INFLUENCE OF TEMPERATURE AND FOOD SOURCE ON THE LIFE-CYCLE OF THE EARTHWORM DENDROBAENA-VENETA (OLIGOCHAETA)

The life cycle of Dendrobaena veneta was studied to assess the potenti al of breeding this species for the fish-bait market. Development, gro wth and reproduction were investigated by rearing worms at 10 degrees, 15 degrees, 20 degrees or 25 degrees C on horse manure or on aerobic paper sludge for 6 months. At 10 degrees C, the maturity was slow with a long period of development (104 d) and a low cocoon production. Pro ductivity at 25 degrees C was better than at 20 degrees C or 15 degree s C. The effect of temperature on cocoon production differed according to the source of food; on paper sludge, cocoons were produced at the same rate at 20 or 25 degrees C while on horse manure cocoon productio n was better at 25 degrees C than at 20 degrees C. Whatever temperatur e, cocoon production was significantly greater on paper sludge than on horse manure. On paper sludge, maturation of juveniles was faster and adult worms larger. Adults started to produce cocoons at a younger ag e and more cocoons were produced worm(-1) and d(-1). These results sho wed that the life cycle of D. veneta may be influenced by the type of food and that horse manure is not the best substrate for breeding this species. (C) 1997 Elsevier Science Ltd.