A Multivariate Assessment of Phenetic Relationships Within the Feather Mite Family Eustathiidae (Acari)

Abstract

Moss, W. W., P. C. Peterson, and W. T. Atyeo (Department of Entomology, Academy of Natural Sciences, 19th and The Parkway, Philadelphia, Pennsylvania 19103, Department of Biological Sciences, Youngstown State University, Youngstown, Ohio 44555, and Department of Entomology, University of Georgia, Athens, Georgia 30602). 1977. A multivariate assessment of phenetic relationships within the feather mite family Eustathiidae (Acari). Syst. Zool. 26:386–409.—Techniques of numerical taxonomy were applied in combination to morphometric data based on 111 characters from 61 OTUs, representing 61 species of the feather mite family Eustathiidae. Smaller subsets of taxa were analyzed to clarify the relationships and status of certain species. A statisfactory classification was obtained, complementing a monographic revision of the family in press. Supraspecific taxa were indicated by the placement of species on minimum spanning trees superimposed upon ordination diagrams. The latter were obtained by nonmetric multidimensional scaling applied to taxonomic distances. An initial configuration for multidimensional scaling was taken from a principal component analysis of character correlations. In every case except one the placement of species into genera by numerical methods matched our impressions of generic entities obtained by traditional approaches, although between- and within-generic relationships were clarified. The combination of Q- and R-mode analysis, including the use of nonmetric multidimensional scaling, provided an effective approach to the analysis of taxonomic structure. Multidimensional scaling is strongly recommended for similar studies as a technique to improve the accurate visual representation of taxonomic relationships. Only moderately strong host-parasite relationships occur within the Eustathiidae, although the group as a whole is restricted to the Apodi. No member of the Eustathiidae occurs on the other suborder of the Apodiformes, the Trochili. This emphasizes the distinction between Apodi and Trochili, and points again toward the question of whether or not these taxa of birds should be placed together. Host-parasite relationships within the Eustathiidae may be associated with resource tracking, but further data on feeding habits and life histories of the mites are needed to answer this question. Finally, this study represents a collaborative approach to the solution of a taxonomic problem. We feel that the collaborative approach has considerable potential in the resolution of difficult relationships within the Acari and other groups of organisms. [Numerical taxonomy; phenetics; ordination; multidimensional scaling; cluster analysis; Acari; Eustathiidae; feather mites; Apodi; swifts.]