Like people, when a spider chooses a home, a best case scenario leads to a longer, healthier life. Spiders and people want a desirable climate, a sturdy foundation, access to food, and somewhere safe to “raise” the kids. Sometimes, after committing to a home, humans run into issues and decide it’s time to move out. Some of us stay and do the best we can with what we have because the energy and resources it takes to move would be more costly than staying. Such is the case with web-building spiders, except they don’t have a listings site to compare homes and neighborhoods. They can’t predict or know if the grass is actually greener somewhere else. With web-building spiders, “should I stay or should I go” boils down to: are there suitable attachment sites for my web, do I have to compete with anyone, is the habitat right (light, humidity, temperature), are predators persistent, will my web constantly get knocked down (by nature or human), and am I able to actually catch anything to eat?
By a simple shift in the direction of the wind, spiders can find themselves in some pretty odd places. If you’ve ever seen spiderlings disperse by ballooning (when a spider lets out thin silk strands which are taken up by the wind or even electrical currents), you’d see that they can go quite far disappearing into the sky to colonize new territory. Or they can float into the next yard and land in the pool. Ballooning spiders at least have a chance to try again if they land in a less than desirable place, but not all spiders balloon; some just start walking. It’s random luck, adaptability, and building that web anyway coz if ya don’t you definitely won’t snare a meal. I actually found a spider IN the toilet tank at a vacation rental. It was a small spider (size of a dime) that built a small funnel web above the water line! I have no idea how that little lady got in there, but she was alive! It’s up to the spider to respond to the cues it receives to move, or it very well may die!
When we wonder about a spider’s seemingly mischievous choices of web location (ask anyone who has a spider taking up residence in their mailbox), it’s not so much about US as it is about them making the best of where they ended up. They don’t even understand that they’ve blocked an entire doorway and now you can’t leave your house unless you duck under it. They’re giving it a go so they can eat, grow, and be healthy enough to make many spider babies until the drawbacks outweigh the benefits. Below are some photos I’ve gathered from friends and colleagues who’ve captured some interesting spider real estate choices:
Sources: Bradley, R. (1993) The influence of prey availability and habitat on activity patterns and abundance of Argiope keyserlingi (Araneae: Araneidae). The Journal of Arachnology, 21, 91–106.
Enders, F. 1976 . Effects of prey capture, web destruction and habitat physiognomy on web-site tenacity of Argiope spiders (Araneidae). Journal of Arachnology, 3 :75-82 .
Enders, F . (1977) Web-site selection by orb web spiders, particularly Argiope aurantia Lucas. Anim. Behav., 25: 694-712.
Glover, N. (2013) The habitat preferences of web building spiders. The Plymouth Student Scientist, 6, (1), 363-375.
Grennell, A. (2018, May 5) Spiders fly on the currents of earth’s electric field. Retrieved from https://www.pbs.org/newshour/science/spiders-fly-on-the-currents-of-earths-electric-field
Janetos, A. (1986) Web site selection: are we asking the right questions? In: Spiders– Webs, Behavior and Evolution (ed. WA Shear), pp. 9–22. Stanford University Press, Stanford, California, USA.
Reichert, S.E and Gillespie, R.G. (1986) Habitat choice and utilization in web building spiders. In: Spiders- Webs, Behavior, and Evolution (ed WA Shear), pp. 22-48. Stanford University Press, Stanford, California, USA.
Smith, H.M. (2009) The costs of moving for a diurnally cryptic araneid spider. The Journal of Arachnology, 37: 84–91.
Feature photo credit: John Stanicar. Used with permission.