A New Spin on Evolutionary Biology

Sandra Correa-Garhwal, Suffolk University’s newest assistant professor of biology, knows that her scientific passion—spiders—might make some people shiver. But for evolutionary biologist Correa-Garhwal, these eight-legged creatures are a window into some of nature’s most fascinating engineering feats. Her research dives deep into the genetics of spider silk, studying its remarkable strength, its adhesive properties, and the specialized hunting skills of net-casting spiders. In this Q&A, she talks about her research and makes a strong case for peacefully coexisting with these web-spinning wonders. 

Q: A LOT of people are afraid of spiders. What’s the typical reaction you get when you mention what you do? 

Sandra Correa-Garhwal: At first they don’t believe me! It’s a very alien concept to most people, and they wonder how I can work with such “creepy” animals. When I tell them a bit more—that it’s not just about spiders but also about their silk, which is lightweight but stronger than steel, so we can even use it to make a bulletproof vest—then they start to become interested. 

Q: What initially drew you to evolutionary biology and to researching spiders and spider silk?

SCG: When I look at photographs of myself as a kid dressing up for Halloween I actually was a spider woman at least twice. Not the Spiderman character, but a custom-made spider woman. So I think it was meant to be.

During my bachelor’s degree program, I fell in love with invertebrate zoology. My mentor was an evolutionary biologist who looked at spiders, so I studied with her and became more intrigued.

Q: What makes spider silk so fascinating?

SCG: There’s a lot of potential in being able to translate how spiders make their silk into many different applications. 

It’s immunogenic, like gold, which means our immune system doesn’t recognize it. That makes it very valuable to the medical field. It’s also made of protein, so it’s biodegradable. Asian civilizations have long used large spider webs as bandages. Now, [we’re able to study its potential] to do sutures and deliver medications. And because our bodies don’t reject it, there is a lot of interest in using it to create things like hip implants which typically have a high rate of rejection. 

If you were to scale it, spider silk is stronger than steel by weight. That attracts attention from the military and from the aviation industry. There’s a lot of research trying to mimic how spiders make their silk to mass produce it and make it into car and airplane parts. And I mentioned bulletproof vests, which make sense because spider silk is super, super light. 

Q: How do you make a spider silk bulletproof vest?

SCG: I collaborated with a colleague [on a project where] I used to manually collect the silk from a spider under anesthesia, and then we would weave it, put epoxy on top of it, then fire gunshots at it and they wouldn’t go through.

Q: So why aren’t we making everything out of spider silk?

SCG: The big challenge is mass producing it. It’s not like the traditional silk that we use for scarves, which comes from growing hundreds of silkworms eating leaves together. Spiders are cannibalistic, so they’ll eat each other. They have to be caged individually. Rearing them is very difficult because spiderlings are super tiny and you somehow have to find food their size and separate them. 

So I mostly concentrate on the underlying genetics of how the silk is produced. I look at the genetics of the gland. There are different types of silk. The orb-web weaver, for example—the spider whose beautifully elaborate webs we often see outside—can produce up to seven different kinds, each with its own properties. Some are like a dry velcro, while others act as a sticky glue. I also look at how the composition of the molecules inside each silk translates into those properties. 

Q: What are you working on right now?

SCG: I have two different projects. One is looking at the genetic differences in that velcro-like glue vs. the wet, sticky glue, and how that innovation and diversification developed.

I’m also studying Deinopis spinosa, the ogre-faced spider. Instead of building a regular web, it builds a square net that it holds with its front legs. It hangs upside down, motionless, in the pitch dark, and waits for insects to either fly or walk in. Then it stretches the net to grab its prey like a fisherman. We’re trying to figure out what genes are driving this night-vision and predatory behavior. 

Q: Your research sounds amazing. Are Suffolk students able to get involved?

SCG: Of course! These techniques might seem very difficult, but there are many things students can do. I’ve had a student working with me in my lab since the summer; she learned how to cage and feed the spiders, and now she’s learning how to silk them. We can get very hands-on with the actual organism, but there are also opportunities for students to work on the genetic piece of the research. So there are ways for students to do exciting novel research on spiders in my lab without actually going near them. 

Q: What do you wish more people knew about spiders?

SCG: All spiders have venom, but very few species have venom that will do any harm to us. Spiders are the main predators of insects. They get rid of our pests. If we were to remove all the spiders from our planet we would be overrun by insects within hours. So don’t kill them! Just gently take them outside.  

Also, just Google “jumping spiders” and watch the cute little dances they do. You shouldn’t be so afraid of them. To them, we’re the giants.