Open AccessSperm length and quality in sperm‐dependent parthenogens
Author(s) -
D'SOUZA THOMAS G.,
BELLENHAUS VERA,
WESSELMANN RAMONA,
MICHIELS NICO K.
Publication year - 2008
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2007.00913.x
Subject(s) - biology , sperm , parthenogenesis , apomixis , human fertilization , evolutionary biology , sperm quality , female sperm storage , zoology , asexuality , fertility , ploidy , ecology , embryo , genetics , sperm competition , human sexuality , demography , population , sociology , gene , gender studies
Is the male function of parthenogenetic hermaphrodites a historic remnant or an adaptive investment? In the first case, one would expect the male function to be ‘degraded’ and, in the second case, fully functional, despite being reduced. To answer this question, we investigated sperm morphology and quality in the hermaphroditic planarian Schmidtea polychroa . Parthenogenetic forms of this species are sperm‐dependent and require allosperm to trigger embryogenesis. Although there is generally no genetic paternal contribution, occasional fertilization of parthenogenetic eggs has been reported, leading to genetic changes in an otherwise apomictic lineage (‘occasional sex’). Comparing two locations, one with pure clonality and one with occasional sexuality, revealed substantial differences in both sperm length and fertility: Occasional sex appears to be coupled with longer sperm and higher sperm quality. We discuss the implications of these results for the maintenance of the male function in sperm‐dependent parthenogens. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 81–87.