Death by cat food

Introducing the cane toad:  a very bad decision

Since their introduction into the Australian landscape many decades ago, cane toads have devastated local flora and fauna. The idea was that they would eat the cane beetle, which threatened sugar cane crops. As it turned out, the thousands of introduced toads had little effect on the cane beetle, but they killed or ate just about everything else they came near.

Naturally, ever since then, Australians have tried to find ways to rid themselves of these self-introduced pests, which kill pets, swarm over the landscape in such numbers they look like a moving, toady carpet, and outcompete many Australian natives for food–or, they just eat them.

Cat food lures meat-eating ants

Recent news from Australia was that cane toad hunters might no longer be able to humanely dispatch the amphibians using carbon dioxide gas. Instead, the advice was going to be that bashing them over the head with a single, toad-dispatching blow would be the best way to control them. Now, some Australians have discovered another way to end a toad’s life: Death by meat-eating ant.

Evidently, the ant does not find the toad naturally attractive, but a spoon of cat food near areas where baby toads emerge from ponds brings the ants by the horde. The horde then finds a lot of tasty toads to eat, and…they eat them. Sounds painful, but evidently, it’s pretty effective, and no human has to bash a toad on the head.

The Australian researcher who made the cat food breakthrough is Rick Shine, a noted herpetologist whose recent research on behalf of native herps turned up this low-tech solution to the problem.

Ideas for thinkin’

Introducing the cane toads ended disastrously for Australia. Find other examples of introduced species. Why is it that populations of introduced species seem so easily able to explode in number? Think about concepts of co-evolution and species interactions.

In Austin, Tex., an invasive plant species, Hydrilla, has choked lakes and water treatment plants. Authorities are trying to control Hydrilla by introducing triploid Asian grass carp, another non-native species. What are the grass carp expected to achieve? Why? Why are they triploid? Can you think of benefits of this second introduction? What are some potential drawbacks, and what might be the first sign that they’re in progress? And where did that Hydrilla come from, anyway?

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