I played hooky last year, taking two semesters off (at half-pay, ouch) for this thing called a sabbatical. As it turns out, my university expects me to justify and explain myself and tell them what I did with my lazy time off, and I guess it’s not enough to fire off a quick note saying that I was playing with spiders. So now today I’m late for the division holiday party because I had to hammer out a longer rationalization. OK, sure, so I include it here, too, as well as mailing it off to my dean and division chair.
Sabbatical Report for PZ Myers
Short summary: I used my sabbatical year to switch from laboratory studies of the development of a highly inbred model system, the zebrafish, to a new animal model, the house spider, which opens up opportunities for exploring natural population variation and ecological interactions in native Minnesotan arthropods. This change required a major restructuring of my lab, and also a major investment of my time in learning a different biological sub-discipline.
I was on leave the academic year of 2018-2019. I took advantage of this year to completely revamp my research program.
Previously, my work had focused on the developmental biology of the zebrafish, Danio rerio. This animal is a popular and useful model system for studying problems in vertebrate development, and has a number of useful properties for genetics and embryology. However, over the last few years my interests have shifted; I’ve become increasingly interested in combining the disciplines of ecology and development, a discipline called eco-devo. I have taught a course in that subject, Biology 4182, Ecological Developmental Biology, in Spring 2017, and wanted to pursue that in more depth in my research.
The zebrafish is not an ideal animal for that kind of work; it is non-native, so I’d have no access to natural populations, and is highly inbred with most of the diversity artificially introduced through mutations. The properties that make zebrafish a powerful tool for analyzing the mechanisms of development at a molecular-genetic level actually reduce its utility for studying the interactions between the embryo and the environment.
For the kind of work I wanted to do, I needed an organism that was native to Morris, Minnesota; that exhibited natural variation in its populations; that preferably was part of a broader array of related species to provide opportunities for comparison; and that was relatively easy to raise in the laboratory. I chose the common American house spider, Parasteatoda tepidariorum, which is also an emerging model system in developmental biology. Parasteatoda is ubiquitous in the area, and most of the animals I’m currently raising in the lab were simply captured in my garage. My first observations revealed considerable variation in fine details, like the pattern of pigment spots in the cuticle. We also live in an area inhabited by a variety of related species, including Parasteatoda tabulata, Steatoda triangulosa, Steatoda borealis, as well as P. tepidariorum.
At the start of my sabbatical, I maintained my zebrafish colony but did not raise new animals, allowing the population to die off by natural causes. I shut down the system of tanks entirely.
Concurrently, I was collecting and observing local spiders, setting up a colony in the lab, and figuring out basic principles of spider husbandry. I was also struggling to grasp the complicated subject of spider taxonomy, and learning to identify spider species in the wild. Through much of the winter I was working on developing a breeding colony of the animals.
The summer of 2019, I had recruited two student volunteers, Preston Fifarek and Maya Shebala, on our first project, a survey of synanthropic (living with humans) spiders in the Morris area. We visited local residential garages and sheds and identified and counted spider species in those specific environments, which I selected in part because they had limited populations that would not overwhelm our ability to categorize them, but also because it would give us baseline data on the size of the local house spider populations as a reference for future studies. We plan to try to publish this preliminary assay this year, and add to it with more spider counts in future summers.
Spider populations crash catastrophically in Minnesota winters, so another part of my research plan is to do laboratory studies of spider development during the winter months. I have begun a preliminary study of spider juveniles that hatch out in the lab; I’m quantifying variation in size, survival, rates of development, and pigment patterns in P. tepidariorum and S. triangulosa juveniles.
My future plans include taking advantage of the rebounding, diverse populations of spiders in the summer to examine variation and habitat preferences, and simply quantify diversity and health of these populations in their natural habitats. Then in the winters we’ll work with laboratory-bred generations of spiders to explore the genetics and embryology of the variations we observe. These are all projects with excellent opportunities for undergraduate participation.