The symbiotic associations between beetles and ants have been observed in at least 35 beetle families. Among myrmecophiles, beetles exhibit the most diverse behavioral and morphological adaptations to a life with ants. These various associations have historically been grouped into discrete but overlapping behavioral categories, many of which are still used in the modern literature. While these behavioral classifications provide a rich foundation for the study of ant-beetle symbioses, the application of these systems in future studies may be less than effective. Since morphological characteristics often provide the only information of myrmecophilous beetles, they should be studied in a species-by-species fashion, as behavioral data are often limited or unavailable. Similarly, behavioral studies should focus on the target species at hand, avoiding discrete classification schemes. I formally propose the rejection of any classification scheme, in order to promote future studies of myrmecophily in both taxonomic and evolutionary studies. 1. Introduction Myrmecophily is a charismatic biological phenomenon that defines the associations, whether casual or intimate, of various organisms with ants. Myrmecophilous life habits have been observed in at least 95 families of arthropods, including several genera of isopods, pseudoscorpions, many araneeid spiders, mites, millipedes, and close to 100 families of insects [1]. Among insects, the beetles are often the most easily recognized and morphologically distinct myrmecophiles, leading to a significant body of work. Currently, at least 35 beetle families are known to be associated with ants in some form or another [1, 2], but for at least fifteen of these families behavioral data are entirely absent. In many cases, presumed ant associates, both within the Coleoptera and other myrmecophilous groups, are cited as myrmecophiles based on unobserved interactions with ants, especially if specimens were collected in or near an ant nest. Specifically, beetles are considered to be myrmecophilous if they bear unique morphological characteristics presumed to be linked to myrmecophily. These morphological modifications frequently include combinations of enlarged or reduced antennae, reddish or “ant-red” integument, and, less often, modified mouthparts or appendages that are sometimes associated with a myrmecophilous habit [3]. Perhaps the most commonly documented and presumably convincing evidence for a life with ants is the presence of trichomes, or tufts of setae associated with exocrine glands, but similar clusters of
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