Navigational Capabilities of Spiders in Locating Webs

gerigent

Dear PF,

At least 30 years ago I first noticed a characteristic of spider web location which went against the popular and scientifically supported (Sir Richard Dawkins) notion that spiders located their webs by trailing filaments in the breeze and forming the web where they stuck.

It was clear from the number of webs I observed in odd locations that spiders, even quite small ones, were capable of attaching filaments to points so diverse that it could not have been done by trailing in the breeze. Firstly, because they were in-doors in still air and also separated by distances of 10's of feet. For example, between roof beams and corners of benches beneath, and of garage walls and the roof ridges of motor cars parked within.

I have no biological education but have approached a few authorities for an explanation (Bristol University, England, UK, Natural History Museum, London, England, UK and a BBC Wildlife Expert). I have not received any reply.

I have an idea about how the spiders do it but I would appreciate it if anybody knows how it is done to illuminate my ignorance.

Monique

What makes you think the filament being carried by air-disturbances does not explain the placement of spider webs? Air is definitely not still indoors.

gerigent

Firstly, I thought that I had explained why I think that already, but, as many a house cleaner will have noticed, a cobweb will hang down in the same place for months. Furthermore, the air in houses IS still for all practical purposes, unless windows and doors are open or there is a high level of draughts. Smokers will have noticed how smoke forms layers and remains substantially where it is unless a door or window is opened. Further, furthermore, I have noticed complete webs across the inside of motor cars left with all doors locked and in a closed garage, such webs having horizontal top bracing filaments which positively could not have been lodged where they were by chance. There is a wealth of evidence to support my observation, including that many, many webs in the hedge row are formed across the wind direction and are also most often lodged on optimum starting points like the tips of twigs and leaves, a feature very unlikely to have occurred if left to chance in the breeze. I hope that quells your doubts.

Monique

The filament needs only the slightest breeze, it is very light. In the case of a closed space the spider could walk itself from point A to B to connect the first line.

Animation of web building: http://science.howstuffworks.com/env...ds/spider5.htm
Real-life web building: http://www.youtube.com/watch?v=eb6bqIWdQao

Evo

Personal theories without acknowledged scientific studies is not allowed.