| Scale insects are involved in numerous intimate relationships with other organisms. They are parasites of plants, hosts of endosymbionts, hosts of parasitoids, and mutualists with social Hymenoptera. Scale insects are sexually dimorphic, neometabolous, and have lineages that are hermaphroditic, asexual, and haplodiploid. Scale insects have had considerable impact on human societies, as pests of agriculture and as sources of food, dyes and lacquer. More than 7,000 species have been described, but a significant fraction of the true diversity is unknown. Our understanding of scale insect evolution is rudimentary. Here, we present seven studies that further our understanding of scale insect diversity and evolution. (1) We evaluate the utility of two nuclear protein-coding genes, dynamin and triose-phosphate isomerase, for scale insect phylogenetics. For a group of felt scales (Eriococcidae) the markers are easy to amplify and are evolving at rates comparable to widely used nuclear ribosomal loci. (2) We estimate the mealybug (Pseudococcidae) phylogeny using a combination of morphological and DNA sequence data. We recover two primary clades, each of which is characterized by distinctive microbial ecology. Based on these results, we propose a new subfamily classification. (3) We describe a new mealybug species from Hydnophytum in Fiji. (4) We estimate the phylogeny of the Nothofagus-feeding felt scales, and recover the monophyly of all but one the Nothofagus -feeding species included in our analysis. We revise Madarococcus Hoy for this group and describe the first six Australian species. (5) We describe a new genus and four new species of felt scales that feed on Eucalyptus. (6) We reconstruct the phylogeny of the Eucalyptus-feeding felt scales and recover a monophyletic group of species within a Myrtaceae-feeding clade. We describe six new species closely related to Lachnodius hirtus Maskell, which we redescribe. (7) We describe a new species from Bursaria in Australia. |
