Dark Banquet - Bill Schutt [53]
Some leeches are neither parasites nor predators. Among these are several members of the family Branchiobdellidae. These species are remarkable for the manner in which they partition their highly specific habitat—the shells of the freshwater crayfish. Although the hard outer covering of these minilobsters might seem an unlikely place for leeches to hang out, there can be up to seven species living on a single individual. In what stands as an extreme example of microhabitat partitioning, different leech species inhabit different regions of the crayfish’s body. For example, one type of leech lives attached to the crayfish’s antennae, while another lives out its life adhering to the pincer-tipped legs (the chelipeds). Unlike parasitic leeches that feed on the blood of their hosts, the behavior of these branchiobdellids is more comparable to the previously mentioned endosymbiotic bacteria living in the guts of mammals like cows. Although not as important as bacterial endosymbionts are to their hosts, these ectosymbionts provide a service to the crayfish by grazing on the micofauna (algae, diatoms, and bacteria) that attach to its body.
This leech/crayfish association is not always positive for the host since some branchiobdellids don’t provide the aforementioned cleaning services. A few species cause no harm—they’re merely opportunists, consuming scraps of organic matter scattered about by the messy crayfish as it shreds its food into bitesized bits. Another branchiobdellid, however, is parasitic. It lives within the crayfish’s gill chamber where it feeds on the gill filaments and blood of the same freshwater crayfish whose bodies are so precisely partitioned by its nonparasitic cousins. Even worse, however, are the instances in which crayfish are infested by lethally high numbers of leeches, which can sometimes cover their bodies like living carpets, ultimately killing them.*72
Early use of leeches by man reflected the importance of bloodletting as a therapeutic tool. Leeches also gave practitioners an alternative when “breathing a vein” wasn’t appropriate. For example, leeches could be applied to parts of the body that were difficult or impossible to bleed by lancing or other means. Inflamed tonsils might call for leeches to be attached to the back of a patient’s throat or the bloodsuckers might be employed to drain persistent hemorrhoids. Leeches were applied to the scrotum to treat the swollen testicles that resulted from gonorrhea and they were also commonly used to treat maladies of the female reproductive system. Additionally, leeches were the preferred method of bleeding women and children “who required a gentle withdrawal of blood.”
In what is arguably the strangest use of leeches on record, the sixteenth-century French historian Pierre de Brantôme recounted how leeches were inserted into the vaginas of women on their wedding nights so that they could “seem like the virgins and maidens they used to be…so as the gallant husband who comes on his wedding night to assault them, bursts their bulb from where the blood flows.”
According to Brantôme, battering this bogus maidenhead (or having it battered for you) invariably led to an annelid-assisted version of postcoital bliss: “And both are bloody and (there is) a great joy for both and in this way the