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MOLECULAR PHYLOGENETICS AND EVOLUTION Molecular Phylogenetics and Evolution 25 (2002) 43–52 www.academicpress.com A preliminary phylogeny of the scale insects (Hemiptera: Sternorrhyncha: Coccoidea) based on nuclear small-subunit ribosomal DNA Lyn G.Cook, * Penny J.Gullan, 1 and Holly E.Trueman 2 School of Botany and Zoology, The Australian National University, Canberra, ACT 0200, Australia Received 9 July 2001 Abstract Scale insects (Hemiptera: Sternorrhyncha: Coccoidea) are a speciose and morphologically specialized group of plant-feeding bugs in which evolutionary relationships and thus higher classification are controversial.Sequences derived from nuclear small-subunit ribosomal DNA were used to generate a preliminary molecular phylogeny for the Coccoidea based on 39 species representing 14 putative families.Monophyly of the archaeococcoids (comprising Ortheziidae, Margarodidae sensu lato, and Phenacoleachia) was equivocal, whereas monophyly of the neococcoids was supported.Putoidae, represented by Puto yuccae, was found to be outside the remainder of the neococcoid clade.These data are consistent with a single origin (in the ancestor of the neococcoid clade) of a chromosome system involving paternal genome elimination in males.Pseudococcidae (mealybugs) appear to be sister to the rest of the neococcoids and there are indications that Coccidae (soft scales) and Kerriidae (lac scales) are sister taxa.The Eriococcidae (felt scales) was not recovered as a monophyletic group and the eriococcid genus Eriococcus sensu lato was polyphyletic. Ó 2002 Elsevier Science (USA).All rights reserved. 1. Introduction comprise the Margarodidae sensu lato (as in Morrison, 1928), the Ortheziidae (Koteja, 1974a, 1996), the The scale insects (Hemiptera: Sternorrhyncha: Coc- Carayonemidae (Kozaar and Konczne Benedicty, 2000), coidea) are obligatory plant parasites which are found in and sometimes the Phenacoleachiidae (Danzig, 1980; all terrestrial zoogeographical regions except Antarctica. Koteja, 1996).However, most of the morphological There are estimated to be more than 7700 species of characters that define the archaeococcoids (abdominal coccoids assigned variously to 20 or more families (Ben- spiracles, compound eyes in males, and an XX–X0 Dov et al., 2001; Gullan and Kosztarab, 1997; Koteja, chromosome system) are plesiomorphies that occur 1974a).Often the families are divided into two major, more widely in the Hemiptera and thus paraphyly of informal groups which sometimes are treated as super- archaeococcoids is likely (e.g., Foldi, 1997). families, the archaeococcoids or archaeococcids The neococcoids, which comprise all of the other ( ¼ Orthezioidea) and the neococcoids or neococcids families and most of the species of scale insects, are ( ¼ Coccoidea sensu stricto) (Borchsenius, 1950; Danzig, treated currently as a monophyletic group.It has been 1980; Kosztarab and Kozaar, 1988; Kosztarab, 1996; defined by synapomorphies such as a chromosome sys- Koteja, 1974a, 1996; Miller, 1984).The archaeococcoids tem involving paternal genome elimination (PGE) (Danzig, 1980; Nur, 1980), needle-like apical setae on * Corresponding author.Fax: +61-2-61255573. the labium (Koteja, 1974b, 1996), shared structural and E-mail address: [email protected] (L.G. Cook). developmental features of the ovaries (Szklarzewicz, 1 Present address: Department of Entomology, University of Cali- 1998), and the absence of abdominal spiracles (Morri- fornia, Davis, CA 95616-8584, USA. 2 son, 1928).Among the neococcoids sensu lato, only Puto Present address: Department of Biology, Imperial College of Science, Technology, and Medicine, Imperial College Rd., London, (XX–X0), sometimes considered part of the Pseudo- UK. coccidae (e.g., Danzig, 1980; Kosztarab, 1996; Miller 1055-7903/02/$ - see front matter Ó 2002 Elsevier Science (USA).All rights reserved. PII: S1055-7903(02)00248-8 44 L.G. Cook et al. / Molecular Phylogenetics and Evolution 25 (2002) 43–52 and Miller, 1993), the eriococcid genus Lachnodius for inclusion as outgroups.The main aims of the (2N–2N), and the Stictococcidae (2N–2N) do not ex- present study were to: (1) provide a hypothesis of the hibit chromosome systems with PGE (Nur, 1980).In relationships among the higher taxa of the Coccoidea, PGE systems, both male and female zygotes are diploid (2) test the monophyly of the Eriococcidae and Erio- and there are no sex chromosomes.Instead, the pater- coccus sensu lato, and (3) provide new data to assist nally inherited haploid set of chromosomes becomes with interpreting coccoid evolution and reassessing heterochromatic, or is lost, in males during early em- higher classification. bryogenesis. Relationships among coccoid families are largely unknown or not supported well by morphological data 2. Materials and methods (Foldi, 1997; Gullan and Kosztarab, 1997; Kosztarab, 1996).Individual families are often well characterized by 2.1. Specimens and DNA extraction autapomorphies but there is controversy concerning the monophyly of some of the traditionally recognized The coccoid taxa used, their current taxonomic families such as the Margarodidae sensu lato (see Foldi, classification (following Ben-Dov et al., 2001), and col- 1997; Gullan and Sjaarda, 2001; Miller, 1984) and the lection localities are shown in Table 1.We obtained Eriococcidae (Cox and Williams, 1987; Miller and sequences from 39 scale insect species belonging to 14 Gimpel, 2000), which are defined mostly by symplesio- families, including all major families and several species- morphies.In the past, Eriococcidae has subsumed sev- poor families whose relationships have been problem- eral other currently recognized families or has been atical.The monophyly of each of the three largest broken into a number of less inclusive taxa (for review families, Coccidae, Diaspididae, and Pseudococcidae, see Miller and Gimpel, 2000).Within the Eriococcidae, has not been questioned and thus only a few species of even the definition of the type genus, Eriococcus, has each of these groups were included. oscillated from a restricted concept (e.g., Borchsenius, The cuticles of adult females were slide-mounted to 1950; Miller and Gimpel, 1996) to a broad one (e.g., allow identification and to provide voucher specimens. Miller and Gimpel, 2000; Williams, 1985). Vouchers are deposited in the Australian National In- A robust phylogeny of the Coccoidea is required to sect Collection, CSIRO Entomology, Canberra and in stabilize classification and to test hypotheses about scale the Bohart Museum of Entomology at the University of insect biology, including biogeography, and evolution, California, Davis.DNA was extracted from fresh or in particular the evolution of chromosome systems and ethanol-preserved specimens using the salting-out host–parasite relationships, the origins of gall induction, method of Sunnucks and Hales (1996).A chloroform and the correlates of radiation events.To date, few wash was performed prior to precipitation with ethanol studies have attempted to reconstruct the phylogeny of if solids or excessive pigments were present. the whole group other than through intuitive phylo- grams (Boratynski and Davies, 1971; Herrick and Seger, 2.2. PCR and sequencing 1999; Kosztarab, 1996; Kosztarab and Kozaar, 1988; Nur, 1980) or preliminary cladistic analysis of mor- The 50 region of the nuclear SSU rDNA was ampli- phological data. fied using the primers 2880 (50-CTGGTTGATCCTGCC Cladistic studies either have had limited taxonomic AGTAG-30) (Tautz et al., 1988) and B- (50-CCGCGGC scope (e.g., Miller, 1984; Miller and Hodgson, 1997) or TGCTGGCACCAGA-30) (von Dohlen and Moran, have not examined node support in a critical manner 1995).PCRs (25 ll) contained 5 pmol of each primer, (Foldi, 1997).This lack of a reliable phylogenetic esti- 10 mM Tris–Cl (pH 8.3), 3 mM MgCl2,50mMKC1, mate is due primarily to the very reduced and highly 0.2 mM each dNTP, 1 unit of Taq-polymerase (Fisher modified morphologies of adult female scale insects, Taq Fl; Biotech), and 2 ll of template.Amplification which leads to there being few phylogenetically infor- was carried out in a Corbett Research FTS-960 thermal mative features that can be scored for taxa across all sequencer using a 45-s denaturation at 94 °C and a 30-s recognized families. extension at 72 °C and using a 5 °C stepdown program This is the first phylogenetic hypothesis for Coc- for annealing with the first cycle at 65 °C and the final 35 coidea based on molecular data.Because of the ap- cycles at 45 °C.PCR products were precipitated and parent age of some of the older lineages within the purified using ammonium acetate:ethanol (1:10) fol- Coccoidea and the likelihood of substitutional satura- lowed by a 70% ethanol wash.Target products from tion in faster-evolving genes, the nuclear small subunit PCR which contained minor bands were excised from a ribosomal RNA gene (SSU rRNA) was considered 1% agarose gel following electrophoresis and purified most appropriate.SSU rRNA data were available for using the BresaClean DNA purification kit (GeneWorks other sternorrhynchans from previous studies (Camp- Cat.No.BT-3000) following the manufacturer’s bell et al., 1994, 1995; von Dohlen and Moran, 1995) instructions. L.G. Cook et al. / Molecular Phylogenetics and Evolution 25 (2002) 43–52 45 Table 1 Coccoidea used in this study Species Current family Source Tissue Length of GenBank classification SSU rDNAa Accession No. Araucaricoccus queenslandicus Brimblecomb Margarodidae Australia wf 563 Callipappus sp.Margarodidae Australia o,e 606 Icerya

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