Abstract
Nine different local populations of Schizotetranychus celarius (BANKS) which inhabited dwarf bamboo were examined from the morphological and behavioral points of view. Morphological variations of dorsal propodosomal seta, P2 and dorsocentral hysterosomal seta, D2 among the nine populations were conspicuous. Comparison of the field and laboratory populations revealed that the variations in the setae, P2 and D2, had been fixed for each local population from generation to generation. Among these populations, there were three distinguishable groups with different length of setae, P2 and D2, (short, medium and long setae). Nest webs which were constructed by adult females under experimental conditions varied in size among the nine populations. The trend of the variation paralleled that of the setae, P2 and D2. Multiple regression analysis was made to estimate which morphological characters (xi) could affect the nest web size (Y). From this analysis, it was concluded that the features of the setae, P2 and D2 exerted an important influence on the nest web size. Behavioral observation of S. celarius females under the nest web showed that the setae, P2 and D2 appeared to operate as a sensor for the recognition of the woven roof of the nest. The statistical data, therefore, were explained by this function of setae.
