Invasive Animals Cooperative Research Centre, Institute for Marine and Antarctic Studies, University of Tasmania, and CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, Tasmania 7001, Australia.
Ecol Appl. 2013 Jun;23(4):801-14. doi: 10.1890/12-1324.1.
This study tests the sensitivity of genetically based pest control options based on sex ratio distortion to intra- and intersexual aggressive interactions that affect male and female survival and fitness. Data on these interactions and their impacts were gathered for the mosquitofish Gambusia holbrooki (Poeciliidae), a promiscuous species with a strongly male-biased operational sex ratio and well-documented male harassment of females. The experimental design consisted of an orthogonal combination of two population densities and three sex ratios, ranging from strongly male-biased to strongly female-biased, and long-term observations of laboratory populations. Contrary to expectations, the number of males in a population had little evident effect on population demographics. Rather, the density of adult females determined population fecundity (as a result of a stock-recruitment relationship involving females, but not males), constrained male densities (apparently as a result of cannibalism or intersexual aggression), and regulated itself (most likely through effects of intrasexual aggression on female recruitment). The principal effect of males was to constrain their own densities via effects of male-male aggression on adult male mortality rates. Through use of a realistically parameterized genetic/demographic model, we show that of three different genetic options applied to control G. holbrooki, one based on recombinant sex ratio distortion (release of Female Lethal carriers) is marginally more efficient than a sterile male release program, and both outperform an option based on chromosomal sex ratio distortion (Trojan W). Nonlinear dependence of reproductive rate on female density reduces the efficacy of all three approaches. The major effect of intra- and intersexual aggression is mediated through females, whose interactions reduce female numbers and increase the efficacy of a control program based on sex ratio. Socially mediated male mortality has a small impact on control programs due to operational sex ratios that are heavily male-biased. The sensitivity of sex ratio-based control options to social factors will depend on the mating system of the targeted pest, but evidence of widespread density-dependent population regulation suggests that, for most species, the effects of elevated adult mortality (due to intra- and intersexual aggression) on control programs are likely to be slight.
这项研究测试了基于性别比例扭曲的遗传害虫控制选项的敏感性，这些选项受到影响雄性和雌性生存和适应力的雌雄间和两性内攻击相互作用的影响。这些相互作用及其影响的数据是为食蚊鱼（Gambusia holbrooki）（胎生鳉科）收集的，这是一种滥交物种，具有强烈的雄性偏向的操作性性别比例，并有大量雄性骚扰雌性的记录。实验设计包括两个种群密度和三个性别比例的正交组合，范围从强烈的雄性偏向到强烈的雌性偏向，以及对实验室种群的长期观察。与预期相反，种群中的雄性数量对种群动态几乎没有明显的影响。相反，成年雌性的密度决定了种群的繁殖力（这是由于涉及雌性而不是雄性的种群补充关系），限制了雄性的密度（显然是由于同类相食或两性内攻击），并自我调节（最有可能通过对雌性补充的两性内攻击的影响）。雄性的主要作用是通过雄性间攻击对成年雄性死亡率的影响来限制自己的密度。通过使用一个现实参数化的遗传/人口模型，我们表明，在三种不同的用于控制 G. holbrooki 的遗传选择中，一种基于重组性别比例扭曲（释放雌性致死携带者）的选择略优于雄性不育释放方案，并且这两种选择都优于基于染色体性别比例扭曲（Trojan W）的选择。生殖率对雌性密度的非线性依赖降低了所有三种方法的效率。雌雄间和两性内攻击的主要影响是通过雌性介导的，它们的相互作用减少了雌性数量，并提高了基于性别比例的控制计划的效率。社会介导的雄性死亡率对控制计划的影响很小，因为操作性性别比例严重偏向雄性。基于性别比例的控制选项对社会因素的敏感性将取决于目标害虫的交配系统，但广泛存在的密度依赖性种群调节的证据表明，对于大多数物种，由于雌雄间和两性内攻击导致的成年死亡率升高对控制计划的影响可能很小。
