Molecular phylogeny of the homoptera: a paraphyletic taxon

Abstract

Homoptera and Heteroptera comprise a large insect assemblage, the Hemiptera. Many of the plant sap-sucking Homoptera possess unusual and complex life histories and depend on maternally inherited, intracellular bacteria to supplement their nutritionally deficient diets. Presumably in connection with their diet and lifestyles, the morphology of many Homoptera has become greatly reduced, leading to major controversies regarding the phylogenetic affiliations of homopteran superfamilies. The most fundamental question concerns whether the Homoptera as a whole are monophyletic. Recent studies based on morphology have argued that the Homoptera Sternorrhyncha (Aphidoidea, Coccoidea, Psylloidea, Aleyrodoidea) is a sister group to a group comprising the Homoptera Auchenorrhyncha (Fulgoroidea, Cicadoidea, Cercopoidea, Cicadelloidea) and the Heteroptera, making the Homoptera paraphyletic. We sequenced the 5' 580-680 base pairs of small-subunit (18S) ribosomal DNA from a selection of Homoptera, Hemiptera, and their putative outgroups, the Thysanoptera and Psocoptera, to apply molecular characters to the problem of Homoptera phylogeny. Parsimony, distance, maximum-likelihood, and bootstrap methods were used to construct trees from sequence data and assess support for the topologies produced. Molecular data corroborate current views of relationships within the Sternorrhyncha and Auchenorrhyncha based on morphology and strongly support the hypothesis of homopteran paraphyly as stated above. In addition, it was found that Homoptera Sternorrhyncha have extra, GC-rich sequence concentrated in a variable region of the 18S rDNA, which indicates that some unique evolutionary processes are occurring in this lineage.

Origin of a haplodiploid beetle lineage

“…Thus in scolytids it is now possible to compare diplodiploid and haplodiploid sister groups that can both be unambiguously inferred to occupy the same ancestral environment and to have (apart from dispersal and breeding biology) largely the same ancestral habits. In no other case is this now possible (Beutel & Haas 1996;Blaxter et al 1998;Crespi et al 1996;Garey et al 1996;Hoernschemeyer 1998;Mable & Otto 1998;Von Dohlen & Moran 1995;White 1973;Whiting et al 1997), though future phylogenetic analyses may ultimately make it possible in other cases, especially in scale insects and mites (Norton et al 1993;Nur 1980).…”

“…There are now thought to have been at least 17 origins of haplodiploidy in Metazoa, 15 of these in arthropods (Mable & Otto 1998). Most of these origins are poorly resolved phylogeneticallyöneither basal haplodiploid lineages nor diplodiploid sister lineages have been identi¢ed (Beutel & Haas 1996;Blaxter et al 1998;Bull 1983;Crespi et al 1996;Garey et al 1996;Hoernschemeyer 1998;Norton et al 1993;Nur 1980;Von Dohlen & Moran 1995;White 1973;Whiting et al 1997)öpreventing an understanding of the ecological, demographic, and cytogenetic context in which haplodiploidy arose. Hamilton (1967) suggested that most origins of haplodiploidy in arthropods have occurred under conditions of extreme inbreeding.…”

Endosymbiotic Microbiota of the Bamboo PseudococcidAntonina crawii(Insecta, Homoptera)

“…In contrast, it has been reported that in aphids and psyllids two types of symbiotic bacteria are harbored separately in distinct types of mycetocytes (6,19,(21)(22)(23). Within the Sternorrhyncha, however, coccids and aphids are thought to be phylogenetically related, while the positions of whiteflies and psyllids are controversial (7,45). In addition, the symbionts of whiteflies and pseudococcids did not exhibit significant phylogenetic affinities (Fig.…”

Huge Symbiotic Organs in Giant Scale Insects of the GenusDrosicha(Coccoidea: Monophlebidae) Harbor Flavobacterial and Enterobacterial Endosymbionts

“…These PCR reactions were performed under conditions of 95°C for 10 min followed by 35 cycles of 95°C for 15 sec, 55°C for 15 sec, and 72°C for 1 min, with negative and positive control samples. To confirm the quality of template DNA in the samples, a 0.65-kb fragment of the insect 18S rRNA gene was amplified with primers 2880 (5'-CTG GTT GAT CCT GCC AGT AG-3') (Tautz et al, 1988) and B (5'-CCG CGG CTG CTG GCA CCA GA-3') (von Dohlen and Moran, 1995) under conditions of 95°C for 10 min followed by 30 cycles of 95°C for 15 sec, 55°C for 15 sec, and 72°C for 1 min.…”