A colony of vulture bees that live in the Amazon have shown the first known adaptation to the carnivorous bite of meat-eating vultures, according to a new study by researchers at the Smithsonian Tropical Research Institute.
Despite their immense size, vultures hunt like small birds — short, nimble and agile and efficient hunters who eat smaller birds, fish and mammals as well as their young. Vultures also hunt each other, especially when a colony has strayed into territory occupied by rival vultures.
The bee vultures may be the first known vulture species to have a symbiotic relationship with its vulture nemesis — one that pits a carnivorous vulture against a food-lovers vulture whose immune system allows it to survive.
During this kind of vulture war, bees vultures, or combates, fly to the food table, where they dine on the carcass of the slain predator. Then, if there are still carcasses, they send another insect into the fray, also hoping to quickly stave off death by disease or direct slaughter by a rival.
But in the case of the fight against vultures, this process also provides a protective barrier from the vultures, which might carry parasites that are more deadly than their traditional meat menu. Also, bacteria from the corpse might kill the bees and turn them into gas.
“Vultures are high on the list of threats to honeybees,” said Savanna Peiris, a vulture researcher at the Smithsonian’s Tropical Research Institute. Vultures eat honeybees, so anything that can protect them is good for the bee vulture.
By showing an ability to rapidly expel bacteria from the honeybee gut to the mosquito’s faeces, the bee vulture has been able to offer bacteria in the food over and over again. The vulture bees are able to get over resistance to the new bacteria by reverting back to feeding on the original food source: antibiotics.
Once you overcome the bacteria, the bees can easily harvest the bacteria from the original food source, a process called sensory cannibalism. “This seems to be something that bees and vultures have picked up over their evolutionary history,” Peiris said.
Peiris and Charles Moore, a honeybee conservationist at the Beekeepers Research Center, observed the bees eat more bacteria during the time of the climactic change that dramatically increased bee populations over the last two millennia. During the period, bees were carrying out a kind of collection of ecological defense tactics.
“They’re scavenging food from carcasses and using their own body as a reservoir,” Peiris said. “That adds back into food production on a day-to-day basis.”
The evidence suggests that the bee vulture can recognize where it has sampled bacteria and then use its immune system to flush it out, like in the case of a Vaxocup or a cold. “That’s basically the insect-lung route,” Peiris said.
The bee vulture and its vulture nemesis are examples of symbiotic relationships where the bacteria one needs can be easily replaced.
“Although bees and vultures can combine to defend themselves from deadly diseases,” Peiris said, “they’re on different paths to recovery.”
The research paper, written by Peiris, Moore and Steven Altemeyer from the Smithsonian, was published recently in the journal Oryxia.