My day is all booked up already


I have plans, so many plans.

First, I’m going into the lab to examine yesterday’s handiwork. We attempted to breed two pairs of spiders yesterday, moving them into two different kinds of larger chambers. My concern is that the vials we keep them in are too small for two spiders and that one of the reasons I’m seeing so much cannibalism of the males is because of overcrowding. If all goes well, I’ll find two females and two live males today. If that works, I’m going to turn my incubator into a fornucopia and pair up all the males with mates. I’d like, for a change, to have more embryos than I know what to do with.

Then we’re surveying some more garages. I’ve arbitrarily set a one week window for data collection in June, so that will be done tomorrow.

This afternoon I have to transcribe all the data into my computer — right now I’ve got a pile of folders and scribblings on paper for each site. I’m keeping paper records of everything (hey, election officials — it’s a good idea!), but I’ve got to get it organized in one place so I can wrap my head around it.

One of the things I have to sort out is some of the bigger picture data. I’m being scrupulous about data privacy — every site is encoded on a master list, and then the individual site data is stored without direct reference to the homeowners (which is good, I planned ahead thinking people might not want it known how many spiders occupy their property), but now I’m seeing glimmerings of interesting spatial distributions of species. I might want to make a map at some point.

In some ways, the data so far is kind of boring. Because we restricted ourselves to one narrow kind of environment, garages and sheds, we’re seeing the same beasties everywhere: Pholcus and Steatoda and Parasteatoda. That’s good for our sanity, because we’re brand new at this spider game, so reducing the number of taxa we have to master simplifies everything. We know, though, that there are hundreds of species around here, and we only occasionally see an orb weaver or funnel web spider or ground spider in these dusty musty cobwebby garages. We might want to think about sampling other sites in the future.

For instance, houses around Lake Crystal here in town have been stunning when we walk up to knock on the front door — the houses are covered in webs, there are swarms of mosquitos and mayflies everywhere, we start out convinced that this place is going to a time-consuming nightmare to sort out. Then we walk into the garage, and dang, it’s nothing but Theridiidae and Pholcidae again, and not particularly rich in them, either. We’re focused on these sheltered mini-environments while there’s a riot going on outside. Maybe at some point, if I get a student interested in that sort of thing, we’ll just stake out an area on the lakeshore and go centimeter by centimeter through that more complex space.

Right now, though, just the relationships between these few species in our limited environment are going to take a while to puzzle out. Garages are either infested with Pholcus or Parasteatoda, but mixed distributions are less common. Will we see shifts over the summer? Do the pholcids, known predators of other spiders, gradually take over? Is there something in the environment that favors one species over another?

We’re also seeing some interesting granularity in the species distribution, which is one reason I’m thinking of mapping. We find Parasteatoda tepidariorum everywhere, it’s probably the most common spider in these sites. But then we found one house that was all S. triangularis, and two widely separated houses with lots of S. borealis. Just chance? Are there little enclaves of these species, like ethnic neighborhoods, that persist over time? If we go door-knocking and check other houses in these neighborhoods, will we find larger patterns?

I haven’t even started on the lab studies. Once we get steady production of embryos, we’re going to start with some simple studies of the effect of temperature on rate of development, seeing if we can induce diapause, that sort of thing, all with the aim of figuring out how spiders survive living in a place where temperatures drop to -20°C every winter. My summer months are split with one week of taxonomic studies to three weeks in the lab, so that’s actually going to take up more of our time soon.

I feel like I’m getting sucked down into a spider hole. It’s delightful! I recommend it! You should all join us down here!

Comments

  1. ndirienzo says

    Hey PZ – For sure give the females a structure to build on. For widow mating trials in the lab I use skeletonized cardboard boxes. The females build for seven days, after which I’ll introduce a male opposite of the female’s retreat. The boxes I get for free from USPS (medium flat rate) and the containers they’re nested in are just 15l sterilite containers. I’ve found that cannibalism is really rare in widows when the males are allowed to court properly and escape as need be… but they need a larger environment for this. We’re obviously studying different species, but they’re both threidids and I’m guessing web structure plays a similarly important role in your spiders’ courtship.

    If you want check out some of my recent papers on spider web structure and courtship/reproductive output go here: https://scholar.google.com/citations?user=NPwlV2wAAAAJ&hl=en

  2. says

    Awesome information. 15L, though? That’s a huge amount of space, bigger than my incubators. I’ve got a few sterilite containers that I used for zebrafish, though, so I’ll try repurposing for spiders.

  3. eliza422 says

    This is just so interesting. I have a live and let live policy with the spiders in my house as long as they don’t approach me. You crawl on my arm, you’re dead!
    I wonder what kind I have around. I have also wondered, living in the Chicago area, how they survive the winter. Clearly the ones inside my house aren’t getting too cold, but in the garage, sure.
    I’m so looking forward to seeing where all this goes.

  4. ndirienzo says

    Yea, I use these containers: https://www.amazon.com/gp/product/B0042FS96G/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1. The USPS medium flat rate boxes. Make sure you leave about 3cm on the back otherwise they like to build outside of the container. Here’s a top down view of them: https://imgur.com/a/ZOX2OTb. I reuse the boxes by pulling out all the silk, giving them an alcohol spray, and then putting in new paper on the bottom and back.

    And yes, normally space is good as most of their courtship is vibratory and chemical. I tend to think too small of spaces influence their ability to tell males from prey, but I haven’t tested that. Regardless, it’s like with mantids in that cannibalism is actually rare when males have space to assess and escape females. The high mortality rates are only in super confined lab settings.

    Just email if you want more info!

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