Negative maternal effect revisited: A test on two populations of Orchesella cincta L. (Collembola : Entomobryidae)

A Dutch population of Orchesella cincta had been demonstrated to exhibit a negative maternal effect on age at first reproduction, which caused alterna tion of shea and long generations. The adaptive significance of such a mech anism was assumed to be associated with the bivoltine life cycle of Dutch O . cincta. We expected that it would be absent in a non bivoltine population sampled in Siena, Italy. To test this hypothesis we performed a parent-off spring regression experiment with both populations simultaneously. The expe riment showed that there was no negative maternal effect in both population s. We leave open the question of the cause of the discrepancy between the p revious result with the Dutch population and the present result. The result s of our experiment were also used to determine heritabilities of the trait s age, mass and number of molts at first reproduction, and size of the firs t clutch. The estimates of heritabilities were often not significantly diff erent from zero, especially in the Italian population which had only one si gnificant heritability.