Effects of Abiotic Factors on the Geographic Distribution of Body Size Variation and Chromosomal Polymorphisms in Two Neotropical Grasshopper Species (Dichroplus: Melanoplinae: Acrididae)
Regressions of body size and body size variability of D. pratensis on latitude and two estimators of genetic recombination. Body size and its variability are represented by the first and second principal components of a PCA analysis of six linear morphometric measurements and their coefficients of variation. PC1 showed high loadings for the six measurements and PC2 for the six CVs. (a) Distribution of body size along the studied gradient. Marginal populations show smaller body sizes than central ones. (b) Distribution of body size coefficients of variation along the studied gradient. Marginal populations show higher variability than central ones. (c) and (d) Regression of body size and body size variability on between-cell variance of mean chiasma frequency. Body size decreases but its variability increases with higher chiasma variance. (e) and (f) Regression of body size and body size variability on an ad hoc recombination index. Body size decreases but its variability increases with higher recombination frequency.