PT  - JOURNAL ARTICLE
AU  - Liu, Ming
AU  - Rubenstein, Dustin R.
AU  - Liu, Wei-Chung
AU  - Shen, Sheng-Feng
TI  - Biological adaptation under fluctuating selection
AID  - 10.1101/457762
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 457762
4099  - http://biorxiv.org/content/early/2018/10/31/457762.short
4100  - http://biorxiv.org/content/early/2018/10/31/457762.full
AB  - Bet-hedging—an evolutionary strategy that reduces fitness variance at the expense of lower mean fitness—is the primary explanation for most forms of biological adaptation to environmental unpredictability. However, most applications of bet-hedging theory to biological problems have largely made unrealistic demographic assumptions, such as non-overlapping generations and fixed population sizes. Consequently, the generality and applicability of bet-hedging theory to real world phenomena remains unclear. Here we use continuous-time, stochastic Lotka-Volterra models to relax overly restrictive demographic assumptions and explore a suite of biological adaptations to fluctuating environments. We discover a novel “rising-tide strategy” that—unlike the bet-hedging strategy—generates both a higher mean and variance in fitness. The positive fitness effects of the rising-tide strategy’s specialization to good years can overcome any negative effects of higher fitness variance in unpredictable environments. Moreover, we show not only that the rising-tide strategy will be selected for over a much broader range of environmental conditions than the bet-hedging strategy, but also under more realistic demographic circumstances. Ultimately, our model demonstrates that there are likely to be a wide range of ways that organisms respond to environmental unpredictability.