This is scientific American's 60 second science. I'm Christopher in Tagyatta.

Just like humans, fruit flies have to eat a balanced diet.

They need sugar to survive, they need amino acids to make eggs, to have stem cells

proliferate. They need salt, they need vitamins.

Carlos Roberto, a neuroscientist at the Champolemo Center in Portugal.

Yeast, he says, is a crucial component of the fly diet.

I always say yeast is the steak of the fly.

Take yeast away and the flies crave it.

They got to make those eggs.

Roberto and his team found that they could also elicit that yearning for yeast by simply removing

a few key amino acids from the fly's diet.

But that only worked in flies that had their gut

microbiome wiped out. Because here's the twist. When Ribero and his colleagues

restored the standard fly gut microbiome, amino acid-deprived flies did not seek out yeast to compensate.

It might seem like the gut microbes are actually

working against the fly's best interest,

blocking their instincts to seek out missing nutrients.

But what actually happened, Roberto says, is that flies with the gut microbes

maintained good egg production despite their nutritional deficiency,

suggesting that somehow the microbes help the flies adapt to nutrient poor conditions.

So somehow the microbes reprogram the metabolism of the fly to now cope better with an absence of a

mino acid in the diet and that might also lead then to the fly not having to

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