Emory University Oct. 11, 2010, press release:
Monarch butterflies appear to use medicinal plants to treat their offspring for disease, research by biologists at Emory University shows. Their findings were published online Oct. 6 in the journal Ecology Letters.
“We have shown that some species of milkweed, the larva’s food plants, can reduce parasite infection in the monarchs,” says Jaap de Roode, the evolutionary biologist who led the study. “And we have also found that infected female butterflies prefer to lay their eggs on plants that will make their offspring less sick, suggesting that monarchs have evolved the ability to medicate their offspring.” (See interview with de Roode at http://tinyurl.com/3995m3u)
Few studies have been done on self-medication by animals, but some scientists have theorized that the practice may be more widespread than we realize. “We believe that our experiments provide the best evidence to date that animals use medication,” de Roode says.
Read more here.