Genetic variation in an introduced aphid pest (Metopolophium dirhodum) in New Zealand and relation to individuals from europe

Abstract

RAPD‐PCR was used to determine the genetic variation of Metopolophium dirhodum collected in a winter wheat field and in a nearby 2.5‐m‐high suction trap at Lincoln, New Zealand. Over three collection dates, five distinct genotypes were identified, using two primers (OPK16 and OPC09) independently. There was a significant temporal effect on the ratio of genotypes in populations collected in the field. There was no significant spatial aggregation or association of these genotypes in the field. Two of the genotypes present in the field were also detected in the suction trap sample. Using a higher resolution method of RAPD‐PCR (with the Stoffel fragment of Taq polymerase), a total of 124 genotypes were distinguished from 142 individuals collected from Scotland and New Zealand. The Jaccard similarity index (S) was used to measure similarity between individual aphids within and between populations from both hemispheres. All populations were very diverse (S < 0.33). However, at similar crop growth stages, M. dirhodum was significantly more diverse in Scotland than in New Zealand. The results are discussed in relation to the value of monitoring aphid flights for pest forecasting, and in terms of the most appropriate RAPD‐PCR techniques.

The biological improbability of a clone

“…Parallels in the animal kingdom include marine bryozoa (Harvell, 1998) ; soft coral, Alcyonium rudyi (McFadden, 1997) ; freshwater snails, Potamopyrgus antipodarum (Fox et al, 1996) ; fish, Poecilia formosa and Ri ulus marmoratus (Turner et al, 1990 ;1992) and aphids, e.g. grain aphid, Sitobion a enae (Sunnucks et al, 1997 ;Simon et al, 1999) and the rose-grain aphid, Metopolophium dirhodum (Nicol et al, 1997). Irrespective of taxa, all these organisms show abundant clonal diversity (genetically typed variants) in the ecosystems that they inhabit.…”

Genetic structure and clonal diversity of an introduced pest in Chile, the cereal aphid Sitobion avenae

“…The mode of reproduction of the introduced organism plays also an important role in modulating these genetic effects (Lynch, 1984;Simon et al, 1999a). Surprisingly, patterns of genetic variation within introduced populations of parthenogenetic species have not been extensively studied (but see Nicol et al, 1997Nicol et al, , 1998Downie, 2002 for aphids). Genetic markers, particularly highly polymorphic ones, have proven useful to identify the genetic source of introduced populations and to document the temporal and spatial dynamics of recent invasions through characterization of their genetic structure (Davies et al, 1999).…”

Temporal genotypic diversity of Schizaphis graminum (Rondani 1852) (Hemiptera: Aphididae) in a black oats (Avena strigosa) field

“…When aphid colonization is at the beginning, there is no significant parasitism and predation. As a consequence, the founder population will have predominance at temporal and spatial scale (Nicol et al, 1997;Nakashima and Akashi, 2005). The second most common genotype, Sg2, was only detected in the samples collected in June, but already detected with higher frequency at this month.…”

“…In this work, even using fewer primers than Lopes-da-Silva et al (2004), it was possible to find in only one black oats field about 30% of the genetic diversity found for S. graminum collected in several regions of Brazil. Within Metopolophium dirhodum, Nicol et al (1997), also using only two primers, distinguished five genotypes from 142 clones. In regions where sexual phase occurs, the genetic diversity of cereals aphids tends to be high even in small areas.…”

“…These apparent disagreements could be attributable to the differences in sampling methodology, type of genetic markers, aphid species and environmental effects. For instance, Martinez-Torres et al (1997) did not find genetic variation into populations of Rhopalosiphum padi (Linnaeus 1758) whereas Nicol et al (1997) reported genetic variation at temporal scale in Metopolophium dirhodum (Walker 1849). The former authors utilized mitochondrial haplotypes for their study and the latter utilized RAPD markers.…”