Host specificity and multivariate diagnostics of cryptic species in predacious cheyletid mites of the genus Cheletophyes (Acari: Cheyletidae) associated with large carpenter bees

Three closely related species of mites of the genus Cheletophyes were collected from large African carpenter bees: C. venator (Vitzthum) is associated with Xylocopa nigrita ; C. torridae sp. nov. and C. mbomba sp. nov. are associated with Xylocopa torrida . Ranges of 21 morphometric variables in C. venator and putative C. torridae are overlapping. However, a large gap between the two groups was detected in multivariate shape space, indicating the presence of two sibling species. The best subset canonical variates analysis (CVA) produced a model with fewer predictors and higher classification accuracy compared to other tested approaches, stepwise CVA and elimination of variables based on absolute correlation with canonical function. The model differentiates the two sibling species with 100% accuracy in jackknife resampling and external validation ( N = 100) using four variables. A logistic regression model built as an alternative to CVA has two variables and 97.6% and 100% classification accuracy for the analysis sample and external validation, respectively. Both models are available online at http://insects.ummz.lsa.umich.edu/ beemites/morphometrics.html. Host specificity of predacious Cheletophyes to their bee hosts in the community that includes bees, cleptoparasitic mites and their predators is discussed. Formal descriptions and synonymy of the species based on the results of the analyses are also given. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 45–58.