Mites and Biological Diversity

Abstract

‘Ubiquitous’ is a much abused adjective that literally means ‘being everywhere’ but in practice it means considerably less. The word is often trotted out by ecologists and systematists to justify their working on a particular group of plants or animals (e.g. ‘rodents make good bioindicators because they are ubiquitous in terrestrial ecosystems’), sometimes with little support for their assertions. However, mites have a fair claim for being truly omnipresent (Fig. 11.1). With the exception of the water column of the open ocean, they exist in every sort of aquatic, terrestrial, arboreal and parasitic habitat. In spite of this, mites rarely appear in general biodiversity surveys (but see Basset et al. 2012). Data on mite diversity in tropical ecosystems is especially rare. Two interrelated reasons for this neglect, shared with other ubiquitous and ‘hyper-diverse’ taxa such as nematodes, are small body size and alleged difficulty of identification. Small-bodied organisms are often overlooked in rapid assessments of biodiversity, particularly when samples are sorted with the naked eye. Even if mites are seen, it is almost impossible to identify them to species in the field; instead, maceration, slide-mounting and microscopic examination are required.