Wilkins Laetitia G E, Marques da Cunha Lucas, Menin Laure, Ortiz Daniel, Vocat-Mottier Véronique, Hobil Matay, Nusbaumer David, Wedekind Claus
Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland.
Department of Environmental Sciences, Policy and Management, 130 Mulford Hall #3114, University of California, Berkeley, CA, 94720, USA.
Oecologia. 2017 Nov;185(3):351-363. doi: 10.1007/s00442-017-3952-y. Epub 2017 Sep 11.
Life-history theory predicts that iteroparous females allocate their resources differently among different breeding seasons depending on their residual reproductive value. In iteroparous salmonids there is typically much variation in egg size, egg number, and in the compounds that females allocate to their clutch. These compounds include various carotenoids whose functions are not sufficiently understood yet. We sampled 37 female and 35 male brown trout from natural streams, collected their gametes for in vitro fertilizations, experimentally produced 185 families in 7 full-factorial breeding blocks, raised the developing embryos singly (n = 2960), and either sham-treated or infected them with Pseudomonas fluorescens. We used female redness (as a measure of carotenoids stored in the skin) and their allocation of carotenoids to clutches to infer maternal strategies. Astaxanthin contents largely determined egg colour. Neither egg weight nor female size was correlated with the content of this carotenoid. However, astaxanthin content was positively correlated with larval growth and with tolerance against P. fluorescens. There was a negative correlation between female skin redness and the carotenoid content of their eggs. Although higher astaxanthin contents in the eggs were associated with an improvement of early fitness-related traits, some females appeared not to maximally support their current offspring as revealed by the negative correlation between female red skin colouration and egg carotenoid content. This correlation was not explained by female size and supports the prediction of a maternal trade-off between current and future reproduction.
生活史理论预测，多次繁殖的雌性会根据其剩余繁殖价值在不同繁殖季节分配不同的资源。在多次繁殖的鲑科鱼类中，卵的大小、数量以及雌性分配到卵中的化合物通常存在很大差异。这些化合物包括各种类胡萝卜素，其功能尚未得到充分了解。我们从天然溪流中采集了37只雌性和35只雄性褐鳟，收集它们的配子进行体外受精，在7个完全析因繁殖区组中实验性地产生了185个家系，单独饲养发育中的胚胎（n = 2960），并对它们进行假处理或用荧光假单胞菌感染。我们利用雌性的红色程度（作为皮肤中储存的类胡萝卜素的指标）及其向卵中分配类胡萝卜素的情况来推断母体策略。虾青素含量在很大程度上决定了卵的颜色。卵的重量和雌性的大小均与这种类胡萝卜素的含量无关。然而，虾青素含量与幼体生长以及对荧光假单胞菌的耐受性呈正相关。雌性皮肤的红色程度与它们卵中的类胡萝卜素含量呈负相关。尽管卵中较高的虾青素含量与早期适应性相关性状的改善有关，但一些雌性似乎并未最大限度地支持其当前的后代，这从雌性红色皮肤颜色与卵类胡萝卜素含量之间的负相关关系中可以看出。这种相关性无法用雌性大小来解释，并且支持了母体在当前繁殖和未来繁殖之间进行权衡的预测。
