The life-history of Haementeria costata (Fr. Müller) (Glossiphoniidae: Hirudinea)

The frequency of occurrence of Haementeria costata in the waters of north-eastern Poland is 66.5%. This leech is usually found in shallow water zones frequented by water fowl and mammals.The different numbers of individuals taking food and different amounts of food consumed at one meal during successive feedings resulted in individuals of a cohort reaching sexual maturity at the age of 1, 2, and 3 years and surviving for 1.5, 2.5 and 3.5 years, respectively. The differences in weight and age of individuals of populations in their natural environment and in the laboratory depend on the accessibility of food.     

Competition and coexistance between Glossiphonia complanata and Helobdella stagnalis (Glossiphoniidae: Hirudinoidea)

Summary The prey utilization of Glossiphonia complanata and Helobdella stagnalis from Bruce Lake, Alberta, Canada was examined quantitatively using serological techniques. While considerable prey range overlap occurred between the species, niche overlap was low during the winter, peaked in March and declined through the summer. Temporal differences in feeding and intraspecific weight class differences in prey utilization were found in both species but more distinctly in G. complanata. It is suggested that co-existance of G. complanata and H. stagnalis is based on adjustments of weight class food resource partitioning on a temporal basis.     

The reproductive biology of Theromyzon tessulatum (Glossiphoniidae: Hirudinoidea), with comments on Theromyzon rude

The reproductive biology and behaviour of Theromyzon tessalatum is described from the commencement of copulation to the release of the young and the death of the parent. Copulation occurs several times over a10–20 day period with either the same or different partners. Eggs were laid6–14 days after copulation in usually four cocoons each containing approximately 100 eggs. The cocoons were brooded by the parents and the young, on development of the embryonic attachment organ and later by the posterior sucker, attached to the ventral surface of the parent's abdomen. The young detached from the parent either on contact with a suitable host for a blood meal or after approximately five months just prior to the parent's death.