Biological control of invasive species is notoriously fraught with risk: It’s hard to know in advance if the biocontrol agent will stay nice and well-behaved, or become an even worse menace than the species you’re trying to eradicate. A researcher in Florida thinks he’s figured out how to get around that problem, by turning the invasive species into its own biocontrol agent using “Trojan” animals. By exposing males of many fish and amphibians to female hormones, scientists can create female animals with male chromosomes. When they mate with normal males, their offspring will be exclusively male, and over time, the population will become extinct. This isn’t the first time the idea of manipulating sex ratios has been discussed, but it’s the first time someone’s thought of a way to do it without genetic engineering.
Source: Louis Buckley, Sex change wipes out invasive species. News @ Nature.com, July 26, 2007. Photo: The invasive cane toad, introduced in Australia to control cane beetles, is an example of biological control gone wrong.
