orbweb spiders

[dido]

Can anyone tell me why do orbweb spiders always seem to hang upsidedown
in their webs.

[No.9 Spider]

Good question. I can't say it's a subject I've read about before, but can surmise that there's a couple of reasons, evolutionary or otherwise.
The retreat of an orb weaver is above the upper half of their web, as this affords good shelter when it rains. When the spider runs out to subdue prey from this position, it is naturally upside down.
When subduing the prey, the spider uses it's fangs for an initial bite and the forelegs for to assist in holding it, the back legs being relied upon to keep hold on the web.
I'd say it's the natural position to be in when dealing with prey, as more limbs are free. If it were the 'right way up' it would tend to fall back if trying to use the front limbs.
Just an idea and one I'll have to look into.

Interesting too that the Tegenaria sp. - House Spiders, are on the top of their horizontal sheet webs whereas many species with similar horizontal sheet webs lie on the underside.

........and welcome to WAB .




No.9 Spider

[Action_Man]

Plus when disturbed they can fall out of there web to escape, if there were pointing upwards, it would make it more difficult ...