A spider’s biological vibration filter: Micromechanical characteristics of a biomaterial surface

• Published in: Acta biomaterialia Vol. 10; no. 11; pp. 4832 - 4842
• Main Authors: Young, Seth L., Chyasnavichyus, Marius, Erko, Maxim, Barth, Friedrich G., Fratzl, Peter, Zlotnikov, Igor, Politi, Yael, Tsukruk, Vladimir V.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2014
• Subjects: Animals; Atomic force spectroscopy; Biocompatible Materials - chemistry; Biomechanical Phenomena; Biomechanics; Biosensor materials; Crystallization; Elastic Modulus; Female; Microscopy, Atomic Force; Optical Imaging; Spiders - anatomy & histology; Spiders - physiology; Spiders - ultrastructure; Stimulus transmission; Surface Properties; Temperature; Time Factors; Vibration; Viscoelasticity; Viscosity; Biomechanics; Viscoelasticity; Stimulus transmission; Atomic force spectroscopy; Biosensor materials
• ISSN: 1742-7061; 1878-7568
• DOI: 10.1016/j.actbio.2014.07.023

[Display omitted] A strain-sensing lyriform organ (HS-10) found on all of the legs of a Central American wandering spider (Cupiennius salei) detects courtship, prey and predator vibrations transmitted by the plant on which it sits. It has been suggested that the viscoelastic properties of a cuticular pad directly adjacent to the sensory organ contribute to the organ’s pronounced high-pass characteristics. Here, we investigate the micromechanical properties of the cuticular pad biomaterial in search of a deeper understanding of its impact on the function of the vibration sensor. These properties are considered to be an effective adaptation for the selective detection of signals for frequencies >40Hz. Using surface force spectroscopy mapping we determine the elastic modulus of the pad surface over a temperature range of 15–40°C at various loading frequencies. In the glassy state, the elastic modulus was ∼100MPa, while in the rubbery state the elastic modulus decreased to 20MPa. These data are analyzed according to the principle of time–temperature superposition to construct a master curve that relates mechanical properties, temperature and stimulus frequencies. By estimating the loss and storage moduli vs. temperature and frequency it was possible to make a direct comparison with electrophysiology experiments, and it was found that the dissipation of energy occurs within a frequency window whose position is controlled by environmental temperatures.