Since being introduced to Australia to combat sugar cane crop destruction caused by the Frenchi cane beetle, the cane toad (Bufo marinus) has wreaked havoc on both native organisms and Australian ecosystems as a whole. Cane toads pose a particularly severe ecological threat due to their virtually limitless diets and poisonous qualities; they readily consume nearly anything in sight and release toxins that can eliminate most of their predators. However, previous research has shown that one of its predators, the meat ant (Iridomyrmex purpureius), can consume cane toads without being afflicted by its toxins.
In the past, researchers have implemented various methods in an effort to control cane toad populations, including certain forms of biocontrol. Unfortunately, their efforts have generally been met with limited success.
However, recent research has been revealed that may help lead to the development of a more effective method of preventing cane toad invasion. Scientists have discovered that cane toads primarily rely on their sense of smell when seeking out prey. This information may be a key component in a novel, innovative control method that utilizes certain odors to which both the cane toad and its predators are attracted.
Duke undergraduate Chris Rzeznik and his team are attempting to further develop this approach in an experiment that exploits both the cane toad’s vulnerability to meat ant consumption and its attraction to the scent of cat food. Building on the knowledge that both cane toads and meat ants have proven to be attracted to cat food, Rzeznik and his team have devised a procedure to lure both species together using their shared food preferences.
The researchers aim to assess how the cane toad’s sense of smell can be used to control its spread by identifying the foods to which both cane toad. To accomplish this, they will replicate the Australian environment in six simulated habitats, four of which will contain cane toads and two of which will contain meat ants. One will contain both species in order to examine the extent to which the ants will prey on the toads when adequately exposed to them. The corners of each habitat will emit the scent of cat food, and the researchers will record activity at each corner for one week to determine the level of attraction that both species exhibit to the odor.
The researchers speculate that if they are successful in using shared food preferences to lure these species together, they can deduce that small rodents and insects will be the most reliable bait in doing so in future studies. If their experiment ultimately produces no conclusive outcome, the researchers plan to retry it with modifications of certain variables, such as the use of insects like the lavender beetle (Cydnidae) as bait instead of cat food.
Although their study may have various motives, the researchers’ main concern is the welfare of the Australian environment. According to Rzeznik, “the overarching effect our team hopes to have is that by stopping the cane toad invasion, we will restore the uniqueness of Australia’s wildlife and rid this country of a pest that has caused problems for decades.”