The mite-produced compounds included representatives of nearly half of the 24 major chemical classes of alkaloids known from poison frogs, Saporito said.
"It is surprising that mites—rather than ants—were found to be the major source of alkaloids," commented Christopher Raxworthy of the American Museum of Natural History in New York.
"The source of many alkaloids in poison frogs have [still] not been identified," Raxworthy added. "Mites were one of the major arthropod groups requiring detailed investigation."
Alkaloids, which include caffeine and nicotine, are a highly diverse group of chemicals with many unusual properties.
Some simply taste bitter, while others are highly toxic. Many experts believe the compounds may be sources of powerful new drugs.
In addition to the alkaloids present in the poison frogs, Saporito's analysis turned up 40 previously unknown alkaloids unique to the mites.
"Many of these compounds show interesting biological activity and are structurally unprecedented in nature," said study co-author John Daly, of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Maryland.
Daly said that the frogs are not harmed by the toxic compounds, presumably because the alkaloids are consumed in very small amounts and become concentrated in the frogs' bodies over time.
"The frogs don't chemically transform [the alkaloids] at all, they just store them in their skin glands and then secrete them," Daly said.
The next big question to answer, FIU's Saporito said, is how the poison frogs accomplish this trick.
"Virtually nothing is known about how the frogs actually take the alkaloids from a dietary source and store them in their glands."
Saporito's research was funded in part by the National Geographic Society's Committee for Research and Exploration. (National Geographic News is part of the National Geographic Society.)
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