Integrating morphology and mitochondrial DNA for species delimitation within the spruce budworm (Choristoneura fumiferana) cryptic species complex (Lepidoptera: Tortricidae)

Abstract

Species in cryptic complexes tend to be very difficult, if not impossible, to identify using morphological characters. One such complex is the spruce budworm (Choristoneura fumiferana Clemens, 1865) species group, an economically important group of Nearctic forest pests. Morphological, ecological, behavioural and genetic characters have been studied to try to understand the taxonomy of this group better, but diagnostic character states differ in frequency rather than being complete replacements between each species. We used mitochondrial DNA (mtDNA), together with a new morphology‐based character system that focuses on forewing colour components, to determine if one or a combination of character sources can be used for species diagnoses within the spruce budworm complex. We characterized 47 forewing morphometric measurements and sequenced a 470 bp region of cytochrome c oxidase I mtDNA for 111 ingroup individuals comprising five taxa within the complex. Larval host association and coloration or adult pheromone attraction were used as the prior method for grouping individuals. Our results showed that linear discriminant analysis of morphometric wing characters gave unique clusters for all species on the first and second canonical axes, except for a partial overlap between C. fumiferana and C. biennis, which are not sympatric in nature. In contrast, mtDNA distinguished C. fumiferana, C. pinus pinus Freeman, 1953 and a group of western species, but the three western species (C. occidentalisFreeman, 1967, C. biennisFreeman, 1967 and C. lambertiana Busck, 1915) shared mtDNA haplotypes. On the basis of the linear discriminant analysis of the combined character set, this study supports the application of both morphology and mtDNA within a framework of integrative taxonomy as the most accurate method for species identification. Furthermore, it demonstrates the utility of quantitative colour analysis, which may be particularly helpful for groups in which colour characters are difficult to divide into discrete units due to intergrading hues.

Comparative ecology of conifer-feeding spruce budworms (Lepidoptera: Tortricidae)

“…Biosystematic analysis supports eight species in the spruce budworm complex of conifer-feeding Choristoneura in North America including six species in Canada (Lumley and Sperling 2010). Many more biotypes are recognised (Volney and Fleming 2007) and so more cryptic species may be revealed eventually (Lumley and Sperling 2011).…”

“…Despite this dedicated search for clear distinctions, effective separation of species requires information on morphology, geography, ecology, and genetics (Lumley and Sperling 2010). As noted by Stehr (1967), the simplest, most reliable method for distinguishing budworm species in Canada remains the geographic location and host-tree associations on which the population in question is found.…”

A toolbox for integrative species delimitation in Machilis jumping bristletails (Microcoryphia: Machilidae)

“…Integrative taxonomy (DeSalle et al, 2005;Padial et al, 2010;Schlick-Steiner et al, 2010) has proven to significantly improve the rigour of species delimitation in various animal taxa (SchlickSteiner et al, 2006;Fontaneto et al, 2007;Bond and Stockman, 2008;Macías-Hernández et al, 2008;Leaché et al, 2009;Bailey et al, 2010;Damm et al, 2010;Glaw et al, 2010;Lumley and Sperling, 2010;Ross et al, 2010;Steiner et al, 2010;Birky et al, 2011;Gurgel-Gonç alves et al, 2011;Moyal et al, 2011;Seppä et al, 2011). Multi-source approaches take advantage of complementarities amongst disciplines: It is assumed that the strength of any species delimitation hypothesis rises with the independence of the information sources , i.e.…”

Phortica eparmata species complex (Diptera, Drosophildae) from the Oriental Region, with DNA barcoding information of Chinese species

“…Although genetic divergence is low in these species of the genus Phortica, the differences in genital morphology are considered as the most reliable characters to delimit these species. The integration of morphological and DNA-based approaches has revealed an effective way to improve accuracy for species identification (An et al 2015;Dayrat 2005;Lumley & Sperling 2010;Padial & Riva 2010). However, the present study raises concern as to the extent to which species delineation can be defined based on COI, which is a widely used gene for barcoding in Drosophila, and emphasizes the necessity of exploring potentially effective morphological diagnosis when lower resolution of molecular data is observed.…”