Shape Observations and Viscosity Measurements of Spiderweb Thread

A laser scanning microscope (LSM) and a scanning probe microscope (SPM) can be used to assess the microscopic structure of living organisms, and can evaluate the physical properties of high viscosity and highly extensible molecules.

Shape Observations Using LSM

Spiderweb threads consist of high viscosity woof threads and low viscosity warp threads. When a spider is mobile, it walks along the low viscosity warp threads.

In this example, the spiderweb threads were observed using an LSM by preserving them on a glass slide. It is evident that something is attached to the woof threads.

After magnifying the woof threads, viscous spheres attached to these threads can be seen.

These viscous spheres were then observed at a higher magnification.

Size Measurements of the Viscous Spheres

Width measurements: The spheres were observed in air.

Height measurements:

From the results of the size measurements, the shape of the viscous spheres was evidently as shown in the figure at left.

Force Curve Measurements Using an SPM

Measurements of the physical properties of the spiderweb thread and viscous spheres were performed by measuring the SPM force curves.

Force Curve Measurements of a Spiderweb Thread

The viscosity of the spiderweb thread was almost zero.

Force Curve Measurements of the Viscous Spheres

Summary

In the observations of the woof threads using an LSM, multiple round viscous spheres were found. Based on the size measurements, these viscous spheres were shown to be almost perfectly spherical.
When the physical properties of the spiderweb thread and viscous spheres were measured via an SPM force curve measurement, the results showed that while the viscosity and extension of the thread was approximately 0.04 μm, the value for the viscous spheres was approximately 120 μm.
This means that the extension of the viscous spheres is at least six times the value for the thread, indicating that the molecules in the viscous spheres are highly viscous and highly extensible.

Citation:
Tokyo Metropolitan Tama High School of Science and Technology, Science Research Department, Ministry of Education, Culture, Sports, Science and Technology, 2013 Super Science Highschool Student Research Presentation, Poster Presentation Award
“In Search of the Possibilities of Spiderweb Thread: Micro-Observations and Spectral Comparisons”