Testing small clutch size models with Daphnia
Testing small clutch size models with Daphnia
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DOI：
10.1086/386553
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发表时间：
2004-06-01
影响因子：
2.9
通讯作者：
Little, TJ
中科院分区：
文献类型：
--
作者：
Guinnee, MA;West, SA;Little, TJ
生活史理论预测，对于小窝，（个体之间）卵大小的差异应该以一种可预测的不变方式随着窝大小的增加而减少。为了验证这一点，我们研究了350种不同食物处理下的大水蚤，并记录了它们第一次产卵的卵数和每个卵的体积。结果表明，卵数与用于繁殖的资源呈线性关系，卵数的方差随卵数的增加而减小，并且在一个卵群中资源的分配是相对平均的。然而，我们发现蛋体积随卵数变化的速率比预测的要慢。我们讨论了这种差异的可能解释，包括鸡蛋产量的下限，以及食物充足时选择较小的鸡蛋。与此一致的是，我们发现平均卵量随着卵数的增加而减少。
Life-history theory predicts that for small clutches, variance in egg size (between individuals) should decrease in a predictable invariant manner as clutch size increases. To test this, we studied Daphnia magna at 350 different food treatments and recorded the number of eggs and the volume of each egg for their first clutch. As predicted, we found that the relationship between clutch size and resources devoted to reproduction was linear, variance in egg volume decreased with increasing clutch size, and resources were shared relatively equally between the eggs in a clutch. However, we found that the rate at which the range of egg volumes decreased with clutch size was slower than predicted. We discuss possible explanations for this discrepancy, including a lower limit on the volume of eggs that are produced and selection for smaller eggs when food is abundant. Consistent with this, we found that mean egg volume decreased with increasing clutch size.