Stamps Judy A, Saltz Julia B, Krishnan V V
Evolution and Ecology, University of California Davis.
Anim Behav. 2013 Sep;86(3):641-649. doi: 10.1016/j.anbehav.2013.07.012.
Intra-genotypic variability (IGV) occurs when individuals with the same genotype, raised in the same environment and then tested under the same conditions, express different trait values. Game theoretical and bet-hedging models have suggested two ways that a single genotype might generate variable behaviour when behavioural variation is discrete rather than continuous: behavioural polyphenism (a genotype produces different types of individuals, each of which consistently expresses a different type of behaviour) or stochastic variability (a genotype produces one type of individual who randomly expresses different types of behaviour over time). We first demonstrated significant differences across 14 natural genotypes of male in the variability (as measured by entropy) of their microhabitat choice, in an experiment in which each fly was allowed free access to four different types of habitat. We then tested four hypotheses about ways that within-individual variability might contribute to differences across genotypes in the variability of microhabitat choice. There was no empirical support for three hypotheses (behavioural polymorphism, consistent choice, or time-based choice), nor could our results be attributed to genotypic differences in activity levels. The stochastic variability hypothesis accurately predicted the slope and the intercept of the relationship across genotypes between entropy at the individual level and entropy at the genotype level. However, our initial version of the stochastic model slightly but significantly overestimated the values of individual entropy for each genotype, pointing to specific assumptions of this model that might need to be adjusted in future studies of the IGV of microhabitat choice. This is among a handful of recent studies to document genotypic differences in behavioural IGV, and the first to explore ways that genotypic differences in within-individual variability might contribute to differences among genotypes in the predictability of their behaviour.
当具有相同基因型的个体在相同环境中饲养，然后在相同条件下进行测试时，若表现出不同的性状值，就会出现基因型内变异性（IGV）。博弈论和风险对冲模型提出了两种方式，当行为变异是离散而非连续时，单一基因型可能产生可变行为：行为多态性（一种基因型产生不同类型的个体，每种个体始终表现出不同类型的行为）或随机变异性（一种基因型产生一种个体，该个体随时间随机表现出不同类型的行为）。在一项实验中，我们首先证明了14种雄性自然基因型在微生境选择变异性（以熵衡量）上存在显著差异，在该实验中，每只果蝇都可自由进入四种不同类型的栖息地。然后，我们测试了关于个体内变异性可能导致微生境选择变异性基因型差异的四种假设。对于三种假设（行为多态性、一致选择或基于时间的选择）均未得到实证支持，我们的结果也不能归因于活动水平的基因型差异。随机变异性假设准确预测了个体水平熵与基因型水平熵之间跨基因型关系的斜率和截距。然而，我们随机模型的初始版本略微但显著高估了每种基因型的个体熵值，这表明该模型的特定假设可能需要在未来微生境选择IGV研究中进行调整。这是最近少数记录行为IGV基因型差异的研究之一，也是首个探索个体内变异性基因型差异可能导致其行为可预测性基因型差异的研究。
