Observations on the Ecology and Morphology of Placobdella papillifera (Verrill) (Hirudinoidea: Glossiphoniidae) in Alberta, Canada

Placobdella papillifera in the laboratory fed readily on fresh heparinized blood of a range of vertebrates, but never attacked vertebrate potential hosts. Growth rate data indicate that at least four blood meals are required to reach mature size and that young need at least one, and possibly two blood meals in the autumn to survive the winter. Field data show a minimum mature weight of 500 mg with eggs brooded in June and July and young brooded in July through September. The embryological development and the main morphological characteristics are described. A second smaller pair of eyes are recorded for the first time and the papillae are differentiated into two distinct types. INTRODUCTION The genus Placobdella (Glossiphoniidae) is represented in North America by eight species (Soos, 1969) of which seven occur in Canada (Davies, 1973) or the northern United States (Sawyer, 1972). All Placobdella species are considered to be temporary, bloodsucking ectoparasites, with P. pediculata (Hemingway, 1908) and P. montifera (Moore, 1906) parasitic on fish, and the remainder of the species parasitic primarily on turtles (Sawyer, 1972). Although P. parasitica (Say, 1824) has been recorded as a parasite on Amphibia (Meyer and Moore, 1954) and fish (Ryerson, 1915; Pearse, 1924), P. phalera (Graf, 1899) on fish (Bere, 1931), P. ornata (Verrill, 1872) on fish (J.P. Moore, 1906; J.E. Moore, 1966) and birds (Moore, 1964, 1966; Scudder and Mann, 1968), and P. hollensis (Whitman, 1892) on fish (Mullin, 1926), Klemm (1972) and Klemm et al. (1979) consider records of hosts other than turtles to be dubious or erroneous. Placobdella montifera, P. hollensis, P. pediculata and P. phalera are readily distinguished and identified (Davies, 1971; Sawyer, 1972), while the separation of P. papillifera (Verrill, 1872), P. parasitica and P. ornata is more difficult being based primarily on the presence, absence and distribution of papillae and tubercules, which may themselves be covered with papillae (Davies, 1971). Little is known about the biology and ecology of Placobdella species presumably because, despite being widely distributed, most species are usually rare. The little information available is usually based on incidental observations of a few individuals. In southern Alberta, Placobdella montifera, P. ornata, P. parasitica and P. papillifera have been recorded (Davies, 1973), but P. papillifera is the most widely distributed although still in low abundance. This study of P. papillifera includes some preliminary field investigations of its population dynamics and a more detailed laboratory study of reproduction, cocoon deposition, egg development, feeding and growth. Additional information on the main morphological characteristics of the species is given. METHODS Placobdella papillifera were collected from three similar ponds/sloughs in the prairiefoothills transition zone of southwestern Alberta W of the city of Calgary. Monthly samples were taken over a 2-year period. During the ice-free periods, collections were 'Present address: Uniwersytet Warszawski, Filia w Bialymstoku, Zaklad Biologii, ul. Sosonowa 64, 15-887 Bialystok, Poland.