Nutrient-mediated architectural plasticity of a predatory trap

Area of Science:

• Animal Behavior
• Ecology
• Biochemistry

Background:

• Nutrient availability influences foraging strategies in many animals.
• Foraging plasticity is common, but effects of nutrient deprivation remain understudied.
• Protein allocation in spiders may conflict between silk production and somatic maintenance.

Purpose of the Study:

• To investigate how protein intake affects foraging plasticity in orb-web spiders.
• To determine the impact of protein depletion on web architecture and silk composition.
• To compare responses between two orb-web spider species.

Main Methods:

• Orb-web spiders (Argiope aemula, Cyclosa mulmeinensis) were fed high, low, or no protein diets for 10 days.
• Web architectural components (e.g., radii, mesh size) were analyzed post-feeding.
• Major ampullate (MA) silk amino acid compositions (proline, alanine, glycine) were compared.

Main Results:

• High protein diets increased web radii in both species and mesh size in A. aemula.
• MA silk amino acid composition varied by species, with contrasting alanine changes.
• Spiders maintained body mass across all treatments, indicating no somatic sacrifice for silk.

Conclusions:

• Dietary protein significantly influences foraging decisions in trap-building predators like spiders.
• Species-specific variations in silk amino acids and web plasticity demonstrate differing responses to protein deprivation.
• Protein intake is a key factor modulating foraging behavior and resource allocation in spiders.