Today we can self-medicate against common illnesses. Animals can get sick too with the sole difference that they do not have a pharmacy around the corner, or do they? Nature in itself is a medicine cabinet. Currently, more than half of the pharmaceutical drugs are derived from natural products. How do animals know which medicine to use and when?
These are the type of questions that Kristel Sánchez is trying to answer. She is a member of Prof. Meghan Duffy laboratory at the University of Michigan. Sánchez comes from Ecuador and completed her bachelors in biology at Florida International University, USA, where she fell in love with chemical ecology. She is currently a second year in the ecology doctoral program at the University of Michigan. Here she studies self-medication in aquatic organisms.
Scientists have observed self-medication in terrestrial organisms. Baboons ingest certain plants to prevent stomach problems. Monarch butterflies feed themselves with toxic milkweeds to protect their offspring. These are only some of the many examples of terrestrial animals. However, In aquatic organisms, self-medication is an under-studied field.
The aquatic animal Sanchez studies is know as Daphnia (Figure 1). When I first saw them,my reaction was "They look like sea monkeys!" to which Sánchez clarified " They look like one but they are totally different". These curious filter feeder animals hangs out in lakes and its primary role is cleaning them. Daphnias are able to dictate lakes purity since they can only survive in pristine waters.
This organism was chosen to answer the question: Do aquatic specimens self-medicate? The scientist feed different types of algae, including poisonous, to daphnias to determine the effect on the host-parasite interaction. En Arroz y Habichuelas, she was looking if the toxin can kill the parasite without killing the host. In her analysis, she found daphnias that ingested algae with toxins were resistant to the parasite. To her surprise, she also discovered that the presence of a certain fungus can increase the production of a certain toxin in the water. The toxin in question is Anatoxin A, a potent neurotoxin. This has a great impact on human health and potable water. Thus, this could open the door to further investigations.
Many questions remain unanswered, can daphnias select toxic algae over normal sources of food? How do they determine when to use this self-medication method? This is only just the tip of the iceberg for Sánchez. We are looking forward to hearing the answer to these and more questions soon in Arroz y Habichuelas!