On the use of DNA sequences for determining the species limits of a polymorphic new species in the stink bug genus Halys (Heteroptera: Pentatomidae) from Pakistan

Abstract

Abstract. We describe a new species of Halys Fabricius (Pentatomidae: Pentatominae: Halyini) based on morphological and DNA sequence data, and demonstrate the value of DNA sequences for taxonomic problems that are difficult to resolve on the basis of morphology alone. Halys sindillus Memon, Meier & Manan, sp.n. varies with regard to characters that are usually constant within the genus (spermathecal bulb of females; blade of male clasper; ratio between the second and third antennomeres; length of labium). The surprising levels of variation raised the question as to how many species were represented in three series of specimens from Pakistan. Because the morphological variability was largely continuous, we hypothesized the presence of one new species, and confirm this result here using sequence data from two mitochondrial markers. The data reveal very little molecular variation within the newly described species (COI: 730 bp: 0-0.16%; COI/tRNA Leu /COII: 563 bp: 0-0.36%), that is, morphology and DNA sequences show very different patterns of variability. The new species is compared with the closely related Halys sulcatus (Thunberg) whose sequences are distinctly different and whose spermathecal bulbs are largely invariable (I: 2.87-3.28%; II: 2.13-2.49%). We discuss the shortcomings of mitochondrial data in taxonomy and compare the genetic distances in Halys with frequency distributions of intra-and interspecific distances obtained for all 878 Hemiptera COI sequences in GenBank. We conclude that the observed distances for Halys are consistent with our taxonomic conclusions, thus demonstrating the usefulness of DNA sequences for Halys taxonomy. However, the observed overlap between intra-and interspecific sequence variability in Hemiptera is so wide that it questions the feasibility of approaches to taxonomy based predominantly on DNA sequences (e.g. DNA taxonomy, DNA barcoding).

Testing the Potential of Proposed DNA Barcoding Markers inNezara virudulaandNezara antennataWhen Geographic Variation and Closely Related Species Were Considered

“…The COI gene as the core of the global bio-identification system for animals has suffered great disputations DeSalle 2005;Hurst and Jiggins 2005;Meier et al 2006;Memon et al 2006, Jansen et al 2009Sundberg et al 2010;Yassin et al 2010). The most important problem is the observed wide overlap between intra-and interspecific sequence variability using COI as the molecular marker (Meyer and Paulay 2005;Meier et al 2006;Memon et al 2006;Alexander et al 2009;Jansen et al 2009). The lack of resolving power of the COI sequence has led researchers to envisage the primary COI-based method.…”

Phylogeny of the South Asian Halyine Stink Bugs (Hemiptera: Pentatomidae: Halyini) Based on Morphological Characters

“…Halys species feed on a variety of host plants, and they show great structural variation with geography and ecology. Recently, Abdul Manan (unpublished) observed great variation in supposedly diagnostic characters (even in the male and female genitalia, previously considered diagnostic at both generic and species levels) among specimens within single populations, mostly from Sindh (Pakistan) but not across the whole of Pakistan and India, where these characters were very constant: DNA sequencing conÞrms that these were all a single species (Memon et al 2006). The signiÞcance of this variation is not yet clear.…”

“…However, their descriptions were based only on external morphology (coloration, length of antennal segment, length of labium of some species, length of body, habitus, and female external genital plate) and did not include anything about the male or internal female genitalia. This led to a high risk of species misidentiÞcation; hence, modern workers have spent a lot of time and effort on synonymization and transfer of species and genera (Abbasi andAhmad 1971, 1976;Chopra 1974;Ghauri 1975aGhauri ,b, 1977aGhauri ,b,c, 1980Ghauri , 1982aGhauri , 1988aAfzal and Ahmad 1981;Ahmad and Parveen 1982;Ahmad and Kamaluddin 1978;Abbasi 1986;Ahmad and Ahmad 1993;Memon and Ahmad 1998, 1999, 2001, 2002a,b, 2003Ahmad et al , 2003Ahmad et al , 2004aMemon et al 2002Memon et al , 2006Rider 2006).…”

Male biased gene flow in banana pseudostem weevil (Odoiporus longicollis Oliver) as revealed by analysis of the COI-tRNALeu COII region

“…The rate of evolution of the mitochondrial protein coding regions is much faster than the 12S and 16S rDNA genes and hence these regions serve as useful markers for deciphering evolutionary history at the levels of family, genera and species (Wan et al 2004). Mitochondrial genes have been used to decipher phylogeny and phylogeography in several insects (Orsini et al 2007) including Heliconius butterflies (Brown 1994), Halys fabriciusm (Memon et al 2006), Diabrotica (Szalanski et al 2000), Adelges cooleyi (Ahern et al 2009), Aphidus ervi (Hufbauer et al 2004) and Apis cerana indica F (Baskaran 2011). In few studies, mitochondrial genes have not proved useful for the estimation of phylogeography at the intraspecies level.…”