Multitasking and the evolution of optimal clutch size in fluctuating environments

Area of Science:

• Ecology
• Evolutionary Biology
• Animal Behavior

Background:

• The fecundity gradient paradox describes contrasting avian clutch size patterns along latitudinal and elevational gradients.
• This paradox challenges the prevailing bet-hedging strategy, where larger clutch sizes are expected with longer breeding seasons.

Purpose of the Study:

• To propose and test the multitasking hypothesis as an alternative explanation for avian clutch size variation.
• To resolve the fecundity gradient paradox by integrating seasonality and predation risk factors.

Main Methods:

• Development of individual-based and analytical models to simulate clutch size strategies.
• Synthesis of existing hypotheses (seasonality, predation) within the new multitasking framework.

Main Results:

• Models demonstrate that smaller clutches are favored in shorter breeding seasons as a multitasking strategy (breeding and recovery).
• Bet-hedging strategies are not favored by natural selection, even with high predation risk or long breeding seasons.
• The multitasking hypothesis offers an integrative model to explain contrasting clutch size patterns.

Conclusions:

• Saving time by avoiding wasted effort is a key benefit favoring small clutch sizes in short seasons.
• The multitasking hypothesis provides a novel perspective on life-history evolution in fluctuating environments.
• This research resolves the fecundity gradient paradox by offering a unified explanation.