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Climate change may alter amphibian evolution

Date:
October 25, 2012
Source:
Smithsonian Tropical Research Institute
Summary:
Most of the more than 6,000 species of frogs in the world lay their eggs in water. But many tropical frogs lay their eggs out of water. This behavior protects the eggs from aquatic predators, such as fish and tadpoles, but also increases their risk of drying out. A researcher has discovered that climate change in Panama may be altering frogs' course of evolution.
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Pantless tree frog embryos within the eggs on a leaf surface. The embryos die within a day if there is no rain to moisten the egg mass.
Credit: Justin Touchon, Smithsonian

Most of the more than 6,000 species of frogs in the world lay their eggs in water. But many tropical frogs lay their eggs out of water. This behavior protects the eggs from aquatic predators, such as fish and tadpoles, but also increases their risk of drying out. Justin Touchon, post-doctoral fellow at the Smithsonian Tropical Research Institute, discovered that climate change in Panama may be altering frogs' course of evolution.

By analyzing long-term rainfall data collected by the Panama Canal Authority, Touchon discovered that rainfall patterns are changing just as climate-change models predict.

"Over the past four decades, rainfall has become more sporadic during the wet season," said Touchon. "The number of rainy days decreased, and the number of gaps between storms increased."

The eggs of the pantless treefrog, Dendropsophus ebraccatus, are extremely susceptible to drying. The embryos die within a day when there is no rain. Heavy rains trigger breeding, so as storms become sporadic, the chance of rain within a day of being laid decrease and so does egg survival.

As weather patterns have changed, the advantage of laying eggs out of water has decreased, not only for pantless treefrogs but potentially for many species. "Pantless treefrogs can switch between laying eggs in water or on leaves, so they may weather the changes we are seeing in rainfall better than other species that have lost the ability to lay eggs in water," said Touchon. "Being flexible in where they put their eggs gives them more options and allows them to make decisions in a given habitat that will increase the survival of their offspring."


Story Source:

The above post is reprinted from materials provided by Smithsonian Tropical Research Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. Touchon J.C. A treefrog with reproductive mode plasticity reveals a changing balance of selection for non-aquatic egg-laying. The American Naturalist, 2012; DOI: 10.5061/dryad.8j1hb

Cite This Page:

Smithsonian Tropical Research Institute. "Climate change may alter amphibian evolution." ScienceDaily. ScienceDaily, 25 October 2012. <www.sciencedaily.com/releases/2012/10/121025095539.htm>.
Smithsonian Tropical Research Institute. (2012, October 25). Climate change may alter amphibian evolution. ScienceDaily. Retrieved August 1, 2015 from www.sciencedaily.com/releases/2012/10/121025095539.htm
Smithsonian Tropical Research Institute. "Climate change may alter amphibian evolution." ScienceDaily. www.sciencedaily.com/releases/2012/10/121025095539.htm (accessed August 1, 2015).

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