spatio-temporal patterns of mortality in pemphigus populicaulis and p. populitransversus on cottonwoods.galls of the aphid species pemphigus populitransversus and p. populicaulis from a single cottonwood in clinton, new york were censused for mortality approximately every ten days during the summer of 1978. p. populitransversus had significantly higher survival than p. populicaulis. both species of aphid showed considerably elevated mortality later in the season. mortality was not spatially random, but neighboring galls had a tendency to die at close to the same time. this tendency to spatially au ...198528311563
pemphigus revisited: changes in geographic variation but constancy in variability and covariation.samples of the gall-forming aphids pemphigus populicaulis and p. populitransversus (both elongate and globular morphs) were re-collected at sites in eastern north america after 13 to 16 years. twenty-three morphometric characters of the galls, stem mothers, and alate fundatrigeniae were analyzed by univariate and multivariate methods. varying proportions of the variance of each character are attributable to the four levels of variation-locality, year, year by locality interaction, and among gall ...199128564143
group size factors and geographic variation of morphometric correlation.within-locality correlations among eight morphological traits of the fundatrix and among 15 morphological traits of the alate fundatrigeniae of the aphid pemphigus populicaulis fitch were examined for among-locality variation. a jackknife procedure revealed highly significant differences among correlation matrices representing 34 local samples from eastern north america. most bivariate correlations also differed significantly among samples. although very low correlations cannot differ, for moder ...198528561352
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