Not All Bees Are Vegetarians: Some Eat Meat

For years we've been taught that wasps are carnivores while bees (which evolved from wasps), are vegetarians.

Don't bees forage only for pollen and nectar (as well as water and propolis)?

Not always so.

Some bees are meat-eaters or "bee vultures," says evolutionary biologist Quinn McFrederick of UC Riverside.

You'll want to hear McFrederick speak on "The Weird World of Pathogens, Microbes, and Meat-Eating Bees" at his Jan. 18 seminar hosted by the UC Davis Department of Entomology and Nematology.

The seminar will take place at 4:10 p.m., in 122 Briggs Hall and also will be virtual. The Zoom link:

"Flowers are more than just a source of food for bees; they can also act as hubs of microbial transmission," McFrederick, an assistant professor, says in his abstract. "Some pathogenic microbes can spillover from social bees into solitary species and move through plant-pollinator networks, while others have more restricted host ranges. We use a combination of fieldwork, laboratory assays, molecular ecology, and genomics to understand the evolution and ecology of these microbes. In this talk I will discuss how plant-pollinator networks can help us understand relationships between bee hosts and pathogens and other microbes."

"I will then explore the evolution of pathogenicity in the fungal genus Ascosphaera. While Ascosphaera is best known as the causative agent of chalkbrood disease, the genus is ancestrally commensal and pathogenicity has evolved independently several times. I will finish by discussing the microbiomes of bees that have reverted to a carnivorous lifestyle, the so-called bee vulture. Our ultimate goal is to leverage these symbionts to improve bee health, and we are just beginning to understand many of these weird and wonderful relationships."

McKendrick studies studies symbionts (pathogens, commensals, and mutualists) of wild and solitary bees, with the goal of leveraging these symbionts to protect bee populations and communities. His research includes a stingless species of bee in Costa Rica. He and fellow researchers "set up baits — fresh pieces of raw chicken suspended from branches and smeared with petroleum jelly to deter ants," according to a UC Riverside news story. published Nov. 23, 2021.

"The baits successfully attracted vulture bees and related species that opportunistically feed on meat for their protein," wrote Jules Bernstein. "Normally, stingless bees have baskets on their hind legs for collecting pollen. However, the team observed carrion-feeding bees using those same structures to collect the bait." McFrederick called them "little chicken baskets."

“The vulture bee microbiome is enriched in acid-loving bacteria, which are novel bacteria that their relatives don't have,” McFrederick related. “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 article noted that "One of the bacteria present in vulture bees is Lactobacillus, which is in a lot of humans' fermented food, like sourdough. They were also found to harbor Carnobacterium, which is associated with flesh digestion."

McFrederick and his colleagues published their research, "Why Did the Bee Eat the Chicken? Symbiont Gain, Loss, and Retention in the Vulture Bee Microbiome?" in the Nov. 21, 2021 edition of the American Society for Microbiology.

 "Diet and gut microbiomes are intricately linked on both short and long timescales," they wrote in their abstract. "Changes in diet can alter the microbiome, while microbes in turn allow hosts to access novel diets. Bees are wasps that switched to a vegetarian lifestyle, and the vast majority of bees feed on pollen and nectar. Some stingless ;bee species, however, also collect carrion, and a few have fully reverted to a necrophagous lifestyle, relying on carrion for protein and forgoing flower visitation altogether. These vulture bees belong to the corbiculate apid clade, which is known for its ancient association with a small group of core microbiome phylotypes. Here, we investigate the vulture bee microbiome, along with closely related facultatively necrophagous and obligately pollinivorous species, to understand how these diets interact with microbiome structure."

McFrederick holds a bachelor's degree in integrative biology (1992) from UC Berkeley, and a master's degree in conservation biology (2004) from San Francisco State University, where he studied with advisor Gretchen LeBuhn. He went on to receive his doctorate in biology in 2010 from the University of Virginia, where he was advised by Douglas Taylor.

Among his awards:

  • 2017: Hellman Fellowship
  • 2016: Outstanding Faculty Award from the UCR Entomology Graduate Student Association.
  • 2010: Award for Excellence in Scholarship in the Sciences from the Vice-President for Research, University of Virginia.  The award recognizes “excellence in original scholarship by Ph.D. students at the University” 
  • 2010: Graduate Teaching Assistant Award from the Department of Biology, University of Virginia 

The UC Davis Department of Entomology seminars, coordinated by urban landscape entomologist Emily Meineke, assistant professor, are held on Wednesdays through March 15. (See schedule.) Eight of the 10 will be in-person in 122 Briggs Hall,  and all will be virtual.

For further information on the seminars or technical difficulties with Zoom, contact Meineke