The pattern of resource allocation into multiple life‐history traits can vary with the environment; for example, high temperatures generally facilitate growth. Changes in investment in growth due to temperature may alter the allocation to other traits that are in trade‐off with that. Here, we investigated the trade‐off between growth and reproduction and whether the proportion of allocation to these varies with increasing seawater temperature in the lancelet Branchiostoma japonicum. We reared the lancelets of early adult stage under three different temperature treatments (control, + 1°C and + 2°C treatments) for 427 days in the laboratory. Although the total body length at initiation did not differ between treatments, the length was influenced by the interaction between elapsed days and temperature treatments, suggesting that growth rate was temperature‐dependent; the lancelets under higher temperature conditions showed a more rapid growth rate than did those under the control conditions. The frequency of individuals with gonads did not differ between treatments throughout their reproductive season. The monthly growth increments were also not significantly affected by the interaction between the presence/absence of gonads and temperature treatments, although the presence of gonads caused the growth increments to decrease. In addition, the effect of temperature treatments was significant. These results suggest that changes in temperature did not alter the pattern of allocation between growth and reproduction that were in a trade‐off, whereas high temperature would solely result in an increase in resource intake, at least in the early adult stage of this species.

中文翻译：

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生长速度是温度依赖性的，但是在成年的长矛状日本分支菜的生长和性腺之间的资源分配比例却没有。

将资源分配为多种生活史特征的模式可能会随环境而变化。例如，高温通常促进生长。由于温度引起的增长投资变化可能会改变对其他特征的分配。在这里，我们研究了生长和繁殖之间的权衡，以及分配在这些植物中的比例是否随海水温度的升高而改变，而该温度则在柳叶菜分支日本枝。在实验室中，我们在三种不同的温度处理（对照，+ 1°C和+ 2°C处理）下饲养了成年早期的长矛，持续了427天。尽管开始时的总体长在不同治疗之间没有差异，但长度受到经过的天数与温度治疗之间相互作用的影响，这表明生长速率与温度有关。与在对照条件下相比，在较高温度条件下的喷枪显示出更快的生长速度。性腺个体的频率在整个生育季节之间在治疗之间没有差异。性腺的存在与否与温度处理之间的相互作用也没有显着影响月生长增量，尽管性腺的存在导致生长增量减少。另外，温度处理的效果是显着的。这些结果表明温度的变化并没有改变权衡取舍的生长和繁殖之间的分配方式，而高温只会导致资源摄入的增加，至少在该物种的成年初期。