Monarch butterflies can cure themselves and their offspring of disease by using medicinal plants, according to a new paper in the journal Ecology Letters.

Analysis by Jennifer Viegas
Fri Oct 8,

The disease is caused by a protozoan parasite called Ophryocystis elektroscirrha. The parasite invades the gut of the caterpillars and then persists when the caterpillars become adult monarchs.
Project leader Jaap de Roode in eScience Commons today said, “We have shown that some species of milkweed, the larva’s
food plants, can reduce parasite infection in the monarchs. 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.”
(Images: Jaap de Roode and Lisa Sharling)
Monarch caterpillar

Adult monarch butterfly

De Roode, assistant professor of biology at Emory University, said,
"“We believe that our experiments provide the best evidence to date
that animals use medication."
Jaap de Roode, who discusses his latest findings in this video


At
Discovery News, we've touched on the topic before for other species.
Spider monkeys, for example, are thought to have discovered a medicated body scratcher. But there are relatively few such studies on self-medication by animals.
(A sick monarch butterfly dying from the parasite)


In
this case, there's added interest because the behavior is enacted by a
creature that, despite its beauty, is fairly low on the food chain.
Plus, the behavior is trans-generational, says Thierry Lefevre, a
post-doctoral fellow in de Roode’s lab. “While the mother is expressing
the behavior, only her offspring benefit.”
Health-related decisions made by non-human species could also
potentially benefit us in future. For example, researchers like chemical
ecologist Mark Hunter have been studying milkweed plants to determine
their medicinal properties.
WATCH VIDEO: Monarch Butterflies Tagged For Trip South These butterflies can migrate 3,000 miles each year.