Do spiders have a sense that can detect the presence of water?

Asked February 13, 2020, 2:15 PM EST

I often find Hololena spiders (an outdoor variety) trapped in my bathtub or kitchen sink, unable to climb back out over the slippery surface. Do they get there by accident, or are they attracted to them by the presence of moisture?

If I relocate them to my basement, where there is no source of water, would they be able to detect and find water if a source is provided? If so what sense is involved?

In the wild, do they rely on stumbling upon it at random, or do they actively seek it when needed? I assume they get some of the water they need from their prey, but when food is scarce, would need to replenish by drinking from puddles, dew drops, etc.

Thanks for your response,
Dan


Spokane County Washington spiders

3 Responses

Thanks for contacting us with your question.

There is a great deal of information and misinformation out there, so this represents the best of what I've found. It may not be the last word on "spider-sense" however, so I encourage you to keep researching a fascinating subject.

Depending on the species and environment, spiders may get most of their water through their prey, but as you mentioned, they also drink water, particularly in dry environments, or if prey is scarce. In the wild, they will drink water droplets from vegetation, from sources like puddles, or from dew drop on their webs.

In our houses during the winter, spiders move around searching for prey, water, and male spiders will look for a mate. If they find a water source such as a sink or bathtub, they move toward the source, usually the drain. They often become trapped because they cannot climb the slick surfaces, and because they are trapped we encounter them there more often than in other parts of the home where they can run away.

Spiders don't have a special sense that tells them where to look for water, but they are able to detect it. They have sensory organs on their legs that are analogous to our senses of taste and smell, although this is an inexact comparison. If these sensors detect water, the spiders will move toward it. Other organs. including the hair on their legs, allow them to pick up vibrations. They seem to be able to interpret these vibrations, for instance rain hitting their web, vs. the vibrations of prey, or the deliberate 'web-strumming' of a potential mate.

If you relocated the spiders to your basement, they would search for prey, water and possibly a mate, until they found it or died. This might mean they would come back upstairs, find a way outdoors, or stay there if their basic needs were met. I could not find a source for how far away a spider can detect water. Anecdotally, some people that keep them as pets report that the spiders easily find water sources in their habitat.

I hope this helps answer your questions. Thanks again for contacting us!

Tim,
Thanks so much for taking the time to reply, and for the information. I spent a good amount of time searching the internet for info, but most of it is centered on identification, and not much at all on behavior or sensory perception.

Besides the tub and sink, I often see them in the late evening scurrying across the floor.
I wish I could fit them with tiny radio collars and track them over time to get a sense of their movements. :) I often wonder if they are making it back upstairs after being banished to the basement, or if a steady stream of newcomers are finding their way in, as there have been encounters throughout the winter. I don't know what they could be eating, as there are very few visible insects in the house. I'll put out a water supply and hope they find it.

The weather will soon be warm enough to release them back outdoors, as they are not true house spiders. My cat sees them as playthings, which is one reason I relocate them to the basement, as they tend not to survive a "play session".

Dan

I think a radio tag study would teach us a lot, and I would like to know where they go all the time. Short of that, I think you have a good plan. I know they will be happier outside when the weather warms and they can eat all the bad bugs they can find.

Tim