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An experimental test of whether the defensive phenotype of an aphid facultative symbiont can respond to selection within a host lineage.

McLean AH, Godfray HC - PLoS ONE (2014)

Bottom Line: Six aphid lineages were exposed to high parasitoid attack rates over nine generations, each line being propagated from individuals that had survived attack; a further six lineages were maintained without parasitoids as a control.At the end of the experiment the strength of resistance of aphids from treatment and control lines were compared.No differences in resistance were found.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.

ABSTRACT
An experiment was conducted to test whether parasitoid resistance within a single clonal line of pea aphid (Acyrthosiphon pisum) might increase after exposure to the parasitoid wasp Aphidius ervi. Any change in resistance was expected to occur through an increase in the density of protective symbiotic bacteria rather than genetic change within the aphid or the bacterial symbiont. Six aphid lineages were exposed to high parasitoid attack rates over nine generations, each line being propagated from individuals that had survived attack; a further six lineages were maintained without parasitoids as a control. At the end of the experiment the strength of resistance of aphids from treatment and control lines were compared. No differences in resistance were found.

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Related in: MedlinePlus

Parasitoid success rates in aphids from exposed and control treatment lines.(a) Proportion of mummies formed for the exposed treatment lines (in grey) and the control lines (in white); (b) Proportion of successful adult emergence of parasitoids from the exposed treatment lines (in grey) and the control lines (in white). No significant differences were observed between or within treatments. Error bars denote standard errors of the mean.
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pone-0111601-g001: Parasitoid success rates in aphids from exposed and control treatment lines.(a) Proportion of mummies formed for the exposed treatment lines (in grey) and the control lines (in white); (b) Proportion of successful adult emergence of parasitoids from the exposed treatment lines (in grey) and the control lines (in white). No significant differences were observed between or within treatments. Error bars denote standard errors of the mean.

Mentions: There was no significant difference between exposed and non-exposed treatments (χ2 = 0.115, d.f. = 1, P = 0.735; Fig. 1a); the average level of successful parasitism was 49.8%. This is very similar to the results of our preliminary assessment of resistance in this aphid clone before the experiment began, which found a mean of 53.0% successful parasitism. Likewise, the rate of successful emergence of parasitoids from the mummies was unaffected by treatment (χ2 = 0.432, d.f. = 1, P = 0.511; Fig. 1b), with emergence at 72.0% in the non-exposed group and 76.6% in the exposed lines.


An experimental test of whether the defensive phenotype of an aphid facultative symbiont can respond to selection within a host lineage.

McLean AH, Godfray HC - PLoS ONE (2014)

Parasitoid success rates in aphids from exposed and control treatment lines.(a) Proportion of mummies formed for the exposed treatment lines (in grey) and the control lines (in white); (b) Proportion of successful adult emergence of parasitoids from the exposed treatment lines (in grey) and the control lines (in white). No significant differences were observed between or within treatments. Error bars denote standard errors of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4232250&req=5

pone-0111601-g001: Parasitoid success rates in aphids from exposed and control treatment lines.(a) Proportion of mummies formed for the exposed treatment lines (in grey) and the control lines (in white); (b) Proportion of successful adult emergence of parasitoids from the exposed treatment lines (in grey) and the control lines (in white). No significant differences were observed between or within treatments. Error bars denote standard errors of the mean.
Mentions: There was no significant difference between exposed and non-exposed treatments (χ2 = 0.115, d.f. = 1, P = 0.735; Fig. 1a); the average level of successful parasitism was 49.8%. This is very similar to the results of our preliminary assessment of resistance in this aphid clone before the experiment began, which found a mean of 53.0% successful parasitism. Likewise, the rate of successful emergence of parasitoids from the mummies was unaffected by treatment (χ2 = 0.432, d.f. = 1, P = 0.511; Fig. 1b), with emergence at 72.0% in the non-exposed group and 76.6% in the exposed lines.

Bottom Line: Six aphid lineages were exposed to high parasitoid attack rates over nine generations, each line being propagated from individuals that had survived attack; a further six lineages were maintained without parasitoids as a control.At the end of the experiment the strength of resistance of aphids from treatment and control lines were compared.No differences in resistance were found.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.

ABSTRACT
An experiment was conducted to test whether parasitoid resistance within a single clonal line of pea aphid (Acyrthosiphon pisum) might increase after exposure to the parasitoid wasp Aphidius ervi. Any change in resistance was expected to occur through an increase in the density of protective symbiotic bacteria rather than genetic change within the aphid or the bacterial symbiont. Six aphid lineages were exposed to high parasitoid attack rates over nine generations, each line being propagated from individuals that had survived attack; a further six lineages were maintained without parasitoids as a control. At the end of the experiment the strength of resistance of aphids from treatment and control lines were compared. No differences in resistance were found.

Show MeSH
Related in: MedlinePlus