechellia are sister species, and provide viable offspring when crossed, while D. melanogaster and D. simulans produce infertile hybrid offspring. The Drosophila genome is often compared with the genomes of more distantly related species such as the honeybee Western honeybee or the mosquito Anopheles gambiae.
The Drosophila modEncode project conducted extensive work to annotate Drosophila genomes, profile transcripts, histone modifications, transcription factors, regulatory networks, and other aspects of Drosophila genetics, and make predictions about gene expression among others.
FlyBase serves as a centralized database of curated genomic data on Drosophila.
The has presented ten new genomes and combines those with previously released genomes for D. melanogaster and D. pseudoobscura to analyse the evolutionary history and common genomic structure of the genus. This includes the discovery of transposable elements (TEs) and illumination of their evolutionary history. Bartolomé et al. 2009 find at least of the TEs in D. melanogaster, D. simulans and D. yakuba have been acquired by horizontal transfer. They find an average rate of 0.035 horizontal transfer events per TE family per million years. Bartolomé also finds horizontal transfer of TEs follows other relatedness metrics, with transfer events between D. melanogaster and D. simulans being twice as common as either of them with D. yakuba.
(2025). 9788788757880 ISBN 9788788757880 but this is not widely accepted. About 250 species are part of the genus Scaptomyza, which arose from the Hawaiian Drosophila and later recolonized continental areas.
Genetics
Drosophila species are extensively used as model organisms in genetics (including population genetics), cell biology, biochemistry, and especially developmental biology. Therefore, extensive efforts are made to sequence drosophilid genomes. The genomes of these species have been fully sequenced:
See also
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