Listener Questions: Bugs!!

This is a buggy listener questions episode as I answer your queries about insect vision, ants outsmarting our poisons, and the impacts of insect farming! 

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Episode Transcript

Speaker 1 (00:06):
Welcome to Creature Feature Production of iHeartRadio. I'm your host
of Many Parasites, Katie Goolden. I studied psychology and evolutionary biology,
and today on the show, it's a Buggy Listener Questions episode.

Speaker 2 (00:21):
I got a bunch of questions about insects, and I
thought i'd answer them all at once, so I.

Speaker 1 (00:29):
Hope you enjoy. Let's get right into it.

Speaker 2 (00:33):
Oh and remember, if you have a question that you
would like answered, you can write to me at Creature
Featurepod at gmail dot com. Doesn't have to be about insects,
but it certainly can be. So let's get right into it, Hi, Katie,
what do bugs c? Specifically, what do insects see, especially
the ones with large, elaborate compound eyes is like a

(00:53):
dragonflies individual eye segment directly connected to their brains. Does
eye size correlate with brain size and intelligence? Thanks love
the show, Juanito. Also some additional context from Juanito. This
question was prompted by reading Adrian Tchaikovski's Children of Time
novel and the book A species of jumping spider Portia

(01:16):
labiata gets accidentally uplifted to sentience and technology developing level.
The author's description of the iraqtid censorium is fascinating. And
you know what, all his books I've read so far
investigate crazy interesting biology, invented the aliens, worlds, or real
the cute little spider guys. I just discovered Adrian Tryikovsky

(01:38):
this year and I heartily recommend his books. He studied
zoology and psych before becoming an author. Wow, that sounds
a lot like me, except I haven't written about super
intelligent jumping spiders, but that sounds very cool. Thank you
Juanito for the question and for the book recommendation. I'll
check that out. So this is a great question about eyesight.

(02:02):
How insects see the world, how compound eyes work, if
eye size correlates with brain size, and intelligence, all really
really good questions. So the broad answer in terms of
insect vision is that it really depends on the insect.
Different insects have different kind of eyes. Even insects who

(02:22):
have compound eyes can have different types of compound eyes
in different ways. Those are wired to the brain. But
let's break down first the components of how vision is processed.
You have the hardware, aspects of the eye, the lens,
the shape of the eye, the retina, whether the animal
has rods, cones or both, or simply light sensitive cells

(02:46):
that can tell the difference between dark and lights. So
there's a lot of hardware to the eye that will
determine how the light goes into the eye and where
it goes to. And then the information has to reach
the brain, usually through some sort of nerve cluster, and
then the brain has to process the raw visual data,

(03:07):
and after that other parts of the brain interpret those
findings and those get sent down to other nerves that
control muscles and reactions. So there are multiple points from
the light hitting the eye to the organism's experience where
that light is being transformed, both physically by the structure

(03:27):
of the eye, by like the lens being directed into
the eye, and then once it's inside, how it's hitting
the back of the eye, what it's hitting, the sensory cells,
the structures inside the eye that are funneling the light,
and then also how that data is perceived, So both
how it goes from the eye to the brain, the

(03:48):
wiring of the neurons that transfer that data, and then
how the brain process is it. So in terms of
what something sees, it's a very interestingly subjective experience, even
for us humans. We might think our site shows completely

(04:08):
objective reality, but if you've ever seen an optical illusion,
you'll realize our brains do a lot of funny business
with that light hitting our eyes. There's a lot that
happens between that and getting processed in our brain to
the point where you can look at an optical illusion
and see something very strange, because that's your brain working
to try to interpret these signals and adding things in

(04:31):
that may not actually be there. So let's also explore
this question of eye size and intelligence. So ie size
and brain size are not always correlated, and brain size
isn't always correlated with superior intelligence. You have some things
that might have really big brains and not necessarily be

(04:53):
as intelligent as something that has a smaller brain. Right,
we certainly don't have the largest brains in the world,
but we're very intelligent. But in general, the general trend
is that brain size can and does correlate with intelligence.
It's just not a hard rule. There's many, many exceptions,
and a similar thing happens with brain and ee size,

(05:16):
or say like sensitive sensory organs and brain size. So
there are some studies that find that eye size is
positively correlated with brain size, though it's highly dependent on
the type of animal. There's been some research on frogs
that find eye size and brain size are linked, but

(05:36):
studies done in guppies the fish found that eye size
and brain size were positively correlated, but it did not
actually predict better visual acuity or necessarily intelligence. So the
idea behind brain size and eye size or eye complexity

(05:57):
being related is a good one. Naturally, bigger eyes and
more complex visual processing should require more space in the
brain are at least more complex brain folds. We do
actually see this kind of correlation in dolphins who have
massive auditory processing parts of their brains to help with
the complex task of echolocation, and in humans we have

(06:21):
huge visual processing areas of the brain and complex large
eyes and very complex vision. But some counter examples. You
have the tarsiir, which is a tiny primate who has
disproportionately large eyeballs. They're so big that they can barely
fit in its head. They can't turn in their sockets,

(06:41):
so if it wants to look around, it has to
move its whole head rotate its head around, and its
brain is not that big. In fact, its brain is
smaller than one of its giant eyeballs. Also, its brain
is relatively smooth, and so the trade off seems to
be that it has ditched a lot of its other
brain mass, say like olfactory brain mass or other you know,

(07:06):
parts of the brain in favor of a disproportionately large
visual cortex, which is still small but enough to take
in the visual data from those giant eyeballs, which are
designed to see at night for feeding on nocturnal insects.
Speaking of nocturnal insects, they have managed to develop a
keen night vision despite often having small eyes and small brains.

(07:31):
They manage this with clever trade offs. Instead of seeing clear,
crisp images like we do, they see very slow course
images with high contrast. So this allows them to react
to threats at in the night in the darkness, or
to find mates while everything kind of looks like an
overexposed black and white image that has been repeatedly compressed

(07:55):
until it's a grainy bunch of pixels moving in sort
of delay slow motion. Other insects have very different visual experiences.
Fruit Flies have eyes and brains that work together to
allow for very rapid responses to visual information with sharp
crisp edges, so kind of quite different from these nocturnal insects.

(08:17):
Many insects see colors that we can't perceive, like those
in the ultraviolet range, which allow them to zero in
on flowers who signal to them with secret colorful runways
to aid in pollination. And this is the case for dragonflies,
who can either be pollinators, they can also be predators,
but they have those big, impressive compound eyes. Compound eyes

(08:41):
are made up of a bunch of distinct units called omatidia,
which each one comes with a lens, a cornea, and
photoreceptive cells. So they are these like individual units of vision.
Whereas you compare it to our e we have one lens,
one cornea, and then a now with a bunch of
photoreceptive cells at the back. They have just like a

(09:04):
bunch of these units. Each one has a lens, in
acornea and photoreceptive cells. There can be tens of thousands
of these on a single eye. Different insects have different
ways in which these compound eyes are connected to the brain,
different methods of resolving the mass of tens of thousands
of single units of information. Sometimes individual units are clustered

(09:28):
together in processing for a more sensitive but lower resolution image.
Others are more complex with an increase in neural wiring
for higher resolution and still sensitive vision. The reason not
all the eyes maximize resolution and sensitivity is because this
precise wiring is a higher neural load, so some insects

(09:52):
will trade off for less neural processing for a lower
resolution image whatever is needed most for survival. Dragonflies specifically
have eyes that are highly sensitive to color, even more
so than human eyes. They also have three hundred and
sixty degree vision with about two hundred images per second,

(10:12):
meaning that they see in bullet time, basically slow motion.
Most of their brain is dedicated to visual processing, like
eighty percent of their brain, so they see a highly
colorful world with ultraviolet and polarized light. It maybe being
a dragonfly would sort of be like taking in a

(10:34):
slow motion movie at an IMAX theater that's really brightly
colored all around you. But again, it's kind of hard
to say how they actually experience this, right, Like, we
can't avatar into a dragonfly brain. We've got our human
brains with our human feelings and thoughts about what we
see in our visions, so it's very hard to know

(10:56):
what they actually experience, but we can kind of say
this is what the information that is reaching their brain
is very interesting, A very different way of viewing the world.
Sounds very trippy. Onto the next listener question. Hi, Katie.
After the first rain of the season, ants began appearing
in my house. Luckily, I have indoor ant traps, so

(11:20):
I am not expecting any ant ant ant mageddon happening. However,
as I was observing the hapless creatures harvesting the poison
in the ant trap, I began to wonder would the
colony ever evolve to become aware of the man made poison,
like how some species of ants are aware if one
of their own is carrying the Cordyceps spores and would

(11:40):
take action to get rid of the infected ant. The
ant traps are designed so the ant would carry the
poison back to the nest and henceforth killing the whole
colony by sharing the poisonous food. At this point, I'm
at the edge of a rabbit hole that I'm hoping
not to fall into because I started reading the ingredients
of the ant trap, which is point zero one percent
avermect and B and ninety nine percent sent other ingredients

(12:01):
and I definitely don't know what any of that really means. Anyways,
I would love to hear your thoughts before I get
too carried away. Thanks Jessec Hi Jesse, this is an
amazing question. First, let me just give some context. She mentions. First,
let me give some context. Courtceps are mentioned. The courdyceps

(12:21):
are spores of a fungus that can infect various arthropods,
including ants, and so ants have learned to identify an
infected individual and carry them far away from the colony
so they don't infect the rest of the colony. So
there are two ways ants might thwart threats or poison

(12:42):
evolution or learning. So evolution is a very slow process
over many hundreds thousands, hundreds of thousands, or even millions
of years. So for ants to develop an innate instinctive
behavior towards, say, human ant bait traps, we would probably
need to co evolve with them for quite a while,

(13:04):
but it would be possible. Some evolutionary traits already seem
to act as potential protection against poisoning. So some ant
species have worker ants that act as living larders. These
are usually older workers who consume some food source and
just kind of stand around and offer it to other

(13:24):
ants via regurgitation, kind of like a living vending machine.
This could potentially help dilute toxins or simply kill off
the ant that has ingested all of these toxins, and
so it may act as a kind of buffer between
these ants that have these sort of living larger members

(13:49):
of the colony eating a bunch of food and then
offering it to other workers after it's already been diluted
in its gut. But it's not a strategy that has
evolved specifically for ant traps or ant poison or toxins,
but it may be a separate benefit. This is a
behavior that's evaulved for things like surviving famine, for economizing

(14:12):
food gathering, things like that, but it could have the
impact of helping them survive human traps. But ants do
have the capacity to learn, particularly as a colony, and
this is a faster process than evolution. You can have
a colony adapt to some threat or something within a

(14:35):
matter of a single generation just by learning. So Argentine
ants have shown signs that as a colony they are
capable of learning about poison bait and change their behavior
in response to it. So the cleverness of ant bait
is that it has a delayed response, so the ant

(14:55):
eats it, it doesn't immediately die, which gives it time
to you lay down pheromone trails to alert other ants
about what seems like tasty food. Bring it back to
the colony. All these ants come and they gather a
bunch of it, bring it back. Still hasn't killed them yet,
and then finally it starts to set in and kill
them off. And by then, you know, hopefully for you

(15:19):
and sadly for the ants, it's too late. They've already
brought it in and so a lot of them die.
But yeah, so this is very insidious. It's a very
clever way to kill ants. But researchers have found that
argentine ants, which are one of the most common ant
species in the world, they are highly invasive, incredibly durable,

(15:43):
really hard to get rid of if you've ever had
an argentine ant invasion. So this might be one reason
why so argentine ants seem to be able to learn
to abandon toxic food sources and human beita traps. So
one of the studies authors that was looking into this

(16:05):
Argentina ant behavior entomologist Roxanna Johnson's happened upon this when
she was trying to help a pediatric hospital get rid
of their Argentine ant problem with baited traps and noticed
that the ants simply abandoned the traps without poisoning the
whole colony. So she got some argentine ants, put them

(16:28):
in the lab, offered out some food sources, some that
was just benign sugar water and some that had boric
acid in it, which is an ingredient that's found in
these ant ant traps or ant poison baits. And so
what they found is that these ants learned to abandon

(16:51):
the poisoned bait after about six hours, and in fact
they had not managed to consume enough of it and
bring back enough of it to destroy the rest of
the ants. Of a few individual died, but not the
entire laboratory colony. So the interesting thing is, we don't

(17:15):
know how they know how to do this. So clearly
there is some sort of algorithm happening where the ants
go to the tainted food less and less and the
pheromone trail weekends, whereas it strengthens for the food source
that's safe but the researchers don't know how they're determining

(17:37):
the tainted food source is unsafe. So still plenty of
research that needs to be done on how these ants
are learning to avoid the ant bait. But we know
that at least argentine ants and possibly other species of
ants do have strategies to counter it and can learn
to avoid it. So yeah, so that is I would

(18:00):
say learning is something that is it's not quite evolving
to counter a threat, because evolution, that's that's a longer
process that implies a fundamental intrinsic sort of change in
the ants biology and species. But learning is of course

(18:22):
something that's really really interesting, and you could absolutely have
ants eventually adapt and evolve to counter ant poison human
made ant poison if it is, oh, if we co
evolve with them for long enough. All right on to

(18:42):
the next listener question. Hi, Katie and or whomever reads this.
It was me and my dog, that's who read it.
I was recently listening to the episode with Janet Varney
where you discussed bugs as alternative food sources and invasive
species from the pet trade. I always want wondering if
there have been any studies about the impact of industrial

(19:04):
bug farming. You discussed animals from the pet trade becoming
issues in an ecosystem. I guess I have several questions.
Is there an industrial bug farm, what does it look like?
And could a breach cause harmful spikes in a population
to the flora and fauna. Thank you, Laura, Hi Laura,
this is a fantastic question. I actually do know someone

(19:25):
who researches crickets and has poked around cricket farms where
they're raised as food. I'll try to get her on
the show someday to talk more about both crickets and
her experience checking out the cricket farm. So, in answer
to your question, could is there this threat of insects
being invasive if you're doing an insect farm? Absolutely yes,

(19:46):
So all farm animals and plants can become invasive, and
this could be absolutely true of insects already. There are
insect farms, some used as food, like crickets being turned
in into cricket meal or meal worms being turned into meal.
Some farms use them as animal feed rather than human feed.

(20:09):
Some farms use maggots like black fly larvae to break
down food waste into frass, which is a nicer term
for maggot poop that can then be used as a fertilizer.
So we do already have bug farms, but a large
bug farming industry doesn't really exist yet, not in the

(20:31):
way that other industrial farms exist. So as you probably
kind of instinctively understand, like, insects are very prolific, they're tiny,
they're perfect candidates for becoming an invasive species. So they
often become invasive just by hitching a ride in cargo

(20:51):
and accidentally getting dropped off somewhere they don't belong. And
they're so fecunned, they produce so much so many offspring,
and they are highly adaptable typically that they're great at
being invasive species. So a farm where you have a
bunch of insects, potentially insects that have been selectively bred

(21:14):
to endure harsh conditions or to breed more prolifically, Yeah,
that would be a prime spot for there to be
an invasive event, right, that could certainly pose a risk.
In fact, we kind of already see that. We have

(21:35):
a big example of that, which is honey bees. So
honey bees, as cute and wonderful as they are, they
are not native to the Americas. We imported them to
make honey for us, for farms and to pollinate crops.
The problem is that they can actually out compete native
species of bees, which can both be harmful to the

(21:57):
native bees themselves and also to the plants and the
flowers that the native bees pollinate. Because you don't always
just replace one pollinator with another, you can have a
really specific relationship between say a wildflower, and a native
species of bees who have co evolved with a wildflower,

(22:18):
and they are a specific size, exhibit a specific behavior
that the flower has co evolved with, and so their
whole pollination structure is based on this species of bee
and not necessarily based on the behavior of a honeybe.
So you could, if you say, threaten a species of

(22:40):
native bees because the honey bees are outcompeting them. You
could also threaten native plants as well. So honey bees,
I mean, I love them, right, and I love honey,
but yeah, they are actually an example of what you're
talking about. Bees that are used in large scale farming
who have become invain because you can't really how do

(23:02):
you keep how do you keep a honey bee in
a cage? You don't they go around, and yeah, they
have caused issues for the environment. Also, Laura, your question
is so important. It is actually being asked by ecologists
now as we're having more and more of these discussions

(23:24):
and sort of proposals for having industrial scale insect farms.
So the ideas that insects are more ecologically friendly because
the sort of feed to waste to protein output ratios
are much better than say a beef farm. So like

(23:47):
cows are pretty wasteful when you consider sort of their
waste and the amount of energy you have to put
in per unit of cow meat, whereas insects are a
lot more efficient in that respect. But there are a
lot of questions that ecologists are raising because we don't

(24:08):
actually have these large scale industrial bug farms that are
similar in scale to other types of industrial farms that
we have currently. So there is an article in Trends
and Ecology and Evolution called Approaching Ecological Sustainability in the
Emerging Insects as Food Industry. So your question is essentially

(24:36):
the subject of this paper by concerned ecologists who are
asking the same questions as you and pointing out a
lack of research on the risk factors of large scale
insects farms and the many unknowns of environmental impacts of
insects farms. One of the points they bring up is
the invasiveness aspect, the fact that these insects could get out,

(25:00):
that these could be heartier than native species because we
might breed them that way, and that they could cause
destruction to the local ecology. And there's also other questions
like even though we do know that they're more efficient
in terms of like feed in protein out, there's not

(25:22):
a lot of data on how you actually how do
you house that many insects? Right, Like I do know
from my friend the one he studies crickets that answers
are very sensitive to things like heat, so in temperature,
so you have to you might have to have really
specific temperature controls for that many insects, both to make

(25:46):
sure that they're eating and breeding and growing things like that.
So also you know, just like how do you how
do you prevent there from being say like disease that
wipes out all of the insects. All sorts of questions
in terms of how sustainable would they be and what

(26:06):
are the risks to the environment that we don't really know.
I mean, I would still say that it's very promising, right,
like the I think it's something that is worth looking
into because our current industrial farming situation is not good.
You know, it's not it is bad for the environment.

(26:26):
It tends to be very wasteful. Also, you know, there's
a lot of ethical concerns in terms of the treatment
of animals. So you know, I think having insects as
a potential alternative food source and looking into it is
really important. But it's also not something to just be

(26:49):
done without actually considering things that you've brought up, like
the invasiveness aspect and what are the what are the
other potential implications of an industrial sized insect form and
it's an impact on the environment. So fantastic question. Uh,
you could you could? You could be an ecologist because

(27:12):
you're asking the very questions that they are asking. H Well,
thank you guys so much for your extremely thoughtful and
intelligent questions. I always enjoy them. It makes me do
a little bit of homework that I really like to
do because it keeps me sort of I guess, more
up to date with uh, with research and stuff that

(27:34):
I might not think to look into, but you guys do,
and so I look into it and it's great. We
all learn. We're all learning together. If you want to
send me a question, you can write to me at
Creature Future pod at gmail dot com. Thank you, guys
so much for listening, and thank you to the Space

(27:55):
Classics for their super awesome song Exolumina. Creature features a
production of iHeart Radio. For more podcasts like the one
you just heard, visit the iHeartRadio app Apple Podcasts, or Hey,
guess what wherever you listen to your favorite shows. I'm
not your mother. I can't tell you what to do,
but yeah, before starting a cricket farm with a bunch

(28:15):
of mutated super crickets, do think about whether they will
take control of your local government and install a cricket autocracy.
You know, consider it. See you next Wednesday.