Phenotypically flexible sex allocation in a simultaneous hermaphrodite

Brauer, Verena S. and Schärer, Lukas and Michiels, N. K.. (2007) Phenotypically flexible sex allocation in a simultaneous hermaphrodite. Evolution, 61 (1). pp. 216-222.

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Previous studies on sex allocation in simultaneous hermaphrodites have typically focused either on evolutionary or one-time, ontogenetic optimization of sex allocation, ignoring variation within an individual?s lifetime. Here, we study whether hermaphrodites also possess facultative sex allocation, that is, a phenotypic flexibility, allowing them to distribute resources to either sex in an opportunistic way during their adult lifetime. We used the simultaneously hermaphroditic free-living flatworm Macrostomum lignano and raised individuals in pairs and groups of eight worms (further called octets) until sexual maturity was reached and sex allocation for the current conditions was expected to be set. Treatment groups were subsequently transferred to the alternative group size, that is, from pairs to octets or from octets to pairs, and compared to two control groups, which were transferred without changing group size. The results show that worms in treatment groups responded as expected by the local mate competition theory for simultaneous hermaphrodites: increasing group size resulted in a shift toward a moremale-biased sex allocation and vice versa. These findings reveal that sex allocation in these animals is not fixed during ontogeny, but remains flexible after maturation. We argue that phenotypically flexible sex allocation in hermaphroditic animals may help us to understand the evolution and ecology of hermaphroditism.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Integrative Biologie > Evolutionary Biology (Schärer)
UniBasel Contributors:Schärer, Lukas
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:20 Sep 2017 06:44
Deposited On:22 Mar 2012 14:02

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