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. Author manuscript; available in PMC: 2010 Nov 1.
Published in final edited form as: Exp Gerontol. 2009 Aug 27;44(11):718–726. doi: 10.1016/j.exger.2009.08.007

Table 3.

Summary of findings: Sensitivity of life span (LS) and reproduction responses to eclosion date across dietary-restriction gradients in the mexfly Anastrepha ludens

  • Hypothesis 0: Date of eclosion modulates longevity.

    Relevant findings are:
    • Eclosion date can affect LS of mexflies independently of diet and female reproduction.
    • The effect of eclosion date on LS can be of similar magnitude as that of DR treatment.

    Conclusion: Yes, date of eclosion is very important to LS even though all cohorts were treated the same as larvae.

  • Hypothesis 1: Caloric restriction extends LS.

    Relevant findings are:
    • LS is weakly sensitive to CR treatment.
    • CR can: (i) favor longevity, (ii) show no beneficial effects, and (iii) reduce LS for certain cohorts, SY treatments, and reproduction activity.
    • Manipulation of CR is not associated with real life extension.

    Conclusion: No consistent CR-effects on life extension across cohorts, SY, and reproduction are revealed.

  • Hypothesis 2: Manipulation of Dietary Composition can extent LS.

    Relevant findings are:
    • All cohorts are sensitive to changes in SY. This sensitivity can in part be attributed to the detrimental effect of the pure sugar diet.
    • Pure sugar diet is consistently unfavorable for longevity across cohorts.
    • Mexflies from distinct cohorts responded markedly differently to SY.
    • LS is more sensitive to SY treatment compared to CR treatment even with the pure sugar diet excluded.
    • Manipulation of SY can be associated with real life extension.
    • Very high yeast negatively affects survival for females irrespective of reproduction.

    Conclusion: Generally yes, there is an optimal SY treatment which is specific for males and for both fertile and non-fertile females, but the effects vary much among eclosion cohorts.

  • Hypothesis 3: DR-induced reduced reproduction extends life span.

    Relevant findings are:
    • Cohorts that do not respond to SY (HC sample):
      • The variability in survival is slightly higher for non-fertile females than for fertile females.
      • There is no consistent SY treatment which could be the most favorable for LS either for fertile or non-fertile flies.
      • Fertile females have smaller baseline mortality risks than non-fertile females for all ages.
    • Cohorts that do respond to SY (LHC sample):
      • The variability in survival is tremendously higher for non-fertile females than for fertile females.
      • Non-fertile females show remarkable consistency for the effect of SY on LS with SY=9:1 treatment as the most and SY=3:1 treatment as the least favorable diet for LS.
      • Fertile females have smaller mortality risks at younger ages whereas at older ages non-fertile females have smaller mortality risks.
    • Cohorts that do and do not respond to SY:
      • SY=3:1 diet tends to be the least favorable for LS both for fertile and for non-fertile females.
      • Maximal fecundity is found for SY=3:1 diet.

    Conclusion: Not so much, the non-fertile flies of particular cohorts respond most to DR.

  • Hypothesis 4: Reproduction depends on protein intake.

    Relevant findings are:
    • Effects of SY on reproduction are remarkably consistent across eclosion cohorts.

    Conclusion: Yes, protein intake is the dominant factor determining female reproduction.

  • Hypothesis 5: There is no sex differential in response to DR.

    Relevant findings are:
    • CR-patterns of mean LS for different SY levels are much more similar across the sexes than across the cohorts.
    • Very high yeast is favorable for longevity for males but not for females irrespective of females’ fertility.

    Conclusion: There are some differences between the sexes in responses to SY, but the effects of CR are similar for the sexes.