Egg size has numerous ecological implications for zooplankton, and can influence hatching duration and female fecundity. In this study, temperature functions of embryonic development time (EDT) were determined in the copepod Eodiaptomus japonicus from Lake Biwa, in the cold and warm seasons, to clarify synergistic effects of egg size and temperature on EDT. EDT was longer for cold season eggs than warm ones, but both seasons were well fitted by Bĕlehrádek’s function. Egg size was significantly correlated with female body size within seasons, but the relationship did not differ significantly between seasons. These results suggest that seasonal variation in EDT, which was associated with egg size, may result from temperature-mediated variation of female body size, because larger females produced larger eggs as temperature decreased. Larger eggs may enhance fitness under severe food conditions in winter due to high hatchability and naupliar survival.

中文翻译：

---

大小介导的温度对日本琵琶湖Eodaptomus japonicus（Copepoda，Calanoida）胚胎发育的影响

卵的大小对浮游动物有很多生态影响，并且可以影响孵化时间和雌性繁殖力。在这项研究中，确定了pe足类古猿Eodiaptomus japonicus的胚胎发育时间（EDT）的温度功能。可以在寒冷和温暖的季节从琵琶湖采摘，以阐明鸡蛋大小和温度对EDT的协同作用。淡季鸡蛋的EDT比暖季鸡蛋的EDT长，但两个季节都符合Bĕlehrádek的功能。鸡蛋的大小与季节内的女性体重显着相关，但各个季节之间的关系无显着差异。这些结果表明，EDT的季节性变化与鸡蛋的大小有关，可能是温度介导的雌性体型变化引起的，因为随着温度的降低，较大的雌性会产生较大的卵。由于较高的孵化率和无节幼体的存活率，较大的鸡蛋可能会在冬季严峻的食物条件下增强体质。