Mattias Hagman

ScienceShot: Cane Toad Carnage

The biggest danger for a cane toad (Rhinella marina) egg isn't a predator of a different species; it's a cane toad tadpole. The tadpoles not only seek out and eat eggs, they also release chemicals into the water that stunt the growth of developing cane toad embryos, new research reveals. It's all part of an intense competition for resources. To study this phenomenon, scientists kept cane toad eggs with tadpoles in tanks and separated them with a mesh divider. When the eggs hatched, the new tadpoles were 11% shorter and 45% lighter than their siblings that developed in eggs that were kept alone. Additionally, the survival rate of the tadpole-exposed eggs was 40% lower, the team reports today in Biology Letters. The researchers haven't isolated the chemical responsible for dwarfing and killing the cane toads, but that's their next step. Such a compound could help control populations of cane toads in Australia, where they are considered an invasive species and threaten the diversity of native reptiles.

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