Norwegian Institute for Nature Research, Gaustadalléen 21, NO-0349, Oslo, Norway.
J Anim Ecol. 2013 Jan;82(1):201-10. doi: 10.1111/j.1365-2656.2012.02022.x. Epub 2012 Aug 20.
The reaction norm between growth rate, age and size at maturity in ectotherms is widely debated in ecological literature. It has been proposed that the effect depends on whether growth is affected by food quality or temperature (called the Berrigan-Charnov puzzle). The present experiment tested this for Atlantic salmon (Salmo salar). We enhanced growth rates by increasing temperature and ratio of lipids to proteins in the food for groups of Atlantic salmon. Both treatments gave higher percentages of early mature and therefore smaller adults in contrast to the proposed Berrigan-Charnov puzzle. There was a difference between sexes in that males could attain maturity 1 year younger than females when reared under similar environmental conditions. Males that matured during the first year in sea water were smaller than similar aged immature males. The probability of that Atlantic salmon attained maturity for the first time during their second year in sea increased with growth rate during the preceding winter and if fed a high-lipid diet. Increased summer temperature exhibited no additional effect. Similar aged fish reared at elevated temperature and fed high-lipid diet attained maturity at a larger body mass and exhibited higher mass-length-ratios than those reared at natural temperature and fed a low-lipid diet, indicating that structural growth has priority over lipid deposits. Increased growth rate before the onset of maturation, whether this is owing to enhanced lipid content in food or increased water temperature, decreased age and therefore size at maturity. Enhanced lipid relative to protein content in food, but not temperature, had an additive positive effect on early maturation probability, likely due to increased amounts of reserve energy. These results may be general for ectotherm organisms.
变温动物的生长速度、年龄和成熟时体型之间的反应规范在生态学文献中存在广泛争议。有人提出，这种影响取决于生长是否受到食物质量或温度的影响（称为贝里根-查诺夫难题）。本实验针对大西洋鲑（Salmo salar）进行了测试。我们通过提高温度和食物中脂肪与蛋白质的比例来提高大西洋鲑的生长速度。这两种处理方法都导致了更早成熟的个体比例更高，因此成体体型更小，与贝里根-查诺夫难题的预测相反。性别之间存在差异，即在相似的环境条件下，雄性可以比雌性提前 1 年成熟。在海水中成熟的雄性比相似年龄的未成熟雄性体型更小。在第二年的海水中首次达到成熟的大西洋鲑的概率随着前一年冬季的生长速度增加而增加，如果它们食用高脂肪饮食。夏季温度升高没有额外的效果。在较高温度下饲养并喂食高脂肪饮食的相似年龄的鱼类达到成熟时的体重更大，并且质量-长度比高于在自然温度下饲养并喂食低脂肪饮食的鱼类，这表明结构生长优先于脂肪沉积。成熟前的生长速度增加，无论是由于食物中脂肪含量增加还是水温升高，都会导致成熟时的年龄和体型减小。食物中相对蛋白质的脂肪含量增加，而不是温度增加，对早期成熟的可能性有积极的附加影响，这可能是由于储备能量增加。这些结果可能对变温动物具有普遍性。
