Some bees have developed a taste for carrion, in a delightfully twisted evolutionary turn. These vulture bees, as they’re known, feature unique gut microbes that help them digest meat.
A team of entomologists, seeking to learn more about these pollen-eschewing bees, recently set up chicken baits in a Costa Rican forest. They ended up collecting a bunch of vulture bees (Trigona necrophaga) and analyzed their guts and genetics in detail.
“These are the only bees in the world that have evolved to use food sources not produced by plants, which is a pretty remarkable change in dietary habits,” said Doug Yanega, an entomologist at University of California, Riverside and a co-author of the recent paper, in a university press release.
While ordinary bees have pockets on their back legs to store pollen as they flit from flower to flower, the vulture bees have repurposed the stores as “little chicken baskets,” according to study co-author Quinn McFrederick, also an entomologist at UC Riverside.
Besides obvious external features, the team wanted to know what was happening inside the bees. Most bees’ guts are occupied by five kinds of microbes that help the animals break down what they eat. So what happens when a species swaps out pollen for raw chicken and nectar for blood?
To figure it out, they collected other bee species that only sometimes eat meat, as well as some that are strictly vegetarian, to compare the bacteria that populate the insects’ guts. The carrion-eaters’ guts had a distinct microbiome, one built for breaking down meat.
“The vulture bee microbiome is enriched in acid-loving bacteria, which are novel bacteria that their relatives don’t have,” McFrederick said. “These bacteria are similar to ones found in actual vultures, as well as hyenas and other carrion-feeders, presumably to help protect them from pathogens that show up on carrion.”
The team thinks that the bees probably began eating meat due to competition for nectar. Whatever the reason, you have to wonder about the new evolutionary trajectory the animals may now be set on—let’s hope they don’t develop a hankering for humans.