The Riverside flies are not alone. Scientists have known about flies’ love of beer since the 1920s. But Anupama Dahanukar, an entomologist at UC Riverside, wanted to know why so she headed to the lab.

She and her colleagues examined the feeding preference of the common fruit fly for the pale ale (the least sweet beer) and other products of yeast fermentation. They found that a receptor (a protein that serves as a gatekeeper) associated with neurons located in the fly’s mouth-parts is instrumental in signaling a good taste for beer.

The receptor in question is Gr64e.  When a fly settles on beer, Gr64e detects glycerol and transmits this information to the fly’s neurons, which then influences the fly’s behavioral response.

Once the group identified the receptor, NPR reports,

Dahanukar and [colleague Zev] Wisotsky even found the particular gene responsible for flies’ ability to detect glycerol. When they created flies missing that gene, and gave them the sugar water-beer choice, the flies went for the sugar water.

“Taste becomes important only after the fly makes physical contact with food,” says Dahanukar. “A fly first locates food sources using its odor receptors—crucial for its long-range attraction to food. Then, after landing on food, the fly uses its taste system to sample the food for suitability in terms of nutrition and toxicity.”

As often happens in science, Dahanukar’s discovery has left her with more questions than when she started this research. Her lab will work to answer them.]

“How do you get information from the chemical environment to the brain—not just in flies but other insects as well?” Dahanukar asks. “How is that information processed to give rise to appropriate behavior? How does feeding behavior change with hunger? These are some questions we would like to pursue.”

The research was published earlier this month in Nature Neuroscience.

Image: UCR Strategic Communications

Israeli researchers, publishing in the Proceedings of the National Academy of Sciences this week, split flies into two different groups, feeding them two separate diets. Previous research showed that when rejoined, the flies preferred to mate with those who had the same diet.

Why?

The Israeli scientists suspected it had something to do with the bacteria living inside the flies. Different bacteria appear in our bodies depending on what we eat. And, according to author Eugene Rosenberg, quoted in Science Now, “Bacteria have to do with smell, and smell has a lot to do with sex.”

To confirm this theory, the researchers treated the flies with antibiotics to rid their bodies of the bacteria. Guess what? When rejoined, the flies mated with anyone, without regard to diets!

With genetic testing, the researchers were even able to specify which bacteria cause the mating behavior in the fruit fly: Lactobacillus plantarum.

This research has scientists excited about other possibilities, too. Mike Ritchie, an evolutionary biologist in the UK who also works with this species of fruit flies, has this to say in Nature: “We know that plant-eating flies show very high speciation rates. This could be a general mechanism.” Meaning that the bacteria could even lead the flies to creating a new species.

And it reaches beyond fruit flies. Ed Yong had this to say in his blog on Discover:

In any case, the study suggests that you can’t understand an animal’s evolution simply by considering the evolutionary pressures that act on its genome. You also have to consider the genes of the bacteria and other passengers that live inside it, which also create variations in its behavior and affect is chances of survival.

These findings could give a whole new spin on the age-old question, “What’s eating you?”

Creative Commons image by TheAlphaWolf

Researchers out of the University of Wisconsin Madison published an article in Nature this week with the possible answer, at least for fruit flies: the Wingless morphogen.

Wingless what?

In studying wing patterns of certain North American spotted fruit flies, the scientists discovered a morphogen (a substance that determines the development of cells and the position of those cells within a tissue) encoded with the Wingless gene (a specific gene that affects wing and limb development during the embryonic and metamorphosis stages).

Late in wing development, the Wingless morphogen diffuses through tissue where it prompts cells in certain areas of the wing to make pigment. “It acts by triggering responding cells to do things, in this case make color,” explains Sean Carroll, the senior author of the report.

“The Wingless molecule is deployed in this species at specific points in time and in specific places — the places where the spots are going to be.”

So the team began experimenting. Three years and thousands of fruit fly embryos later, they found that by inserting the Wingless gene into different parts of the fly’s genome, they were able to successfully manipulate the decoration of the fly’s wing, creating stripes instead of spots, and patterns not seen in nature. “We can make custom flies,” notes Carroll. By manipulating the gene, “we can make striped flies out of spotted flies.”

Although the study was conducted in teeny fruit flies, the principles uncovered by Carroll’s group, he argues, very likely apply to many animals, everything from butterflies to boa constrictors. “This is animal color patterning, how they are generated, how they evolved.”

Creative Commons image by photoholic1