Why Are Some Bees Attracted to Meat?

A small group of tropical stingless bees, nicknamed “vulture bees,” have evolved to get their protein not from pollen but from the flesh of dead animals. Three species have abandoned pollen collection entirely and feed exclusively on carrion, while several closely related species supplement their pollen diet with meat when the opportunity arises. This dietary quirk makes them a genuine oddity in the bee world, and the story of how they pull it off involves specialized gut bacteria, modified mouthparts, and a relationship with rotting flesh that would make most pollinators flee.

What Vulture Bees Are

Nearly all of the world’s roughly 20,000 bee species are herbivores. They collect pollen as their protein source, mix it with nectar, and feed it to their larvae. Vulture bees break that rule completely. These are stingless bees in the genus Trigona, found in lowland tropical forests from southern Mexico through South America. Three species have been identified as obligate necrophages, meaning carrion is their only protein source, and they do not visit flowers for pollen at all.¹ They still drink nectar for sugar, but when it comes to the protein side of their diet, they are full carnivores.

Researchers have described vulture bees slicing chunks of meat from animal carcasses on the forest floor in tropical rainforests.² The bees arrive at a carcass in large numbers, sometimes hundreds at a time, and work in coordinated groups much like other stingless bees cooperate on floral resources. They have a small extra tooth on their mandibles that helps them tear into flesh, a physical adaptation not found in their pollen-eating relatives. The meat is chewed, mixed with secretions, and carried back to the nest in the corbiculae (the pollen baskets on the hind legs that, in these species, carry something very different from pollen).

How They Find and Handle Carcasses

One of the first questions people tend to ask is how a bee even finds a dead animal in dense rainforest. Vulture bees locate carcasses largely through smell. While typical bees have finely tuned olfactory systems calibrated to detect floral volatiles, vulture bees respond strongly to the chemical compounds released by decomposing tissue. The sulfurous, amine-rich plume rising from a dead lizard, bird, or frog on the forest floor is, for them, what the scent of blooming flowers is for a honeybee.

Once a scout finds a carcass, she recruits nestmates. The bees then descend on the body and begin to work it methodically, chewing off small pieces and loading them into their leg baskets. This process can continue for days on a single carcass. Field researchers who have set out bait (usually raw chicken) in tropical forests have documented colonies dispatching steady streams of foragers to retrieve meat over extended periods. The bees also secrete substances onto the carcass as they work it. Some observations suggest these secretions help pre-digest the meat and possibly slow bacterial growth on the portions being harvested, though the exact chemistry of these secretions is still not fully mapped.

The Gut Microbiome That Makes It All Work

Eating rotting meat is a risky business. Carcasses teem with pathogenic bacteria, and an animal that regularly feeds on decomposing flesh needs some way to avoid being poisoned by its own food. Vulture bees have solved this problem partly through their gut microbiome. The bacterial communities living inside these bees are strikingly different from those found in their pollen-eating relatives.

A 2021 study compared the microbiomes of vulture bees with those of closely related species that eat only pollen, as well as species that eat both pollen and carrion. The researchers found that vulture bees harbor bacteria more commonly associated with carrion-feeding organisms, including acid-producing bacteria like Lactobacillus and carnivore-associated microbes like Carnobacterium. These bacteria are thought to help the bees break down animal protein and, critically, to outcompete or suppress the dangerous pathogens present on rotting meat.²

A follow-up metagenomics study further clarified this picture. The obligate carrion-eaters had highly specialized microbiomes with gene profiles geared toward overcoming the cellular stress and microbial competition that come with a carrion-based diet.¹ Researchers have hypothesized that these microbiomes may have evolved social phenotypes such as biofilms, essentially cooperative bacterial structures that protect the bees from opportunistic pathogens found on carcasses.¹ In other words, the bacteria living inside vulture bees may form a physical barrier against infection, not just a chemical one.

The In-Between Species

The story is not a clean binary between “meat bees” and “flower bees.” Several stingless bee species are facultative necrophages: they eat pollen most of the time but readily switch to carrion when it is available. These species represent what may be an evolutionary middle ground, and their microbiomes reflect that flexibility. Facultative necrophages carry a broader and less specialized assortment of gut bacteria, including many environmental microbes associated with multiple dietary niches.¹

This pattern makes intuitive sense. If you eat everything, your gut community needs to be versatile. If you specialize in one challenging food source like rotting flesh, your gut community becomes more narrowly adapted to handle that particular set of threats. The obligate pollen-eaters at the other end of the spectrum also have specialized microbiomes, just specialized in a completely different direction. Pollen is tough to digest in its own right, so pollen-specialist bees have their own suite of microbial allies tailored to extracting nutrients from plant material.

The existence of facultative necrophages also suggests that the transition from pollen-eating to meat-eating was probably gradual. Ancestral stingless bees may have occasionally scavenged protein from carcasses when floral resources were scarce, and over time a few lineages became more and more reliant on this alternative food, eventually dropping pollen from their diet entirely.

What Happens to the Meat Back at the Nest

Like all stingless bees, vulture bees build enclosed nests, often in tree hollows or underground cavities. Inside, they construct small pot-shaped storage cells made of cerumen, a mixture of wax and plant resin. In pollen-eating stingless bees, these pots hold pollen mixed with nectar. In vulture bees, the pots hold processed meat.

The foragers deposit chewed flesh into these pots, where it is further broken down by enzymes and microbial activity over a period of about two weeks. The result is a protein-rich, semi-liquid substance that some researchers have informally called “meat honey,” though that nickname is misleading. It is not honey in any conventional sense. True honey is made from nectar and consists almost entirely of sugars. The vulture bees’ meat product is a fermented protein paste, more analogous to the “bee bread” that pollen-eating species produce by fermenting stored pollen. This paste is what the adult bees feed to their larvae, providing the protein the developing brood needs to grow.

Vulture bees do also produce actual honey from nectar, stored in separate pots. Local communities in parts of Central and South America have long harvested honey from various stingless bee species, and vulture bee nests are sometimes included. Reports from people who have tasted vulture bee honey describe it as intensely sweet with an unusual smoky or savory undertone. Whether the meat-processing side of their lifestyle influences the flavor of their honey is an open question, but the two products are stored separately in the nest and produced from completely different raw materials.

Why Evolve to Eat Meat at All

Tropical rainforests are some of the most competitive ecosystems on Earth, and competition for floral resources among bees, butterflies, hummingbirds, and other pollinators can be fierce. One explanation for why vulture bees evolved their unusual diet is simple competitive release: by switching to a protein source that almost no other bee uses, they sidestepped the intense competition for pollen. Dead animals are a reliable, if patchily distributed, resource in any forest ecosystem, and by tapping into this niche, vulture bees gained access to a food supply with almost no competitors from their own order.

There is also a nutritional logic to the shift. Pollen is protein-rich but encased in a durable outer wall that requires significant energy and specialized enzymes to digest. Animal tissue, by contrast, is protein-dense and already partially broken down when it starts to decompose. If a bee lineage happened to develop the gut bacteria and behavioral traits needed to tolerate carrion, the reward would be a highly concentrated protein package with lower processing costs than pollen, at least once the microbial safety problem was solved.

All three obligate vulture bee species belong to the broader corbiculate bee clade, which includes honeybees and bumblebees as distant relatives. This clade is known for an ancient and stable association with a small core group of gut microbe lineages.² The vulture bees have modified that ancestral microbiome dramatically, losing some of the traditional core symbionts and gaining new ones suited to their diet. This pattern of symbiont gain and loss tells researchers that the shift to necrophagy involved co-evolution between the bees and their gut bacteria, not just a behavioral change in what the bees chose to eat.

Are These the “Bees” at Your Barbecue

If you have ever had insects buzzing around your hamburger at an outdoor cookout, you were almost certainly dealing with yellowjackets, not vulture bees. Yellowjackets are wasps, not bees, and they are widespread across North America, Europe, and other temperate regions. They are predators and scavengers that are readily attracted to protein sources like grilled meat, deli platters, and pet food. Their bold, aggressive behavior around food is a common summer nuisance.

True vulture bees, by contrast, live only in the Neotropical region, primarily in lowland rainforests from southern Mexico to Brazil. You will not encounter them at a park in the United States or Europe. They are also stingless, as their name implies, so they cannot sting you even if provoked. They can bite, and some species secrete mildly irritating chemicals when their nest is threatened, but they are far less aggressive than yellowjackets and have no interest in your sandwich. Their interest is in carrion that is already well into the decomposition process, not in freshly cooked food.

Honeybees and bumblebees, the bees most people are familiar with, are committed herbivores. A honeybee visiting your outdoor meal is almost certainly after sugary drinks or fruit, not the protein. She has no biological interest in meat and no ability to digest it. The confusion between wasps and bees around food is one of the most common insect misidentifications, and it shapes a lot of the folk belief that “bees like meat.” In temperate regions, they simply do not.

Do Vulture Bees Still Pollinate Anything

The three obligate vulture bee species have essentially dropped out of the pollination economy for protein. They do not collect pollen, so they do not transfer it between flowers the way other bees do. However, they still visit flowers to drink nectar, and in doing so they may provide some incidental pollination service, though it is likely minor compared to dedicated pollen-collecting species.

The facultative species are a different story. Because they still collect pollen alongside occasional carrion, they remain active pollinators. Their dual diet does not appear to reduce their effectiveness as pollen vectors when they are visiting flowers. In diverse tropical ecosystems, these species contribute to the pollination of numerous native plants while also playing a decomposer role that is unusual for any bee.

From an ecological perspective, vulture bees occupy a niche that overlaps more with carrion flies and beetles than with other bees. They help recycle nutrients from dead animals back into the ecosystem. In the dense, humid forests where they live, carcasses can attract vulture bees alongside the more expected cast of blowflies and dermestid beetles. The bees are simply one more decomposer in a crowded guild, albeit a surprising one given their lineage.

Open Questions in Vulture Bee Research

Despite growing interest, there is still a lot researchers do not know about these bees. The exact species boundaries within the vulture bee group remain somewhat fuzzy, with some taxonomists debating whether certain populations represent distinct species or variants of the same one. Field observations are limited because these bees live in remote tropical forests and nest in places that are hard to access and study over long periods.

The chemistry of the secretions vulture bees apply to carcasses is another gap. Researchers suspect these secretions contain antimicrobial compounds, but detailed chemical analyses have not yet been published widely. Understanding what the bees are adding to the meat before they carry it home could reveal novel antimicrobial compounds with potential applications, a possibility that has been floated but not yet explored in depth.

Perhaps the most interesting open question is how the microbiome transition happened over evolutionary time. The evidence so far shows a clear correlation between diet type and microbiome composition, with obligate necrophages, facultative necrophages, and obligate pollinivores each hosting distinct bacterial communities.¹ But whether the microbiome changes drove the dietary shift, or whether the bees started eating meat first and their microbiomes adapted afterward, is a chicken-and-egg question (or perhaps, in this case, a chicken-and-bee question) that remains unresolved. Answering it would tell us something broader about how tightly animal behavior and gut ecology are coupled during evolutionary transitions, a question that extends well beyond the world of bees.