Sexual selection and mate limitation shape evolution of species' range limits

Area of Science:

• Ecology
• Evolutionary Biology
• Sexual Selection
• Speciation

Background:

• Geographic range limits are shaped by ecological and evolutionary processes.
• Sexual selection's role in shaping range dynamics, particularly in marginal populations, is under-theorized.
• Mate limitation at low population densities can influence extinction-colonization dynamics at range margins.

Purpose of the Study:

• To investigate how different forms of sexual selection affect the formation of species' geographic range limits.
• To explore the interplay between sexual selection, mate limitation, and spatial demography.
• To understand the eco-evolutionary dynamics at range margins.

Main Methods:

• Utilized a spatially explicit eco-genetic model.
• Simulated scenarios with varying sexual selection pressures (mate encounter vs. mate competition).
• Incorporated trait evolution and demographic consequences.

Main Results:

• Sexual selection favoring mate encounter ability expanded geographic ranges by reducing female mate limitation.
• Sexual selection via mate competition narrowed ranges due to increased male mortality and female mate limitation.
• Combined effects of mate encounter and competition on range limits varied with mating systems (polygyny vs. monogamy).

Conclusions:

• Sexual selection significantly shapes species' geographic range limits.
• Feedbacks between sexual selection and spatial population dynamics are crucial for range evolution.
• The specific mode of sexual selection and mating system determine range expansion or contraction.