Foraging strategy as a route for sexual size dimorphism evolution.

Area of Science:

• Evolutionary Biology
• Animal Behavior
• Zoology

Background:

• Female-biased sexual size dimorphism (SSD) is common, often explained by fecundity selection favoring larger females.
• Increased body size requires greater energy intake, potentially limiting female size evolution.
• Lucrative foraging tactics may enable larger female sizes, influencing SSD.

Purpose of the Study:

• To investigate the relationship between foraging strategies and sexual size dimorphism in crab spiders.
• To test if more lucrative foraging strategies correlate with increased female body size and SSD.

Main Methods:

• Collected body size data for 614 crab spider species across 43 genera.
• Classified species based on their foraging strategies (e.g., flower foraging, prey-luring).
• Statistically analyzed the correlation between foraging strategy and SSD.

Main Results:

• Species employing lucrative foraging strategies exhibit significantly larger SSD.
• Females in high-energy-input species are 91% larger than males, versus 26% in non-high-energy-input species.
• Larger female size is linked to fecundity selection, while smaller male size may result from scramble competition.

Conclusions:

• Lucrative foraging strategies are associated with amplified sexual size dimorphism in crab spiders.
• The evolution of enhanced foraging tactics likely played a crucial role in the body size and SSD evolution of these spiders.