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The relationship between the tropical acacia plant and 'guard' ants that defend it from predators has long been a fascinating example of symbiosis in nature: the ants feed on the acacia's sugary nectar, and in turn aggressively sting and bite other animals that would eat and damage the plant. But it turns out that this arrangement might not be as friendly as previously thought. New research reveals that the acacia plant actually produces a chemical that drives the ants into a defensive frenzy--alternately persuading them to fight to protect it and banishing them from its flowers when convenient.The BBC spoke with Dr. Nigel Raine about his findings on the subject, and he explained how the ants greatly assist the acacias. "They guard the plants they live on," said Dr Raine. "If other animals try to come and feed on the rich, sugary nectar, they will attack them." In Africa, one type of ant-guard, known as Crematogaster, will even attack large herbivores that attempt to eat the plant.And yes, that includes mammals vastly larger than them: "If a giraffe starts to eat the leaves of an acacia that is inhabited by ants, the ants will come out and swarm on to its face, biting and stinging," he said. "Eventually, the giraffe will get fed up and move off."Living the Good Life of an Acacia Guard AntIn return, the ants get more than just access to the rich, sugary nectar of the plant. They also get protection, and in some cases, a home customized specifically for them--the acacia provides a hollowed-out, reinforced structures for the ants to nest in. The acacia also provides the ants with a sort of easy-access VIP pass to the nectar, preventing them from making the longer trip to the flower to feed. When the temptation potentially becomes too much--like when the acacia needs to produce extra pollen to draw in pollinators--things get ugly. The acacia, as the BBC notes, resorts to 'chemical warfare'. It produces a chemical that's physically repellent to the ants, keeping them out of the flower and driving them into a frenzy. Dr Raine and his colleagues found that the plants with the closest relationships with ants - those that provided homes for their miniature guard army - produced the chemicals that were most effective at keeping the ants at bay.The chemical is thought to be in the pollen itself--and when it's carried off by the bees and hummingbirds, the ants return, no longer repelled.The acacia and its guard ants no doubt have a fascinating symbiotic relationship--but the surprising use of chemicals to govern that relationship could perhaps have even more fascinating ramifications for the study of other natural pairings. What else out there is being duped and tamed by chemicals?
To escape predators, the hagfish exudes copious quantities of a viscous slime. That's the nice bit. To feed, it enters its victim through the mouth, gills or anus, and devours it from the inside out.
Three years ago, after a young Peruvian girl bathed in a river, she began to experience an odd sensation in the her nose--like something was moving back there... And it turns out there was. After visiting with a local physician about the problem, researchers realized that the girl had inadvertently 'discovered' a rather nasty species of leech, previously unknown to biologists. According to them, the leech is a bit different from other species in that it packs a wallop of a bite with the eight "enormous teeth" that line its single jaw