Image

Title: Fish leech life cycle
Description: This image shows the life cycle of the fish leech [i]Piscicola geomtera[/i] and is adapted from Malecha, J. 1984. Cycle biologique de l'hirudin?e rhynchobdelle [i]Piscicola geometra[/i] L. [i]Hydrobiologia[/i] 118 pp. 237-243. In spring the larger overwintering leeches ('A') secrete cocoons which hatch in late April/early May giving birth to the 'B' generation. The 'B' leeches breed throughout summer and lay the first eggs in mid-June ('C1') and the last ones in late August/early September ('C2') (although the 'C2' generation may not be very numerous). The cocoons secreted by 'C1'give birth to 'D1' from early August and then to 'D2' in September. The 'D1' leeches may be the original of the 'E' generation at the end of September. The last leeches issued from the summer generations ('B', 'C1', 'D1') die off in early October whilst the store of overwintering leeches ('A') is made up of the 'C2', 'D2' and 'E' generatons.
Copyright Holder: Roger Sweeting
Geographic Keywords: United Kingdom

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