Remote monitoring of vibrational information in spider webs

Abstract

Spiders are fascinating model species to study information-acquisition strategies, with the web acting as an extension of the animal’s body. Here, we compare the strategies of two orb-weaving spiders that acquire information through vibrations transmitted and filtered in the web. Whereas Araneus diadematus monitors web vibration directly on the web, Zygiella x-notata uses a signal thread to remotely monitor web vibration from a retreat, which gives added protection. We assess the implications of these two information-acquisition strategies on the quality of vibration information transfer, using laser Doppler vibrometry to measure vibrations of real webs and finite element analysis in computer models of webs. We observed that the signal thread imposed no biologically relevant time penalty for vibration propagation. However, loss of energy (attenuation) was a cost associated with remote monitoring via a signal thread. The findings have implications for the biological use of vibrations by spiders, including the mechanisms to locate and discriminate between vibration sources. We show that orb-weaver spiders are fascinating examples of organisms that modify their physical environment to shape their information-acquisition strategy.Electronic supplementary materialThe online version of this article (10.1007/s00114-018-1561-1) contains supplementary material, which is available to authorized users.

Toward Computing with Spider Webs: Computational Setup Realization

“…5.a,b) rather than lateral waves (Fig. 5.c) are arguably the potential key for spider signal processing due to (i) higher signal to noise ratio and (ii) lesser sensitivity to environmental disturbance [7,8]. The longitudinal waves should be measured along the threads (local frame) ( Fig.…”

“…The role of the spiral is to capture prey, benefiting from its sticky thread and large strain elasticity that creates a strong and effective snare, capable of capturing large prey relative to the web [4]. Typically, orb-weaving spiders have poor eyesight and in consequence are heavily dependent on (i) web vibrations, to provide information on current surroundings [4], and (ii) highly sensitive mechanoreceptors on all eight legs [5,6], which together enable the animal to interpret propagating web vibrations [7,8]. The structural [9,10] and vibration properties [5,11,12] of the spider web has been studied extensively .…”

“…The structural [9,10] and vibration properties [5,11,12] of the spider web has been studied extensively . Mortimer et al have recently studied and summarized the relevant research on the relationship between material properties of the web and its ability to transmit vibrations in experiments and finite element modeling, [7,8]. The following elements are proposed as control mechanisms that the spider employs in order to influence the structure sonic properties such as speed and amplitude [7,8]: super-contraction, web tensioning, and altering longitudinal (along with the threads), lateral (perpendicular to threads in web plan) and transverse (perpendicular to threads and web plan) vibrations.…”

“…There, the adopted definition for a morphological computation setup is discussed. The experimental procedure used by Mortimer et al [7,8] is explained. A mathematical lumped mass-spring-damper system model, similar to [9] by using the parameters in [7,8,11], is derived, as the theoretical part for a morphological computation setup.…”

Decoding the locational information in the orb web vibrations ofAraneus diadematusandZygiella x-notata

“…Spiders detect web vibration via their legs, through slit sensilla sensory organs distributed on their exoskeletons that detect leg displacement [14] as well as, probably, stretch receptors in their tendons [15]. There are two common strategies for monitoring orb web vibration [16]. The webdwelling orb weaver Araneus diadematus spends most of its time on and around the hub, or web centre.…”