Abstract

This study reports variation between populations of the phytoseiid mite Kampimodromus aberrans (Oudemans). The influence of seasons (summer and winter), different host plants, and localities on morphological variation was investigated to determine the reliability of the parameters usually used to distinguish species in the genus Kampimodromus. This study was conducted in southern France. The specimens examined consisted of three summer and three winter populations each collected from Celtis australis L., Quercus pubescens Willdenow (referred as Q. pubescens no. 1 in the text) and Corylus avellanae L., and three additional summer populations collected from each of Q. pubescens (referred as Q. pubescens no. 2 in the text), Vitis vinifera cv. Carignan and Vitis vinifera cv. Cabernet-Sauvignon.

Significant differences were observed between the winter and summer populations. Females of summer populations had longer setae than females of winter populations. However, these differences are usually very small. Greatest differences were observed within the population collected in summer on Q. pubescens no. 1 from which two distinct groups of specimens were distinguished. To determine if more than one species of Kampimodromus were present on this plant, measurements of other closely related species were also included in the analysis. It was concluded that all the females studied belong to K. aberrans. However, the setal variations observed raised the following questions. (i) What is the validity of other closely related species whose setal lengths differ only slightly from those of K. aberrans? (ii) Are setal lengths useful characters to distinguish between closely related species in the genus Kampimodromus?