A molecular phylogeny of Hemiptera inferred from mitochondrial genome sequences

Abstract

Classically, Hemiptera is comprised of two suborders: Homoptera and Heteroptera. Homoptera includes Cicadomorpha, Fulgoromorpha and Sternorrhyncha. However, according to previous molecular phylogenetic studies based on 18S rDNA, Fulgoromorpha has a closer relationship to Heteroptera than to other hemipterans, leaving Homoptera as paraphyletic. Therefore, the position of Fulgoromorpha is important for studying phylogenetic structure of Hemiptera. We inferred the evolutionary affiliations of twenty-five superfamilies of Hemiptera using mitochondrial protein-coding genes and rRNAs. We sequenced three mitogenomes, from Pyrops candelaria, Lycorma delicatula and Ricania marginalis, representing two additional families in Fulgoromorpha. Pyrops and Lycorma are representatives of an additional major family Fulgoridae in Fulgoromorpha, whereas Ricania is a second representative of the highly derived clade Ricaniidae. The organization and size of these mitogenomes are similar to those of the sequenced fulgoroid species. Our consensus phylogeny of Hemiptera largely supported the relationships (((Fulgoromorpha,Sternorrhyncha),Cicadomorpha),Heteroptera), and thus supported the classic phylogeny of Hemiptera. Selection of optimal evolutionary models (exclusion and inclusion of two rRNA genes or of third codon positions of protein-coding genes) demonstrated that rapidly evolving and saturated sites should be removed from the analyses.

Figure 1. Graphical representation of the mitochondrial genome of Pyrops candelaria.

Lines within the circle represent the amplification products. The other two fulgoroid species (Lycorma delicatula and Ricania marginalis) sequenced in this study have the same mitogenome structure as Pyrops.

Figure 2. Maximum-parsimony phylogram of 49 hemipterans.

Phylogenetic analysis was based on 13 protein-coding genes (only including first and second codon positions) and two rRNA genes. The tree was rooted by Orthoptera and Psocoptera. Only bootstrap support values above 50% are shown.

Figure 3. Maximum-likelihood phylogram infered from 13 protein-coding genes (1st and 2nd codon positions) and two rRNA genes.

The tree was rooted by Orthoptera and Psocoptera. Only bootstrap support values above 50% are shown.

Figure 4. Bayesian phylogram inferred from 13 protein-coding genes (1st and 2nd codon positions) and two rRNA genes.

The tree was rooted by Orthoptera and Psocoptera. Only posterior probabilities above 50% are shown.

Figure 5. Maximum-parsimony trees from datasets excluding long-branch taxa.

(A) Analysis of dataset ALL_123. (B) Analysis of dataset PCG_123. Only bootstrap values above 50% are shown.

Figure 6. Maximum-parsimony trees from datatsets excluding outgroups.

(A) Excluding all four outgroups. Branch support values are given as bootstrap values for the dataset ALL_123 (left) and PCG_123 (right). (B) Outgroups excluding only psocid. Only bootstrap values above 50% are shown.