Brightly coloured beetles nibbling on a plant may signal the presence of chemical compounds active against cancer cell lines and tropical parasitic diseases, researchers at Smithsonian's Tropical Research Institute in Panama have revealed.
For the study, scientists used plants already known to have anti-cancer compounds; those proven to be active against certain disease-carrying parasites; and plants without such activity.
The study showed that beetles and butterfly larvae with bright warning coloration were significantly more common on plants that contained compounds active against certain diseases, such as breast cancer and malaria.
There was no significant difference in the number of plain-colored insects between plants with and without activity.
"These findings are incredibly exciting and important," said Todd Capson, STRI research chemist, who directed the project.
"The results of this study could have direct and positive impacts on the future of medical treatment for many diseases around the world," he added.
"We put two and two together," said researcher Julie Helson. "We knew that brightly colored insects advertise to their predators that they taste bad and that some get their toxins from their host plants.
"But because other insects cheat by mimicking the toxic ones, we weren't sure if insect color was really going to work to identify plants containing toxins-it did!" Helson was a student at McGill University when she conducted this research in 2005.
The study suggests that a quick screen for insects with warning coloration on tropical plants may increase the efficiency of the search for compounds active against cancer and tropical parasitic disease by four-fold.
The report is published in the Ecological Society of America's journal Frontiers in Ecology and the Environment.