[slow upbeat music] If you think about how long Earth has been around, and even the history of insects, they've been around for hundreds of millions of years.

Then think about when cities arrived, and then cities as we know them, it's less than a blink of an eye.

Urban insects are interesting because they're finding a way to live amongst the humans in a way that we've manipulated the Earth, in a way that they've never been used to, in a way that their ancestors have not prepared for.

[slow upbeat music] [birds chirping] In most major cities, a phenomenon called an urban heat island traps heat in the city center, creating a much hotter environment than surrounding, natural areas.

Now we're seeing that in insects and wildlife in the city this new environment is causing them to have new behaviors and change the way that they find food, change the way that they find mates and change the way that they raise their young.

[door closing] Cool, cool.

To understand how insects are adapting to these hot modern environments, Sylvana Ross is on the hunt for a tiny test subject: tampinoma sessile, the odorous house ant.

Most people have probably encountered tampinoma sessile without even really knowing that that's what that ant is.

[slow upbeat music] Also known as the sugar ant because they do really well amongst humans because they really like sugary liquid and sweet things to eat.

I'm gonna go see over this big pile.

Anytime I like, lift up a log or anything I look for.

Oh, oh.

We got ants!

Hold on.

When that happens, I got to be like, oh, my gosh.

So I actually look for scurrying.

Like I look for little tiny things that are moving around.

These guys do look like tapanoma.

So when I lift it up and I see the scurrying, I grab my aspirator and suck them up.

Oh yeah.

[slow upbeat music] Ants do so many different ecosystem services.

One of the major ones is that they're ecosystem engineers.

There are ants that spend their entire lives in the tree canopy and are arboreal ants.

And so they're able to fill these different niches.

An ant colony is made up of majority of female workers.

They use pheromones and they use vibrations and touch in order to talk to each other.

They're able to tell each other warnings that there's predators around.

They're able to communicate where there's good food.

And one ant in and of it itself can't survive on its own, but an ant with a thousand sisters can then change an ecosystem.

There's a piece of mesh right there, so nothing gets in my mouth, but there's nothing in here.

So the ants can, like, shoot down through there.

So as I put this in my mouth, if I see anything running or scurrying, they just get like inhaled into the tube.

[slow upbeat music] There's some places in cities that are a lot hotter than others.

And we can see that in neighborhoods that lack the resources to have green spaces and parks.

This is colony 85.

And there's historic reasons why we've broken up our neighborhoods.

Across the United States, the practice of redlining in the 1930s determined which neighborhoods of a city would constitute a high risk for a housing loan.

Affluent neighborhoods with low risk were labeled A and B.

Those with majority black or immigrant populations were labeled C and D and colored red.

Those designations continue to dictate the ecosystems of these neighborhoods today.

And so lower income black neighborhoods that have been segregated in the past, lost a lot of financial resources.

They have more concrete and asphalt.

They have less green spaces, less parks, less tree cover.

And so those areas tend to be a lot hotter.

Dumpsters are a good spot.

I know that's kind of gross.

If you were to look at a 1930s redlining map and then compare it to temperature data, today we can see that the neighborhoods that were graded as hazardous and colored red are also the hottest areas of our city today.

Not ants.

In Baltimore, I'm picking eight different neighborhoods, two of each graded from redlining and I'll be going looking for tapanoma in each of those neighborhoods.

What's really interesting about the odorous house ant is that populations in natural areas tend to be a lot smaller.

Their colonies are made up of only one to a few queens.

Their workers are only a couple hundred.

I mean, their whole colony might live in an acorn or under a small rock.

But when we see tapinoma out in the city, her colonies can be ginormous.

And I'm talking hundreds of queens, millions of workers.

And something about the city is causing that change.

Whether that's because we've eliminated their competition, Or is it because we provide them sugary liquids in our trash and in our homes that can give them more energy and resources to have larger colonies?

The ants that are living in neighborhoods that have more concrete and asphalt and hotter temperatures have had to adapt to this really strong selection pressure, so I can compare ants from A graded neighborhoods to ants in D graded neighborhoods and see what temperature that they can withstand.

[slow upbeat music] My hypothesis is that ants from D and C graded neighborhoods will be able to withstand higher temperatures than those in A and B graded and also especially natural areas.

For this round of assays, we actually have two colonies, one from a C graded and one from a D graded neighborhood.

And then we have a colony from our natural state park.

I take a little ant and I put them in a dry block, and I crank up the temperature in intervals, and so I can check to see at what temperature that ant loses their muscle function.

Oh yep.

See this one?

She's on her back.

And if I give her a little tap, she can't flip back over.

And so I can compare that temperature across ants from different neighborhoods.

And I can see if ants from really hot neighborhoods have a higher thermal tolerance than those from cooler, more shaded neighborhoods.

Now we're at 46.8 which is 116 degrees Fahrenheit and the only girls left are our city ants.

It's seven, eight and one.

So one from a D graded and two from a C graded neighborhood.

Then I can look at their DNA and compare their DNA and gene expression across these different neighborhoods to see if there's internal mechanisms that they are using to tolerate these really hot temperatures.

These are the ants I got from the state park.

And then these are all my city ants.

And so the ones living in the city can withstand higher temperatures than those living in the natural areas.

I mean this is really cool, this is really exciting.

[slow upbeat music] First results show that some ants may be tough enough to adapt to a warming planet.

But for Sylvana, it will take time to answer her questions about how they're doing it, and what it means for other animals in the ecosystem.

When you see your hypothesis come to fruition, it's very validating but it's also scary because you understand that humans are changing the environment so much and so this really tiny ant, if it's being impacted by these hot temperatures, what does that say about the birds that are living in hot areas and the reptiles and even the people that are exposed to these hotter temperatures?

And if racial segregation is creating these really hot neighborhoods and those really hot neighborhoods can impact evolution in ants, it can be impacting entire ecosystems and all these other organisms that we see in cities.

As the planet continues to change, some bugs will be evolutionary winners.

While others are already losing out.