Phenotypic and Genetic Covariance Structure in Milkweed Bug Life History Traits
Variation in life history characteristics is critical for any species because it influences the timing and extent of population growth. When the variability is caused by gene differences among individuals, changes in population growth differ among genotypes. Gene frequencies will change at loci with effects on life history traits, and selection and microevolution of life history traits should occur. However, if many life history characteristics vary among individuals, there may be pairwise covariance caused, in part, by genetic linkage disequilibrium or by pleiotropy. Change caused by selection acting on additive genetic variance for any single character will be accompanied by change in other genetically correlated characters. Darwin (1859; see Darwin 1958) commented on this situation in reference to domestication and artificial selection, which he said “will almost certainly modify unintentionally other parts of the structure, owing to the mysterious laws of correlation” (p. 35). The importance of genetic correlations in the context of life history variables and natural selection is the primary motivation for the work reported here.
KeywordsLife History Genetic Correlation Life History Trait Clutch Size Female Offspring
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