Female Egyptian fruit bats trade morsels of food for sex, new research has revealed.

Scientists were initially confused when they saw captive female bats taking food right out of the mouths of their male peers, who generally seemed not to mind.

However, after observing three colonies for more than a year, researchers found that males were repaid for their generosity with sex and offspring weeks later.

Females stole food from several eligible males and strengthened their bond with them before choosing which one to mate with.

“We found a strong relationship between producer-scrounger feeding interactions and reproduction. Namely, females bore pups of the males they often scrounged food from,” said lead researcher Yossi Yovel from Tel-Aviv University in Israel. “These foraging interactions start many weeks before the copulation. The females strengthen these interactions with several males and they eventually mate with one of them."

Flying tonight? Bats under threat Show all 6 1 /6 Flying tonight? Bats under threat Flying tonight? Bats under threat Hanging in the balance: A greater horseshoe © David Chapman / Alamy Flying tonight? Bats under threat Pipistrelle Bats © FLPA / Alamy Flying tonight? Bats under threat Mexican free-tailed bats Rex Curry / Alamy Flying tonight? Bats under threat Pipistrelle Bats in flight Carl Morrow / Alamy Flying tonight? Bats under threat A greater mouse-eared bat AFP / Getty Images Flying tonight? Bats under threat A noctule bat © David Chapman / Alamy

Scientists explored the food-for-sex hypothesis by observing interactions between the bat colony and then determining the paternity of pups, according to the paper published in Current Biology.

The study revealed that there was no overlap between males preferred by each female.

This showed that the choice of whom to scrounge on is based on individual preference - rather than a few alpha males that everyone mates with. The males that females chose to scrounge off changed each year.

This behaviour has been seen in other animals such as birds and insects but this is the first time it has been reported in bats. Dr Yovel said the result “surprised” researchers.

“Animals can exhibit extremely complex social behaviour and structure. Bats account for more than 20 per cent of mammalian species, but there is still a lot that we do not know,” he added. “Many bat species roost in colonies that have the population of human cities. They show many types of social behaviour.

Support free-thinking journalism and attend Independent events

“The use social vocalizations and seem to recognise each other over many years. We are still far from understanding their social complexity.”

Egyptian fruit bats can live in colonies with thousands of individuals. They give birth to a single pup up to twice a year.