Validation of a novel stereo vibrometry technique for spiderweb signal analysis

Authors: JUSTUS, NATHAN - Oregon State University; Krugner, Rodrigo; HATTON, ROSS - Oregon State University

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2022
Publication Date: 3/22/2022
Citation: Justus, N., Krugner, R., Hatton, R. 2022. Validation of a novel stereo vibrometry technique for spiderweb signal analysis. Insects. 13(4). Article 310. https://doi.org/10.3390/insects13040310.
DOI: https://doi.org/10.3390/insects13040310

Interpretive Summary: Western black widow spiders have been found in produce sold in domestic and international markets. Because black widow spiders have potent latrotoxins in their venom, which may be lethal to a person, the species is now considered an important agricultural pest. The overall goal of this project is to identify behavioral mechanisms that can lead to development of methods to suppress black widow spider infestations in vineyards. While male and female black widow spiders are known to use vibrational signals in mating communication, nothing was known about female-female rivalry behaviors. Analysis of spider behaviors in this study showed that when two female black widow spiders find themselves on the same spiderweb, they exhibit displays of rivalry by plucking the web to determine which spider will get to stay in the web. The rivalry plucks create a large enough visual signature that the web vibrations can be analyzed using video vibrometry on high-speed video of the communication exchange. In this study, a method of three-dimensional vibration analysis was developed by combining video vibrometry with stereo vision. The method was verified against laser vibrometry on a black widow spiderweb that was experiencing rivalry plucks from two female spiders. Understanding the mechanism of intraspecific competition may lead to development of novel methods to prevent spiders from colonizing a grapevine canopy and/or to repel existing spiders from the canopy and fruit bunches.

Technical Abstract: When two female black widow spiders find themselves on the same spiderweb, they exhibit displays of rivalry by plucking the web to determine which spider will get to stay in the web. Knowledge of these rivalry signals will provide significant insight into how a black widow perceives the world through its web, and could lead to novel techniques of pest dispersion during crop harvest in fields with black widows. The rivalry plucks create a large enough visual signature that the web vibrations can be analyzed using video vibrometry on high-speed video of the communication exchange. Using video vibrometry to examine these signals has numerous benefits over the conventional method of laser vibrometry, including the ability to analyze three-dimensional vibrations. In this study, a method of three-dimensional vibration analysis was developed by combining video vibrometry with stereo vision. The method was verified against laser vibrometry on a black widow spiderweb that was experiencing rivalry plucks from two female spiders.