Leech Hunters!

Macrobdella decora, the North American Medicinal Leech, from southern Maryland.

Hello colleagues! 

Let me introduce myself, my name is Ricardo, better known as Rico. I am a Masters student at the Universidad Nacional Autónoma de México (UNAM) in Mexico City and I have been studying leeches for the last three years. Now I even find these slimy annelids adorable.

Most people think of leeches as segmented, slimy worms that feed on blood, but what if I told you that many leeches do not suck blood? There is a wide diversity of leeches that feed on small invertebrates such as insect larvae, mollusks and earthworms. Leeches are cute in many ways, some of them are even really good parents. When the offspring are born, rhychobdellid (proboscis-bearing) leech babies are carried on the belly of their parent who protects them and even takes them to their first meal. Once the leech babies have grown enough to look for their own food, they leave the parent leech to start living an independent life.

Ricardo Salas Montiel searching for ticks during fieldwork in southern Maryland.

I work on the North American medicinal leech, Macrobdella decora, that ranges from northern Mexico to southern Canada. Its coloration patterns are beautiful, and it is the most widely distributed species of the genus. Macrobdella decora is a good model to study phylogeography because the populations are isolated from each other and individuals cannot move easily from one freshwater body to another without facing desiccation. In order to better understand the processes that shaped the geographic distribution of Macrobdella decora, I need specimens from as many populations as possible. As part of my degree studies in Mexico, I had the opportunity to spend a 9-week research visit at the Smithsonian’s National Museum of Natural History collecting specimens and working in the molecular lab with Dr. Anna Phillips and Dr. Herman Wirshing. 

The first five weeks of my stay we collected leeches from Maryland. I had some experience collecting leeches in Mexico; however, collecting leeches in Mexico and collecting leeches in Maryland are two completely different experiences mainly because of the extreme summer weather and because of ticks and chiggers in Maryland. The weather was very unpredictable with summertime thunderstorms. There were times when I was more worried about looking for ticks than for leeches feeding on my blood.

Ricardo Salas Montiel knee-deep in a swamp in southern Maryland looking for the North American Medicinal Leech, Macrobdella decora.

I also examined some specimens at the Museum Support Center. I was astonished to see how huge the Invertebrate Zoology collection was. I knew that the largest leech ever collected was deposited there and I really wanted to have a look at it. Haementeria ghilianii could perfectly take up the space between my wrist and my elbow, just as it did on Roy Sawyer’s arm some years ago. Even though I saw it in a jar, it was still amazing. Surprisingly, I found that a few leech specimens from New Hampshire in the Collection that were misidentified as M. decora but are in fact M. sestertia, a species that has been only a handful of times since it was described in 1886. 

We traveled to Omaha, Nebraska where I presented the preliminary results of my thesis at the 90^th Annual Meeting of the American Society of Parasitologists. Once the conference was over, I traveled to Illinois where I was hosted by Agustín Jiménez, a researcher that kindly supported and joined me in leech hunting for five days. We collected in several localities near Southern Illinois University and we found leeches, although not the species we were seeking.

Roy T. Sawyer, author of Leech Biology and Behaviour (1986; Clarendon Press) with a particularly large individual of Haementeria ghilianii on his arm.

The last four weeks of my visit I spent most of the time working at the Laboratory of Analytical Biology (L.A.B.). I was able to sequence different mitochondrial and nuclear markers such as COI, ND1, and 18S and also started sequencing microsatellites, all with the support and guidance of Dr. Herman Wirshing.

In the blink of an eye, nine weeks had gone by and I had to say goodbye. I am in Mexico now and I am very happy because I obtained valuable data for my Masters thesis. I am also very grateful to Anna for having me in D.C. as her student as well as to the NMNH for allowing me to use its facilities. I hope I have the chance to go back to D.C. in the future, but for now I will focus in finishing my masters on time.

See you soon colleagues!  

 

By Ricardo Salas Montiel

 

 

Comments

[Cameron Cass]

Is Macrobdella decora a leech that feeds on blood or intevertebrates? Additionally will they prey on small fish?