- Welcome everyone to Wednesday Nite @ The Lab,
I'm Tom Zinnen.
I work here at the UW-Madison Biotechnology Center.
I also work for UW-Extension Co-Operative Extension
and on behalf of those folks and our other core organizers,
Wisconsin Public Television,
the Wisconsin Alumni Association
and the UW-Madison Science Alliance,
thanks again for coming to Wednesday Nite @ The Lab.
We do this every Wednesday night, 50 times a year.
Tonight it is my pleasure to introduce to you
Julie Lesnick of Wayne State University.
She's here at UW-Madison this week
as a special speaker for the Darwin Days celebrations.
She's going to be talking with us
about her work on the evolution of insects as food
from hominids to the United Nations.
Julie was born in Lockport, Illinois
and graduated from Lockport Central High School.
She got her undergraduate degree
at Northern Illinois University in DeKalb in Anthropology
and then she got both a Master's degree
and a PhD at the University of Michigan.
The Master's degree was in Kinesiology,
which is the study of ki-nes (audience laughs)
And she got her PhD in Anthropology
and then she went directly to Wayne State University,
which is in Dearborn, over by Detroit.
- [Julie] It's right in Detroit.
- It's right in Detroit, okay.
And she's here to talk about one of my favorite topics,
food and sex, please join me in welcoming Julie Lesnick
to Wednesday Nite @ The Lab.
(audience applauds)
- Thank you. Thanks Tom.
Thank you, I already feel at home.
(audience laughs)
So thank you for that welcome.
I am honored to be here as a Darwin Day featured speaker,
I'm going to be talking about human evolution
but a part of it that you maybe don't think too much about
but is actually very important, and that's diet, right?
So in order for us to be who we are
and have these giant powerful brains,
we need to fuel it with the right foods
and so that's really been my area of interest
for over my career so far
and I've really honed in on this idea of edible insects
and how they can be contributing
a lot of the necessary nutrients that we need
over the course of our human evolution.
But before we get started,
I do want to dedicate tonight's talk to Gene DeFoliart.
He was here in your Department of Entomology
starting in 1959, he became Emeritus in 1991
and he just passed away only a couple years ago in 2013.
He founded the Insects as Food newsletter,
which is still super important to the work we're doing today.
So in the 70s and 80s, when he was trying to get people
to eat bugs, he was thought to be crazy.
And you might think the same of me,
but now there's more of us.
And so we really do owe a great debt to Gene
and so I did want to dedicate tonight's talk to him.
So, to get you started, I want to give you a little outline,
basically we're going to do a little past, present, future
kind of thing, but we're going to go a little out of order
and so we're going to start with the future first
because, right now, people are talking about edible insects
as something that could really be the food of the future,
it can solve malnutrition, all these great things
and so, we're going to start there
but then we're going to look at my research,
which is really focused on the past.
I'm a paleoanthropologist by training
and so that's the evolution of the human diet part.
However, all of this has to do with how we eat bugs today
and the fact that all of you here
are probably still a little squeamish
about the idea of eating bugs
and so I really want to look at the evolution of it
and really how that has impacted us
in our decisions to, or not to, eat insects.
So going into the future, like I said,
we have the food of the future here with edible insects
and so in 2013, the UN Food and Agriculture Organization
wrote a statement, about 200 pages,
outlining the benefits of edible insects.
It was widely picked up by the press.
This was an Associated Press headline,
and you can see, solve malnutrition,
solve hunger, solve pollution, all of these things
and so that's a pretty tall order.
And so what I want to start with is
what was the UN actually saying.
So there's a difference between the news headlines
and the science, believe it or not, all right?
So what the UN was saying, is that
insects are a very healthy alternative
to traditionally raised livestock,
so starting with the nutrition, what do they offer?
Well, when it comes to amounts of protein
per kilogram of the food, it's very comparable
to our other types of livestock
but the important part of it
is that what it's offering is an alternative
in a sustainable form, and we'll look at that in a second,
but also it's still an animal protein
and you're getting all of the essential amino acids
that come with animal protein.
So, you need these essential amino acids
because without any one of them
all of your amino acids are useless
and so that's why it's tough to be a vegan.
It's not like oh, are you getting enough protein.
It's are you getting enough of those amino acids,
so that all of them can be utilized in your body.
So here, all of our diagrams are going to look at crickets,
so crickets right now, are one of the most popular
kind of foods, insects, for people here,
like in the United States and Canada, and Europe.
Basically, we know a lot about farming them already
from the pet food industry
and so now, shifting that over to human facilities,
you know, you have to now meet the requirements of the FDA
and different standards, but we have a lot of knowledge
about how to do it, so a lot of what we're going to talk about
in this part of the talk, is about crickets.
So here we see that crickets offer a lot of calcium
but there are many edible insects
and depending on which one you eat,
you're going to see different amounts
of that micronutrient offer
but all of them are going to offer you some amount
of that useful animal protein.
But the big thing about edible insects
is the sustainability idea, the amount of resources
that go into farming insects as food as opposed
to traditionally raised livestock is greatly reduced.
So, everything scales down.
So cows are going to be the least efficient
and then pigs will be a little bit more efficient.
And then chickens, and then when you get
to the scale of insects, they're tiny.
The amount of turnover, what you put in
versus what you get out, is such a better ratio
than when you scale it up to larger animals.
So the amount of land it takes to produce a kilogram of beef
is 200 square meters.
So that's counting the area you need for the cows,
but the corn that you had to grow to feed those cows,
and all of the different facilities you need
to butcher those cows.
There's a lot of land that goes into producing beef.
You scale it all the way down to crickets?
And you're working with 15 square meters.
So crickets, you can work in a warehouse.
You can scale everything up vertically,
so you can have a box on a box on a box
and really increase the amount that you can produce
in a small area, like a warehouse
in an abandoned area of the rust belt, for instance.
And so that's really great and another thing I like to point out is,
for the most part, we're thinking about bugs,
they already like dark, cramped spaces
so the ethics of this.
And you can still have too many.
There is overpopulation problems,
there is balance.
You need to keep your crickets happy
but it's not like packing cows into a CAFO.
Because cows don't like being crammed into small spaces
with other members of their species,
so that's another benefit of edible insects.
The one that I think is the most important,
what stands out to me the most, is water usage,
so fresh water is a limited resource.
And so going into the future,
we're just going to need to be smarter
and smarter about how we use our water
and so, agriculture and livestock
is one of our greatest uses of freshwater
and so it takes 22,000 liters
to produce that kilogram of beef,
you scale that all the way down to the crickets
and you're looking at about 50 liters.
And so again, there's just so...
So much less resources that go into this.
But also, the output, so next to automobiles,
cows are our biggest producer of greenhouse gases
such as methane and so we look at cows
giving us nearly 3,000 grams of methane or greenhouse gases
when we produce that kilogram, scale it down for your crickets
and it's only a gram of those greenhouse gases
so there's a lot of benefits to changing
to this alternative food source.
So with those numbers, the FAO still says
we know there's a long way to go,
there's a lot of information we still need,
they end their statement with these
sort of future directions, what do we still need to study?
We need a better understanding of the nutritional values,
so we have some numbers for crickets,
we have some numbers for other edible insects
but people don't necessarily do standard methods
and there's a bunch, there are over 2,000
known edible insect species consumed today around the world
so we don't have all of that info,
so there's definitely more to do in nutrition.
The environmental sustainability,
the numbers I'm showing you, are kind of projections.
They're based on what the pet industry is doing
and what we can see in the couple of years
that we've had large scale farms
for people, for human consumption,
but we don't know what that actually looks like.
We don't have these cricket farms for people
that have been around for many decades
so we need that longitudinal data still
to really understand the sustainability.
Economic impacts, that's another thing.
So if we're going to solve world hunger,
this has to be a resource that's available in cheap
and right now it's not, especially not here in the U.S.
and we have hungry people here in the U.S.
And that's something that I think we don't talk about enough
and so these crickets aren't going to help those people here.
To get about a pound of crickets,
or a pound of ground up crickets as powder,
is almost $50 and so that's not
economically viable for a lot of people
to be like your normal source of protein.
However, if we think about it as a global problem,
the people who are already eating insects,
if they can just continue to do it
instead of wanting to abandon their traditional food ways
and try to become members of our global food system,
and so if they stop eating insects
because it's stigmatized here,
but they don't replace it with another animal source,
that's hugely problematic
and that is something Gene DeFoliart talked about.
There was a very important paper
about why the Western attitude is important
and we're still really working on that today
and seeing these impacts.
And then lastly, the legal framework.
So right now, food regulations,
we know how many insect parts you can accidentally eat
but there isn't really great information
on how to choose to eat insects,
so there's a little bit more that needs to be done there
but for the most part right now,
insects are just produced as any safe food.
It needs to be produced at a facility
just for human consumption, you need to have your standards,
to the same bacteria levels and whatever
as if you were producing cheese or anything else
and so there isn't really good, specific language
for edible insects and that's stopping some people
from wanting to carry it on their shelves in their stores.
But, my major point, is that this food of the future
is actually a very valued food of the past
and so, in talking about nutritional values,
I like to kind of play with those words a little bit
because it's not necessarily how much protein,
how much calcium, but also how do insects fit into a diet?
How is it valued, is it a snack?
Is it a delicacy, is it a staple?
And so I think we need that information as well
and I lump that into what the FAO is saying
about nutritional values.
And so this is where I've done my work
and where we're going to spend most of tonight's talk focusing.
So, in South Africa there is a site
that's part of the Cradle of Humankind World Heritage Site,
so there are multiple hominid sites
in this part of South Africa
and one of them is the site of Swartkrans.
And Swartkrans yields the fossil remains
of a hominid species known as Australopithecus robustus
sometimes called Paranthropus robustus.
And so these hominids lived about 1.7 million years ago,
they're related to us somehow,
they're probably not our direct ancestor
but they're definitely on our human lineage
and so their behavior is going to be somewhere
towards what chimpanzees might do
but they're upright walking, they're larger brained
than chimps and so they're definitely a hominid
and one of the big things about them
is that they are a tool user
and so also at the site of Swartkrans,
we get bone tools at that site.
So these bone tools are pictured in this bottom left corner
are about the size of a Sharpie marker
is what I like to think about them as,
and they're digging implements of some sort.
And so there's a lot of research done trying to figure out
what these digging implements were used for.
And so my colleagues, Lucinda Blackwell
and Francesco d'Errico published their research in 2001
and found that, on tools that they used,
they made their own bone tools
and they used them on a range of things.
They stripped bark off of trees.
They dug into the ground for tubers, they processed fruit.
They tanned hides, they did a bunch of things,
but they also dug into termite mounds
and it was found that the striations
at the ends of these bone tools
best matched digging into a termite mound
than any of those other tasks.
And so this was announced as evidence
of termite foraging for these hominids and it's great,
that's what launched my research interests from there.
But the reason why people got really excited
about termites as a possible food source for these hominids
is what we call the isotope conundrum for hominid diet.
So when we reconstruct hominid diet,
one thing that we can do,
is we can use stable carbon isotopes.
We literally are what we eat.
And so the carbon that we take in as food,
is then stored in our bodies
and so carbon follows a couple of different pathways.
Grasses have a way of photosynthesizing faster
because they evolved in strong sunlight,
but then woody plants like trees
and then the fruit and the leaves that come from those trees
have a different pathway, and so depending
on which of those foods you're eating,
you're going to store carbon isotopes
reflecting those two carbon pathways of photosynthesis.
And so chimpanzees and gorillas and all the great apes,
they eat fruit, they eat leaves,
so they have, what we call, a very strong C3,
carbon three signature of the foods they eat.
So we always assumed hominids would be the same.
Our signature, I think it was actually
Michael Pollan that said it, is that we,
basically, look like walking corn chips,
I think is how he said it.
We have very, very strong C4 signatures
because everything we eat here, basically,
can be traced back to corn.
So even the beef we eat eats corn
and so we're getting that signature.
So, a C4 signature can suggest meat,
because it moves up the trophic level,
it can also mean eating grasses and things like that.
And so we always expected hominids
had a signature that would be like chimpanzees
but in 2005, Matt Sponheimer and colleagues
reported the isotope signatures of these Australopithecines,
of Australopithecus robustus, and found
that about 35% of the diet was coming from C4 resources.
So then you go, well hominids.
Man the hunter, that's how we became human,
well that's not true, but also,
we don't think that Swartkrans hominids were hunting.
And to kind of confirm that,
we look at older hominids that have no tools,
so Swartkrans we have bone tools, we have some stone tools,
you might think they were able to get some meat in their diet
but with Australopithecus africanus,
who's older, we have no stone tool record for them.
Nobody thinks Australopithecus africanus was eating any meat
and they have that same 35% of their diet
coming from this C4 resource, so what was it?
That's the isotope conundrum.
And so termites provided a possible answer.
The termites that exist in the Cradle of Humankind today,
the termite mounds that were used
for those original digging experiments,
were grass foraging termites, so if you ate those termites
you would get that grass signature.
You would get that C4 signature.
Well this is where I come in.
I go, so you're eating termites,
and you're just going to lump termites together
and say that they're going to give you this C4 signature?
And I'm like one, when you think of termites,
you generally don't think grass.
And you don't think that they're eating grass
and so I started researching termites
as a possible food source
and understanding the diversity of the different species
and what it would be like to eat one over the other.
So termites, there's over 2,700 species.
85 genera of the termite clade exist in Sub-Saharan Africa
but the termite diets vary.
We generally think of them as eating wood.
We know that the termites in the original studies
were grass foragers, but they can also eat soil
and they can also eat a very mixed diet.
So depending on which termite you actually eat,
it's going to affect that carbon signature.
Also affecting variability, just because nothing's easy,
is that termites have a caste system.
So if you eat the soldiers versus the workers
versus the reproductive termites
you're going to get different nutrients
and possibly even a little bit
different of those carbon signals.
So my research question was which genus
of termites were these hominids eating?
Because that matters, if we're going to reconstruct the diet,
if we're going to model what they were eating
two million years ago, this is going to matter.
And so I have basically two candidates,
so I started simple.
It's either like let's try to figure out
if we can figure out which of these.
So the first genus is Trinervitermes,
Trinervitermes are the grass foraging termites
currently present day in South Africa
where these fossil hominid sites are.
So they're grass foragers, they have that C4 resource,
they're central to those earlier studies.
However, these termites like disturbed areas
so you tend to see them in agricultural fields.
They pop up, so after you kind of plow the ground
then these termites are like oh, it's perfect for a home.
So that's not exactly what the hominids
were doing two million years ago.
So I don't necessarily think these termites were all over
that same part of the landscape two million years ago.
But more notable about these termites
is that, because evolution, we're all evolving,
we're all competing with something,
they have a chemical defense mechanism.
The number one enemy of termites are ants,
and so ants want to come in and take over the termite mound.
It's a ready-built structure, they would love to move in.
And so termites have different defense mechanisms
and what these termites do,
is they have like a toxin, they spit glue
and it immobilizes the ants.
And in trying to think of things that sound delicious,
spitting glue termites is not usually
what comes to the top of one's mind.
So I thought these might not be
the best ones to model the diet with.
So the other genus that I think is a very viable candidate
for what these hominids were eating, is Macrotermes.
Macrotermes are consumed by chimpanzees very preferentially,
so of those 85 genera of termites
that are available in Sub-Saharan Africa,
chimpanzees strongly select Macrotermes.
They pretty much eat nothing else.
There's another genus that they eat occasionally,
known as Pseudocapritermes
and they're very closely related to Macrotermes.
So Macrotermes are large.
They have mechanical defenses,
instead of glue spitting defenses
and so that's how chimps eat them.
The pinchers of those termites
bite grass tools that chimpanzees thread into the mound,
so chimpanzees use this termite defense mechanism
against them and they're able to pull them out of the mound.
These termites are wood foraging termites.
They would offer that C3 signature.
So I wanted to figure out which of these two.
If I can just, if I can look back
at those bone tools and try to figure out
which of these termites might have been eaten,
because the two different termites
also build very different mound structures.
Macrotermes, when they harvest wood
and bring it back to their nest,
they actually have fungus in there
and the fungus breaks down the wood
and then they eat the liquid that's produced by the fungus.
So they have this symbiotic relationship
and they farm, they have a little fungus farm in their homes
and it has to be ventilated, and it has a central chimney
and the outside of the mound is very cement-like.
But the Trinervitermes has a much softer soil matrix.
It crumbles a lot easier, so to me,
very different substrates to use bone tools on.
So I did my own experiments. I dug into Macrotermes mounds.
I dug into Trinervitermes mounds.
I molded the ends of these tools
with dental impression material.
So you probably didn't know this,
but if you've ever had your teeth molded at the dentist
for braces, or a partial or whatever it is,
you get every single little pit and scratch on your tooth
preserved in that dental molding material.
So we use that in paleo, we can look at scratches
on fossil teeth, and so I used that same technology
to look at the scratches on the ends of the artifacts
as well as ends of tools
that I used to dig into these termite mounds.
Well, science is unpredictable.
I had a hypothesis, I tested it,
and I found no result.
So it was a great idea,
but the resolution of these bone tools
and those different termite mounds, there was no difference.
I had control groups, I dug into the ground
and did some other things and the artifacts
still best matched the termite tools
but there wasn't enough difference between the two genera.
So, not willing to give up.
Still feeling like this is a valid question to ask,
I tried to think of how else can I try to figure out
what hominids were eating in the past
and so we started looking at models of termite selectivity.
Like I said, chimpanzees are super strongly preferential
in eating those Macrotermes termites
but chimpanzees aren't the only termite eaters
of relevance to this study.
So I went and I wanted to look
and see how other apes and how humans
utilized termites in their diets.
Gorillas eat termites, they don't use tools.
They have a very strong preference for these termites
of Cubitermes as the genus,
and they build these little mushroom-y mounds
and gorillas, with their giant hands,
just go and knock down the mounds
and they eat the termites.
So they're not very slick about it
but they have a very strong preference for Cubitermes
and then even then, in the caste system,
they want the workers, they don't eat the soldiers,
they eat the workers, so chimpanzees want the soldiers
that are going to attack and pinch,
and gorillas want the workers
of a completely different genus.
Human termite eating preferences
are a little bit more variable, but for the most part,
humans still prefer Macrotermes over other genera.
We have the most variation though
in our termite eating preferences.
We do eat more genera than any of the other apes.
But most strongly, humans prefer
when the flying termites are out.
So seasonally, usually after rains,
the reproductive termites fly out of their natal mounds
and go start new colonies and so that time of year
you see kids running around, they're super excited,
they're knocking the termites out of the sky
and then scooping them up off the ground.
But some people do eat the soldiers year round
and how people forage for those soldiers,
is very similar to chimpanzees,
they just modify the technology a little bit
by increasing the surface area on their tools
by sticking a broom into the mound
instead of just a single piece of grass.
So after a day of foraging,
you can come home with a very large pan of these termites.
This is in the northern province of Limpopo in South Africa.
They boil them. They add a little salt.
And when they're fresh, they are so good
and they taste a lot like popcorn.
And what I realized is, like popcorn,
when they are not fresh, they are not good.
So I do try to tell people if you're traveling
and there's edible insects available,
have what the locals eat.
Go into their kitchens with them and see what they eat,
or have somebody take you to their favorite spot,
because what they're trying to hawk
to the tourists on the street,
is not the best quality of these foods.
They're doing it because people want
to take pictures eating the food,
not because they want to really experience
how delicious this food can be and they know that.
They can make the same amount of money
by giving you the dregs of their supply
as they can by giving you the good stuff.
So, if you're going to travel and eat some edible insects
be a little discerning in which ones you try.
So I said, so people have a preference
for these flying termites, the winged alate,
also maybe larvae if you can get the,
like if you're digging into the mound right before they fly
you can catch them while they're still larvae
or before they've differentiated into those castes.
And so we see from this, that--
Oops.
So when we look at the nutritional offerings
of these termites, the preferred termites for each group,
we actually see differences.
Chimpanzees, and their preference for Macrotermes soldiers
are getting termites that are really high in protein.
Gorillas, and their preference for Cubitermes workers
are getting lots of micronutrients
and then humans, going for the reproductive alates
or the larvae, have a lot of fat content in those termites
and so we're seeing three very different kind of models here.
And what it-- It works out beautifully
in that the supplements that chimpanzees are choosing
fits what they need in their diet, and similar for gorillas,
the supplemental termites they're adding to their diet
is the right one for their overall diet.
So chimpanzees are frugivores, that means over 50%
of their diet comes come fruit.
Fruit is great in micronutrients but it has no protein in it
and so chimpanzees have to supplement
protein into their diet and they usually do that through leaves and such
but they can also do it from these termites.
Gorillas on the other hand, don't eat a lot of fruit.
They eat leaves, they're folivores.
Almost 100% of their diet comes from leaves
and leafy greens have a lot of protein in it
so gorillas aren't at risk for protein deficiency
but they're lacking the micronutrients
that they could get from fruit.
So each of these great apes are eating the exact termites
that they need in their diet
and so with humans, when we're eating the fattier termites,
that's a different nutrient.
And I think in trying to model the past
and figure out what was going on in the hominid line,
is that this human model is more variable.
You might be able to get protein year round
but at certain times of the year
you can get a hugely valuable fat resource.
And so in thinking about early hominids,
brain size expansion was important.
And so we know that these Australopithecines
couldn't be eating a diet that was the exact same as chimps.
They had to increase their dietary quality somewhere,
somehow, something had to be different.
And so if we think about how they can support
that large, expensive brain,
adding fat to the diet is really important.
So essential fatty acids are some of the most
crucial nutrients that we need for brain function.
And so by shifting to having just fattier termites
we start seeing an easy way that these Australopithecines
could be adding these essential amino acids to their diet.
And so just a very small shift,
seasonally, using it when it's available,
would be a really smart thing for them to do
and I really think that's probably what was going on.
So in continuing our discussion of human evolution
and edible insects, we see
that these Australopithecines likely focused on termites
or maybe ants, other social insects.
Basically, you walk up to a termite mound,
you have millions of termites.
It's a very reliable resource.
And then we're starting to get to the genus Homo,
I think we're probably seeing insect utilization
more how we see people around the world using it today.
There are thousands of available edible insects
and so whatever environment Homo erectus was in.
So Homo erectus was the first hominid to leave Africa.
So they're going to be in Southeast Asia
and a lot of different parts of the world,
and when you get to different environments, you're going to have different
edible insects available to you and so Homo erectus was probably
taking advantage of some of those.
When we get to Neanderthals,
the first hominid to be in Europe.
And the first, we're talking about our culture,
the first hominid that's really
relevant to how we might eat insects today,
we have the Neanderthals to look at.
And so, when we're thinking about our choices,
why we don't want to eat insects,
here in the U.S. or in Europe,
Neanderthals give us a bit of enlightenment on the topic.
So Neanderthals, being the first hominids in Europe
were there during Glacial Maximums
and the last glacial Maximum
existed until about 18,000 years ago
and so people in Europe, until 18,000 years ago
were pretty much in a snowy, cold environment
and so if you're thinking of where
you're going to be able to forage for edible insects,
you're thinking not the cold tundra of Glacial Maximum
northern environments of the world at this time,
and so, if we're tracing our history
back in Europe all the way to Neanderthals,
edible insects weren't there in their diet.
Edible insects would be important
to hominids that were anywhere else in the world
except in those really cold environments.
And so when we look at edible insects today,
so this map comes from an online database
of known edible insects.
And so what the map shows, by country,
is number of insect species that are known to be consumed
and if you look at it, you can see
that north of the 45th parallel,
we have pretty much no edible insects
being utilized in diets
and so that's where you're getting into, even today,
these environments that have harsh winters.
And so if there's a big portion of the year
where that's an unavailable resource to you,
and the way that Neanderthals survive in the north,
and the way that humans did it even when they started
with domestication, is by eating livestock.
So we can't get enough fruit
or vegetable matter up in the wild
but if you can eat an animal like a caribou
or a deer that can eat the woody plants that we can't,
that's a valuable food resource.
So the only way to survive up there is to eat animals.
And so if you're already eating animals,
it's not like well, these bugs are great too.
You're not-- You don't have the need
for alternative insect protein
when you are eating meat all year round.
So we really see that edible insects are a tropical resource
and so it's a tropical resource
probably because in the tropics,
we have larger species diversity so you have what we call,
and it's an ecological phenomenon,
well-known, well-documented.
Here is a map of terrestrial land mammals
and so more biodiversity in the tropics
and as you leave the tropics, species diversity reduces.
So why there's more species in the tropics
is probably a couple of things.
Stronger solar radiation allows for more photosynthesis.
More photosynthesis allows for more food for more species
and more niche creations, so you get speciation
and diversification that way.
Also, the seasonality there is different
that what we see up here.
So you might have wet and dry seasons,
you might have an El Nino, but you don't get the
really harsh winters that wipe out a large amount
of your species diversity for part of the year.
And so because there is more diversity in the tropics,
we're going to see more people
have edible insects available to them,
and ones that they're going to find delicious.
You have better odds of finding one you like,
when you have more diversity.
So this is a pretty, sort of well-documented,
in that people say oh yeah, people eat bugs in the tropics.
But the other thing, when people are trying to figure out
who eats bugs and why we don't,
is it's often described as a fallback food.
It's often that, "Oh, you don't have meat."
Or, "You don't have anything else."
And so one of my favorite things to do in science
is to test things that people think they know.
And so what I did is, working with
the online database of edible insects,
I used the CIA World Factbook.
I used just other online, published
government demographic data.
And I used these variables for each country.
The number of insect species consumed in each country,
the latitude, centroid latitude for each country.
How much arable land, how much land is being farmed
because if insects are a fallback food.
Or another way people say is that
part of the reason why we might not eat insects here
is that insects are a pest to crops
and once you have a crop-based diet
then you have a stigma against insects.
So I looked at arable land, I was like okay.
Well then that means the countries with the least farming
should be the ones that eat the most insects,
so I used that variable.
I looked at area and population
to come up with population density.
So if it's a fallback food,
the countries with the largest population density
that's outstripping the resources,
those should be the ones that eat more insects.
And I also looked at kind of a marker of poverty
using Gross Domestic Product as trying to figure out
how rich or poor a nation is.
And so what I found is there's absolutely no correlation
between the number of insects consumed in a country
or presence or absence of edible insects in a country
and population density and no correlation
between those edible insects' variables and arable land.
So there's no correlation there.
But in a logistic regression model,
latitude could correctly predict the presence
of edible insects about 80% of the time.
And so where you are in the world,
latitude seems to be the number one indicator,
number one predictor of who's going to be eating insects.
But thinking about that latitudinal gradient of diversity,
there should be a gradient then, of edible insects.
It shouldn't just be like oh, you crossed the 30th parallel,
nobody eats bugs anymore.
So I wanted to test that idea of a gradient
and so in thinking about that, I was like
well, how do you test a gradient?
So here I'll use the color spectrum
to kind of model it, is that if it's a gradient,
you should never notice the change as you go.
So two adjacent areas should not be significantly different
but as you get further and further away from each other
you should start seeing significant differences
between the equator and northern latitudes.
But you shouldn't see any significant differences
as you move along that gradient.
So using this kind of ideal model,
I tested how latitude and edible insects went.
So this is kind of a mess, it looks crazy.
But what I did, is I paired--
I created what I called latitude lots.
So the easy way to start was to go
from zero to 10 degrees and call that a lot.
And then go from 10 to 20 and call that a lot
and 20 to 30 and compare those lots
to each other and to all the others.
So the dark boxes are the adjacent lots.
And so there should not be, the predictive model says,
that there should not be significant differences
in those dark, bold, outlined boxes.
And that instead, you should see
more significant differences in what's shaded.
Well you can't really say-- It would be shaded
in kind of the bottom left corner.
These are the further and further apart you get.
And so that's pretty much what I found.
Of this is that I did-- A latitude lot,
because it's completely arbitrary.
One to 10, 10 to 20, I mixed up my lots.
I did one to nine, 10 to 18.
I did one to 11 and a half, and like to 21.
And so I just, I kept mixing up how I made my lots
and that's why there's so many paired lots here,
because I kept changing how I defined those boundaries.
And so what I found is that
of the 30 tests of adjacent lots, only three of them
were significantly different from each other.
These three, actually, were all pretty close in latitude,
they were all kind of around that 40 degrees north area.
But it wasn't always there, so I would find
when I mixed up my lots and we had a boundary
between 40 and 45 over here,
they weren't necessarily significantly different.
But when I mixed it up again,
they might be significantly different in those three times.
So, for the most part, my data for this
is showing that gradient, we don't see as much
significant difference in those adjacent lots.
And so, like I said, latitude, 80% of the time,
is what can predict edible insects in that it does follow
that sort of latitudinal gradient of diversity model.
So concluding from there.
So paleoanthropology perspectives
is how I even thought to look at the importance of latitude.
In reconstructing it for the hominids,
hominids have existed-- Our ancestry of human evolution
was in Africa for millions and millions of years.
And so that was in very warm, tropical environments
and so if it wasn't for the Neanderthals,
getting up to Europe and me going,
"They probably weren't eating bugs up there,"
I probably never would have tested that latitude hypothesis
and also the hypothesis of it being used as a fallback food.
So I think there's a lot that these
kind of paleo-human evolution perspectives
can really offer us today.
It also shows that edible insects were an important resource
for most of human evolution, so our ancestors,
you know, those two million years ago,
or one million years ago with Homo erectus
were likely utilizing insects in their diet.
Also, as we think of brain size expansion
over the course of human evolution,
insects give us an opportunity
to add essential fatty acids to our diets
without having to go and hunt risky game.
You can get hurt when you go hunt large game.
You can also spend three days trying to hunt
and come home with nothing, but edible insects are reliable
and they offer a very similar nutritional profile.
So if I haven't convinced you to try edible insects,
I do say that don't knock it, until you try it.
So, we're all here, we're all in America.
We're all westerners, we all have been raised
with this idea of they are gross, and even me,
like I've had to make myself eat bugs.
So I got into this as a completely academic pursuit
and then I've been convinced by the data of the FAO
and the sustainability, and so it's like
when I did first six years of my research,
I never ate a bug, and then it turned into,
I should probably eat some bugs.
If I'm going to promote this,
I should probably start trying it.
And so every day, if I try a new bug,
so I eat a lot of crickets, I eat a lot of meal worms,
I now eat a lot of termites when I'm in the field,
but if somebody gives me something new,
I tried June bugs this past summer, or something like that.
Every new bug, I have to like,
gear up for.
But the thing I really try to promote
is that we have our biases,
but our kids don't actually have those yet
and so if we can just let our kids try it,
figure it out for themselves,
that's going to be how we see this change occur in the world.
And it's them that's going to need to save water,
and re-think how to use land.
They're the ones that are going to be really fighting
the resource crises that we see on the horizon.
And so you don't have to try it
but try to not pass on that stigma
and let people make the decision for themselves.
So we have edible insects for you to try.
There are some chocolate covered crickets,
but then there are also other crickets
that look more like crickets.
And then there's some meal worms.
If you have any severe allergies,
it's always probably smart to not try something
that's very outside the box, however, reminder,
we do eat a bunch of insect parts all the time
in any processed food, so you are eating
some bugs in your diet at all times.
But shellfish allergies,
they're all arthropods, they all have exoskeletons
and chitin and all the proteins
that bind up in that exoskeleton
and so severe shellfish allergies
could be triggered by eating the exoskeleton of a cricket
so I do like to point that out.
But thank you so much for your attention.
This was a lot of fun
and I'm happy to take as many questions as you have.
(audience applauds)