Emory University biologists have found Monarch butterflies may use milkweed plants to reduce infections in their offspring. Female monarch adults infected with a parasite, choose to lay their eggs on the leaves of milkweed plants. The leaves act as both food and medicine for the offspring, as they are toxic to parasites in the larvae. Non-infected female monarchs had no preference for the types of milkweed leaves they laid their eggs on.
Researcher Jaap de Roode said, “We believe that our experiments provide the best evidence to date that animals use medication.” (Source: Sciencedaily.com) Their findings were published October 6, in the journal Ecology Letters.
They also found the mother’s behavior benefits only the offspring, and not the mother, which means the behavior is trans-generational. How the behavior, which resembles human foresight, came to be is a mystery.
The fact such behavior exists, suggests a kind of intelligence in nature that is not always conceded or understood.
Ecologist Mark Hunter who assisted with the research said, “When I walk around outside, I think of the plants I see as a great, green pharmacy. But what also strikes me is how little we actually know about what that pharmacy has to offer. Studying organisms engaged in self-medication gives us a clue as to what compounds might be worth investigating for their potential as human medicines.” (Source: Sciencedaily.com)
Dozens of milkweed species make up the caterpillar’s diet. Some of the milkweed plants contain a chemical that is harmless to caterpillars, but is toxic to their predators. Jaap de Roode wanted to investigate whether the choice of milkweed plants for egg laying was not only about acquiring the toxin to ward off predators. It appears he made an important discovery, not only for science, but potentially for human medicine. Mr. Hunter said such use of plants might indicate they have medicinal value for humans as well as insects. He has been awarded a grant to examine the chemical components of milkweed plants for potential therapeutic agents.
Monarchs are famous for their colors and annual migratory movements to Mexico from the United States. Soon they might also be known for their use of natural medicine.
Image Credit: Tulip32