Many kinds of snails are invading ecosystems all over the world, but the apple snail (Pomacea canaliculata) has a unique advantage: Almost no predators will eat its eggs. That's because the bright pink objects (pictured) are filled with a neurotoxin that scares off every predator except for red fire ants. Now, researchers have discovered that the neurotoxin, called PcPV2, is unusual for animals. First, it's a so-called AB toxin, which is used by plants and bacteria. And second, the apple snail creates it in an unprecedented way, combining a pair of molecules that resemble those belonging to the immune system of other animals. As for the embryonic snails, cocooned in a toxic egg, they are equipped with enzymes that can degrade the neurotoxin and use it for nutrition during development, researchers reported last week in PLOS ONE. No one knows how the ants survive.
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