The evolution of phally polymorphism in Bulinus truncatus (Gastropoda, Planorbidae): the cost of male function analysed through life-history traits and sex allocation
- 1 June 1996
- journal article
- Published by Springer Nature in Oecologia
- Vol. 106 (4), 464-469
- https://doi.org/10.1007/bf00329703
Abstract
In the hermaphrodite freshwater snail Bulinus truncatus, two sexual morphs, euphallic (regular hermaphrodites) and aphallic individuals without a male copulatory organ, co-occur at various ratios in natural populations. Both aphallic and euphallic individuals can reproduce by selfing, but when outcrossing aphallic individuals can only play the female role. A comparison of life-history traits and sex allocation in these two forms provides the opportunity to investigate the evolution and maintenance of sexual polymorphisms. This study was performed to test whether a reallocation of resources from the lost male function to the female function occurs in aphallic snails at the level of both sex organs (sex allocation) and life-history traits. In a first experiment we compared life-history traits over a whole life-cycle under selfing between the two sexual morphs. In a second experiment, the sex organs were weighed to test for a difference in sex allocation between the two morphs. No difference in resource allocation to female function between the two morphs was observed in either experiment. This is in contrast to patterns frequently observed in sexually polymorphic plants, and in a previous study performed on aphally in the same snail species. We discuss the genetic and physiological hypotheses that could explain these results, and their consequences for the evolution and maintenance of phally polymorphism in B. truncatus.Keywords
This publication has 19 references indexed in Scilit:
- Temperature-Determined Outcrossing Ability in Wild Populations of a Simultaneous Hermaphrodite SnailEcology, 1994
- Effects of Schistosoma haematobium infection on reproductive success and male outcrossing ability in the simultaneous hermaphrodite, Bulinus truncatus (Gastropoda: Planorbidae)Parasitology, 1994
- Do self-fertilization and genetic drift promote a very low genetic variability in the allotetraploidBulinus truncatus(Gastropoda: Planorbidae) populations?Genetics Research, 1993
- Sex and genetic variation in a helicid snailHeredity, 1993
- Aphally Versus Euphally in Self-Fertile Hermaphrodite Snails from the Species Bulinus truncatus (Pulmonata: Planorbidae)The American Naturalist, 1992
- Trade-Offs in Life-History EvolutionFunctional Ecology, 1989
- Costs of Reproduction: An Evaluation of the Empirical EvidenceOikos, 1985
- The Effects of Varying the Quantity and Quality of Various Plants on Feeding and Growth of Biomphalaria Glabrata (Gastropoda)Oikos, 1983
- Some Reproductive Factors Affecting the Selection of Self-Fertilization in PlantsThe American Naturalist, 1979
- Population genetics of partial male-sterility and the evolution of monoecy and dioecyHeredity, 1978