INBREEDING DEPRESSION AND SELF-FERTILIZATION IN LYMNAEA-PEREGRA (GASTROPODA, PULMONATA)

The effects of self-fertilization and cross-fertilization on several fitness traits were examined in the freshwater hermaphrodite snail Lymnaea peregra. Laboratory strains were established from Lake Geneva populations. Comparisons of F2 snails and their offspring showed that there are no differences in hatching time, nor in the size of young snails monitored over one month. But there was a significant difference, when the distribution of the capsule weight against the number of eggs was compared, although the effects of this on fitness are probabfy small. There was also a significant difference for egg production and juvenile viability over one month; the selling snails are 94 per cent less fit for these two traits than the outcrossing. © 1990 The Genetical Society of Great Britain.