EPOW - Ecology Picture of the Week

Each week a different image of our fascinating environment is featured, along with a brief explanation written by a professional ecologist.

13-19 September 2021

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Do Not Eat This Strawberry!

Strawberry Poison-dart Frog (Oophaga [Dendrobates] pumilio), Family Dendrobatidae
La Selva, Costa Rica

Credit & Copyright: Dr. Bruce G. Marcot

Explanation:  Looks tasty, and has a tasty name with "strawberry" in it!  But NO!  Do not eat!

This is a Strawberry Poison-dart Frog.  Its bright coloration is a fine example of what is called aposematic coloration, or, more simply, warning coloration ... warning potential predators that this is a very highly toxic morsel, in fact, the most toxic species member of its genus.

Consuming this generator of alkoid toxins can cause paralysis, convulsions, and death.  

I discovered this beauty in the understory of the dense tropical rainforests of La Selva Biological Station and Reserve in the Caribbean side of Costa Rica.  



The general idea is that a highly aposematic organism -- one that is toxic and displays bright coloration or other warning signals -- might be "taste-tested" by some predator who then fails to consume it, so that the prey escapes to live another day ... while the predator has learned the lesson to not attack it, or its kind, again.  A further idea is that predators have evolved the sensibility -- through much trial and error -- to not even attack aposematic prey at all.  

An interesting study (Hegna et al. 2013) used models of the strawberry poison-dart frog, painted different colors, with and without spots, and with other warning patterns, to test predation rates.  They found that the color of the frog greatly affected whether it would be attacked or not.  The red-colored frogs -- as in these photos -- were attacked least frequently, serving as the best warning.  

But now you have been warned.  Taste not. 


  
Information:
     Hegna, R.H., R.A. Saporito, and M.A. Donnelly.  2013.  Not all colors are equal: predation and color polytypism in the aposematic poison frog Oophaga pumilio. Evolutionary Ecology 27:831-845.
     Saporito, R.A., R. Zuercher, M. Roberts, K.G. Gerow, and M.A. Donnelly.  2007.  Experimental evidence for aposematism in the Dendrobatid poison frog Oophaga pumilio.  Copeia 4:1006-1011.

For more on poison frogs:  
     https://nationalzoo.si.edu/animals/poison-frogs
     Saporito, R.A., M.A. Donnelly, T.F. Spande, and H.M. Garraffo.  2011.  A review of chemical ecology in poison frogs.  Chemoecology 22:159-168.  

      

  

Next week's picture:  Maasai in the Crater

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