Identification, distribution, and molecular characterization of the apple aphids Aphis pomi and Aphis spiraecola (Hemiptera: Aphididae: Aphidinae)

Abstract

Morphometric techniques, DNA mitochondrial cytochrome c oxidase subunit 1 gene (COI) barcoding, and microsatellite flanking region sequences were used to assess the reliability of suggested morphological characters in distinguishing the green apple aphid (Aphis pomi De Geer) from the spirea aphid (Aphis spiraecola Patch), and to assess variation within these species. Both molecular approaches clearly distinguished two groups corresponding to the morphologically defined species. Differences in the length of the distal rostral segment and the number of lateral tubercles were found to be robust indicators of species membership, performing as well as multivariate approaches. Among A. pomi samples, microsatellite flanking region sequences were relatively uniform, whereas A. spiraecola exhibited much variability, which suggests that North American populations of the latter species are genetically much more complex.Résumé-Des techniques morphométriques et l'utilisation de codes à barres d'ADN de COI et de séquences de la région flanquante des microsatellites nous ont servi à évaluer les caractères morphologiques qu'on a proposés pour distinguer le puceron vert du pommier (Aphis pomi De Geer) du puceron de la spirée (Aphis spiraecola Patch), et à déterminer la variation au sein de ces espèces. Les deux approches moléculaires permettent de distinguer clairement les deux groupes qui correspondent aux espèces définies morphologiquement. Les différences dans la longueur du segment distal du rostre et le nombre de tubercules latéraux sont des indicateurs robustes de l'identité spécifique; l'utilisation de ces caractères fonctionne aussi bien que les méthodes multidimensionnelles. Les séquences de la région flanquante des microsatellites sont relativement uniformes chez A. pomi, mais elles sont très variables chez A. spiraecola, ce qui laisse croire que les populations nord-américaines de cette dernière espèce sont génétiquement beaucoup plus complexes.[Traduit par la Rédaction]

Aphis pomi and Aphis spiraecola (Hemiptera: Sternorrhyncha: Aphididae) in Europe - new information on their distribution, molecular and morphological peculiarities

“…outdoors also in Latvia (2008) and Lithuania (2005Lithuania ( , 2012Lithuania ( -2014 (R. Rakauskas, unpubl.). The aim of this study is to identify the available European samples of the A. pomi-spiraecola species complex using partial sequences of mitochondrial COI and nuclear EF-1α genes and test the reliability of the morphological characters used to discriminate between these two species (Blackman & Eastop, 2000;Foottit et al, 2009). …”

“…Numbers of caudal hairs in both species showed much more overlap (Table 5). In addition to these three characters, Foottit et al (2009) suggest the ratio of siphuncular length to caudal (apical part) length, with the threshold discriminating value being 2.45. In our case, this ratio ranged from 2.00 to 3.86 in the apple aphid, and for the spirea aphid it was 0.67-2.77 and 1.74-2.95 for samples from Europe and China, respectively (Table 5).…”

“…Samples representing different clades in the molecular tree and haplotype network were used to verify the characters commonly used in the morphology-based keys discriminating both species (Halbert & Voegtlin, 1992;Blackman & Eastop, 2000;Foottit et al, 2009). The following characters were selected: URS -ultimate rostral segment length; SIPHON -siphunculus length; CAUDA -length of cauda (apical part); MT2-4(5) -numbers of marginal tubercles on abdominal tergites II-IV(V); HCAU-DA -numbers of caudal hairs; SIPHON/CAUDA -ratio of siphuncular length to caudal (apical part) length.…”

“…Unlike the males of the apple aphid, those of the spirea aphid are winged and the oviparae have swollen tibiae (Palmer, 1952;Halbert & Voegtlin, 1992). Despite suggested morphology-based discrimination characters (Stroyan, 1985;Heie, 1986;Halbert & Voegtlin, 1992;Blackman & Eastop, 2000;Foottit et al, 2009), close morphological similarity of winged and apterous viviparous females together with overlapping of host plant lists has caused confusion over the identity of both species (Singh & Rhomberg, 1984;Stroyan, 1985;Heie, 1986;Halbert & Voegtlin, 1992;Blackman & Eastop, 2000). Namely, authors reporting winged males of the apple aphid (Davletshina, 1963;Karczewska, 1965) might actually refer to the spirea aphid.…”

“…Competitive displacement of apple aphid by spirea aphid is reported as mediated by human activities in North America (Hogmire et al, 1992;Brown et al, 1995;Lowery et al, 2006;Smirle et al, 2010), making host plant based discrimination of both species even more complicated. Recently, a resolution of this discrimination problem was proposed using molecular taxonomy (Lushai et al, 2004;Foottit et al, 2009;Naaum et al, 2012).…”