Mating group size and evolutionarily stable pattern of sexuality in barnacles

Area of Science:

• Marine biology
• Evolutionary ecology
• Reproductive strategies

Background:

• Barnacles, a type of marine crustacean, display a wide array of sexual patterns, including simultaneous hermaphroditism, androdioecy, and dioecy.
• Understanding the environmental factors that shape these diverse reproductive strategies is crucial for evolutionary biology.

Purpose of the Study:

• To develop a predictive model for barnacle sexuality patterns.
• To investigate the influence of food availability and larval settlement fraction on reproductive strategies.
• To explain the spectrum of sexual patterns observed in barnacle species.

Main Methods:

• Developed a model incorporating two key environmental factors: food availability and larval settlement fraction.
• Utilized dynamic programming to calculate optimal resource allocation (male function, female function, growth) for small and large barnacles.
• Defined sexuality patterns based on optimal resource allocation combinations and analyzed mating group size as a dependent variable.

Main Results:

• Sexuality patterns are strongly correlated with food availability, mediated by mating group size.
• Simultaneous hermaphroditism is predicted in food-rich environments with large mating groups.
• Androdioecy, dioecy, and sex change are observed in food-poor environments with small mating groups; protandric simultaneous hermaphroditism occurs in intermediate conditions.

Conclusions:

• Food availability is a primary driver of sexual pattern evolution in barnacles, influencing mating group dynamics.
• The model successfully explains the rich diversity of barnacle sexual patterns, including the capacity for small males to grow into larger individuals.