Saturday, April 9, 2011
Invasive Herps & Brain Size
They found brain size relative to body size was, in fact, larger in species of amphibians and reptiles reported to be successful invaders, compared to species that failed to thrive after translocation to new sites.
This was the same evolutionary trend previously found in birds and mammals suggesting that larger brain size enhances the ability to deal with novel environmental challenges in all major clades of terrestrial vertebrates. Interestingly, this pattern was present in all biogeographic regions, except Australasia. Introduced amphibians and reptiles with smaller (rather than larger) brains were more successful at establishing populations in Australasia. This may result from environmental factors selecting against larger brain size where a lack of resources exacerbates the energetic costs of maintaining such an energy expensive organ. The authors prpose that low resource availability in Australasia may favour small brain size and other traits that reduce an animal's total energy requirements. They note evolutionary trends towards reduced fecundity levels in rodents and in birds that have invaded Australia over longer time periods reinforce this hypothesis.
Amiel JJ, Tingley R, Shine R (2011) Smart Moves: Effects of Relative Brain Size on Establishment Success of Invasive Amphibians and Reptiles. PLoS ONE 6(4): e18277. doi:10.1371/journal.pone.0018277