All about the leeches of Montezuma Well

Govedich, Fredric; Bain, Bonnie

Montezuma Well is a unique ecosystem with many interesting animals living within it. One very important group of animals are the freshwater leeches that make Montezuma Well their home. Most people think of leeches as nasty bloodsucking creatures with little or no worth, and no interesting behaviors, let alone any parenting skills, but this popular perception of them is way off the mark. A common misconception about leeches is that there is only one kind of leech. In fact, there are between 700 and 1000 species of leeches worldwide and they can be found in a variety of different habitats including marine, estuarine, moist terrestrial (particularly in Australia and Southeast Asia) and freshwater ecosystems. Within these habitats, leeches can be found attached to various substrates including fish and other marine creatures (marine and estuarine), underneath rocks or clinging to vegetation (moist terrestrial), or living on submerged wood, stones, and aquatic vegetation in ponds, streams, and rivers. Even if you know where to look for them, leeches can still be difficult to find since many species are often well camouflaged, blending in perfectly with their environment and making them extremely hard to locate. . . . . . Because fish cannot survive within the Well, an endemic leech, Motobdella montezuma, has evolved to become a pelagic hunter. In fact, this is the only known species of leech that is an open water hunter! Motobdella spends much of its day at the bottom of the Well, safely hidden from its predators (ducks, insects, etc.) while at the same time, its primary prey, the amphipod Hyalella montezuma, waits higher up in the water column at around 4 meters in depth. At sunset, the amphipods move to the surface to feed on algae and at the same time the leeches move up from the depths to begin feeding on the amphipods. This is the only place in the world where we see a migration pattern like this and it involves two endemic species that are not found anywhere else in the world! (Two of four Introduction paragraphs copied verbatim from the report.)