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Correlations between sex rate estimates and fitness across predominantly parthenogenetic flatworm populations
Author(s) -
D’SOUZA T. G.,
MICHIELS N. K.
Publication year - 2008
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2007.01446.x
Subject(s) - biology , parthenogenesis , flatworm , sexual reproduction , reproduction , sexual selection , adaptation (eye) , natural selection , population , genetic fitness , zoology , sex allocation , offspring , selection (genetic algorithm) , ecology , asexual reproduction , evolutionary biology , demography , biological evolution , genetics , embryo , pregnancy , neuroscience , artificial intelligence , sociology , computer science
One explanation for the success of sexual reproduction is that sex increases the efficacy of natural selection. Recombination and segregation lead to fitness variance among offspring which then offers a wider target for natural selection. Consequently, adaptation to changing environments is accelerated and population mean fitness will increase. We investigated whether low levels of sex are associated with increased fitness variance and mean in parthenogenetic biotypes of the planarian flatworm Schmidtea polychroa . Parthenogenetic S. polychroa are triploid and reproduce clonally with occasional sexual reproduction. By‐products and measures of occasional sex are the local presence of tetraploids and elevated levels of genotypic diversity. We correlated the proportion of tetraploids and genotypic diversity with fitness attributes of six genetically differentiated locations within one meta‐population. Results indicate strong, positive correlations with variance and with mean offspring number produced during a 5‐week period. The ecological and evolutionary implications for the maintenance of parthenogenetic S. polychroa are discussed.