Model and Data Concur and Explain the Coexistence of Two Very Distinct Animal Behavioral Types

Area of Science:

• Behavioral ecology
• Evolutionary biology
• Animal behavior

Background:

• Behavioral syndromes, or linked behaviors, are crucial for understanding behavioral diversity in populations.
• The spillover hypothesis suggests female aggression towards prey and males enhances fecundity at the cost of sperm acquisition.

Purpose of the Study:

• To investigate ecological conditions favoring the evolution of the spillover strategy in female aggression.
• To compare the "spillover strategy" with an "early-spillover strategy" and a "sperm-acquisition-first" strategy.

Main Methods:

• An individual-based model was used to simulate behavioral evolution under different ecological scenarios.
• Empirical data from the spider *Lycosa hispanica* were analyzed to support model predictions.

Main Results:

• A classic spillover strategy was not evolutionarily stable.
• An "early-spillover" strategy, involving earlier maturation and larger size, could be maintained and invade populations under specific ecological conditions.
• Frequency-dependent selection can lead to the coexistence of both behavioral strategies.
• Data from *Lycosa hispanica* support the coexistence of these strategies in natural populations.

Conclusions:

• The evolution and maintenance of animal personalities are influenced by ecological factors and trade-offs.
• The "early-spillover" strategy provides a viable mechanism for the evolution of complex behavioral syndromes.
• Behavioral plasticity and timing play critical roles in reproductive success and strategy evolution.