Prey type, vibrations and handling interactively influence spider silk expression

Area of Science:

• Biochemistry
• Animal Behavior
• Materials Science

Background:

• Spider silk's chemical and mechanical properties vary with prey, influenced by MaSp1 and MaSp2 gene expression.
• The specific prey cues triggering differential gene expression remain largely unknown.
• Prey nutrients, vibratory stimuli, and handling are hypothesized influences.

Purpose of the Study:

• To investigate the relative influence of prey nutrients versus vibratory stimuli and handling on silk protein expression.
• To decouple prey-associated stimuli from nutrients in the orb web spider Nephila pilipes.
• To understand how spiders adjust gene expression for silk production based on prey type.

Main Methods:

• Experiments were designed to isolate vibratory stimuli/handling from nutrients using crickets and flies.
• Amino acid composition of major ampullate (MA) silks was analyzed in Nephila pilipes under different feeding conditions.
• Gene expression changes were inferred from amino acid composition shifts.

Main Results:

• Spiders feeding on crickets produced MA silks with higher percentages of glutamine, serine, alanine, and glycine compared to those fed flies.
• Proline composition in MA silks was unaffected by feeding treatments.
• Stimuli-swapped feeding treatments (crickets with fly stimuli, flies with cricket stimuli) did not induce differential MaSp gene expression.

Conclusions:

• Vibratory stimuli and handling interact with nutrients to prompt gene expression adjustments in Nephila pilipes for prey-specific silk properties.
• Spiders can genetically modify silk's chemical and mechanical properties in response to different prey.
• The MaSp model for Nephila clavipes may not universally apply to all Nephila species, as indicated by proline composition.