Maggots prefer food their peers have already eaten

Fruit fly maggots take the "I'll have what she's having" approach to choosing food, suggesting that they can learn from their peers, despite their paltry intellects.

Study suggests they are capable of social learning; presence of others a sign of healthy food

Fruit fly maggots seem to use the presence of other maggots to indicate the location of a high quality food source. (McMaster University)

Fruit fly maggots take the "I'll have what she's having" approach to choosing food, suggesting that they can learn new information from their peers despite their paltry intellects.

Given a choice between fresh, new food and other maggots' leftovers, fruit fly larvae overwhelmingly choose food that their peers have already chewed through, McMaster University researchers in Hamilton have discovered.

Like people who choose a restaurant by going where the lineups are, maggots prefer new odours that are associated with the presence of other maggots feeding, reported McMaster University biologists Zachary Durisko and Reuven Dukas in an article published this week in the journal Proceedings of the Royal Society B.

On one hand, it's disadvantageous for fruit fly larvae to choose food that's already crawling with maggots, so to speak, or that had previously been picked through, since that means having to compete with others for a share, the paper acknowledges.

Popular hangouts indicate better food

The researchers found, however, that when maggots were given a range of food choices, they tended to choose sources with a higher nutritional value. They suggested that the presence of other maggots therefore signals to their peers the presence of higher quality food. The researchers found that the maggots pick up on the presence of other maggots or their previous activity at a food site via a distinctive odour that they leave behind.

The results suggest that fruit fly larvae are capable of social learning — the ability to learn new information from others. "This is especially exciting given that larvae have only about 3,000 functional neurons and that there are powerful tools available for studying their neurogenetics," the researchers wrote.

That makes fruit flies far easier to study than other animals that rely on social learning, such as humans, which have about 10 billion neurons each. Consequently, fruit flies may help researchers understand social learning in more complex animals, Durisko and Dukas suggested.