Mention foraging bees and most of the people will image bugs flitting from flower to flower in quest of nectar. But within the jungles of Central and South America, “vulture bees” have developed a style for decaying flesh.
They are “the weirdos of the bee world,” says insect biologist Jessica Maccaro of the University of California, Riverside. Most bees are vegetarian.
Scientists have puzzled over why the stingless buzzers appear to desire rotting carcasses to nectar (SN: 2/11/04). Now, Maccaro and colleagues suppose they’ve cracked the riddle by wanting into the bees’ guts.
Vulture bees (Trigona spp.) have much more acid-producing intestine micro organism than their vegetarian counterparts do, Maccaro and colleagues report November 23 in mBio. And these micro organism are the identical sorts that shield carrion feeders equivalent to vultures and hyenas from getting sick on rotting meat.
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To probe the bees’ insides, Maccaro’s colleagues trekked right into a Costa Rican jungle. Since vulture bees feed on virtually any lifeless animal, together with lizards and snakes, the researchers minimize up store-bought rooster and suspended the uncooked flesh from tree branches. To deter ants, the staff smeared petroleum jelly on the string that the meat dangled from.
“The funny thing is we’re all vegetarians,” says entomologist Quinn McFrederick, additionally of UC Riverside. “It was kind of gross for us to cut up the chicken.” That gross issue rapidly intensified within the heat, humid jungle: The meat rotted, turning slimy and smelly.
Bees took the bait inside a day. As the scavengers stopped by to dine, the researchers trapped about 30 bees. The staff additionally captured one other 30 or so of two different sorts of native bees — one which feeds on solely flowers and one kind that dines on each flowers and rotting meat. All bees had been saved in alcohol-filled vials to protect the bugs’ DNA for evaluation, in addition to the DNA of any intestine microbes.
Strictly meat-eating bees had between 30 % and 35 % extra acid-producing intestine micro organism than strictly vegetarian bees and those that typically eat meat, the staff discovered. Some sorts of these microbes confirmed up solely within the solely carnivorous bees.
Similar acid-producing micro organism within the guts of vultures and hyenas preserve toxin-producing microbes in rotting meat from making the animals sick. The microbes most likely do the identical for the meat-eating bees, the staff says.
The well being profit extends past particular person bees, says David Roubik, an evolutionary ecologist on the Smithsonian Tropical Research Institute in Balboa, Panama, who was not concerned within the work. Vulture bees regurgitate a number of the meat they eat, storing it of their nests the place it serves as meals for younger bees. Some of the acid-loving intestine micro organism find yourself on this meals reserve, Roubik says. “Otherwise, destructive bacteria would ruin the food and release enough toxins to kill the colony.”
In the tip, Maccaro says, it’s exhausting to know which advanced first — the intestine micro organism or the bees’ capacity to eat meat. But the bees most likely first turned to meat as a result of there was a lot competitors for nectar for meals, she suspects.
