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Ambulatory dispersal in Tetranychus urticae: an artificial selection experiment on propensity to disperse yields no response.

Tien NS, Sabelis MW, Egas M - Exp. Appl. Acarol. (2011)

Bottom Line: Upward and downward selection on propensity to leave the colony was performed for seven generations in four replicate artificial selection experiments and the results were compared to control lines.No consistent responses to selection were found and no significant effect on life-history traits (oviposition rate, juvenile survival, development rate and number of adult offspring) or sex ratio was present across the replicates.The data suggest that our base population of spider mites harbours at best a low amount of additive genetic variation for this behaviour.

View Article: PubMed Central - PubMed

Affiliation: Institute For Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O.Box 94248, 1090GE Amsterdam, The Netherlands. N.S.H.Tien@uva.nl

ABSTRACT
Dispersal to new hosts is an important process for an invasive herbivore, such as the two-spotted spider mite. A recent study, using artificial selection experiments, has suggested that genetic variation and genetic trade-offs are present for propensity to disperse in this species. However, due to the experimental setup alternative explanations for the response to selection could not be ruled out. Using an altered setup, we investigated whether the propensity for ambulatory dispersal differs genetically between individuals and whether genetic correlations with life-history traits exist. Upward and downward selection on propensity to leave the colony was performed for seven generations in four replicate artificial selection experiments and the results were compared to control lines. No consistent responses to selection were found and no significant effect on life-history traits (oviposition rate, juvenile survival, development rate and number of adult offspring) or sex ratio was present across the replicates. The data suggest that our base population of spider mites harbours at best a low amount of additive genetic variation for this behaviour.

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Fraction of females that dispersed within 30 min, relative to the total number of dispersing females (individual dispersal index). Both selection treatments (high/low) were compared to their control line within replicates (1–4); *P < 0.05. Numbers under the treatments depict the total number of dispersing females. Total number of examined females (including non-dispersers) was 18 per line
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Fig2: Fraction of females that dispersed within 30 min, relative to the total number of dispersing females (individual dispersal index). Both selection treatments (high/low) were compared to their control line within replicates (1–4); *P < 0.05. Numbers under the treatments depict the total number of dispersing females. Total number of examined females (including non-dispersers) was 18 per line

Mentions: When placing a single female on a bad-quality leaf disc, 88% of the females dispersed to a nearby fresh leaf within a day, while the remaining females died. Figure 2 depicts the fraction of fast dispersers, i.e. the females that dispersed within 30 min (the individual index). In replicate 1, the frequency of fast dispersers was not significantly different between the control line and the high line (Gadj,1 = 1.70, P = 0.19) or the low line (Gadj,1 = 0.01, P = 0.92). In replicate 2, the high line had significantly less fast dispersers than the control line (Gadj,1 = 3.92, P = 0.05), while the low line was not different (Gadj,1 = 0.25, P = 0.61). In replicate 3, the low line had significantly more fast dispersers than the control line (Gadj,1 = 4.51, P = 0.03), while the high line was not different (Gadj,1 = 0.26, P = 0.61). In replicate 4, neither selection line was significantly different from their control line (high line: Gadj,1 = 1.74, P = 0.19, low line: Gadj,1 = 0.15, P = 0.70).Fig. 2


Ambulatory dispersal in Tetranychus urticae: an artificial selection experiment on propensity to disperse yields no response.

Tien NS, Sabelis MW, Egas M - Exp. Appl. Acarol. (2011)

Fraction of females that dispersed within 30 min, relative to the total number of dispersing females (individual dispersal index). Both selection treatments (high/low) were compared to their control line within replicates (1–4); *P < 0.05. Numbers under the treatments depict the total number of dispersing females. Total number of examined females (including non-dispersers) was 18 per line
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040828&req=5

Fig2: Fraction of females that dispersed within 30 min, relative to the total number of dispersing females (individual dispersal index). Both selection treatments (high/low) were compared to their control line within replicates (1–4); *P < 0.05. Numbers under the treatments depict the total number of dispersing females. Total number of examined females (including non-dispersers) was 18 per line
Mentions: When placing a single female on a bad-quality leaf disc, 88% of the females dispersed to a nearby fresh leaf within a day, while the remaining females died. Figure 2 depicts the fraction of fast dispersers, i.e. the females that dispersed within 30 min (the individual index). In replicate 1, the frequency of fast dispersers was not significantly different between the control line and the high line (Gadj,1 = 1.70, P = 0.19) or the low line (Gadj,1 = 0.01, P = 0.92). In replicate 2, the high line had significantly less fast dispersers than the control line (Gadj,1 = 3.92, P = 0.05), while the low line was not different (Gadj,1 = 0.25, P = 0.61). In replicate 3, the low line had significantly more fast dispersers than the control line (Gadj,1 = 4.51, P = 0.03), while the high line was not different (Gadj,1 = 0.26, P = 0.61). In replicate 4, neither selection line was significantly different from their control line (high line: Gadj,1 = 1.74, P = 0.19, low line: Gadj,1 = 0.15, P = 0.70).Fig. 2

Bottom Line: Upward and downward selection on propensity to leave the colony was performed for seven generations in four replicate artificial selection experiments and the results were compared to control lines.No consistent responses to selection were found and no significant effect on life-history traits (oviposition rate, juvenile survival, development rate and number of adult offspring) or sex ratio was present across the replicates.The data suggest that our base population of spider mites harbours at best a low amount of additive genetic variation for this behaviour.

View Article: PubMed Central - PubMed

Affiliation: Institute For Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O.Box 94248, 1090GE Amsterdam, The Netherlands. N.S.H.Tien@uva.nl

ABSTRACT
Dispersal to new hosts is an important process for an invasive herbivore, such as the two-spotted spider mite. A recent study, using artificial selection experiments, has suggested that genetic variation and genetic trade-offs are present for propensity to disperse in this species. However, due to the experimental setup alternative explanations for the response to selection could not be ruled out. Using an altered setup, we investigated whether the propensity for ambulatory dispersal differs genetically between individuals and whether genetic correlations with life-history traits exist. Upward and downward selection on propensity to leave the colony was performed for seven generations in four replicate artificial selection experiments and the results were compared to control lines. No consistent responses to selection were found and no significant effect on life-history traits (oviposition rate, juvenile survival, development rate and number of adult offspring) or sex ratio was present across the replicates. The data suggest that our base population of spider mites harbours at best a low amount of additive genetic variation for this behaviour.

Show MeSH