Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604 Republic of Singapore.
Int J Biol Sci. 2010 Feb 17;6(1):107-15. doi: 10.7150/ijbs.6.107.
Reproductive strategy is a central feature of the ecology of invasive species as it determines the potential for population increase and range expansion. The red swamp crayfish, Procambarus clarkii, has invaded many countries and caused serious problems in freshwater ecosystems. However, little is known about the effects of environmental conditions on crayfish paternity and offspring traits in the wild. We studied these reproductive characteristics of P. clarkii in wild populations from two different habitats (ponds and ditches) in three locations with different environmental conditions in China. Genotyping of 1,436 offspring and 30 mothers of 30 broods was conducted by using four microsatellites. An analysis of genotyping results revealed that gravid females were the exclusive mother of the progeny they tended. Twenty-nine of 30 mothers had mated with multiple (2-4) males, each of which contributed differently to the number of offspring in a brood. The average number of fathers per brood and the number of offspring per brood were similar (P>0.05) among six sampling sites, indicating that in P. clarkii multiple paternity and offspring number per brood are independent of environmental conditions studied. Indirect benefits from increasing the genetic diversity of broods, male and sperm competition, and cryptic female choice are a possible explanation for the high level multiple paternity and different contribution of fathers to offspring in this species.
繁殖策略是入侵物种生态学的一个核心特征，因为它决定了种群增加和分布范围扩大的潜力。克氏原螯虾（Procambarus clarkii）已入侵许多国家，对淡水生态系统造成了严重问题。然而，对于环境条件对野生螯虾亲代和后代特征的影响知之甚少。我们在中国三个具有不同环境条件的地点的两个不同生境（池塘和沟渠）中研究了 P. clarkii 的这些繁殖特征。通过使用四个微卫星对 1436 只后代和 30 只母虾的 30 个窝进行了基因分型。基因分型结果分析表明，怀孕的雌性是它们所抚养后代的唯一母亲。30 只母虾中有 29 只与多个（2-4 个）雄性交配，每个雄性对窝中后代的数量都有不同的贡献。六个采样点的每个窝的平均父本数和窝中后代数相似（P>0.05），表明在 P. clarkii 中，多父本和每个窝的后代数量与所研究的环境条件无关。从增加窝的遗传多样性、雄性和精子竞争以及隐蔽的雌性选择中获得的间接利益可能是该物种高水平多父本和父亲对后代不同贡献的一个解释。
