Drugs alter web-building of spiders: a review and evaluation.

Abstract

Twenty-two years of investigation of spider-web-building and its sensitivity to drugs has produced insight into this invertebrate behavior pattern and its vulnerability. Most data were collected by measuring and analyzing photographs of webs built under different circumstances; groups of web data were subjected to statistical comparisons. Another approach was through analysis of motion pictures of the construction of orbs, built with or without interference. Drugs (chlorpromazine, diazepam, psilocybin), as well as temperature and light conditions could prevent onset of web-building and pentobarbital sodium could cause end of radius construction before completion. D-amphetamine caused irregular radius and spiral spacing, but showed regular execution of probing movements; the severity of the disturbance in geometry corresponded to drug concentration in the body. Scopolamine caused wide deviation of spiral spacing distinctly different from amphetamine, while LSD-25 application resulted in unusually regular webs. Size of catching area, length of thread, density of structure, thread thickness, and web weight were varied in different ways through treatment with cholinergic and anticholinergic drugs, tranquilizers, etc. Glandular or central nervous system points of attack for drugs are identified, and disturbed webs regarded as the result of interference at any of several levels which contribute to the integrated pattern. Web-building as a biological test method for identification of pathogenic substances in patients' body fluids is evaluated.