School of Biological Sciences, Illinois State University, 251 S. School St., Normal, IL, 61761, USA.
Sci Rep. 2022 May 16;12(1):8075. doi: 10.1038/s41598-022-11909-y.
Understanding the relationship of population dynamics to density is central to many ecological investigations. Despite the importance of density-dependence in determining population growth, the empirical relationship between density and per capita growth remains understudied in most systems and is often assumed to be linear. In experimental studies of interspecific competition, investigators often evaluate the predicted outcomes by assuming such linear relationships, fitting linear functions, and estimating parameters of competition models. In this paper, we experimentally describe the shape of the relationship between estimated population rate of change and initial density using laboratory-reared populations of three mosquito species. We estimated per capita growth rate for these experimental populations over a 30-fold range of larval densities at a standard resource abundance. We then compared fits of linear models and several different nonlinear models for the relationship of estimated rate of change and density. We find that that the relationship between density and per capita growth is strongly non-linear in Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), and Aedes triseriatus (Say) mosquitoes. Components of population growth (survivorship, development time, adult size) are also nonlinearly related to initial density. The causes and consequences of this nonlinearity are likely to be important issues for population and community ecology.
理解种群动态与密度的关系是许多生态学研究的核心。尽管密度依赖性在决定种群增长方面很重要，但在大多数系统中，密度与个体增长率之间的经验关系仍未得到充分研究，并且通常假定为线性关系。在种间竞争的实验研究中，研究人员通常通过假设这种线性关系、拟合线性函数和估计竞争模型的参数来评估预测结果。在本文中，我们使用实验室饲养的三种蚊子种群，实验描述了种群变化率与初始密度之间关系的形状。我们在标准资源丰度下，在幼虫密度的 30 倍范围内，估计了这些实验种群的个体增长率。然后，我们比较了线性模型和几种不同的非线性模型对估计的变化率和密度之间关系的拟合程度。我们发现，在埃及伊蚊（Linnaeus）、白纹伊蚊（Skuse）和三带喙库蚊（Say）蚊子中，密度与个体增长率之间的关系呈强非线性。种群增长的组成部分（存活率、发育时间、成虫大小）也与初始密度呈非线性关系。这种非线性的原因和后果可能是种群和群落生态学的重要问题。
