we were surprised to discover that medicinal milkweeds could change the morphology of monarch parasites
June 29, 2017
The Journal of Parasitology – Parasites are some of the most common and diverse organisms in the world. Studying the relationship parasites have with their hosts gives insight into their effects on wildlife, domestic animals, agriculture and humans. By observing parasites through their life stages, researchers are able to identify how they use their morphological changes to their advantage. This understanding may assist in reducing the effects parasites have on their hosts.
Researchers from Emory University in Atlanta, Georgia, recently published a study in The Journal of Parasitology in which they took an innovative approach to studying host–parasite interactions. Realizing that many species will use a medicinal approach to combat parasite infiltration, they observed how the monarch butterfly utilizes toxins in milkweed plants as a form of resistance to parasites. By focusing on the spore stage of the parasite life cycle, the researchers were able to track the effects of the milkweed on the morphology of the parasite.
Forty-one monarch butterflies and three different types of milkweed plants were used in the experiment. The researchers measured the concentration of cardenolide (a type of steroid) in each plant type. During the butterfly larvae stage, parasite spores were introduced into the butterfly’s development. The goal was to study the effect that the host’s diet had on the morphology of the parasite.
The researchers found that higher concentrations of cardenolide reduced parasite spore sizes, which left them more unprotected against their host’s defences. For the host,…