Tests for sex differences in fitness-linked traits in the spider Agelenopsis aperta (Araneae: Agelenidae)

The idea that traits linked to individual fitness may differ between males and females was tested in the desert funnel-web spider, Agelenopsis aperta. The study entailed comparison of juvenile male and female behavior with respect to three traits previously shown to be linked to female body mass and ultimately to individual female fitness: habitat discrimination, territorial behavior, and agonistic behavior. As juveniles, male and female spiders behave similarly: they utilize the same habitat cues in locating web sites, maintain similar territory sizes, and exhibit the same behavior patterns in territorial disputes. Like females, males that obtain the highest-quality web sites achieve a greater body mass and are more likely to survive to maturity.