PALEO-ENTOMOPHAGY:
Reconstructing the Insect Portion of the Hominin Diet
Study Guide Questions
• How can archaeologists tell that the bone tools from South
Africa were used as digging tools? What experimental task
best matches the wear patterns preserved on these artifacts?
• What do stable carbon isotopes tell about diet (C3 vs C4
photosynthesis)? Why are the results of this kind of analysis
surprising for australopithecines?
• What is the latitudinal gradient of diversity? How does it
relate to the clinal variation seen in global insect
consumption?
• What were the opinions of European explorers/colonizers
when they encountered insect eating?
• When is disgust learned? Why is knowing this important for
changing opinions about eating insects?
Outline
• Future first
– A movement towards a more sustainable protein
source
• Past
– Creating and testing a model of hominin termite
foraging
• Present
– Global patterns of insect consumption
Future
Food and Agriculture
Organization recommendations
• Further documentation of nutritional values
• Investigate environmental sustainability
• Clarify socio-economic benefits
• Develop legal framework for production
and trade
“Further documentation of
nutritional values”
This should also include understanding their
traditional nutritional role,
past and present
Outline
• Future first
– A movement towards a more sustainable protein
source
• Past
– Creating and testing a model of hominin termite
foraging
• Present
– Global patterns of insect consumption
Past
About 1.7 mya
3 cm
Photo: Backwell &
d Errico, 2001
High amount of wear and polish on one end
Tools of this sort are known from three sites in the Cradle of
Humankind
Largest sample coming from the site of Swartkrans.
86 total Swartkrans bone tools.
Termite foraging?
Cover story of PNAS v98(4) 2001
By Backwell and d Errico
Display at the Ditsong National
Museum of Natural History
Pattern and width of the striations on the
Swartkrans tools match that of tools used to
experimentally excavate termite mounds
Photo: Backwell & d Errico, 2001
Why termites?
• Nutritional food source eaten today by
populations of each of the great apes,
including humans
• Evidence for termites in Plio-Pleistocene
Africa
• Compatible with stable carbon isotope
analyses of hominin teeth?
Stable Carbon Isotopes (C12 and C13)
• Two pathways
• Most plants utilize
the C3 pathway woody plants
• Chimpanzees and
gorillas have a
primarily C3 diet
Stable Carbon Isotopes (C12 and C13)
• C4 plants
photosynthesize
faster than C3 plants
under high light
intensity and high
temperatures
• Grasses and most
savanna plants use
a C4 pathway
Hominin Carbon Isotopes
C4 control
C3 control
Sponheimer, et al 2005
Hominin Carbon Isotopes
Chimpanzees
C4 control
C3 control
Sponheimer, et al 2005
Swartkrans
Chimpanzees
C4 control
C3 control
Sponheimer, et al 2005
Earlier non-tool using hominins
Swartkrans
Chimpanzees
Sponheimer, et al 2005
It was proposed that termites could
provide the answer to the isotope
conundrum
• Grass-foraging termites could be contributing
to C4 signal
• The evidence of termite foraging from the
Swartkrans bone tools made this an
appealing answer to the conundrum
Termite Diversity
• Worldwide there are over 280
genera and 2,700 species
• There are 85 genera in SubSaharan Africa
• Termite diets vary by clade
feeding on wood, grass, soil
• The caste system brings
additional intraspecies variation
Modeling the past
• There is no available direct evidence of
hominin termite selection
• Therefore, modeling the past based
present-day analogs is the best way to
estimate preferences
Termite desirability
• Termites are consumed by populations of the
great apes, including humans
• Not all apes show the
same preference for
Macrotermes
Bwindi Mountain
Gorilla
Gorilla preferences
• Gorillas highly select the workers of soilfeeding termites such as Cubitermes
Dja, Cameroon
Deblauwe and
Janssens, 2008
Modern human termite preferences
Thohoyandou, Limpopo, South Africa.
April, 2016
• Populations of humans across Africa regularly
dig for termites, often of the genus
Macrotermes, but also of other genera such
as Hodotermes
• Eat soldiers year-round and alates (winged
reproductives) when seasonally available
Termite Preferences and Nutrition
Species
Caste
Preferred By
Crude
Protein (%)
Crude Fat(%)
Fe
(mg/100g)
M.
muelleri**
Soldiers
Chimps
72
5
10
C. heghi**
Workers
Gorillas
15
13
2962
M. falciger*
Alates
Humans
21
22
_
* Phelps et al 1975
**Deblauwe and Janssens, 2008
Termite preferences reflect their
diets
Frugivorous chimpanzees
receive plenty of
micronutrients, but protein
requirements are more difficult
to meet
Folivorous gorillas receive
plenty of protein from leaves,
but micronutrient
requirements are more
difficult to meet
Photos: Abigail Lubliner & Rob Kroenert
Models for hominins eating
termites
• Chimp model
• protein-rich termites
• Gorilla model
• micronutrient-rich termites
• Human model
• variable, but definite inclusion of fat-rich
termites
• Robust australopithecines
had an average cranial
capacity of about 550 cc
• Similar in size to
specimens some attribute
to early Homo
• Utilization of resources
beyond what is seen in
chimpanzees would be
necessary to support the
large, expensive organ
• Fatty acids are among the
most crucial molecules that
determine your brain's
integrity and ability to
perform
• Hominins could have dug up
larvae and alates in a
manner similar to some
modern human populations
• Macrotermes termites are
likely what they were going
after
Testing the Model
Olduvai Gorge,
Eastern Tanzania
Gombe,
Western Tanzania
GC-FID and GC-MS results termites
M. falciger
[nonpreferred]
Macrotermes show indistinguishable intraspecific saturated hydrocarbon distribution
patterns dominated by odd, longer chain-length homologues (n-C21 to n-C27).
Lesnik et al. (in preparation)
GC-FID and GC-MS results termites
M. falciger
[nonpreferred]
Macrotermes show indistinguishable intraspecific saturated hydrocarbon distribution
patterns dominated by odd, longer chain-length homologues (n-C21 to n-C27).
Lesnik et al. (in preparation)
Termite biomarkers are conserved in modern mounds
100
m/z 85
m/z 85
m/z 91+97
m/z 91+97
Macrotermes falciger
50
0
10
m/z 85
m/z 91+97
Lesnik et al. (in preparation)
20
30
40
m/z 85
50
m/z 91+97
Macrotermes subhyalinus.
Active termitarium
Termite biomarkers are also apparent in ancient mounds
100
m/z 85
m/z 85
m/z 91+97
m/z 91+97
Macrotermes falciger.
50
0
10
m/z 85
m/z 91+97
m/z 85
m/z 91+97
Lesnik et al. (in preparation)
20
30m/z 85
m/z 85
40
50
Active termitarium
m/z 91+97
m/z 91+97
PTK fossil termitarium
Termite biomarkers are also apparent in ancient mounds
100
m/z 85
m/z 91+97
m/z 85
m/z 91+97
–24.2‰
Macrotermes spp. (soldier [edible])
50
0
10
20
30
40
50
–23.0‰
m/z 85
m/z 91+97
m/z 85
–23.5‰
m/z 91+97
Macrotermes spp. (worker [edible])
FLK Zinj (fossil termitarium)
For compound specific: C4 = -20‰; C3 = -36‰
Lesnik et al. (in preparation)
Outline
• Future first
– A movement towards a more sustainable protein
source
• Past
– Creating and testing a model of hominin termite
foraging
• Present
– Global patterns of insect consumption
Present
• Termites are not the only available edible
insect
• Caterpillars, beetle larvae, ants and many
more are consumed regularly around the
world
• All are highly variable in nutrients, but
protein seems to be high in most
Human preferences
Jongema, 2012
Tropic of Cancer
Tropic of Capricorn
Jongema, 2012
Clinal variation: Change in
frequency over geographic space
Tropic of Cancer
Tropic of Capricorn
Jongema, 2012
Latitudinal Diversity Gradient
• Widely recognized phenomenon in
ecology that there tends to be an increase
in species richness moving towards the
tropics
• No single explanation. Possible
combination of increased energy
availability and environmental stability
Latitudinal Diversity Gradient
• Gradient displayed for terrestrial mammals
•
From: Mannion et al. (2014), based on work by Clinton Jenkins.
Europe under ice until 18,000 ya
Statistical test
• Variables per country
– Number of insects species consumed
– Centroid latitude
– Area
– Percentage arable land
– Population
– Gross domestic product
Statistical test
• Variables per country
– Number of insects species consumed
– Centroid latitude*
– Area
– Percentage arable land
– Population
– Gross domestic product*
• Logistic regression found that latitude could correctly
predict the presence of edible insects in 80% of the cases
Testing the gradient
*
53
Testing the gradient
*
In the next slide, these predictions are are indicated as gray boxes
and bold-lined boxes
54
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Paired Mann-Whitney tests of latitude
and presence of edible insects
LatLot 10 (α= .003)
LatLot 9 (α = .002)
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LatLot 9.5 (α = .003)
LatLot 10.5 (α = .003)
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LatLot 10 (α= .003)
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45N
• Of the 30 tests of paired adjacent lots, only three yielded
results that were significantly different to the level of the
Bonferroni correction
• These three boundaries fall between 40 and 46 degrees
– Transition out of the “mid-latitudes” towards less temperate
environments
– Where the majority of “western” countries reside
56
Removing “western” countries
• The correlation with GDP goes away
Image: StatisticsTimes
J. Lesnik (In Press). The strangeness of not eating insects. In Lee and Willermet (Eds.)
Scientific Approaches to Biological Anthropology: The Strange and the Familiar.
Cambridge University Press.
57
By why the
strong
negative
reactions in
the US and
across
Europe?
entomoanthro.org
Image: Library of Congress
Diego Álvarez Chanca, companion of Columbus
on his second voyage (1493):
“They eat all the snakes, and lizards, and spiders,
and worms, that they find upon the ground;' so
that, to my fancy, their bestiality is greater than
that of any beast upon the face of the earth.”
60
The disgust is real
• Embedded psychological disgust gets programmed in the
developing brain of children
• Before the age of 2, kids will put anything in their mouths
• They learn from the reactions of adults what is disgusting
• Digitally available
through our library
• https://elibrary.wayne
.edu/search~/?searc
htype=X&searcharg=
julie+lesnik
62
Summary
• Edible insects were likely a valuable, fat-rich resource
utilized by hominins. Fatty acids are critical to brain
development and growth.
• A termite nest found on the hominid layer at Olduvai
Gorge shows that C4 termites were available; they may
be part of the answer to the isotope conundrum
• Today, people in the tropics consume insects more than
people living further from the equator, but Western bias,
stemming back to colonial explorers, are why many find
them disgusting
• But disgust is learned! We can make a difference for
future generations.
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