Seasonal transition spins up a spider showcase
Itsy, bitsy spiders stymied by spring showers are all grown up and spinning an autumn show.
From lightning-quick wolf spiders sauntering across kitchen floors to bulbous orb weavers spinning giant webs everywhere outdoors, the average person might wonder if an arachnid invasion is underway.
To find out if this perceived influx of spiders is part of a natural cycle or the start of a dastardly Halloween trick, we sat down for a quick question-and-answer session with Eileen Hebets, professor of biological sciences and an arachnid researcher.
Hebets studies various arachnid groups, seeking answers to questions relating to the evolution and function of animal signals. She also strives to educate the public about arachnids through her research and outreach projects, which include the "Eight-Legged Encounters" exhibition, the University of Nebraska State Museum's Sunday with a Scientist program, area summer camps, and various presentations on spiders. Learn more about her research by clicking here.
Are we seeing more spiders this year or does it just seem that way because they are larger and more visible in the fall?
I believe it's the latter. We actually saw a lot more spiders in the spring when they were small. People just didn't know that the spiders were there because they were smaller and building much smaller webs in deep grass. During the season, predation of the spiders as they grow reduces their overall numbers. People think there are more spiders at this time of year simply because they are larger and building webs in more conspicuous spaces.
Are spiders moving indoors for warmth at this time of year?
No, but we do hear about and see more spiders, especially wolf spiders, in our houses in the fall. This is because males are on the move searching for mates before the end of the season. They do not come into homes seeking warmth or shelter from the weather. They are there by happenstance, searching for a dragline or silk that will lead them to a female.
What types of spiders build the large webs we see — and run into — at this time of year?
Those are orb weavers. Primarily, the brown ones are barn spiders (Neoscona crucifera) and two types of garden spider, the black and yellow garden spider (Argiope aurantia) and banded garden spider (Argiope trifasciata). All three make the large orb-shaped webs you can easily see.
Will the large spiders we see now survive winter?
No. In this climate, spiders pretty much have a one-year life cycle. The spiders we are seeing now would have been born around last October. They did survive winter and have been growing all summer. They've reached maturity and are producing the next generation of spiders that will emerge in the spring.
When will next year's spiders emerge from egg sacs?
They will all emerge before winter arrives. For most species, it's about three weeks after mating when they lay the eggs in the sac. Then, it's another three weeks before they hatch. When that happens, the baby spiders will seek shelter from winter weather.
How do spiders survive winter?
They have a kind of built-in antifreeze and burrow under leaves or other ground litter to stay warm. Of course, some do not survive the hardships of winter, but they are well equipped to handle cold weather.
How should people react when they see a spider?
I always encourage people not to harm them because spiders offer huge benefits to the environment. If a spider is in your house and you do not want it there, you can certainly move it outside.
Why do you think some people have adverse reactions to spiders?
For most people, the fear of spiders comes from a lack of knowledge. One of my passions is to educate the public about this organism and to eliminate negative reactions to it. My approach is to try and put people at ease by telling a couple of fun stories about spiders and getting them interested. Then, I encourage them to go out and learn more. It's a useful approach and duplicates concepts we integrated into the "Eight-Legged Encounters" exhibition.
Is there a benefit in spiders being so visible at this time of year?
In terms of education and learning about spiders, absolutely. Now is the time to go out and appreciate that you can see spiders in action. I went out for a walk last week in the early morning when there was still dew on the ground and a number of webs. It was spectacular seeing the sun light up these little works of art. It's also a great time to go out in the early evening and watch spiders as they spin their webs. It's really an amazing process.