The scale insects (Insecta: Hemiptera: Coccoidea) are small, plant-sucking insects with extraordinary biological and morphological characteristics. They display unusual development, sexual dimorphism, and have a remarkable diversity of genetic systems, including parthenogenesis, hermaphroditism and paternal genome elimination. Many species are important pests, causing plant damage via sap removal, growth distortion, pathogen vectoring and honeydew contamination. Although more than 7500 species of scale insects have been described, there are many additional undescribed species, and a substantial proportion of the named species, especially in the tropics and southern hemisphere, are difficult or impossible to identify with existing literature. Scale insect taxonomy is based largely on microscopic cuticular features of adult females and identification requires special technical skills in microscope slide preparation. Worldwide the number of scale insect researchers (coccidologists), especially taxonomists, is declining and recruitment via student training is minimal. This project combines the expertise of scale insect systematists, Drs. P.J. Gullan and D.R. Miller, and molecular systematist, Dr. B.B. Normark, to train coccidology students in taxonomic monography, phylogenetic systematics and computer-based data analysis, illustration and dissemination. Three clades of Coccoidea that display unusual modes of reproduction and are poorly-known and/or difficult to identify are targeted for study. These are (1) the tribe Iceryini of the Margarodidae, (2) the genus Chionaspis Signoret, tribe Diaspidini, of the armored scale family, Diaspididae, and (3) the subfamily Myzolecaniinae of the soft scale family, Coccidae. Students will be trained in field techniques and in taxonomic and curatorial methods, as well as in phylogenetic analysis of morphological and molecular character data. The trainee researchers will utilize the specimens and specialist libraries of the two largest scale insect collections in North America - the United States National Collection of Coccoidea at the United States Department of Agriculture, Maryland, and the Bohart Museum of Entomology, University of California, Davis.
Students will learn to score morphological and molecular characters, to manage those data using computer programs, to use the data to infer phylogenetic trees, and to use those trees to construct classifications and infer the evolution of biological traits. This will result in training a new generation of taxonomic specialists on these important insects. Products of the project will include published monographs, databases, and web-based interactive keys that employ digital images that will have broad impact and utility to ecologists, agriculturists, conservation biologists, geneticists, and others.
