Meat-eating “Vulture Bees” Sports sour guts and an extra tooth to bite meat

Stingless Bee

A little-known species of tropical bee has developed an extra tooth to bite meat and an intestine that looks more like vultures than other bees.

Typically, bees do not eat meat. However, a species of stingless bee in the tropics has developed the ability to do so, presumably due to intense competition for nectar.

“These are the only bees in the world that have evolved to use non-plant food sources, which is a rather remarkable change in diet,” said UC Riverside entomologist Doug Yanega.

Honeybees, bumble bees and barren bees have intestines colonized by the same five core microbes. “Unlike humans, whose intestines change with each meal, most bee species have retained the same bacteria over about 80 million years of evolution,” said Jessica Maccaro, a UCR entomology doctoral student.

Given their radical change in food choices, a team of UCR researchers wondered if the gut bees’ gut bacteria differed from a typical vegetarian bee. They differed quite dramatically, according to a study published by the team on November 23, 2021 in the American Society of Microbiologists’ journal mBio.

Vultures love chicken

Raw chicken bait attracts vultures in Costa Rica. Credit: Quinn McFrederick / UCR

To track these changes, the researchers went to Costa Rica, where these bees are known to reside. They set up bait – fresh pieces of raw chicken suspended from branches and smeared with Vaseline to deter ants.

The baits successfully attracted vultures and related species that opportunistically feed on meat for their protein. Usually, stingless bees have baskets on their hind legs to collect pollen. However, the team observed bees feeding carrion that used the same structures to collect bait. “They had small chicken baskets,” said Quinn McFrederick, a UCR entomologist.

By comparison, the team also collected breadless bees that feed on both meat and flowers, and some that feed only on pollen. By analyzing microbiomes of all three bytes, they found the most extreme changes among exclusive meat feeders.

The microbiome of the vulture is enriched in acid-loving bacteria, which are new bacteria that their relatives do not have, “McFrederick said.” These bacteria are similar to those found in actual vultures, as well as hyenas and other carrion that give birth to carrion, presumably to help protect them against pathogens that appear on carrion. “

One of the bacteria found in vulture bees is Lactobacillus, which is in many people’s fermented foods, such as sourdough. They were also found to house Carnobacterium, which is associated with meat digestion.

“It’s crazy for me that a bee can eat dead bodies. “We could get sick of it because of all the microbes on meat that compete with each other and release toxins that are very bad for us,” Maccaro said.

The Trigona family of stingless bees

Individual from the Trigona family of breadless bees, some of which eat meat. Credit: Ricardo Ayala

The researchers noted that these bees are unusual in a number of ways. “Although they can not sting, they are not all defenseless, and many species are completely unpleasant,” Yanega said. “They range from species that are really harmless to many who bite, to a few that produce bladder-causing secretions in their jaws, causing the skin to erupt into painful sores.”

In addition, even though they live on meat, their honey is reportedly still sweet and edible. “They store the meat in special chambers that are sealed for two weeks before they have access to it, and these chambers are separated from where the honey is stored,” Maccaro said.

The research team plans to dive further into microbiomes of vultures in hopes of learning about the genomes of all bacteria as well as fungi and viruses in their bodies.

Ultimately, they hope to learn more about the greater role that microbes play in the overall health of bees.

“The strange thing about the world is where a lot of interesting discoveries can be found,” McFrederick said. “There is a lot of insight there into the results of natural selection.”

Reference: “Why did the bee eat the chicken? Symbiont Gain, Loss, and Retention in the Vulture Bee Microbiome” by Laura L. Figueroa, Jessica J. Maccaro, Erin Krichilsky, Douglas Yanega and Quinn S. McFrederick, November 23, 2021, mBio.
DOI: 10.1128 / mBio.02317-21

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