Dlùth-shealladh air beatha nam biastan-dubha ann an Sealtainn
ann an 1983 a bha mar phàirt dhen t-sreath, The World About Us. A
fascinating insight into the life of the wild otter in Shetland filmed
by wildlife cameraman Hugh Miles, and broadcast in 1983 as part of the BBC TV series 'The World About Us'.
Two scientists and an entrepreneur are
crunching the science behind edible caterpillars to help fight
malnutrition and food security problems in West Africa.
For
most people the idea of chewing on a caterpillar or tucking in to a
tarantula is pretty unpalatable, to put it mildly. Yet according to the
United Nations, some two billion people around the world consume insects
regularly. This prompted World Service listener Saman from Pakistan to
ask the BBC CrowdScience team "are insects a serious food source?"
In
order to tackle this question the programme team headed out to Burkina
Faso in West Africa, where shea caterpillars are an important part of
the local diet in a country where over 30% of children suffer from
chronic malnutrition and 2.7 million people are at risk for food
insecurity. Image caption
Shea caterpillars contain high levels of protein and micronutrients
Caterpillar enthusiast Charlotte Payne is a PhD
student at Cambridge University who is currently conducting research on
the caterpillar lifecycle.
"Shea caterpillars have the potential
to help people break out of a cycle of poverty," she exclaims when we
met her on a farm in the rural village of Soumousso in the West of
Burkina Faso.
At the moment the caterpillars are only available
for a few weeks a year. But with their high levels of protein and
micronutrients like iron and zinc, they have the potential to fend off "hidden hunger",
as micronutrient deficiency is sometimes called, and change the
financial situation of the poorest people in West Africa, especially
women and children. Image caption
Caterpillars can be cooked whole or turned into products, such as protein bars or croquettes
How to breed caterpillars
Together
with her colleague Darja Dobermann, a PhD student at the University of
Nottingham and Rothamsted Research, Charlotte is trying to crack the
science behind shea caterpillars and make them available all year round.
"In the same way they keep chickens in their backyard, the women would be able to keep caterpillars too," Charlotte explains.
While
in Burkina Faso, Charlotte is collecting as much information as she can
about the needs and wants of the local people. Her preliminary results
suggest that breeding caterpillars would be very welcome in the region.
"It would be great if I could rear the caterpillars all year round
because I would have enough to eat and earn a lot of money selling
them," one woman in Soumousso told us. Image caption
Once processed and packaged, shea caterpillars stay edible for up to 18 months
To help accomplish this vision there are many
hurdles that the researchers must overcome. For starters the
caterpillars are fussy customers. They only feed on the leaves of the
shea trees.
Similar to how scientists have spent years working out
what the best feed for livestock is, Darja explains, the same needs to
happen for the caterpillars. From an environmental point of view it is
of some consequence how these caterpillars are fed.
Environmentally savoury
Insects
are often touted as a panacea for the environmental problems that come
with producing meat, because they emit less greenhouse gasses and take
up less space.
"The unfortunate thing is that the majority of
insects that are commercially farmed are predominantly fed with chicken
feed. Chicken feed is made out of soy and this isn't very sustainable.
Unless you can get the insects onto a waste product as their food
source, they aren't more sustainable than chickens from an environmental
perspective," Darja explains. We
investigated caterpillar farms after Saman from Pakistan asked us: "Are
insects a serious food source?" If you've got a science question you
want BBC CrowdScience to look into, get in touch via the form below and we'll investigate a selection.
In her lab in England, Darja will be
analysing shea tree leaves to uncover why the caterpillars like them so
much. This includes figuring out what nutrients the caterpillars are
getting from the leaves and discovering whether the leaves send out a
special "smell" - volatile aromatic compounds - that the caterpillars
are drawn to.
"There might be something particularly appealing
about these leaves that we could synthesise and spray onto artificial
feed to attract the caterpillars," Darja explains.
Charlotte and
Darja are not alone in their quest to turn caterpillars into a
sustainable food source. They work closely with local entrepreneur,
Kahitouo Hien, who is betting all on the success of these nutritious
critters.
Caterpillar cook-out
Outside
Kahitouo's factory in the capital Ouagadougou a huge caldron filled
with thousands of caterpillars is bubbling and filling the air with a
pungent aroma. With his business, FasoPro, Kahitouo is trying to create
an industry for shea caterpillars. Something that no-one else has dared
do before.
Today he sells 10 tonnes of caterpillars every year to
markets and shops around the country. But it has not been easy to get
to this point.
"A lot of people laugh when they hear about my
business," Kahitouo explains as he leads us into a room filled from top
to bottom with tightly packed boxes of dried caterpillars.
Media captionKahitouo Hien and Charlotte Payne have kick-started an initiative to commercialise caterpillar productionEven though caterpillars are traditionally eaten in Burkina
Faso, Kahitouo has had a hard time convincing the community that they
should eat more of them.
"In the beginning it was very difficult
for me to find even one shop that would sell the product, but now I
don't even have to leave my office. The shops call me up. When I think
about that I feel really proud of myself and the business."
Kahitouo hopes to spread the business model to other countries but using the local insects found in each place.
Bugs to the rescue?
With
nine billion people in the world by 2050 and food production needing to
increase by 70% according to the UN, we may all have to get used to the
taste of bugs like many people in Burkina Faso already have.
Indeed, there is scope for edible insects to play a serious role in food culture beyond being a fashionable snack.
However working out how to farm them in an environmentally friendly way is a question that continues to bug. BBC CrowdScience, Should We Eat Insects? airs on the World Service at 19:32 GMT on the 7th of April 2017. After this you can listen online or download the podcast.
Ravenous, famished, starving. We all have hungry days, but are you ever 4 tonnes of seafood hungry?
Let's
be honest, the blue whale, giant of the seas and the largest living
animal on Earth, beats everything when it comes to a big appetite. On a
daily basis, this leviathan gulps down 40 million tiny crustaceans known
as krill to maintain its bulk.
But there are other animals with a reputation for supersizing their meals, and some of them might surprise you.
An African elephant (Loxodonta africana) mid-meal (Credit: Denis-Huot/naturepl.com)
Like the blue whale, giant land animals have appetites to match their impressive stature. According to African elephant expert Norman Owen-Smith
of the University of the Witwatersrand, Johannesburg in South Africa,
adult males eat around 1% of their bodyweight in dry mass every day,
while lactating females eat up to 1.5% to keep themselves going.
Pandas eat as much as 12.5kg of bamboo a day
Males
can weigh as much as 6 tonnes, so that is up to 60kg (132 lb) of dry
food – without factoring in the water content, which can make it four
times heavier.
These mega-mammals are herbivores so they spend
most of their day foraging for enough green matter to power themselves.
They can feed for as long as 18 hours a day, depending on what is
available.
Similarly, the giant panda spends 14 hours a day munching on bamboo. Researchers have suggested that this diet is not optimal for the animals,
which actually have an omnivorous digestive system that is not best
suited to breaking down lots of plant fibre. This could explain why
pandas eat as much as 12.5kg of bamboo a day to get the nutrition they
need – and why they produce such a lot of poo.
Generally,
vegetarians must spend a lot of time at nature's buffet table to consume
enough calories, while carnivores can focus on fast food.
A little brown bat (Myotis lucifugus) (Credit: Visuals Unlimited/naturepl.com)
Little brown bats are said to be able to devour 1,000 mosquitoes in an hour. But scientists view this figure with suspicion. Brock Fenton of Western University, Canada, says the claim is "preposterous", the result of confusion between two studies of two different species of bat in the 1950s.
Japanese house bats plan their next meal before they have even eaten the current one
Fenton says that one study examined the stomach contents of a tricoloured bat
after a period of feeding, while the other recorded little brown bats
in a laboratory catching mosquitoes and fruit flies. Neither give an
accurate picture of how many insects little brown bats eat in the wild.
Furthermore,
little brown bats eat more than just mosquitoes: they prefer larger
prey items, such as moths, when they can catch them. A study of the bats in Canada revealed that mosquitoes only made up a small proportion of their diet.
So, it is probably a bit of a stretch to say they can eat a mosquito every 3.6 seconds.
However,
there is evidence to suggest bats really optimise their hunting
strategies to make the most of the available prey. A 2016 study revealed
that Japanese house bats plan their next meal before they have even eaten the current one. Far from winging it, the bats plan their flight routes according to what snacks they can pick up along the way.
A pygmy shrew (Sorex minutus) (Credit: Artur Tabor/naturepl.com)
There are other small brown mammals with an unshakeable reputation as voracious predators: the shrews.
The average hummingbird eats half its bodyweight in sugar every day
The common shrew
must eat every 2-3 hours and consume 80 to 90% of its bodyweight in
food each day to sustain itself. At half the size of its common cousin,
the pygmy shrew eats 125% of its bodyweight every day.
These
mammals have extremely fast metabolic rates, meaning they break down
and use energy rapidly. So, they must feed regularly on high-protein
invertebrate meals or face starvation.
Any discussion of metabolism will also feature hummingbirds.
A bee hummingbird (Mellisuga helenae), temporarily between meals (Credit: Mike Potts/naturepl.com)
These flying marvels favour a sugar fix to power
their energy-intensive hovering flight. Beating their wings as many as
50 times per second, the birds have some of the highest metabolic rates
among vertebrates.
You may have heard that the average hummingbird
eats half its bodyweight in sugar every day, feeding every 15 minutes
on floral nectar. But there are over 300 species of hummingbird.
It takes immense energy reserves to transform from a tiny larva to a silk moth
"The amount of nectar consumed can vary quite a bit by hummingbird species," says Adam Hadley,
a leader in the hummingbird research team at Oregon State University.
"Particularly since they have a very large range in body size, from the
2.5g bee hummingbird to the 24g giant hummingbird."
While the
larger species consume more nectar overall, they burn their energy more
slowly than smaller birds. This means that, proportionally, the smaller
species are hungrier.
Hadley says the birds also store energy for
when they need it. "Interestingly they can often be storing up as much
as 17% of their body weight each day in fat reserves, so that would be
like the average North American putting on 30lbs in a single day."
Other
species only display a prodigious appetite at certain points in their
lives. For example, it takes immense energy reserves to transform from a
tiny larva to a silk moth.
A Polyphemus moth (Antheraea polyphemus) (Credit: Barry Mansell/naturepl.com)
The Polyphemus moth is named after Homer's mythical cyclops,
because it has a single eyespot on each wing. But the man-eating
monster and crop-devouring caterpillar are perhaps more similar in their
gigantic appetites.
To match a caterpillar, we would have to eat 50-200lb of lettuce each day
According
to the Guinness Book of World Records, this caterpillar can eat 86,000
times its bodyweight in 56 days. But Andrei Sourakov, collections
co-ordinator at the Florida Museum of Natural History,
says this is a dubious figure. It is a bit like measuring how much a
person eats through their entire childhood, then comparing it to their
weight as a newborn baby.
Sourakov says that a recent project at the University of Florida found that luna moths, a similarly sized species, typically ate between half and two-thirds of their body weight each day.
"Still,
I think it is impressive," says Sourakov. "To match a caterpillar, we
would have to eat 50-200lb of lettuce each day." Clearly, Eric Carle's
famously very hungry caterpillar was not far off the mark.
Our
final candidates for the hungriest animal on Earth are not likely to be
the stars of a popular children's book. Even though their peculiar
eating habits have been harnessed to save human lives, they have a
reputation as vampires.
A medicinal leech (Hirudo medicinalis) (Credit: Willem Kolvoort/naturepl.com)
Medicinal leeches are famous for drinking blood,
and have been used to heal wounds and thin the blood for centuries.
However, most of the world's 700 species of leech are actually predators
of invertebrates, like the worm-hunting monsters of Borneo.
Leech champion Mark E. Siddall at the American Museum of Natural History has seen "unnaturally huge" leeches in captivity, where they have easy access to food and no predators.
"The largest leeches I have ever seen are specimens of the giant Amazonian leech Haementeria ghilianii and of the Asian buffalo leech Hirudinaria manillensis," says Siddall. "These individual leeches no doubt consume the most blood."
But
in the wild, opportunity dictates appetite. Jungle leeches that are too
small to hunt must wait for their hosts to come along. Since the wait
can be a long one, it is not surprising that they gorge themselves given
the chance, swelling up to seven times their bodyweight with one bloody
meal. That is a lot for anyone to swallow. Join over six million BBC Earth fans by liking us on Facebook, or follow us on Twitter and Instagram. If you liked this story, sign up for the weekly bbc.com features newsletter
called "If You Only Read 6 Things This Week". A handpicked selection of
stories from BBC Capital, Culture, Earth Future and Travel, delivered
to your inbox every Friday.
Two scientists and an entrepreneur are
crunching the science behind edible caterpillars to help fight
malnutrition and food security problems in West Africa.
For
most people the idea of chewing on a caterpillar or tucking in to a
tarantula is pretty unpalatable, to put it mildly. Yet according to the
United Nations, some two billion people around the world consume insects
regularly. This prompted World Service listener Saman from Pakistan to
ask the BBC CrowdScience team "are insects a serious food source?"
In
order to tackle this question the programme team headed out to Burkina
Faso in West Africa, where shea caterpillars are an important part of
the local diet in a country where over 30% of children suffer from
chronic malnutrition and 2.7 million people are at risk for food
insecurity. Image caption
Shea caterpillars contain high levels of protein and micronutrients
Caterpillar enthusiast Charlotte Payne is a PhD
student at Cambridge University who is currently conducting research on
the caterpillar lifecycle.
"Shea caterpillars have the potential
to help people break out of a cycle of poverty," she exclaims when we
met her on a farm in the rural village of Soumousso in the West of
Burkina Faso.
At the moment the caterpillars are only available
for a few weeks a year. But with their high levels of protein and
micronutrients like iron and zinc, they have the potential to fend off "hidden hunger",
as micronutrient deficiency is sometimes called, and change the
financial situation of the poorest people in West Africa, especially
women and children. Image caption
Caterpillars can be cooked whole or turned into products, such as protein bars or croquettes
How to breed caterpillars
Together
with her colleague Darja Dobermann, a PhD student at the University of
Nottingham and Rothamsted Research, Charlotte is trying to crack the
science behind shea caterpillars and make them available all year round.
"In the same way they keep chickens in their backyard, the women would be able to keep caterpillars too," Charlotte explains.
While
in Burkina Faso, Charlotte is collecting as much information as she can
about the needs and wants of the local people. Her preliminary results
suggest that breeding caterpillars would be very welcome in the region.
"It would be great if I could rear the caterpillars all year round
because I would have enough to eat and earn a lot of money selling
them," one woman in Soumousso told us. Image caption
Once processed and packaged, shea caterpillars stay edible for up to 18 months
To help accomplish this vision there are many
hurdles that the researchers must overcome. For starters the
caterpillars are fussy customers. They only feed on the leaves of the
shea trees.
Similar to how scientists have spent years working out
what the best feed for livestock is, Darja explains, the same needs to
happen for the caterpillars. From an environmental point of view it is
of some consequence how these caterpillars are fed.
Environmentally savoury
Insects
are often touted as a panacea for the environmental problems that come
with producing meat, because they emit less greenhouse gasses and take
up less space.
"The unfortunate thing is that the majority of
insects that are commercially farmed are predominantly fed with chicken
feed. Chicken feed is made out of soy and this isn't very sustainable.
Unless you can get the insects onto a waste product as their food
source, they aren't more sustainable than chickens from an environmental
perspective," Darja explains. We
investigated caterpillar farms after Saman from Pakistan asked us: "Are
insects a serious food source?" If you've got a science question you
want BBC CrowdScience to look into, get in touch via the form below and we'll investigate a selection.
In her lab in England, Darja will be
analysing shea tree leaves to uncover why the caterpillars like them so
much. This includes figuring out what nutrients the caterpillars are
getting from the leaves and discovering whether the leaves send out a
special "smell" - volatile aromatic compounds - that the caterpillars
are drawn to.
"There might be something particularly appealing
about these leaves that we could synthesise and spray onto artificial
feed to attract the caterpillars," Darja explains.
Charlotte and
Darja are not alone in their quest to turn caterpillars into a
sustainable food source. They work closely with local entrepreneur,
Kahitouo Hien, who is betting all on the success of these nutritious
critters.
Caterpillar cook-out
Outside
Kahitouo's factory in the capital Ouagadougou a huge caldron filled
with thousands of caterpillars is bubbling and filling the air with a
pungent aroma. With his business, FasoPro, Kahitouo is trying to create
an industry for shea caterpillars. Something that no-one else has dared
do before.
Today he sells 10 tonnes of caterpillars every year to
markets and shops around the country. But it has not been easy to get
to this point.
"A lot of people laugh when they hear about my
business," Kahitouo explains as he leads us into a room filled from top
to bottom with tightly packed boxes of dried caterpillars.
Media captionKahitouo Hien and Charlotte Payne have kick-started an initiative to commercialise caterpillar productionEven though caterpillars are traditionally eaten in Burkina
Faso, Kahitouo has had a hard time convincing the community that they
should eat more of them.
"In the beginning it was very difficult
for me to find even one shop that would sell the product, but now I
don't even have to leave my office. The shops call me up. When I think
about that I feel really proud of myself and the business."
Kahitouo hopes to spread the business model to other countries but using the local insects found in each place.
Bugs to the rescue?
With
nine billion people in the world by 2050 and food production needing to
increase by 70% according to the UN, we may all have to get used to the
taste of bugs like many people in Burkina Faso already have.
Indeed, there is scope for edible insects to play a serious role in food culture beyond being a fashionable snack.
However working out how to farm them in an environmentally friendly way is a question that continues to bug. BBC CrowdScience, Should We Eat Insects? airs on the World Service at 19:32 GMT on the 7th of April 2017. After this you can listen online or download the podcast.
Like the blue whale, giant land animals have appetites to match their impressive stature. According to African elephant expert Norman Owen-Smith
of the University of the Witwatersrand, Johannesburg in South Africa,
adult males eat around 1% of their bodyweight in dry mass every day,
while lactating females eat up to 1.5% to keep themselves going.
Little brown bats are said to be able to devour 1,000 mosquitoes in an hour. But scientists view this figure with suspicion.
There are other small brown mammals with an unshakeable reputation as voracious predators: the shrews.
These flying marvels favour a sugar fix to power
their energy-intensive hovering flight. Beating their wings as many as
50 times per second, the birds have some of the highest metabolic rates
among vertebrates.
The Polyphemus moth is named after Homer's mythical cyclops,
because it has a single eyespot on each wing. But the man-eating
monster and crop-devouring caterpillar are perhaps more similar in their
gigantic appetites.
Medicinal leeches are famous for drinking blood,
and have been used to heal wounds and thin the blood for centuries.
However, most of the world's 700 species of leech are actually predators
of invertebrates, like the worm-hunting monsters of Borneo.
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