Animal dispersal dynamics promoting dioecy over hermaphroditism

Area of Science:

• Ecology
• Evolutionary Biology
• Mathematical Modeling

Background:

• Dioecious species have separate male and female individuals, leading to fewer reproductive individuals and potential disadvantages.
• Theoretical models predict dioecious females need significantly higher fecundity than hermaphrodites, but empirical data often show lower advantages.
• This discrepancy suggests unmodeled factors influence the reproductive success of dioecious species.

Purpose of the Study:

• To investigate how animal foraging dynamics affect the reproductive success of dioecious species.
• To reconcile the theoretical fecundity requirements of dioecious females with empirical observations.
• To explore the role of seed dispersal and competition in dioecious plant populations.

Main Methods:

• Developed a spatially explicit mathematical model incorporating animal foraging behavior.
• Included parameters for seed production, seed dispersal, and mortality at germination sites.
• Simulated scenarios with preferential foraging on dioecious females.

Main Results:

• Preferential animal foraging on dioecious females significantly reduces the predicted fecundity advantage required for dioecy.
• The model's predictions align with empirical estimates of female fecundity advantages in dioecious species.
• Increased seed dispersal, linked to higher female fecundity, plays a crucial role in population dynamics.

Conclusions:

• Animal foraging dynamics are essential for understanding the evolutionary viability of dioecy.
• The findings help explain the correlation between dioecy and the evolution of fleshy fruits.
• Mutualistic interactions with animal dispersers are vital for the success of dioecious plants.