Alcoholic Fruit Flies

There have been several papers in recent months on alcohol consumption by one of our smaller neighbors – the fruit fly. Before we rush off and criticize their drinking behavior we need to keep in mind that there are medicinal benefits from supping a wee dram.

Fruit flies start their drinking early on in their lives. The larvae eat the yeast on rotting fruit and develop a tolerance to alcohol when very young. A paper in Current Biology last month by Milan et al from Emory U brings out the medical benefits of their self-medication by killing parasites in their blood (1).

Endoparasitoid wasps inject their eggs into fruit fly larvae to provide a live meal for their offspring. Firstly, an alcoholic larva is repellent to the wasps, and secondly, the alcohol in the blood kills off the parasites. If a larva gets infected, it is aware of what happened and goes off to find some alcohol to sort itself out.

Of course, it’s not only parasites that fruit flies have to worry about. Their busy lives can, like ours, be quite stressful. Male fruit flies spend a deal of their time finding mates and if successful, the levels of neuropeptide F are enhanced. If their love life is going badly the levels are reduced.

For the bio-geeks among us, neuropeptide F controls the feeding response in the larvae and when it is reduced in older larvae they get into burrowing mode. It is the analogue of neuropeptide Y that we mammals make use of to regulate our feeding habits. Neuropeptide Y deficient mice overeat and end up with a severe obesity problem.

Now Shohat-Ophir et al from U Cal. SF reported on their experiments with groups of male fruit flies and their drinking habits in the current edition of Science (2). They took some males (fruit flies, that is) and introduced them to a large group of eager females and checked out their alcohol consumption. They then compared that to another group of males after introducing them to a group of pregnant females who had no interest in amorous males.

They noted that the alcohol consumption was markedly higher in the group of males who had been put under stress by universal rejections. Of course, they weren’t just allowed to drown their sorrows in peace, but, like their successful colleagues, were thrown into the blender and the levels of neuropeptide F measured. A successful love life led to high levels and rejection led to low levels and loss of control on the alcohol.

  2. G.Shohat-Ophir, K.R.Kaun, R.Azanchi and U.Huberlin, Science, 335, 1351, (2012)

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