Multivariate analyses of Canadian and Japanese populations of Glycyphagus destructor (Schrank) (Acarina, Glycyphagidae)

Two multivariate statistical procedures were used to determine the basic trends of morphologic and geographic variations between males of a common stored-grain mite, Glycyphagus destructor (ScHRANK) collected from Canada and Japan. All analyses were carried out on physical measurements of 25 morphological features. Three principal component analyses based on the Canadian (50 specimens), Japanese (50 specimens) and the combined populations from the 2 countries (100 specimens) revealed that the first component, accounting for 40% of the variability, in all 3 solutions represented a measure of the morphologic dimension of the body. The second component, which explained over 18% of the variability, is a measure of the leg dimension. Smaller clusters of variates characteristic of the population from each county were also evident. Discriminant analysis, performed with the Canadian and Japanese populations, identified the variates that differed between the 2 populations and provided an approximate appraisal of interrelations. The general conclusion based on these analyses is that the Canadian and the Japanese populations are morphologically distinct. The difference is most evident in the diameters of genu 2, lengths of the sensory seta W~, lengths of the body, and the distances between the vertical external setae.