Spider web and silk performance landscapes across nutrient space

Sean J Blamires,I.-Min Tso,Chung-Lin Wu,David Raubenheimer,Yi-Hsuan Tseng,Søren Toft

doi:10.1038/srep26383

Abstract

Predators have been shown to alter their foraging as a regulatory response to recent feeding history, but it remains unknown whether trap building predators modulate their traps similarly as a regulatory strategy. Here we fed the orb web spider Nephila pilipes either live crickets, dead crickets with webs stimulated by flies, or dead crickets without web stimulation, over 21 days to enforce spiders to differentially extract nutrients from a single prey source. In addition to the nutrients extracted we measured web architectures, silk tensile properties, silk amino acid compositions, and web tension after each feeding round. We then plotted web and silk “performance landscapes” across nutrient space. The landscapes had multiple peaks and troughs for each web and silk performance parameter. The findings suggest that N. pilipes plastically adjusts the chemical and physical properties of their web and silk in accordance with its nutritional history. Our study expands the application of the geometric framework foraging model to include a type of predatory trap. Whether it can be applied to other predatory traps requires further testing.

Highlights

Stationary predators that build traps, such as spiders, caddisfly, ant lions and glow worms, encounter an unpredictable range of prey[16,17,18,19,20]
Many spider web and silk properties are plastic so may serve as parameters that can be plotted as “performance landscapes” over nutrient space, enabling us to ascertain whether these traps are regulated in response to the nutritional history of the foraging spider
We used the web and silk property measurements made after each feeding round to build a geometric framework model

Summary

Introduction

Stationary predators that build traps, such as spiders, caddisfly, ant lions and glow worms, encounter an unpredictable range of prey[16,17,18,19,20]. For example flies have been reared on nutrient enriched vs nutrient poor media to alter their nutritional composition[21,25] In this case any changes in feeding strategy of the spider as a consequence of their nutritional history or diet induced variability in the behaviour of the prey remain unquantified. Experiments were done to ascertain whether the giant orb web spider Nephila pilipes varied its silk investment and web architectures as a result of extracting different nutrients from crickets or flies when receiving different kinds of vibratory stimuli[30,34] These experiments found that N. pilipes extracted different quantities of protein and lipid from the same prey type when different stimuli were applied to their web. We thenceforth used a geometric framework model to assess whether the spider’s recent nutrient intake was likely to influence its web architecture and silk physico-chemical properties

Methods

Results

Conclusion