Saturday, April 07, 2007

You are what you eat


I was at the National Zoo in DC yesterday. I haven't been to a zoo in probably 15 years, but it's nice to know that 2.5 science degrees later, I can still learn a thing or two from such an outing. In this instance, I discovered that the beautiful but deadly 'poison dart frogs' are not naturally toxic. Raised in captivity, these amphibians are harmless. The reason for their toxicity is the accumulation of alkaloid compounds from ants and other arthropods that they consume. This is true of frogs from Madagascar as well as those from Australia or South America. Geographically isolated, the ants that are the source of the toxin for frogs from these regions are not closely related, making this a cool example of convergent co-evolution of arthropod and frog species.


5 comments:

Bayman said...

I wonder why the frogs are resistant to the alkaloid accumulation? If I ate a lot of insects, could I become poisonous too?

Anonymous Coward said...
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Anonymous said...

so should i focus on collecting the ants instead of the frogs to use as muscle relaxants during surgery?
Tania

Anonymous Coward said...

I wonder what plant/insect are eaten by the frogs that people lick to get high?

kamel said...

I couldn't find any good information on the mechanism of resistance to those alkaloids, but I'll keep looking to see if I turn anything up. The impression I get is that they are stored, unmetabolized so maybe they lack a protein involved in breaking them down into toxic by-products. I also found an instance of a similar phenomenon in birds discovered at the same zoo.