It may be hard for people in the U.S. to imagine, but just like the bunnies that nibble at beans and carrots, elephants in parts of Africa are huge garden pests, trampling crops and nomming up the vegetables. Many conflicts—and elephant deaths—happen after they raid the precious crops of villagers. In recent years, however, conservationists have noticed something about elephants—they really, really don’t like bees. Now, reports Kimberly Hickok at LiveScience, a new study suggests that the elephants react to a pheromone produced by the bees, one that can be synthesized in the lab and used as an effective pachyderm repellent.
Villagers and conservationists have studied the elephant/honeybee rivalry for a few years now. Karen Weintraub at The New York Times reports that the elephants aren’t scared off by one or two bees, especially since the bees' stingers can’t penetrate their thick hides. But when the bees swarm, they can do some damage to sensitive spots like the eyes, mouth and trunk. That's why the massive animals tend to shy away from active beehives.
Over the past few years, researchers have tested whether bees can serve as an elephant deterrent, constructing bee fences around crops. So far, farmers in 11 countries in Africa and Asia have participated, putting up beehives about every 65 feet around their crops. Not only do the bees keep the elephants away, the theory goes, but the farmers get honey from the hives twice a year. Kimbra Cutlip at Smithsonian Insider, reports, however, that the technique is not fool-proof, and that the activity at the hives needs to be at a certain level before elephants take notice. Besides that, the hives are an added expense and take time and labor to maintain, meaning farmers may not be able to afford the hives or their upkeep.
A better solution might be creating an elephant repellant based on bees. That’s why, according to a press release, researchers experimented with bee pheromones at South Africa’s Greater Kruger National Park. Researchers treated white socks weighted with rocks with a slow-release blend of pheromones that African honeybees produce when they are alerted to danger, then hung them around the Jejane watering hole in the park. They observed that 25 of the 29 African bush elephants—Loxodonta africana—that approached the hole and got a whiff of the pheromones left the area. The elephants did not flee the socks that weren't treated with eau de honeybee, in some cases even picking them up and trying to taste them. The results appear in the journal Current Biology.
“Our results complement previous studies that have demonstrated that active bee hives can deter elephants from crops,” says lead author Mark G. Wright of the University of Hawaii at Mānoa. “We hope to expand this work to develop additional tools for sustainable passive management of elephant movements, to augment the current approaches used.”
While this is the first time that pheromones have been used to keep large mammals away from plants, using pheromones to keep insects away from crops is a popular idea. Damian Carrington at The Guardian reports that synthetic pheromones are currently used to protect berry and tomato crops by attracting pests into traps and away from the valuable fruit. But synthesizing those chemicals is expensive. That’s why researchers are using genetically modified plants to bioengineer the pheromones. In the future, Carrington reports, plants producing the insect-attracting pheromones could be planted next to crops to protect them. For instance, pheromone-producing tobacco could draw citrus mealybugs away from orange groves. This would keep females from finding mates, disrupting their life cycle and population without the use of pesticides.
Who knows, maybe one day farmers in Africa will be surrounding their crops with tobacco plants that give elephants a whiff of angry bees.