Blackman rl; Spence Jm 1994

• Authors: Blackman rl; Spence Jm
• Title: The effects of temperature on aphid morphology, using a multivariate approach.
• Location: European journal of entomology, 91 (1). 1994. 7-22.
• Abstract: clonal samples of aphids were used as the groups in canonical variate (cv) analysis, in order to compare the temperature responses of single genotypes, and thus to distinguish genotypic and environmental contributions to the phenotypic response pattern. the analysis was based on a large data set obtained by measuring 19 linear variables on adult apterae reared at four temperatures (10, 15, 20 and 26.5 degree c). the species used were myzus persicae (sulzer) and its close relative, m. Antirrhinii (macchiati). two vectors - the scores on the first two cv's - were invariably needed to describe the temperature response. in each of three m. persicae clones, the first cv had a close linear correlation with temperature, partly corresponding to the decrease in body size at higher temperature, whereas the temperature relationship of the second cv fitted a quadratic function, being less at both high and low temperatures, and reflecting a change of "shape", partly comprising a relative decrease in lengths of appendages at low temperature. in m. Antirrhinii the temperature relations of these two cv's was reversed, that of cv1 being quadratic and that of cv2 linear. when different genotypes of a species were combined in the same analysis, the first and second cv's still described the "two-way" response to temperature as for clones analysed separately, but the third and fourth cv's were totally independent of rearing temperature and separated samples according to their genotype. the consistency with which temperature effects are allocated to the first two variates seems to indicate the presence of two different aspects of the phenotypic response to temperature, perhaps reflecting different metabolic pathways by which temperature affects the pattern of growth.