Food caching in orb-web spiders (Araneae: Araneoidea).

Area of Science:

• Behavioral Ecology
• Arachnology
• Animal Behavior

Background:

• Prey caching is a survival strategy observed in many vertebrates but is rare in invertebrates.
• Golden orb-web spiders (Nephila edulis) possess permanent webs, allowing for potential prey storage.
• Understanding the evolution of prey caching requires examining invertebrate behaviors and ecological factors.

Purpose of the Study:

• To investigate prey caching behavior in Nephila edulis and its adaptive significance.
• To compare prey caching strategies between Nephila edulis and Argiope keyserlingi.
• To identify preadaptations for the evolution of prey caching in orb-web spiders.

Main Methods:

• Experimental manipulation of prey caches for Nephila edulis of varying weights.
• Monitoring weight loss in spiders with and without access to stored prey.
• Observing prey attack behavior in Nephila edulis and Argiope keyserlingi under different prey availability conditions.

Main Results:

• Heavier Nephila edulis spiders experienced reduced weight loss when accessing prey caches.
• Lighter Nephila edulis spiders showed no significant difference in weight loss regardless of cache availability.
• Nephila edulis consistently attacked new prey, while Argiope keyserlingi reduced attacks when prey was already cached.

Conclusions:

• Prey caching in Nephila edulis is an effective strategy for heavier individuals to mitigate starvation risk.
• The permanent web structure of Nephila edulis is a crucial preadaptation for the evolution of prey caching.
• Orb-web spider prey caching likely evolved in species with durable webs, facilitating food storage.