Is ‘the Drosophila‘ actually Drosophila?

Celebrities commonly change their names on the path to stardom. Elton John began life as Reginald Kenneth Dwight, John Denver as Henry Deutschendorf, Jr, and Bela Lugosi as Be’la Ferenc Dezso Blasko. A name change can make someone more marketable in the fickle entertainment industry. However, once someone makes it big, their name usually stays the same (excepting P-Diddy and Prince, whose constant name changes became marketing strategies in themselves). A celebrity’s name becomes the branding that represents and sells their fame.

What about name changes for scientific celebrities? I’m not talking about people, but rather the components of nature that we observe around ourselves and adorn with nomenclature. There was (unnecessary) public uproar when Pluto was re-designated as a Kuiper Belt planetoid. Neil deGrasse Tyson even got hate mail from children when the American Museum of Natural History updated its displays accordingly. The change was the result of a non-unanimous scientific consensus attempting to better define the bodies of the solar system, but many people had become attached to the idea of PLANET Pluto and reacted negatively to the news.

Now a new conundrum is brewing within scientific circles as biologists try to decide what to do when the nomenclature describing a celebrity organism no longer jives with scientific observation. Nature News asks, ‘What’s in a name?’. Well, when the name is Drosophila melanogaster, there’s 100 years of glorious scientific discoveries in a name.

Photo by mr.checker

D. melanogaster, the common fruit fly, was a major workhorse behind the early 20th century genetic revolution. Researchers like Thomas Hunt Morgan harnessed the fly’s fast reproductive cycle and simple care requirements to elucidate the fundamentals of heredity. Since then, the powerful D. melanogaster model has exploded to become a principle contributer to research in genetics, neurology, development, biomechanics, and evolution. Found in almost any biology department around the world, this animal is of tremendous historical and contemporary importance to science; a true celebrity.

However, there is one slight problem; Drosophila melanogaster is probably not Drosophila melanogaster.

The issue here is the status of the genus, Drosophila. This genus, as it is currently recognized, contains 1,450 species of fruit flies. A genus, or any level of taxonomic organization, is supposed to be monophyletic, that is; composed only of species that are evolutionarily closer to one another than they are to the members of any other genus. However, with Drosophila, this has been shown through extensive molecular and morphological analysis not to be the case.

Fruit Fly supertree. Adapted from Van der Linde and Houle, 2008

Look at the phylogenetic tree to the left (for an overview of phylogenetics, read this post). Each node on the tree represents a group of species of the same genus. Notice, however, that the 1,450 species of the Drosophila genus are split up into six different clades, interspersed with other genera. This is called paraphyly, and it points out an error in the taxonomic nomenclature. All the species of a given genus should be grouped together, in a monophyletic relationship. Ultimately, this means that there is going to have to be some reorganization of the genus. Some members of Drosophila are going to be ousted and given new names.

The obvious solution to preserve the celebrated D. melanogaster species name would seem to be leaving its clade (marked with a red arrow) as genus Drosophila and renaming the others. However, there are two problems with this. First of all, restructuring the genus in the manner would push out, and require the renaming, of 1,100 species of fruit flies. Furthermore, the type species Drosophila funebris (marked with an orange arrow), the animal from which the Drosophila genus was originally described in 1787, lies in a different clade than D. melanogaster. A recent petition to re-designate the genus type species as D. melanogaster was voted down by the International Commission on Zoological Nomenclature.

As it looks at the moment, D. melanogaster is probably on its way to becoming Sophophora melanogaster. This has generated shock and disbelief from biologists; citing possible research impediments should the name change go through. In addition, they surely have a sentimental attachment to the name of their favorite laboratory arthropod. When biologists say ‘Drosophila‘, they mean Drosophila melanogaster. This celebrated animal has a strong claim to being the most important and powerful research tool biologists have in their arsenal. However, even D. melanogaster, like Pluto, may need to bend in name to the powers of parsimonious taxonomic nomenclature.
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Read more about the Drosophila name fight here and here at Nature News, or here at Catalogue of Organisms

Check out some of my other posts about phylogenetics:

• We contracted crabs from gorillas
• Unraveling Arthropoda

References:

Kim Van der Linde, & David Houle (2008). A supertree analysis and literature review of the genus Drosophila and closely related genera (Diptera, Drosophilidae)Insect Syst. Evol., 39, 241-267

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Arthropod Roundup, April 6, 2010

News, research, and posts about arthropods from around the web:

• See amazing photos and learn all about hummingbird hawk moths, Macroglossum stellatarum at Scienceray.
• Check out this video about lightning-fast animal movements. The first segment is about a gecko but the second one is about mantis shrimp strike mechanics (I talked about this in detail here).
• Read about the mechanics of fruit fly auto-righting during flight at New Scientist. Research suggests that they use motion sensors in their second wing vestiges, called halteres, that are wired directly into the wing muscles; allowing the flies to react to perturbances faster than a visual signal can be processed.
• Kevin over at Deep Sea News has a great post about the bazaar retina of the vent shrimp, Rimicaris exoculata. This retina has migrated from the eyes to the animal’s dorsal carapace where it may be used to sense blackbody radiation given off by the (infra)red-hot vents.
• PZ at Pharyngula has a nice write-up about female crayfish, Pacifastacus leniusculus, antagonizing males to fight so that they can choose a more suitable mate. Bonus: Blindfolded male crayfish battling in a fluorescent urine cloud, set to Star Trek battle music.
• Learn about how barnacles attack to whales at Scienceline.

Fruit fly sperm race

Check out this awesome video of fluorescent labeled fruit fly sperm racing through the reproductive tract of a female Drosophila melanogaster. The sperm from one male are labeled with a green marker and sperm from another male are labeled with a much fainter red marker. Read more about the high stakes world of sperm competition at Not Exactly Rocket Science, which recently moved to Discover Blogs.

This video is from recent research published in Science.

Arthropod Roundup: Crabzilla, altruistic ants, and neuronal recordings from Drosophila in flight.

Quick notes about recent Arthropod news and research:

• The National Sealife Centre in Birmingham, England is hosting a special guest, on loan from Japan. Meet ‘Crabzilla’, a not-quite full grown Japanese spider crab, Macrocheira kaempferi. Crabzilla has an impressive leg-span of about 10 ft, but members of this species can reach over 13 ft. By length, they are the largest know arthropods on the planet. You can read more about Crabzilla’s visit to the UK at the Daily Mail.
• New research on the ant species, Temnothorax unifasciatus, found compelling evidence of altruistic behavior. Altruism is commonly observed in social insects, as single individuals often sacrifice their energies or lives for the good of the colonial super-organism. In the present study, the researchers showed that ants infected with a deadly and contagious fungus would often leave the colony and die in seclusion. This prevents transmission of the disease to other members of the closely interacting colony. Read more at the BBC.
• Finally, researchers have developed new techniques for recording electrical signals from fruit fly neurons while the animals are in tethered flight. Fruit flies, Drosophila melanogaster are the go-to arthropod model organisms, and a plethora of molecular and physiological tools are available for studying any aspect of their biology. This new neuronal recording technique was applied to look at the activity of visual pathways in the brain during flight. The researchers found that the stimulus response time of the Drosophila visual system nearly doubles when the animal is in flight. This allows the flies to change direction rapidly mid-flight in order to avoid obstacles. This work was published in Nature Neuroscience. Read more at Science Daily.

  A tethered fruit fly in flight with a pink electrode in its brain. Photo by Gaby Maimon and Michael Dickinson.