The Essentials: The X-Flies

A friend of mine told me that he was comped two drinks a while back.  The first was because there were fruit flies in the glass and the second for the same reason.  He speculated that the establishment neglected to cover their bottles over night and the flies enjoyed their own free drinks.  The story immediately reminded me of a study that showed how an attraction to alcohol was advantageous to the flies.

Fruit flies could have just as easily been named bar flies because their habits lead them to imbibe in alcohol on a regular basis.  Fruit flies dine on over ripe, and therefore fermenting, fruit.  The fermentation process converts the fruit sugars into alcohol and in that way alcohol becomes part of the fly’s daily diet.  The study showed that alcohol consumption increased the flies fitness because it helped them ward off attacks from a would be predator.

The foiled predator is of the most insidious and sneaky kind.  This predator attacks undetected (possibly) and from within. This predator is a parasite: specifically a parasitic wasp. The strategy of the wasp is to get its eggs into the fly, then once the eggs hatch, the newborns feast on the fly from the inside out.  As a result the wasp has a buffet of fresh fly guts to feast on and the fly dies from the inside out.

The fly has no real defense against the parasitic attack.  There are no fly surgeons to extract the unwanted wasps and left untreated the prognosis that accompanies diagnosis for an infected fly is certain death.  That is unless the condition is caught early enough and the correct preventative measures are taken.  In this case the best medicine is one of the oldest remedies around, booze.

The increased alcohol in the fly’s system creates an environment inhospitable for the development of the wasps and the fly lives to eat another banana. This conclusion isn’t a simple conjecture made by the authors of the paper but is actually backed up by experimental evidence.  You can read more about the study in the New York Times article that presented it to the general public.

(I experienced some inconsistencies with the first link so if that doesn't work try this one from the Huffington Post.)

What is amazing to me is that the defenseless flies found a solution to their parasitic problem.  Of course flies don’t create committees around public health or engage in research to find cures to diseases. Flies main concern (concern is probably to anthropomorphic – instinct is probably better) is the same as all other organisms - live and reproduce.  Just like every other organism the solution comes from the variability that is already present in the.  Variety results in some individuals being more fit to survive and ultimately those fit individuals pass on their genes to their offspring. 

If you are reading this and are suddenly experiencing déjà vu it is probably because I keep coming back to this point.  Populations are made up of individuals and those individuals are all different.  It is the presence of these differences, and the realities of limited resources, that drives species to evolve. But where does this variability come from?

The answer is that, just like the flies, we are all mutants. We are all X-Men, mutated at random and against our will or control. We are mutated without our knowledge and without knowledge of the consequences.  Though we can’t shoot laser beams out of our eyes or move metallic objects with our minds, the collective mutations of ours, and every species, have shaped us into who we are today and have given us the super power of survival.