Indiana University Seminar In Ecology & Environmental Biology Series. Bloomington, IN. Contributed talk. 2019/03/05

1. Experimental evolution of longevity
Roy Z Moger-Reischer
rzmogerr@indiana.edu

2. Acknowledgements
• Jay Lennon, Megan Behringer,
Daniel Schwartz, Jordan Bird,
Will Shoemaker, Nathan
Wisnoski, Emmi Mueller
• Betsy Snider, Kelsey McKenzie,
Danni Boylan, JD French
• Farrah Bashey-Visser, Jake
McKinlay, Matt Hahn
• Kevin Webster, Ashwini Ramesh,
Etienne Nzabarushimana, Katie
Beidler, Misty Proffitt

3. log(lx)
x
No senescenceSenescence
• Background theory
• Laboratory experiments
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥

4. Life-history theory
• Define?

5. Life-history theory
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥
Age x
Expectedfecundity
α …∞

6. log(lx)
x
Life-history theory
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥
Extrinsic mortality

7. log(lx)
x
No senescenceSenescence
Life-history theory
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥
Senescence is a problem for evolutionary biology.

8. log(lx)
x
No senescenceSenescence
𝑠 𝑥 = න
𝑥
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥 = 1 − න
0
𝑥
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥
Life-history theory

9. Senescence
qE
Life-history theory

10. Life-history theory
Ricklefs 2010 (Aging Cell)

11. log(lx)
x
No senescenceSenescence
Life-history theory
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥

12. Life-history theory
Luckinbill et al. 1984 (Evolution)

13. Life-history theory
Khazaeli & Curtsinger 2010 (Evolution)Luckinbill et al. 1984 (Evolution)

14. log(lx)
x
No senescenceSenescence
• Background theory
• Laboratory experiments
Alberts 2008

15. Experiment: antagonistic pleiotropy
• Reveal reproduction-longevity tradeoffs
• Show whether selection for one life-history trait constrains the
other life-history trait

16. Experiment: antagonistic pleiotropy
• Treatment 1: Experimental evolution, serial transfer, every 3 days
• Age-associated mortality: 0%
• Proportion total fitness from longevity component: 0.00 (a
priori)

17. Experiment: antagonistic pleiotropy
• Treatment 2: Experimental evolution, serial transfer, every 12 days
• Age-associated mortality: ~95%
• Proportion total fitness from longevity component: ~0.54 to ~0.58
(via simulation)

18. Trt 1 (no long)
Reproductivefitness(W)
Trt 2 (longevity selection)

19. Trt 1 (no long)
Lifeexpectancy(days)
Trt 2 (longevity selection)

20. Experiment: dietary restriction

21. Experiment: dietary restriction
• Dietary restriction == reduction in energy consumed, without
malnutrition
• Most reproducible and phylogenetically broadly applicable
environmental intervention to ↑ longevity
• Evolutionary basis of dietary restriction effect?

22. Experiment: dietary restriction
• Evolutionary basis of dietary restriction effect?
• Adaptive reallocation hypothesis
• Cellular recycling hypothesis
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥

23. Control evolution
Lifeexpectancy(days)
Evolution on DR

25. Control evolution
Reproductivefitness(W)
Evolution on DR

27. log(lx)
x
No senescenceSenescence
• Life-history theory makes testable
predictions about the evolution of
longevity and senescence
• I did some laboratory experiments
• I want to show whether selection
for longevity constrains the
evolution of reproductive fitness
• I showed that life extension by
DR is not adaptive reallocation
𝑅0 = න
𝑥=𝛼
∞
𝑙 𝑥 𝑚 𝑥 ⅆ𝑥

28. extra materials

29. Experiment: antagonistic pleiotropy
• Treatment 2: Experimental evolution, serial transfer, every 12 days
• Age-associated mortality: ~95%
• Proportion total fitness from longevity component: ?

32. log(lx)
x
No senescenceSenescence
Life history theory is an elaborate answer
to the simple question of why having more
offspring is not always selected for. (van
Noordwijk & de Jong, 1986, p. 137)
1 = න
0
∞
𝑙 𝑥 𝑚 𝑥 ⅇ−𝑟𝑥
ⅆ𝑥

33. log(lx)
x
No senescenceSenescence
Life history theory is an elaborate answer
to the simple question of why having more
offspring is not always selected for. (van
Noordwijk & de Jong, 1986, p. 137)
Similarly, life history theory ventures to
answer why unlimited longevity is not
always selected for.

34. log(lx)
x
No senescenceSenescence
Life-history theory
𝑉 𝑥 =
ⅇ 𝑟𝑥
𝑙 𝑥
න
𝑥
∞
ⅇ−𝑟𝑥
𝑙 𝑦 𝑚 𝑦 ⅆ𝑦