Subject matter of experiments and observations of water animals in school aquarium IXV (Leeches, Hirudinea)
Abstract
Leeches are segmented parasitic or predatory invertebrates within the phylum Annelida. The majority of leeches live in freshwater habitats, while some species can be found in terrestrial or marine environments. A majority of leech species are predatory, mostly preying on small invertebrates.
European medicinal leech Hirudo medicinalis is hematophagous. Leeches are protandric hermaphrodites. Their eggs are enclosed in a cocoon; members of one family, Glossiphoniidae, exhibit parental care, the eggs being brooded by the parent.
Many leeches avoid light. Leeches live in damp surroundings and in general respire through their body wall. The exception to this is in the Piscicolidae, where branching or leaf-like lateral outgrowths from the body wall form gills. Leeches move using their longitudinal and circular muscles in a modification of the locomotion by peristalsis, self-propulsion by alternately contracting and lengthening parts of the body, seen in other annelids such as earthworms. They use their posterior and anterior suckers to enable them to progress by looping or inching along, in the manner of geometer moth caterpillars.
Leeches explore their environment with head movements and body waving. The Hirudinidae and Erpobdellidae can swim rapidly with up-and-down or sideways undulations of the body; the Glossiphoniidae in contrast are poor swimmers and curl up and fall to the sediment below when disturbed.
In the contribution are presented some observations of leeches in school aquarium.