THE BIOLOGY AND ADAPTATIONS OF THE HIPPOPOTAMUS LEECH PLACOBDELLOIDESJAEGERSKIOELDI (GLOSSIPHONIIDAE) TO ITS HOST

The specificity of the association between the freshwater leech Placob delloides jaegerskioeldi and the hippopotamus was confirmed both by co llections from the Kruger National Park and by laboratory experiments. Placobdelloides jaegerskioeldi is established as the only leech showi ng species specificity for a mammal. Forty sexually mature leeches wer e collected free-living and 2260 mature and immature leeches were coll ected from 40 of 53 culled hippopotami. In the field P. jaegerskioeldi was never found on any of the alternative hosts, and none fed in the laboratory when offered a range of potential hosts. A combination of u nique attributes, including mode of locomotion, anatomical features, a nd feeding behaviour, makes it possible for this leech to utilize the hippopotamus as a host. Evidence suggests that mating in P. jaegerskio eldi is restricted to the rectum of the hippopotamus.