THE LIFE-CYCLE AND FEEDING OF THE AFRICAN FRESH-WATER LEECH HELOBDELLA-CONIFERA (GLOSSIPHONIIDAE)

The life-cycle, breeding and feeding of the freshwater leech Helobdell a conifera were examined in the laboratory. The life-cycle is annual w ith the young brooded by the parent for the first two months after hat ching. Sexual maturity is attained two months after leaving the parent when the first batch of eggs are produced and the young brooded. The number of broods ranges from one to four with the majority producing t hree. A few young leeches fed on the snail Helisoma duryi while still attached to the parent but the majority did not feed until 11 days aft er leaving the parent with 12-23 small (4.0-7.0 mm) snails consumed be fore producing their first batch of eggs. The life time consumption of small snails ranged from 26-60 with no correlation between the number s of snails consumed and the numbers of broods or the numbers of proge ny. Leeches only fed on small, live H. duryi and did not feed on large (10.0-13.0 mm) individuals although they led as scavengers on dead la rge snails. A strong preference was exhibited by H. conifera for small H. duryi compared to small P. acuta with the most of the feeding occu rring in the dark.