Invasive Biology: The Cane Toad

1. Invasive Biology: The Cane Toad

2. In many cases, a foreign species which was introduced to reduce or eliminate a pest becomes a pest itself. As in the case of Cane toad (Bufo marinus), reckless introduction has had a negative impact on native fauna. • The cane toad has changed many of the native environments through different mechanisms such as interspecific competition, consuming resources or by reducing the numbers of native predators due to its high toxicity (Smith, 2005). • Australia has been impacted the most by the invasion of the cane toad, which was introduced to Queensland in 1935, as away to eliminate agricultural pests (Phillips et al, 2006).

3. The Cane Toad • Scientific name: Bufo marinus • Also known as Bufo toad or Giant toad • Native to Central and South America • Introduced to approximately 40 countries • However, introduction to the U.S. was accidental

4. Toads Worldwide

5. The Cane Toad • Can weight up to 5.8 lbs • Adults can reach length of up to 15 inches • Females breed once a year, laying up to 30 thousand eggs • Eggs and tadpoles are toxic • Juvenile and adults have toxic skin • Toxins originate from the parotid glands, located posterior to the eyes • Amount of toxicity typically varies with size

6. The Cane Toad • The surface of the skin is dry and warty • They can vary in coloration from grey, brown, red and olive • Most active at night

7. Cane Beetle • The Cane Toad was introduced to control sugar cane pests, such as the cane beetle

8. Toxicity • Bufotenin is a chemical excreted by the Cane Toad • Can cause mild hallucinations • Lasts for less than an hour • Classified as a Class 1 drug in Australia • The practice of toad licking can lead to illness or death

9. Toad Licking • Please DO NOT try this at home!

10. Impact on the Ecosystem • Devastate the natural ecosystem • Voracious appetites • Can consume up to 200 invertebrates in a single meal • It can also devour small mammals • Remove more prey items form the ecosystem than native frog species • Compete with native species

11. Impact on the Ecosystem • Kill native species • Toxins present on skin kill native predators • Toxic tadpoles kill aquatic predators

12. Invasion • They were introduced to Queensland, Australia in 1935 • Now they cover over 1 million square kilometers

13. Australia

14. Effects on Native Species • Some animals have adapted to the presence of the Cane Toad • Australian snakes • Morphological Change • Birds • Hunting strategies

15. Beware! • Toxins produced by Cane Toads can be fatal to pets

16. Solutions • There is no ONE specific method of controlling the Cane Toad invasion • Studies have shown that Cane Toads prefer open space • Therefore, adding barriers can effectively slow down distribution • Some people kill toads on site or…..

17. Make them into wallets and key chains

18. The End

19. Bibliography • Brown G.P., Phillips B.L., Webb J.K, Shine R. (2006) Toad on the road: Use of roads as dispersal corridors by cane toads (Bufo marinus) at an invasion front in tropical Australia. Biological Conservation 1 3 3: 8 8 –9 4. • Greenlees M.J., Brown G.P., Webb J.K., Phillips B.L., Shine R. (2007) Do invasive cane toads (Chaunus marinus) compete with Australian frogs (Cyclorana australis)? Austral Ecology32: 900–907. • Phillips B.L., Brown G.P., Webb J.K., Shine R. (2006) Invasion and the evolution of speed in toads. Nature 439: 803. • Phillips B.L., Shine R. (2006) Adapting to an invasive species: Toxic can toads induce morphological change in Australian snakes. PNAS 101: 17150-17155. • Phillips B.L., Shine R. (2006) Spatial and temporal variation in the morphology (and thus, predicted impact) of an invasive species in Australia. Ecography 29: 205-212. • Smith K.G. (2005) Effects of nonindigenous tadpoles on native tadpoles in Florida: evidence of competition. Biological Conservation 123: 433-441.