Fruit flies may be attracted to the scent of ripened fruit when looking for a treat, but when looking for a mate they are attracted to the scent of nothing. Joel Levine conducted a study where oenocytes, pheromone-producing cells, were selectively killed off in the abdomens of Drosophila melanogaster(fruit flies). Without the pheromones the flies had no scent and that made them all the more attractive to other flies.
When normal male flies had their pick between females lacking pheromones, males lacking pheromones, and normal females they would pick the females and the males lacking the pheromones. Not only were males of the same species more attracted to the scentless flies, but males from three other species found the scentless females desirable.
To figure out what messages the pheromones were sending Levine and his colleagues added back a female pheromone (7, 11 HD), which is an aphrodisiac. They found that adding the pheromone did not make the flies any more attractive. Adding cVa, a pheromone that warns males to stay away, made both the normal and the scentless females unattractive to males. If both of the pheromones were added then the female chemical 7,11 HD won and the flies were no longer found to be unattractive.
7, 11 HD is not only an aphrodisiac that is able to overcome the cVa pheromone, but it also a species marker. When it was added back to the scentless females the other species of Drosophila no longer found them to be desirable.
By killing off the pheromone-producing cells and manipulating 7,11 HD and cVa Levine was able to determine that pheromones not only distinguish between sexes, but they also distinguish between species.
-Tara Quist (3)
This story was definitely one of the most interesting. Fruit Flies must really live their life by scent. That is amazing the way they use that one skill of theirs for multi-purposes in life. I thought it was incredible the way they could change the scent but not the anatomy of a fly and genuinely fool flies of its own species.
ReplyDeleteAre there any other species (besides flies) that follow this method or are fruit flies distinct in their ability?
I was also wondering what causes the release of these pheromones, is it voluntary or involuntary?
Commented by Amanda Lee
It seems crazy to me that fruit flies are attracted to scentless mates. I would think that fruit flies have an extra sensitive sense of smell due to the fact that they are so attracted to the smell of ripening fruit. Do fruit flies have an extra sensitive sense of smell? If so why do you think male flies are attracted to others of the same species that are scentless?
ReplyDeleteIt seems odd to me also that when adding a strong pheromone that is anaphrodisiac - scentless flies are still more desirable. I wonder why this is the case?
If pheromones are distinguish between species and sexes how come flies that are more attractive if they are scentless? How are other normal flies able to identify them?
Posted by Tiffany Mallet
Not going to lie I chose this article because of your awesome neon green fly picture. Turned out to be a good choice though because it was very interesting! The fact that mates would be chosen on a lack of pheromones is in itself puzzling because in that case how would a female be able to find a male? Although the research seems sound It seems as if this case is truly exceptional because it goes against the whole aspect of pheromones in my opinion.
ReplyDeleteAlex Bourdois
Very interesting post. I know I have done many labs for many hours with Drosophila so this hits pretty close to home for many of us. Do you know what other species they were using in the experiments? And why did they choose the aphrodisiac 7,11 HD? Does this pheromone work "better" with other species? If so, which species and what experiments has it been successful in?
ReplyDeleteJillian O'Keefe
Thanks for the comments! I also though it was strange that they are more attracted to the scentless flies because I always thought that pheromones were what they used to attract mates. In this study it seems that they were able to prove that pheromones act to attract as well as to repel mates. The pheromones are used to attract mates from the same species, but they can also be used as a way for the female to keep them at an arms length if you will so that they have the opportunity to asses the males before picking a mate. When the pheromones were not present the males were attracted to everyone because the flies were not giving off a scent to keep them away. They chose 7,11 HD because it is not made by other Drosophilia species. That is why when they added it to the scentless flies the males of different species no longer found them attractive. The three other species that they used were D.simulans, D.yakuba, and D.erecta. Sorry I couldn't answer all of the questions, but I hope this helped a bit!
ReplyDelete-Tara Quist