- Coming up on Sci NC, can we fight a changing coast using nature itself?

Is that sweat-soaked shirt actually working against you?

And a caterpillar like you've never seen one, next.

- Quality public television is made possible through the financial contributions of viewers like you, who invite you to join them in supporting PBS NC.

- Sci NC is supported by a generous bequest gift from Dan Carrigan and the Gaia Earth Balance Endowment through the Gaston Community Foundation.

(gentle music) ♪ - Hi, and welcome to Sci NC.

I'm Laura Smith.

We're happy to have you again today.

Every storm that brushes our coast leaves it a little different.

So what will our beaches look like down the road?

Scientists are turning to living shorelines, natural defenses built to protect our coast and marshes.

Here's producer Evan Howell.

- [Evan] On North Carolina's barrier islands, it's a tale of two coasts, the beach and on the other side, the marsh, both facing the same rising tide.

- I think the thing that concerns communities the most in places like this is how is the shoreline going to change over time?

- [Evan] Over the decades, the North Carolina coast has been hit many times by tropical storms and hurricanes.

While experts say climate change won't increase the number of storms in the future, they say they'll be stronger.

Hurricane Erin, for example, never made landfall in mid-August of 2025.

It stayed 200 miles offshore, yet its wind field and storm surge still reshaped the coast.

Months later, twin storms Imelda and Humberto sent powerful surf into Buxton, undercutting homes and pulling them into the sea.

For the communities that call this coastline home, the danger is only growing on both sides.

- We need to protect the infrastructure that exists here.

- [Evan] Scientists like Jana Haddad are studying how tides and waves shape our coasts and how to protect them.

Their focus is on what are called living shorelines, natural defenses helped along by humans.

The waves, tides, and their impact all feed into powerful computer models, showing how future storms could reshape the coast.

- And that tells us, like, will the living shoreline actually dissipate waves and mitigate coastal erosion under these scenarios?

Or will it not work?

And we need a different type of solution for that community.

The computer models, the simulations, are a really key tool that we use.

You know, we want to maintain the recreational use of this beach.

You can see there's a lot of folks out here enjoying the beach today.

And the wave dynamics today and in the future are going to impact how wide the beach is over time.

So you might, you know, we wanna make sure that there's enough beach width for the future to be able to enjoy the beach here.

- [Evan] From a distance, the ocean looks calm, but beneath that surface, those wave dynamics are always at work as that energy nears the shore, rises and breaks, shaping our coast, sometimes cutting it apart.

- On a normal day like today, these waves typically will be depositing sand on the beach a little bit.

During a storm, however, the water level might be even higher.

The wave energy literally essentially clawing at the sand and taking it out shoreward.

The dunes along our barrier islands here in North Carolina are our first line of defense because they're literally high and also because they're vegetated.

And so the vegetation on the dunes kind of holds the dune in place for us.

- [Evan] If you travel just a short distance from the dunes and surf, you'll get to the other side of the barrier island with its own set of wave dynamics.

It's quiet, but driven by the same tides and wave action.

Landscape is a lot different and requires a totally different approach.

- We had to carry a lot of heavy equipment, so that was kind of part of it.

It was really useful to have lots of folks.

- [Evan] While a graduate student at UNC in 2022, Haddad placed sensors through the grass and water, measuring how marshes absorb energy and blunt the force of waves.

Walking out here, what first struck you?

- Well, I came out here knowing, like we were planning on measuring waves in the marsh.

That was the goal of the work.

We wanted to look at how waves are transformed from the kind of open ocean to, you know, once they reach the marsh, their energy starts to dissipate and the waves literally look different.

- [Evan] Living shorelines, they help a marsh trap sediment and dissipate waves that can be destructive during a high tide or worse, a storm.

- These systems here, they really absorb kind of like a sponge.

- [Evan] These living shorelines are built on what's called a sill.

Yes, like a window sill.

Set low along the water's edge.

These sills are made from things like rock, wood, or some types of biodegradable matter.

They work with nature, not against it.

And oysters are a critical component.

- Well, just here, actually, there is a great example of two different types of living shoreline sills that the folks have installed here.

So this is a rock sill, and you can see it's kind of been here for a little while 'cause there's a lot of oyster growth on it.

It's a lot like riprap or like a revetment.

It's just large rocks.

And then the oyster growth just happens because this is a brackish saltwater area that is really hospitable to oyster growth.

And the other sill is made up of modular poured concrete sections that are placed there in front of the marsh.

The oyster growth is great for things like water quality improvements, but it also adds to the wave energy dissipation element.

So the more oyster growth, the kind of larger the sill becomes.

Like it just takes up more volume.

- [Evan] Haddad says protecting the coast isn't about a single fix.

It's about building layers of protection, natural and engineered, working together when storms arrive.

- We want these nature-based solutions to be just one element of a broader, super comprehensive, well thought out plan where all the different elements work together.

Because as we said earlier, these are dynamic systems.

- [Evan] Along our coast, there is hope in what science and nature can achieve together.

That resilience doesn't have to mean resistance.

Each project adds to a larger plan, one shaped by data, driven by design and rooted in the belief that the coast can and will endure.

- Communities really care about what is the shoreline going to look like in 10 years, 20 years, and what can we do to address the challenges that we're gonna face as a community.

- The power of mother nature really quite incredible.

Let's talk athletic apparel.

It's comfortable, right?

But does it perform the way it should?

Turns out there is a real science behind why some shirts leave us absolutely soaked halfway through the workout.

NC State researchers are looking at what's helping or hurting you during exercise.

Here's producer Michelle Lotker.

- Textiles really are in so many things that impact our daily lives.

My name is Dr.

Kedena HHenriques-Thompson.

I am a textile scientist, engineer, and technologist.

My love for textiles stemmed in ag and fiber science and then transformed and bloomed into the different layers of things I've been able to study and research on top of that.

I saw so much waste in the apparel and fashion industry and the consumer goods industry that I wanted to be able to speak to what I saw from a scientific standpoint.

- [Michelle] Dr.

HHenriques-Thompson and her students conduct research at the Skin Textile Interface Lab at NC State's Wilson College of Textiles, where they test the performance of textiles like athletic apparel.

- With my background being footwear and performance apparel, I look at the impact of friction on different comfort zones, right?

So when you're looking at footwear, that's gonna be your tongue, your heel counter, but specifically your insole and that sock liner textile that interacts if you're wearing barefoot with your skin or with your socks, that interaction.

In terms of apparel, you think about high friction areas like under your arms.

For women, around the breast region.

For men, sometimes it's their shoulders.

So being able to analyze different parts, that leads to comfort, that leads to performance.

A lot of times, wearers have issues where they get blisters or sometimes their materials or their shirts are pooling because their sweat isn't dissipating.

Just looking at those type of interactions and the biophysics of it all and how the materials impact the comfort and performance, how they perform alone as materials, but more importantly, how do they perform when they are in function with the human body?

- [Michelle] To look at how textiles interact with the human body during athletic activity, Dr.

HHenriques-Thompson and her students conducted a study recording parameters like skin temperature while male and female study participants perform moderate physical activity.

- This is the skin temperature probe for the wonderful Biopak machine we have here.

So we have Andreana here and she's going to put the probe on her finger.

- [Michelle] The probe is given time to calibrate to the person's base temperature before activity starts.

For the first phase, Andreana will lift light weights at a steady pace.

- And you can see that she started at 83 degrees and now we're about 86.

So if you want to go ahead and start doing some activity, she's doing light weightlifting, light activity, which is what we did for this study, an activity that's pretty normal and very common for people who do weightlifting at home, your average, like, athlete.

- [Michelle] In addition to the temperature probe, a SEEK thermal infrared camera gives additional insight into where heat is building on participants' bodies.

- Where she is exerting energy in her arms, you see, is the warmest part.

We can also see that she's warming up in her calves and lower legs and in her upper chest region, which makes sense.

So when you have these thermal images, this is what helps to inform you where is the wearer actually feeling the most discomfort.

- [Michelle] Dr.

Henriques-Thompson explained that during physical activity, including dynamic exercises like weightlifting, your feet can actually start sweating before your body feels hot because of increased metabolic demand in your extremities.

- Her toes on her right foot are actually starting to warm up, and her left foot is slowly matching that, which makes sense because your feet are holding you in place.

- [Michelle] This highlights the importance of footwear choice when it comes to athletic apparel.

- Ideally, what you want is to have breathable socks, and you want to make sure that your footwear is breathable as well.

She has on cotton socks and a knit upper.

That's breathability.

That allows some of the moisture and the sweat and the temperature to dissipate through her feet.

- [Michelle] As Andreana continued lifting weights, her skin temperature increased as expected.

But an unexpected outcome of the study occurred during the times when participants weren't active.

Are we ready to go into a rest phase?

- We are ready to go into a rest phase in three, two, and one.

Thank you.

And so now we just see the trends of her body temperature, and you can see it's teetering right now.

She stopped moving, but her temperature is still the same, and it is still increasing slightly.

When she stopped her activity, she was about 90.2, and it went as high as 91.3.

- [Michelle] This increase in temperature during the rest phase was only observed in female study participants.

- The anthropometric differences between males and females, I mean, it is something that is so underexplored in so many different industries, especially when it comes to textiles.

One of the things that we saw was that males in this study generally had a higher calibration five-minute temperature prior to the actual activity than females did.

However, in our rest time cycles, females had a higher increase in temperature during the rest after the light activity.

- [Michelle] The study also had participants run in place with the temperature probe held to their chest.

- We had participants do a full 45 minutes, so you can imagine at the end, they were really exhausted and sweaty and tired.

- [Michelle] Data averaged from the running portion of the study shows the variability in female skin temperature, measured by the probe, during active and rest periods, while average male skin temperatures were less variable, as shown by the smoother curve.

Dr.

Henriques-Thompson says this variability and the temperature increase during rest periods has implications for both apparel choice and design.

- If apparel is intended only to keep you cool and functional only during activity, then the wearer is going to experience some discomfort during rest because the heat is already still built up.

It's still pushing more heat to the surface of the skin and you're still sweating.

So it is a delayed thermal response during the rest time.

So it's important that we're not just looking at materials and how they're functioning in activity, but really how do they function post-activity for that optimal wearer comfort.

For the most part, when you think about performance apparel materials or performance footwear materials, they're kind of tested under these extreme conditions, right, so extremely cool or extremely hot or these really peak levels, and that's not realistic.

That's not the average person going into the gym and doing a light jog on the treadmill and experiencing that their sweat is pooling and it's not spreading, it's not dissipating, and it's not being absorbed, it's not being wicked.

This condition that we did our test under showed that, once again, it's more about the human response than it is about the fiber.

That is really important when we're thinking about performance apparel design, that it's more about the wearer.

- [Michelle] And this study is just the first step.

- If you think about the results and what it means for so many stakeholders in the supply chain, it means something for science, it means something for design, it means something for the wearer, you know, it means something for athletes.

And so there's so many different angles that we can apply these data findings to, like when we think about design, designing not only for activity but also for rest.

When you see the problems of textiles, those problems influence research questions and applications that are yet to be discovered.

- Very interesting there.

Well, now it's time to get up close and personal with the Caterpillar, who knew it would be doing this?

Because up close, it's a whole different world.

In slow motion, we meet a few of them, like the long-haired saltmarsh caterpillar eating its way across a thorn-covered plant before it transforms into a delicate white moth.

Take a look.

- This incredible creature is a moth caterpillar, and it's doing one of the most important things any insect or animal in an ecosystem can do.

As plant consumers, caterpillars unlock nutrients locked up in leaves and convert it to usable energy that millions of animals and birds to wasps depend on.

Of course, that means besides eating leaves, the other thing a caterpillar tries to do is avoid being eaten themselves.

They have some incredible features and behaviors to help them stay alive.

And in this video, I wanna show you some of those and highlight some of the incredible caterpillar diversity I've been able to find in my own backyard and that you might be able to find in yours too.

First up is this, a saltmarsh caterpillar.

Saltmarsh caterpillars are one of the woolly worm or woolly bear types that are covered in a dense set of long, protective hairs.

I found this one on a patch of blackberry, and that's what I raised it on and filmed time-lapse sequences of it eating here in the lab.

I imagine being covered in long, spiky hairs while feeding on a densely thorned plant is a pretty good strategy for staying out of harm's way.

Once this one finished feeding, it dug down into some soil and spun this cocoon.

It'll stay in that over winter and then emerge as an adult.

When it emerges as an adult, it'll be a white tiger moth that looks very similar to this one, a Virginian tiger moth, which is a closely related species.

In comparison to the earlier caterpillar stages, the winged part of a moth's life is brief.

Most of its life's work of plant digesting, growing, and evading predators is over.

As an adult, it flies off to live a different, much shorter life in a completely different body.

The caterpillars that might go to the most extreme lengths to defend themselves are slug moth caterpillars like this one, the monkey slug.

In its final larval stage, which you see here, it arms itself with densely haired appendages, some of which it can use to inject a defensive venom into anything that attempts to eat it.

Watch its reaction here when I touch it with some metal forceps.

Instead of moving away, it leans into the touch with those appendages to try to stick whatever just came at it.

Younger versions of this caterpillar, here you see one molting from one stage to another, are also covered in venom-injecting spines, but they don't have that same hairy appearance that the final stage does.

This one, after it molts, partially consumes the old cuticle it just shed.

When they feed on leaves, they can eat a bunch of different plants.

The ones I filmed for this video were eating persimmon and hickory leaves.

Now, the common name for this type of caterpillar, a slug caterpillar, comes from how they move.

Instead of having stubby prolegs on the underside of their abdomens, the whole abdomen attaches to the substrate like a slug, and an undulating wave of that underside glides them along as they move.

You can see that movement strategy a little clearer with this slug caterpillar, one called a stinging rose.

In this shot, you can see that they still have three pairs of legs like other caterpillars, but the legs only briefly touch the ground or are completely off the ground when the caterpillar is moving.

With their fleshy, spine-covered appendages and their bright orange coloration, to me, they look like a nudibranch or a sea slug as much as they look like a caterpillar.

Their bright colors likely serve as a warning sign for the painful, stinging spines.

These ones overwinter in the pupal stage, so I wasn't able to rear them to adults yet.

But I was able to film some other adult slug moths, these spiny oak slugs.

They look very similar in the adult stage to what a stinging rose caterpillar develops into.

Now, not all caterpillars defend themselves with hairs and venoms.

Some, like the snout moth caterpillar on a mulberry leaf, uses the leaves themselves for protection while they feed.

They're usually not out in the open like you see here.

Instead, they're like this, in between a folded-over leaf that they've stitched together by spinning silk threads between the two sides.

If you watch here closely, you can see this one laying down these silk threads.

The caterpillar will stay in this protective leaf tent, hidden away from danger, while eating away at the leaf tissue it's surrounded by.

Another strategy for protection while exposed on a leaf is a strength-in-numbers tactic like what you see here.

Now, these are not moth or butterfly caterpillars.

These are actually sawfly larvae.

Sawflies are closely related to wasps, but here, in their larval stage, they look and act a lot like caterpillars.

One difference between true caterpillars and sawfly larvae is that prolegs running down the abdomens of sawflies are much poorer at gripping leaf surfaces.

So, sawflies grip leaves with their three pairs of legs and hold their abdomens up and wave them around if they're disturbed.

Feeding together as a collective group means they're better protected individually and also that they can make quick work of a leaf.

Here, you see them feeding on a birch, eventually stripping it down to nearly nothing before moving down the stem to find another leaf to devour.

Swallowtail butterflies, like this spicebush swallowtail, have some unique anti-predator adaptations.

For instance, that black spot near the head is paired with another one on the other side to form what is thought to mimic the eyes of a snake to scare off vertebrate predators.

This one also visually mimics bird droppings as a form of camouflage.

This butterfly, a pipevine swallowtail, with its tentacle-like fleshy projections, looks kind of like a tropical velvet worm.

In this next shot, you'll see my finger come in and touch its back.

In response to that, it inflates a structure called the osmoterium.

This aversible gland contains volatile defensive chemicals which repel potential predators, including other insects.

Now, in this video, I've mostly mentioned caterpillar adaptations to avoid predators, but another thing driving caterpillar defenses are parasitoids, like these eulophus wasp larvae.

Caterpillars, besides being required fuel for developing birds, are primary hosts to thousands of parasitoid insects.

These insects can develop inside of caterpillars and then emerge from them like you see here.

This is a saddleback slug moth caterpillar covered in silk cocoons spun by wasp larvae that have emerged after they finished feeding.

Here's an adult wasp cutting one open and coming out of one of the cocoons spun on the back of a hornworm caterpillar.

So sometimes, despite everything being out to get them, a moth or butterfly makes it to the adult stage.

And I wanna show you what that looks like for this spicebush swallowtail you saw earlier in the video.

As they grow older, they change to be more uniform in color, usually becoming orange like you see here right before they pupate.

At this point, this one's searching for and prepping a spot for where it's gonna hang inside of its chrysalis.

Once it decides on a location, the first thing it'll do is spin a silk pad that it will stick itself to to keep it attached to the vegetation.

When this one turns around, you'll see it fit the end of its body onto that pad.

The next step is spinning a silk girdle attached to the leaf and looped around its upper body.

You can see this one doing that right now.

If I slow down the time-lapse footage, you can see that it's not yet got the thread around its body.

Instead, it's spinning it and holding a loop between its front legs and its head.

It'll keep spinning that girdle loop over and over until the thread is thick enough to support its weight.

Once it's there, it has to squeeze its head underneath that line and lean back so its body is inside and supported by the silk harness.

At this point, it's done.

All it's gonna do is a caterpillar and is about ready to molt into the pupal stage.

And here's what that looks like.

As the larval cuticle is pushed down, you'll see white lines appear underneath the molt.

These are the tracheal or breathing tubes being pulled out.

They're also made of cuticle and have to be shed with every molt.

With this one, I wasn't able to catch the exact moment the adult butterfly emerged, but I did get to film the adult shortly after it came out.

So here it is.

This is a sight you don't often get to see, a newly emerged butterfly with perfect undamaged wings taking its first couple flaps into the air.

♪ Of course, in this stage, it still has some ecosystem surfaces to contribute, both through pollination and as potential food.

♪ and as potential food.

♪ So that's all the caterpillar footage I have for right now.

I hope you saw something new and interesting in this video.

I know I have.

Thanks for watching.

- Ah, thanks so much, Adrian Smith for that.

Caterpillars are cool.

That's the bottom line there.

And they look cool.

They don't even look real.

Well, that's it for Sci NC this week.

If you want more Sci NC, be sure to follow us online.

We've got our website, pbsnc.org.

And then of course we have YouTube and Instagram.

Give us a follow, subscribe, give us a like as well, and come back for some more.

I'm Laura Smith.

Thanks for watching.

Have a good one.

(gentle music) ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ - Sci NC is supported by a generous bequest gift from Dan Carrigan and the Gaia Earth Balance Endowment through the Gaston Community Foundation.

- Quality public television is made possible through the financial contributions of viewers like you who invite you to join them in supporting PBS NC.