University Place

The Evolution of Insects as Food

[Tom Zinnen, Outreach Specialist, Biotechnology Center, University of Wisconsin-Madison]

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 masters degree and a PhD at the University of Michigan. The master’s degree was in Kinesiology, which is the study of kin-ese.

[laughter]

And she got her PhD in Anthropology –

[Julie Lesnick]

Yes.

[Tom Zinnen]

– and then she went directly to Wayne State University, which is in Dearborn, over by Detroit.

[Julie Lesnick, Assistant Professor, Department of Anthropology, Wayne State University]

It’s right in Detroit. Right in Detroit.

[Tom Zinnen]

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.

[applause]

[Julie Lesnick]

Thank you. Thanks Tom.

Thank you, I already feel at home.

[laughter]

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.

[dedication slide featuring a photo of Gene R. DeFoliart (1925-2013), UW-Madison Department of Entomology, 1959-1991 and founder of the Insects as Food newsletter]

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.

[Julie Lesnick]

So, in the 70s and 80s, when he was trying to get people to eat bugs, he was thought to be crazy, right? And you might think the same of me, but now there’s more of us.

[laughter]

And so, we really do owe a great debt to Gene and so I did want to de-dedicate tonight’s talk to him.

[slide with an outline of the lecture including the bullet points, Future first Past and Present]

So, to get started, I want to give you a little outline, basically we’re going to do a little, you know, 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 – food of the fu-future, it can solve malnutrition, all these great things. And so, but be – 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 –

[Julie Lesnick]

– 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 U.N. Food and Agriculture Organization wrote a statement, about 200 pages –

[slide titled, Future with the headline of the finding of the U.N. report]

– outlining the benefits of edible insects. It was widely picked up by the press. This is an Associated Press headline, and you can see, like, solve malnutrition, solve hunger, solve pollution, all of these things and so that’s a pretty tall order, right? And so, what – what I want to start with is –

[Julie Lesnick]

– what was the U.N. actually saying, right? So, there’s a difference between the news headlines and the science, believe it or not, alright?

So, what the U.N. 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 –

[slide with a bar graph comparing the amount of protein, iron and calcium between chicken, beef, pork and an adult cricket]

– 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, all of the – 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 F.D.A. and different standards, but we – 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 –

[return to the slide with the bar graph comparing chicken, beef, pork and crickets]

– 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.

[new slide with a graph comparing the land use of beef, pork, chicken and crickets]

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 –

[Julie Lesnick]

– 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, right? 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, right? 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 – 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, right? And you can still have too many, right? There is overpopulation problems, there is balance, right? You need to keep your crickets happy but the amount – it’s not like packing cows into a C.A.F.O, right? 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 –

[slide with an illustration of the amount of water used per grams of feed for beef, pork, chicken and crickets]

– is a limited resource, right? 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, right? And so, again, there’s just so –

[Julie Lesnick]

– so much less resources that go into this.

But also, the output; so, next to automobiles, cows are our biggest producer of meth – greenhouse gases such as methane. And so, we look at cows giving us nearly –

[slide with an illustration of the amount in grams that beef, pork, chicken and crickets produce in greenhouse gasses]

– 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.

[new slide titled, Food and Agriculture Organization recommendations with regard to insects as food]

So, with those numbers, the F.A.O. still says we know there’s a long way to go; there’s a lot of information we still need. They – 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 how – 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.

Enviro – or economic impacts, that’s another thing. So, if we’re going to, you know, 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. –

[Julie Lesnick]

– and we have hungry people here in the U.S., right? 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, like, $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 stop – instead of wanting to abandon their traditional food ways and try to become members of our global food system, you know. 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. It 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 –

[laughter]

– 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, right? It needs to be produced at a facility just for human consumption, you need to have your standards, to, you know, 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 –

[slide with an animation of a caveperson hitting their hand on a big rock]

– 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, right? How is it valued? Is it a snack? Is it a delicacy? Is it a staple?

[Julie Lesnick]

And so, I think we need that information as well and I lump that into what the F.A.O. 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 –

[slide titled, Australopithecus robustus with a map of Africa showing the location of the Cradle of Humankind World Heritage Site, a still of the caveperson and the rock animation, a photograph of primitive tools and the illustration of the stages of man from ape to human]

– 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 –

[Julie Lesnick]

– 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 –

[slide with two photos of the bone tools, one of a group of bone tools and one of a close-up of the ends of two of the 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 –

[Julie Lesnick]

– 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. Alright? 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 – 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.

[laughter]

We have very, very strong C4 signatures because everything we eat here, basically, can be traced back to corn, right? 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 –

[slide with a graph illustrating the carbon values for earlier hominids, Swartkrans hominids and Chimps]

– about 35% of the diet was coming from C4 resources. So, then you go, Well hominids, right? 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.

[Julie Lesnick]

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, right? 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 –

[slide titled, Termite Diversity with a bulleted list of information about termites and five illustrations of various termites]

– there’s over 2,700 species. 85 genera of the termite clade exist in Sub-Saharan Africa, but the termite diets vary, right? We generally think of them as eating wood. We know that the – 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 –

[Julie Lesnick]

– 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.

[slide featuring two photos of the most likely termite candidates that early hominids may have eaten]

And so, I have basically two candidates, so I started simple, right? It’s either, like, Let’s try to figure out if we can figure out which of these.

[new slide titled, Trinervitermes with a photo of this type of termite and its vital statistics]

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.

[Julie Lesnick]

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.

[slide titled, Macrotermes, with two photographs, one of two of the Marcrotermes termites and one of a chimp using a branch at a termite mound. Also included are the vital statistics of this potential Hominid food source]

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 – 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, right? If I can just –

[Julie Lesnick]

– 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, like, 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 – at scratches on fossil teeth, and so I used that same technology to look at the scratches on the ends –

[slide titled Use wear study with three photographs of Julie and associates experimenting on termite mounds]

– 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 –

[new slide of Use wear study with a photo of a microscope and a microscopic image of marks on tools used for the study along with the results of the study]

– and I found no result.

[laughter]

So, it was a great idea, but the resolution of these bone tools and those different termite mounds, there was no difference. I – 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, alright? 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 –

[slide titled, Modeling termite selectivity, with info about selectivity and a photo of an ape at a termite mound]

– 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 – right? – 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.

[new slide titled, Gorilla preferences with a photo of the type of termite mound gorillas prefer]

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, like, little mushroom-y mounds and gorillas, with their giant hands, just go and knock down the mounds –

[laughter]

– and they eat the termites. So, they’re not very slick about it but they have a very strong preference for –

[Julie Lesnick]

– 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 –

[slide titled, Modern human termite preferences with two photos, one of a Black woman fishing for termites and one with Julie holding a large bowl full of termites]

– 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.

[return to the Modern human termite preferences slide]

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.

[laughter]

So, I do try to tell people if you’re, like, traveling and there’s edible insects available, like, have what the locals eat, right? 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 –

[Julie Lesnick]

– 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, kind of, 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 –

[slide with illustrations of the types of termites, soldier, worker and winged adult]

– 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 –

[slide titled, Termite Preferences and Nutrition, with a table of which termites are preferred by which class of hominids along with their nutritional values]

– that – Oops.

[return to the slide of the illustrated types of termites]

[return to the Termite Preferences and Nutrition slide]

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.

[new slide titled, Termite preferences reflect their diets, with two photos, one of a chimp and one of a gorilla and the info of how termites fit into the diets for both]

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 – 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 –

[Julie Lesnick]

– 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, right? It has – you might be able to get protein year-round –

[slide titled, Models for hominins eating termites, with the chimp, gorilla and human models]

– but at certain times of the year, you can get a hugely valuable fat resource.

[new slide with an illustration of an Australopithecus eating a fruit and the vital statistics of this hominid]

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 –

[new slide with a photo of a museum reproduction of Australopithecus using a primitive tool and more finding of Julies research]

-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, you know, 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.

[new slide with the illustration of evolution from ape to man with the final man holding a U.N. flag]

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.

[Julie Lesnick]

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, right? 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. –

[slide with the game of Taboo and the question of why people dont eat bugs in the U.S. or Europe]

– or in Europe, Neanderthals give us a bit of enlightenment on the topic. So, Neanderthals, being the first hominids in Europe –

[slide with a map of the world during the last glacial maximum 18,000 years ago]

– 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 –

[Julie Lesnick]

– 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 –

[slide of a color-coded map of the world showing the number of insects known to be consumed currently with darker colors indicating more and lighter colors fewer]

– 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 there 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. Right? So, 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 –

[slide with new map of the world showing the Latitudinal Diversity Gradient]

– 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 –

[Julie Lesnick]

– 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 than 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, like, 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 C.I.A. World Factbook. I used just oth-other online, published government demographic data. And I used these variables for each country.

[slide titled, Testing a latitude model and fallback food model with a list of the variables that Julie used in her research]

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 – 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 their resources, those should be the ones that eat more insects. And I also looked at, kind of, a – a marker of – of poverty or Gross – using Gross Domestic Product as a – as trying to figure out how rich or poor a nation is.

[new slide titled, Testing the models with the results of Julies research]

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, theres 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 –

[Julie Lesnick]

– seems to be the number one indicator, number one predictor of whos going to be eating insects.

But thinking about that latitudinal gradient of diversity, there should be a gradient then, of edible insects. Alright? It shouldn’t just be like, Oh, you crossed the 30th parallel, nobody eats bugs anymore. Alright? 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, you know, the color spectrum –

[slide titled, Testing the gradient, with an illustration of the color gradient from Red to Violet]

– to – to, kind of, model it, is that if its 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, you know, 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.

[new slide with the title Paired Mann-Whitney tests of latitude and presence of edible insects with six different tables of research findings]

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 should – 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 sh – in 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, right? One to 10, 10 to 20, I mixed up my Lots. I did one to nine, 10 to 18. I did –

[Julie Lesnick]

– 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 – how I defined those boundaries.

And so, what I found is that of the 30 tests of adjacent lots –

[slide with the results of the survey]

– only three of them were significantly different from each other. These three, actually, were all pretty close in, like, latitude; they were all, kind of, around that 40 degrees north area. But in – 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 – 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.

[new slide titled Conclusions with the conclusions of the study]

So, concluding from there. Alright? 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 – 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 – and also the hypothesis of it being used as a fallback food.

[Julie Lesnick]

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 –

[new Conclusions slide with two photos of early skulls showing the difference in brain size from early to late hominids along with other conclusions from Julies research]

– 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. Alright? 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.

[new slide with a page from Dr. Suess Green Eggs and Ham with a cricket on the tray instead of the aforementioned green eggs and ham]

So, if I haven’t convinced you to try edible insects, I – I do say that Don’t knock it, til you try it. Right? So, I mean, we’re all here; we’re all in America. We’re all westerners. We all have been –

[Julie Lesnick]

– raised with this idea of theyre 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 F.A.O. 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. Right? If I’m going to promote this, I should probably start trying it. And so, every day, like, you know, 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. Like, every new bug, I have to like –

[laughter]

– gear – gear up for. But the thing I really try to promote is that we have our biases, but our kids dont actually have those yet and so if we can just let our kids try it, figure it out for themselves, thats going to be how we see this change occur in the world. And its them thats going to need to save water, and re-think how to use land. Theyre 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, its always probably smart to not try something that’s very outside the box –

[slide with the questions Severe allergies? Shellfish? with photos of a lobster, a cricket, the logo for Wayne State University and the logo for the entomophagy and anthropology organization and thanks to these sponsors]

– 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 –

[Julie Lesnick]

– 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.

Oh, yeah.

[applause]