title: Distinguishing intrapopulational categories of plants by their insect faunas: galls on rabbitbrush.
abstract: Within a population of rubber rabbitbrush, Chrysothamnus nauseosus, the subspecies C. nauseosus consimilis and C. nauseosus hololeucus, and a third unidentified group were better segregated by their insect galls, than by differences in plant morphology. This level of segregation was further increased when morphological measurements and counts of insect galls were analyzed simultaneously. We interpret this result to mean that plant morphology and insect distributions reflect two different, perhaps overlapping, portions of the host's genome. By using both sets of characters concurrently, rather than either set independently, we increased the portion of the plant's genome being sampled and increased the probability of detecting differences among host genotypes. Hence, knowledge of the distributions of insect galls may be useful for augmenting the level of separation, obtained by morphological measurements, among intrapopulational categories of plant genotypes. This application may be of greatest benefit when hybridization blurs morphological distinctions among plant taxa, when morphological traits are highly variable within genotypes, or when ephemeral morphological traits (e.g., leaves, flowers) are not available for measurements.
authors.affiliation: Agriculture and Agri-Food Canada, P.O. Box 3000, TIJ 4B1, Lethbridge, Alberta, Canada.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Floate
authors.affiliation: Departamento de Biologia Geral, ICB/Universidade Federal de Minas Gerais, CP 486, 30161-970, Belo Horizonte MG, Brazil.
authors.forename: G Wilson
authors.initials: GW
authors.lastname: Fernandes
authors.affiliation: Central Arizona College, Supertition Mountain Campus, 85219, Apache Junction, AZ, USA.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Nilsson
keywords: Arizona; Discriminant function analyses; Plant systematics; Taxonomy