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Nutrient deprivation induces property variations in spider gluey silk.

Blamires SJ, Sahni V, Dhinojwala A, Blackledge TA, Tso IM - PLoS ONE (2014)

Bottom Line: We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein.We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute.We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Science, Tunghai University, Taichung, Taiwan.

ABSTRACT
Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition.

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Load extension curves for the gluey silks of pre-treated, protein fed and protein deprived spiders.Showing: (A) representative curves for Nephila clavipes, and (B) representative curves for Latrodectus hesperus.
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pone-0088487-g005: Load extension curves for the gluey silks of pre-treated, protein fed and protein deprived spiders.Showing: (A) representative curves for Nephila clavipes, and (B) representative curves for Latrodectus hesperus.

Mentions: We found that, in both species, the thread pull-off force (N. clavipes: p = 0.04, L. hesperus: p = 0.01; Fig. 4a,b) differed between threads from protein deprived and protein fed spiders. The work done at pull-off, WT, however differed between protein deprived and protein fed N. clavipes (p = 0.02; Fig. 4c) but not protein deprived and protein fed L. hesperus (p = 0.36; Fig. 4d). For both species, the slopes of the load-extension curves for the threads from the protein deprived spiders visually differed from those from the protein fed and pre-treated spiders (Fig. 5). This indicates that more force was required to pull the threads of protein deprived spiders off the stage. The extension of the thread at pull-off did not differ between the threads from protein deprived spiders and those from protein fed spiders, suggesting that changes in glue properties but not axial thread properties were responsible for the increased stickiness in the gluey silks of protein deprived spiders.


Nutrient deprivation induces property variations in spider gluey silk.

Blamires SJ, Sahni V, Dhinojwala A, Blackledge TA, Tso IM - PLoS ONE (2014)

Load extension curves for the gluey silks of pre-treated, protein fed and protein deprived spiders.Showing: (A) representative curves for Nephila clavipes, and (B) representative curves for Latrodectus hesperus.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921163&req=5

pone-0088487-g005: Load extension curves for the gluey silks of pre-treated, protein fed and protein deprived spiders.Showing: (A) representative curves for Nephila clavipes, and (B) representative curves for Latrodectus hesperus.
Mentions: We found that, in both species, the thread pull-off force (N. clavipes: p = 0.04, L. hesperus: p = 0.01; Fig. 4a,b) differed between threads from protein deprived and protein fed spiders. The work done at pull-off, WT, however differed between protein deprived and protein fed N. clavipes (p = 0.02; Fig. 4c) but not protein deprived and protein fed L. hesperus (p = 0.36; Fig. 4d). For both species, the slopes of the load-extension curves for the threads from the protein deprived spiders visually differed from those from the protein fed and pre-treated spiders (Fig. 5). This indicates that more force was required to pull the threads of protein deprived spiders off the stage. The extension of the thread at pull-off did not differ between the threads from protein deprived spiders and those from protein fed spiders, suggesting that changes in glue properties but not axial thread properties were responsible for the increased stickiness in the gluey silks of protein deprived spiders.

Bottom Line: We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein.We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute.We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Science, Tunghai University, Taichung, Taiwan.

ABSTRACT
Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition.

Show MeSH
Related in: MedlinePlus