Hatle John D, Crowley Michael C, Andrews Amanda L, Juliano Steven A
Department of Biological Sciences, Behavior, Ecology, Evolution, and Systematics Section, Illinois State University, Normal, IL, 61790-4120, USA.
Oecologia. 2002 Aug;132(4):517-523. doi: 10.1007/s00442-002-0994-5. Epub 2002 Aug 1.
We investigate plastic and interpopulation variation of trade-offs among reproductive tactics. There is a potential three-way trade-off among timing of reproduction, somatic storage, and investment in reproduction. We tested whether this trade-off shows latitudinal interpopulation variation. We studied populations of the lubber grasshopper, Romalea microptera, from Florida (FL; lowest latitude), Louisiana (LA; intermediate latitude), and Georgia (GA; highest latitude), each tested at three diet levels. All three populations differed in their multivariate responses of the three reproductive tactics we studied. This difference across populations was due primarily to age at first reproduction, secondarily to somatic storage, and less so to clutch mass. Age at first reproduction was least in GA, intermediate in LA, and greatest in FL grasshoppers. Somatic storage was greatest in FL and LA, and least in GA grasshoppers. Clutch mass was greatest in LA and GA, and least in FL grasshoppers. Diet levels also differed in this suite of reproductive tactics, primarily due to variation in age at reproduction. In contrast to significant, independent effects of population and diet, we find no evidence that the trade-off itself varies across populations (as indicated by the non-significant interaction of population and diet level). Thus, we show that the innate allocation of resources among reproductive tactics is different across populations, but all three populations responded similarly to a range of diet levels.
我们研究了繁殖策略之间权衡的可塑性和种群间变异。在繁殖时间、体细胞储存和繁殖投入之间存在潜在的三向权衡。我们测试了这种权衡是否表现出纬度种群间变异。我们研究了来自佛罗里达州（FL；最低纬度）、路易斯安那州（LA；中间纬度）和佐治亚州（GA；最高纬度）的美洲沙漠蝗种群，每个种群在三种食物水平下进行测试。我们研究的三种繁殖策略的多变量反应在所有三个种群中都有所不同。种群间的这种差异主要归因于首次繁殖的年龄，其次是体细胞储存，而卵块质量的影响较小。首次繁殖的年龄在佐治亚州的蝗虫中最小，在路易斯安那州的蝗虫中居中，在佛罗里达州的蝗虫中最大。体细胞储存在佛罗里达州和路易斯安那州的蝗虫中最大，在佐治亚州的蝗虫中最小。卵块质量在路易斯安那州和佐治亚州的蝗虫中最大，在佛罗里达州的蝗虫中最小。食物水平在这一系列繁殖策略中也有所不同，主要是由于繁殖年龄的差异。与种群和食物的显著独立效应相反，我们没有发现权衡本身在种群间变化的证据（种群和食物水平的非显著交互作用表明了这一点）。因此，我们表明，繁殖策略之间资源的固有分配在不同种群中是不同的，但所有三个种群对一系列食物水平的反应相似。
