Tag Archives: moths

Episode 215: The Cutest Invertebrates

Thanks to Lorenzo and Page for suggestions used in this week’s episode, and a belated thanks to Ethan for last week’s episode! Let’s learn about some of the cutest invertebrates out there!

Further reading:

Photosynthesis-like process found in insects

Mystery of the Venezuelan Poodle Moth

Further viewing:

Dr. Arthur Anker’s photos from his Venezuela trip, including the poodle moth

The pea aphid, red morph and regular green

So many ladybugs:

The sea bunny is a real animal, but it’s not a real bunny:

A larval sea bunny is SO TINY that fingertip looks like it’s the size of a BUILDING:

The bobtail squid not hiding (left) and hiding (right):

The bobtail squid is SO CUTE I MIGHT DIE:

The Venezuelan poodle moth:

Not a Venezuelan poodle moth–it’s a female muslin moth from Eurasia:

Not a Venezuelan poodle moth–it’s a silkworm moth from Asia:

The dot-lined white moth:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week I promised we’d cover a cute, happy animal to make up for last week’s extinction event episode, but instead of mammals let’s look at some cute invertebrates! One of them is even a mystery animal. Thanks to Page and Lorenzo for suggesting two of the animals we’re going to cover today!

We’ll start with Lorenzo’s suggestion, the pea aphid. Years and years ago I spent a slow day at work making a list of cute foods with a coworker, and peas were at the top of the list. Blueberries were second and I don’t remember the rest of the list. Generally, cuteness depended on how small the food was and how round. Aphids are really small and peas are round, so the pea aphid has to be adorable.

The pea aphid, however, is not round. It’s shaped sort of like a tiny pale-green teardrop with long legs, long antennae, and teeny black dots for eyes. It’s actually kind of big for an aphid, not that that’s saying much since it only grows 4 mm long at most. It’s called the pea aphid because it likes to live on pea plants, although it’s also happy on plants related to peas, such as beans, clover, and alfalfa. Cute as it is, farmers and gardeners do not like the pea aphid because it eats the sap of the plants it lives on, which can weaken the plant and can spread plant diseases.

During most of the year, all pea aphids are females. Each adult produces eggs that don’t need to be fertilized to hatch, but instead of laying her eggs like most insects, they develop inside her and she gives birth to live babies, all of them female. An aphid can have up to 12 babies a day, called nymphs, and the nymphs grow up in about a week or a little longer. Then they too start having babies. Even though lots of other insects and other animals eat aphids, as you can see, they will always be numerous.

As the summer turns to fall and the days become shorter, some of the baby aphids are born with wings. Some are also born male, and sometimes the males also have wings, although they might not have mouths. These males and winged females mate and the females fly off to lay their eggs on clover and alfalfa plants, assuming they aren’t already on clover or alfalfa plants. The eggs don’t hatch until spring, and all the resulting nymphs are female.

Sometimes winged females are born if the plants where the aphids live get too crowded. The winged females can fly away and find new plants.

If you’ve ever had a garden, you’re probably familiar with aphids. They spend most of the time on the undersides of leaves, drinking sap through specialized mouthparts called stylets. You may also have noticed that when you try to smush the aphids, all of them immediately drop to the ground. This protects them not just from being smooshed by a gardener’s thumb, but from being eaten along with the leaves when a deer or other animal browses on the plants where they live.

Sometimes, instead of being leaf green, pea aphids are a pale reddish color. This is called the red morph. Red morph pea aphids are more likely to live on certain plants while the ordinary green pea aphids are more likely to live on others, although many times you can find both varieties on a single plant.

The red coloration of red morph pea aphids is due to larger quantities of a chemical called carotenoid [kerOTenoid] in its body. All pea aphids contain carotenoids, though, and it’s not just used for coloration. Research suggests that the carotenoids absorb sunlight and produce energy that the aphid can use. It’s a limited form of photosynthesis—you know, that thing that only plants do.

Not only that, the pea aphid produces the carotenoids in its body. Every other animal that needs carotenoids absorbs them from plants it eats, with the possible exception of a type of mite. The genetic sequence that allows the pea aphid to make its own carotenoids originally came from fungi. Somehow the aphid captured the genetic material from fungi, probably after eating it, and passed those genes down to its descendants. This is called lateral gene transfer and scientists aren’t sure exactly how it works or how common it is.

Pea aphids also contain beneficial bacteria that produce nutrients it needs that it doesn’t get from the sap it eats. The aphids can’t live without the bacteria, and the bacteria can’t survive outside of the aphids.

Even though the pea aphid is really common just about everywhere these days, it’s actually an invasive species in most places. It’s native to temperate parts of Eurasia but has spread to the rest of the world on cultivated plants. For small infestations of aphids, some people release certain species of ladybugs into their gardens, because many ladybugs love eating aphids.

Ladybugs, of course, are another cute invertebrate, specifically a family of beetles. They’re also small and round, although not as small as aphids. A typical ladybug grows about 10 mm long at most. Depending on the species, a ladybug can be red, orange, yellow, or brown, usually with black spots but sometimes with black stripes, or it may be mostly black with red or yellow spots. Most eat tiny insects and other animals, but some species eat plant material.

The ladybug’s bright coloring warns birds and other predators that it contains a toxin that makes it taste nasty. This even affects humans. I mean, obviously don’t eat ladybugs, but sometimes if there are ladybugs on grapes used to make wine, and the ladybugs end up crushed along with the grapes in a wine press, the whole batch of wine will end up tasting bad. It’s called ladybird taint so winemakers try to make sure any ladybugs are removed from the grapes before they’re crushed.

In many cultures around the world, ladybugs are supposed to bring good luck. In some places, if you see a ladybug you should make a wish. We’ve talked about ladybugs before, most recently in episode 203, so let’s move on to our next cute invertebrate.

This one lives in the ocean. It’s called the sea bunny or sea rabbit, a type of nudribranch [noodi-bronk] that lives along the coastline of the Indian Ocean, especially in tropical waters. Nudibranchs are a type of mollusk that are sometimes called sea slugs. Many are brightly colored with beautiful patterns. Compared to some, the sea bunny is a little on the plain side. It’s white, yellow, or rarely green, with tiny brown or black speckles. It looks fuzzy because it’s covered in little protuberances that it uses to sense the world around it, as well as longer, thinner fibers called spicules. It also has two larger black-tipped protuberances that look for all the world like little bunny ears, although they’re actually chemoreceptors called rhinophores. It really is amazing how much the sea bunny actually resembles a little white bunny with dark speckles, which would make it cute right there, because bunnies are cute, but it’s also really small. It barely grows an inch long, or 2.5 cm.

Like other nudibranchs, the sea bunny is a hermaphrodite, which means it produces both eggs and sperm, although it can’t fertilize its own eggs. When it finds a potential mate, they both perform a little courtship dance to decide if they like each other. After mating, both lay strings of eggs in a spiral pattern. The eggs hatch into larvae that are free-swimming, although the adults crawl along the ocean floor looking for small animals to eat. Some nudibranch larvae have small coiled shells like snails, which they shed when they metamorphose into an adult, but the sea bunny hatches into a teeny-tiny miniature sea bunny.

Cute as it is, don’t pet a sea bunny! It’s toxic! One of the things that sea bunnies especially like to eat are sponges, and many sponges contain toxins. The sea bunny absorbs these toxins to protect it from predators. Even its eggs are toxic.

Next we’ll talk about another intensely cute marine animal, the bobtail squid. It’s only a few inches long, or up to 8 cm at most, with a rounded mantle and short little arms. Small and round, the hallmarks of cuteness. It’s also sometimes called the dumpling squid, which is extra cute and potentially delicious. Basically, it’s no longer than your thumb and smaller around than a golf ball.

The bobtail squid lives along the coast of the Pacific Ocean and parts of the Atlantic and Indian oceans, and it’s not just one species. It’s an entire order containing around 70 species. The oceans are full of adorable little squids.

The bobtail squid has a symbiotic relationship with a type of bacteria, much like the pea aphid and its beneficial bacteria, but in the bobtail squid’s case, the bacteria don’t provide nutrients, they provide light. The bacteria are bioluminescent and help the squid hide from predators. You may be thinking, “Wait a minute, how does it help the squid hide to be lit up from within like a tiny squid-shaped lamp?” but that just proves that you’re a land animal and not a water animal. If you’re a big fish on the hunt for yummy bobtail squid to eat, you’re probably hiding in deep water where the squid can’t see you in the darkness, looking up for the telltale shadowy outline of a squid against the surface of the water. Day or night, the water’s surface is much brighter than the water underneath it because it’s reflecting sun, moon, or starlight, but if the squid is glowing faintly, instead of showing up as a dark shape against the brighter surface, it blends in. The light only shines downward and the squid adjusts it to be brighter or dimmer to match the amount of light shining on the water.

The bobtail squid is mostly nocturnal and will hide in the sand during the day or if it feels threatened, using its arms to pull sand over its body. All squids have large eyes, but the bobtail squid’s eyes are especially large in comparison to its small body, which makes it even cuter. It eats small animals and especially likes shrimp. It can also change colors to blend in with its surroundings and communicate with other squid.

Let’s finish with Page’s suggestion, the Venezuelan poodle moth. I was going to start the episode with this one because it’s so fuzzy and cute, but when I started research I realized that there’s a mystery associated with this insect. I like to end episodes with a mystery if I can. I want to keep everyone guessing.

In late 2008 and early 2009, a zoologist named Arthur Anker was in southeastern Venezuela in South America, and photographed a fuzzy white moth he found. He didn’t know what it was so he labeled it as a poodle moth when he posted the picture online. I’ve put a link in the show notes to all the photos he posted from his trip, including the poodle moth, and they’re absolutely gorgeous. He has a lot of moth photos but the poodle moth was the one that went viral in 2012.

There are other cute, fuzzy moths that sometimes get called poodle moths, such as the silkworm moth. Silkworm moths are native to Asia and are one of the few domesticated insects in the world, together with the honeybee. If you’ve ever had a silk shirt, that silk probably came from the domestic silkworm, which has been raised for at least 5,000 years in China and other places.

Silk comes from the cocoons the silkworm moth larva spins. Each cocoon can contain up to a mile of silk fiber, or 1.6 km, in one long, thin thread. The problem is, to harvest the silk properly, you have to kill the silkworm inside, usually by throwing the cocoon into boiling water. If the silkworm is allowed to mature, it releases enzymes to break down the silk so it can get out of the cocoon, and that weakens any fabric made from the silk. You can get silk made from cocoons of silkworms that weren’t killed, though, sometimes collected from wild moths.

Domestic silkworm moths have been bred so that they don’t produce pigments, since that means the silk won’t have any pigments either and can be dyed more easily. Domestic silkworms differ from their wild relatives in other ways too. Their cocoons are bigger, they no longer have any fear of predators, and they can no longer fly because their wings are too small for their bodies. The moth is covered in short white hairs that make it look fuzzy and cute, with black eyes. The larvae eat the leaves of the white mulberry tree or related trees, but adult moths don’t eat at all and don’t even have functional mouths.

So the silkworm moth is definitely a cute invertebrate, but what’s going on with the Venezuelan poodle moth? What’s the big mystery?

Well, no one knows what species it is. Some people have even accused Dr. Anker of making it up completely. Considering how many thousands of moths live in Venezuela, and how many new moth species are discovered every year, it’s likely that the poodle moth is new to science. The trouble is that no one has seen it since. Anker wasn’t on a collecting trip and he didn’t realize the poodle moth might be something new to science, so he just took a picture of it and left it alone.

The best guess by entomologists who’ve examined the picture is that the poodle moth is a member of the genus Artace, possibly a close relation of the dot-lined white moth. The dot-lined white moth is white and fuzzy with tiny black dots on its wings. It mostly lives in the southeastern United States but there have been sightings in Colombia, which is a country in South America just west of Venezuela.

There are other fuzzy white moths in the world that are known to science, including the muslin moth that’s equally small and cute. Female muslin moths are white and fuzzy with some gray or brownish-gray speckles on the wings, while male muslin moths are dark gray and fuzzy with black speckles on the wings. They live mostly in Eurasia.

Hopefully soon a scientist can find and capture a Venezuelan poodle moth and solve the mystery once and for all. Hopefully that scientist will also take lots of pictures so we can verify that it’s just as cute as it looks in its first picture.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


Episode 203: Swarms!

Thanks to Nicholas and Juergen for their suggestions! Let’s learn about some insects that migrate and swarm!

Further listening:

The Animal Migrations Patreon episode (it’s unlocked so anyone can listen)

Further reading:

Ladybugs Are Everywhere!

Monarch butterflies gathered in winter:

The painted lady butterfly:

The bogong moth:

The globe skimmer dragonfly:

Ladybugs spend the winter in bunches, sometimes in your house:

A stink bug, one of many potentially in your house:

This person is not afraid of locusts even though I would be freaking out:

A field in Australia being eaten by locusts (the brown part):

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Let’s learn about some insects this week, but not just any old insects. Let’s learn about insects that swarm. Thanks to Nicholas and Juergen for suggestions that led to this episode!

Nicholas suggested long-distance migrators ages ago, and I did do an episode about migration for a Patreon episode. I’ve unlocked that episode so anyone can listen to it, with a link in the show notes. I’ve also used some of the information in that episode for this one, specifically the part about monarch butterflies.

In fact, let’s start with the monarch butterfly. The monarch is a good-sized butterfly, with orange and black wings with white spots along the edges and a wingspan of up to four inches, or 10 cm. It lives in many parts of the world, but only the North American subspecies of monarch migrates.

Every autumn, monarch butterflies living in North America, where they breed, head south to winter in the mountains of central Mexico, a trip that can be as long as 3,000 miles, or 4,800 km. They spend the winter in oyamel fir trees, millions of butterflies in the branches. When spring arrives, the butterflies head north again, but they don’t get all the way back to their original range. If they’re lucky, they reach Texas, where they mate and lay eggs on milkweed plants before dying. The caterpillars hatch, eat up the milkweed, spin cocoons, and emerge transformed into new butterflies that continue the flight north, deeper into North America. But those butterflies don’t make it all the way to their parents’ home range either. They too stop to mate, lay eggs, and die. It can take four or five generations for monarch butterflies to reach Canada and other distant parts of North America, and by that time it’s autumn again. The butterflies fly back to Mexico.

Butterflies heading north live out their entire life cycle in only five or six weeks, but the butterflies that return to Mexico live up to eight months. Researchers think the northward migration follows the blooming of milkweed plants. Milkweed contains toxins that make the monarchs poisonous to a lot of animals, but some birds and a lot of insects will eat the caterpillars. Some populations of North American monarchs overwinter in California, Arizona, or Florida instead of Mexico.

The North American monarch is declining in numbers, probably mostly due to the decline of milkweed. The best way to help the butterfly is to plant milkweed in any area you don’t want to mow very often.

While the monarch migration is astounding, it’s not the only butterfly that migrates. A small, pretty butterfly called the painted lady lives throughout much of the world, even the Arctic, but not South America for some reason. Some populations stay put year-round, but some migrate long distances. One population winters in tropical Africa and travels as far as the Arctic Circle during summer, a distance of 4,500 miles, or 7,200 km, which takes six generations. The butterflies who travel back to Africa fly at high altitude, unlike monarch butterflies that fly quite low to the ground most of the time. Unlike the monarch, painted ladies like many kinds of flowers, not just one plant, and they don’t always migrate every year.

In Australia, some populations of the bogong moth migrate some 600 miles, or 965 km. It’s a dark brown moth with a wingspan of up to two inches across, or 5 cm, and naturally enough, it migrates at night. Unlike the butterflies we’ve talked about, the migration doesn’t take successive generations. In spring the moths fly from the lowlands into the mountains, where they spend the summer mostly hiding in caves and other dark places. The bogong moth actually breeds and lays eggs in winter, because it doesn’t like hot weather.

Birds and some other animals depend on the moth migration for food, when they can eat a lot of big fat moths and get lots of protein. Some Aboriginal tribes of southeastern Australia also used to follow the migration into the mountains, where they would gather lots of moths from caves and roast them. Apparently they taste like nuts.

But the insect that migrates farthest is a species of dragonfly. The globe skimmer, also called the wandering glider or winged wanderer, lives in much of the world, but not in Europe. Researchers think it can’t cross the Sahara to reach Europe, but it can cross the Himalayas. It’s the highest-flying dragonfly known as a result. Even though it’s a small dragonfly, less than two inches long, or 4.5 cm, it has big wings, with a wingspan of almost three and a half inches, or 8 and a half cm. Its abdomen is usually yellow, although males are sometimes more reddish. It’s a strong, fast flier and that’s a good thing, because an individual dragonfly may fly as far as 3,700 miles, or 6,000 km, during migration.

Different populations migrate to different areas, naturally, but scientists have compared the genetic profiles of globe skimmers from different parts of the world and discovered that they’re all extremely similar. This can only happen if the dragonflies from different continents are breeding with each other, which suggests that they’re traveling even farther than we already know. The globe skimmer crosses the Indian Ocean between Asia and Africa, and it shows up on incredibly remote islands, so obviously it’s able to cross vast distances without too much trouble.

The reason the globe skimmer migrates is that it needs fresh water to lay its eggs in. Many parts of the world have well-defined rainy seasons and dry seasons, and the globe skimmer wants to stay where it’s rainy. As it travels, it meets up with other dragonflies, mates, and lays eggs as it goes. The eggs develop quickly and the larvae mature within a few weeks, and immediately join the migration.

The reason the globe skimmer is able to migrate is because of its big wings and flying style. Its wings are broad as well as long, which allows it to ride the wind like a surfer riding a wave. It can glide long distances without needing to move its wings, which saves a lot of energy.

But most insects don’t exactly migrate, or at least they only travel relatively short distances to find a place to winter. The ladybug, for instance.

Juergen emailed me a few months ago about meeting one ladybug outside, then going inside to find a bajillion ladybugs. This happens a lot in autumn and it’s amazing how such a pretty little insect can suddenly seem horrifying when there are hundreds or even thousands of them in your home. It happens because many species of ladybug gather together to spend the winter in a sheltered area. Usually the sheltered area is a forest floor or a rock with lots of crannies for them to hide in. But sometimes it’s your house.

The outside of a light-colored house reflects heat from the sun, which is good for your house but which also attracts ladybugs. When a ladybug finds a nice place to spend the winter, it releases pheromones that attract other ladybugs, and before you know it, your house is ladybug central. Even if you bring in an exterminator to get rid of the bugs, the pheromones remain and will continue to attract ladybugs for years. All you can do is make sure ladybugs can’t get into your house by sealing up every little crack and gap. If the ladybugs do remain, a lot of them will probably die because most houses are too dry for them in winter. The ones that do survive will leave in spring, and at least they don’t eat anything while they’re hibernating. Ladybugs eat aphids and other plant pests during warmer months, so they’re helpful to gardeners and farmers. There are special traps you can get that attract ladybugs and hold them inside until you take them out and release them.

Another insect, commonly called the stinkbug for the nasty odor it releases if it feels threatened, also called the shield bug for its shape, also sometimes comes into houses to spend the winter, sometimes in huge numbers. The most common species in North America these days is the brown marmorated stinkbug, which is a mottled brown with small black and white markings to help it blend in with tree bark. It can grow up to three-quarters of an inch long, or two cm, and is big and heavy and a very clumsy flyer.

The brown marmorated stinkbug is an invasive species from Asia that arrived in North America in the 1990s and has spread throughout the continent, especially the eastern United States. It eats plants and can destroy fruit crops and other crops like beans and tomatoes. So unlike the ladybug, it’s not a beneficial insect to humans. But despite its bad smell, it’s not dangerous to humans or pets. The stinkbug will often appear in your house in fall but also in spring, when it emerges from its little hiding spot in your house and tries to find its way outside.

Finally, let’s look at an infamous swarming insect, the locust. Locusts are responsible for untold thousands of humans dying of starvation when clouds of them sweep through a location, eat up every scrap of food they can find, and move on when all the food is gone. But what are locusts, and why do they do this?

The locust is a type of grasshopper. Specifically, it’s one of several species of short-horned grasshoppers. Ordinarily the grasshoppers are no different from other grasshoppers. But occasionally there’s a drought where a population of the grasshoppers live, and after the drought is over and the plants that died back start to grow really fast, the grasshoppers change.

First, the grasshoppers start to breed much more than usual. When those eggs hatch, the nymphs, which is what baby grasshoppers are called, stay together in groups instead of dispersing and start moving together. They don’t have wings until they grow up so they just hop together and meet up with more and more nymphs. Once they metamorphose into adult grasshoppers, they’re called locusts although they’re still the same grasshoppers as before, just with different behaviors. Some species also look a little different during swarming seasons, often larger than usual and sometimes with different coloration or markings.

Many of these species of grasshopper are large, up to four and a half inches long, or 11 cm, with large wings that make them strong fliers. The swarms can fly up to 93 miles a day, or 150 km, and land when they find a lot of food, which may be crops planted by humans. After the swarm has eaten everything it can find, it moves on to find more. It also leaves behind lots of eggs that soon hatch into new grasshopper nymphs that eat anything that’s started growing again.

If you’re wondering how even a whole bunch of grasshoppers can cause people to starve to death, you don’t have an idea yet of the size of the swarms. Locust swarms can contain tens of billions of grasshoppers. That’s billion with a B. An individual swarm can easily cover more than 100 square miles, or 260 square km, and when they land, they will literally eat every growing plant down to the ground, every single leaf, every single blade of grass, everything. Not only is there nothing left of crops when a locust swarm has come through, there’s no grass or leaves for animals to eat.

The largest locust swarm that we know of was seen in 1875 in the western United States. The swarm covered an estimated 198,000 square miles, or 510,000 square km. That’s larger than the entire state of California. There may have been over 12 trillion individual grasshoppers in that swarm.

This was the Rocky Mountain locust, which was adapted to the prairies of North America. As white settlers pushed west and planted crops where there had formerly only been prairie grass and other prairie plants, the farmers were repeatedly visited by locusts that ate not just their crops, but everything else they could find. The locusts ate leather, wool, wood, and there are even reports of locusts eating the clothes people were actually wearing. There were so many locusts that they couldn’t be avoided. They would get into houses and eat up food in the pantries, along with blankets and clothing. People tried everything they could think of to destroy the locusts, from setting entire fields on fire to building horse-drawn bulldozers that smashed the locusts flat. But nothing helped. There were too many of them.

But as the years passed and more and more prairie was converted to fields or pastures for cattle, and more cities and towns grew up in the west, the Rocky Mountain locust started to decline in numbers. In 2014 it was declared extinct, but by then no one had seen a Rocky Mountain locust since 1902. It’s possible they’re still around in small numbers, but a combination of habitat loss and active eradication of the insect probably drove it to extinction. Another species of North American grasshopper, the high plains locust, is rare these days and almost never swarms, with the last big swarm reported in the 1930s.

But there are plenty of other locusts throughout the world, reported throughout recorded history, including the ancient Egyptians, ancient Greeks, and ancient Chinese. Plagues of locusts feature in the Quran and the Bible. The most well known species are the desert locust, which lives in Africa and parts of the Middle East and Asia, and the migratory locust, which lives in Africa, Asia, Australia, New Zealand, and Europe, although it’s quite rare in Europe these days.

Not all locust swarms are enormous, of course, but even a small swarm can destroy local farms and pastures. In the days before easy communication and travel, this could mean people starved in one village even if the next village over was fine. Researchers estimate that a locust swarm that’s only one square kilometer in size, which is less than half a square mile, or about 250 acres, can eat as much as 35,000 people in a single day. WHOA, I did not realize when I wrote that that it would make it sound like the locusts were eating people. Locusts don’t eat people, they don’t hurt you, but the locusts eat as much food as 35,000 people do. That’s what I meant.

The thought of locust swarms is scary, but fortunately it doesn’t happen every year or even every decade. But it does still happen. In 1988, locusts swarming in Africa crossed the Atlantic Ocean and arrived in South America. This year, 2020, started out with desert locusts swarming in parts of north and east Africa in January, spreading into parts of Asia by May. In November, some localized swarms of locusts were spotted in parts of Australia after heavy rains, especially in west and northwest Victoria.

These days, though, people have the advantage of early warning. Locust swarms can be tracked by satellite and drones, people whose crops are eaten up can have food shipped in to help keep anyone from starving, and there are pesticides that can kill a lot of locusts in a short amount of time. But a new experimental biological control has been working really well. The dried spores of a fungus that kills grasshoppers are sprayed on the ground where locusts are laying eggs, since grasshoppers lay their eggs in soil or sand. The fungus kills the grasshoppers and stays on the ground to kill the ones that hatch or arrive later. Best of all, unlike chemical pesticides, the fungus doesn’t kill other insects.

And don’t forget, of course, that the locust is edible. Cultures throughout much of the world traditionally ate locusts and they’re still considered delicacies in many places. They’re also more nutritious than meat from mammals like cattle. Besides, if locusts arrive and eat all your food, it’s just smart to eat the locusts that ate your food. You gotta get that food back somehow.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 111: Poisonous moths, venomous bugs

Let’s get gross and horrible this week! Are there any bugs with so much venom they could kill you? What would happen if you ate 5,000 moth digestive tracts? Why am I even talking about this stuff? Listen and find out! Thanks to Grady and Tania for today’s topic suggestions!

The giant silkworm moth caterpillar. Do not touch. No seriously, don’t! You might d i e

The southern flannel moth and its larva, a puss caterpillar. Fuzzy, yes, but don’t pet the caterpillar:

A luna moth and its caterpillar. It will not kill you:

A bullet ant. Look at those chompers!

The white-spotted assassin bug. At least you can see it coming:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week’s episode is a suggestion from Grady, who also sent several other really good suggestions we’ll hopefully get to soon. The one we’re looking at this week is poisonous bugs! And because another listener, Tania, suggested we cover moths, we’ll also make sure to talk about a lot of poisonous or venomous moths too.

Technically, if an insect is poisonous that means it will make you sick if you eat it. If an insect bites or stings you and it injects poison into the wound, it’s referred to as venomous. But you can call both poisonous because everyone will know what you mean. Also, you would probably get sick if you ate a venomous bug too, now that I think about it.

You might think I’m joking when I talk about eating bugs, but in many parts of the world people do. If you think about it, it’s no weirder than eating shrimp, lobster, oysters, or eggs. Remember that humans are omnivores, and that means we will eat just about anything. Those things don’t all have to be cookies and peanut butter sandwiches, although I haven’t had my lunch yet and if I had to choose between a PB&J with maybe a couple of Thin Mints afterwards, I’d choose that over a big bowl of deep-fried crickets. But lots of people would choose the crickets. It all depends on what you’re used to and what’s considered acceptable in your culture.

But even in areas where people eat lots of insects, they don’t eat every kind of insect. Some really are poisonous because they eat plants that contain toxins and store those toxins in the body. The monarch butterfly caterpillar eats milkweed, which contains poisons that can harm the heart, so don’t eat monarch butterflies. But because insects are generally quite small, the toxins one insect can hold aren’t usually enough to make you really sick unless you eat a whole bunch of them. That’s why children in some parts of Italy can eat a particular moth without dying even though it contains the deadly poison cyanide.

You know what? Let’s start with this moth, because what the heck, Italian children. Why are you eating these moths anyway, and why are you not dying of cyanide poisoning?

There are a number of closely related moth species that children in the Carnia region of Italy traditionally eat. The moth’s wingspan is only about an inch wide, or 30 millimeters. It’s most common in the Italian Alps and it flies around during the day, which makes it easy to find and catch. Its body is grayish, and one pair of its wings are greenish or gray with red spots, while the other pair of wings is mostly red. There’s also a variety with yellow wing markings instead of red. The reason it has such bright colors is because it stores a liquid containing cyanide in its digestive system, and the bright colors tell potential predators to leave it alone, it’s poisonous.

The problem is, the moth’s digestive system also contains sugars called glucosides, which makes it taste sweet. And before you laugh at little Italian children catching moths to eat because they’re sweet-tasting, think about how much effort you may have put into extracting a tiny bead of nectar from honeysuckle blossoms.

But honeysuckle doesn’t contain cyanide. Why don’t those little moth-eating kids get sick?

Researchers have studied this, mostly because they were worried about the children. It turns out that there’s so little cyanide in each moth that even a small child would have to eat at least 170 moths whole in a short period of time to die. Since most of the time the kids pull the moths apart and only eat the tiny piece of the digestive tract that contains sugar, that reduces the amount of cyanide they ingest. A kid would have to eat 5,000 moth digestive tracts to die, and frankly if a kid was that determined to have that much sugar, they’d probably be more likely to spend their time doing odd jobs for money to buy candy instead of catching thousands of moths.

Well, that was gross. I feel like we’re off to a really good start in this episode.

So, eating 5,000 moth digestive tracts aside, are there any bugs out there that are so venomous that they could kill you?

Yes there are. But you’re probably not going to run across them, and even if you do, you’re probably going to be just fine. It’s rare that someone dies after touching Lonomia moth caterpillars, although it does happen. But if you do touch one of the caterpillars, even if you don’t die, you’re not going to feel very good.

There are a number of Lonomia species. The adult moths are brown or grayish, with the males sometimes yellow. It has delicate darker brown markings to help it mimic small dead leaves. The species that is most venomous is sometimes called the giant silkworm moth, Lonomia obliqua, and it lives in South America. It’s especially well known in southern Brazil. The caterpillar grows to about two inches long, or 5.5 cm, and is either green or brown with lots of hair-like spines growing from the back and sides.

A lot of caterpillars have these hair-like spines, and most of them aren’t venomous. They can cause a rash, though, since the spines are very thin, detach easily, and can irritate the skin. But the caterpillar of the giant silkworm moth has spines with powerful venom. The venom contains an anti-clotting agent that causes internal bleeding that can eventually lead to death. But one little caterpillar doesn’t contain enough venom to kill a person all by itself. The trouble comes when the caterpillars are gathered in groups on leaves or tree trunks, because then it’s easier for someone to accidentally touch a bunch of caterpillars at once, receiving hundreds or even thousands of tiny stings from the venomous hairs. Fortunately, the mortality rate for people who are stung by these caterpillars is only a little over 2%. That means almost 98% of people stung by one survive.

Another moth with a venomous caterpillar lives in the United States, especially the southeastern states. It’s called the southern flannel moth and it’s really pretty and fuzzy, yellow and white with some brown markings. The caterpillar is often called the puss caterpillar because it’s also fuzzy and somewhat resembles the end of a cat’s tail or a cat’s paw. But don’t touch it! The puss caterpillar has spines with venom sacs at the base just like the giant silkworm moth caterpillar has. If someone brushes against the spines, they inject venom into the skin. The puss caterpillar isn’t deadly, and most people who touch it only end up with a painful swelling at the injection site that feels like an extra bad bee sting. But some people have a more severe reaction, including fever, vomiting, and heart trouble.

Incidentally, in case you were wondering if caterpillars poop, of course they do. Some caterpillars, though, including the puss caterpillar, actually eject fecal pellets so that they fly away like tiny bullets of poop. This is partly so the caterpillar doesn’t make a mess on the leaf it’s eating, but mainly so that predators aren’t able to find the caterpillar after seeing or smelling its poop. But sometimes the puss caterpillar will fire fecal pellets at predators, so that’s yet another reason not to touch one.

Puss caterpillars build really tough cocoons, so tough that they can stay on a tree or bush for years after the moth is long gone. Some ant species actually move into puss caterpillar cocoons to raise their eggs. Spiders also sometimes live inside empty puss caterpillar cocoons.

There are other venomous moth caterpillars, but they’re all pretty similar to the ones we’ve discussed already. But while we’re on the subject of moths, let’s talk about just how amazing and weird they are. This goes for butterflies too, of course, which are very similar.

As an example, let’s discuss a type of moth that isn’t venomous or poisonous or dangerous in any way, the luna moth.

The luna moth is one of the largest moths in North America, and it’s fairly common in the eastern part of the continent. It’s beautiful, with pale green wings and a white body. Its wingspan can be as much as seven inches across, or 18 cm. The wings have yellow eyespots and long swallowtails that confuse bats’ echolocation by fluttering as the moth flies, scattering the reflections of the bat’s echolocation calls. The bat attacks the swallowtail instead of the moth’s body, allowing the moth to fly away.

This is the life cycle of the luna moth, which is similar to most moths’ life cycles. A female moth will lay several hundred eggs on the undersides of leaves the caterpillars will eat, usually only one or a few eggs per leaf spread across many trees. The luna moth caterpillar especially likes persimmon, sweet gum, wild cherry, hickory, willow, black walnut, and white birch trees. The eggs hatch into little green caterpillars after about a week. The caterpillars eat leaves, grow big enough to molt, eat and grow some more, molt again, and so on. The period between molts is called an instar, which in the luna moth is about a week, give or take. After five instars, the caterpillar is as big as it will get, generally around 3 ½ inches long, or 9 cm. It’s not dangerous, but if a predator approaches, it will rear up, clack its mandibles, and puke up the contents of its digestive system, which stinks.

Finally, the caterpillar leaves the tree where it’s lived its whole life and crawls around in the leaf litter underneath the tree. There it spins a cocoon out of silk, wrapped inside leaves to hide it, expels any water or food still in its intestines, and transforms within the cocoon into a pupa. The pupal stage takes about two or three weeks, and let’s find out what’s going on inside the cocoon during that time.

First, the pupa is encased in a sort of exoskeleton called a chrysalis, which is inside the cocoon. Within the chrysalis, the caterpillar’s body starts to digest itself using its own digestive juices. This breaks its body down into cells in a sort of soup inside the chrysalis, and the cells then reform into the adult moth or butterfly.

Clearly, if you go through a metamorphosis like this that requires all your cells to turn into cell soup, you aren’t going to retain any memories from before you ensouped. Right? Well, according to a 2008 study with a moth called the tobacco hornworm, caterpillars that learned to avoid a particular odor retained those memories as full-grown moths. The moths would also avoid that odor. Researchers aren’t sure how this happens and I wasn’t able to find any follow-up studies, but it’s pretty mind-blowing. My brother sent this article to me ages ago, so thanks, Richard!

So, the luna moth has developed from a caterpillar into caterpillar soup and then into a newly-formed luna moth. The moth has serrated spurs made of chitin at the base of the front wings, which it uses to tear its way out of the cocoon. Its new wings are soft and wet, so it will spend a couple of hours waiting for the wings to harden before it can fly.

Male luna moths usually hatch first and fly away to find females. When a female luna moth hatches, she flies around until she finds a tree she likes, and then she stays in the tree and releases pheromones once it grows dark. Pheromones are chemicals that attract males, which is why the male moth has wider antennae than the female. He detects pheromones with his antennae, and can sense them up to six miles away from the female, or about 11 km. After he finds her, the pair mate, and within a day or so she starts laying eggs.

Like many moth species, adult luna moths don’t eat. They only have vestigial mouths and no digestive system at all. They mate, lay eggs, and die within about a week of hatching.

The luna moth is harmless even if you eat it or pet it—please don’t do either—but it is related to the deadly giant silkworm moth of South America. Fortunately, they look totally different and live in different places.

One last note before we leave moths behind and look at some other venomous insects. Back in episode 93 where we talked about some of the biggest insects in the world, I mentioned the queen alexandra’s birdwing butterfly. I put a picture of it in the show notes, or so I thought. Listener Judith caught my mistake and pointed out that the picture I’d posted was actually of an atlas moth. The atlas moth is in fact bigger than the queen alexandra’s birdwing butterfly, with a wingspan just shy of a foot across, or 30 cm. I swapped out the picture so it’s correct, so thank you to Judith for letting me know!

Now let’s take a look at some venomous insects that aren’t moths. Let’s just skip right over the ones you know about, like bees, and talk about a few interesting ones you might not have heard of. Like the bullet ant. It gets its name because its bite is so painful it feels like you’ve been shot with a gun.

The bullet ant lives in the rainforests of Central and South America. Worker ants are about an inch long, or 3 cm, which is pretty darn big for an ant. The queen ant is about the same size as the worker ants. It’s not closely related to any other ants alive today, but an ant discovered in amber dated to at least 15 million years old was determined to be the bullet ant’s closest relative. The bullet ant looks more like a wasp without wings than an ant, in fact. It’s black in color with massive jaws.

The bullet ant’s bite is considered the most painful of any insect. The ant injects venom with the bite that causes a burning pain throughout the body that lasts for a solid 24 hours without fading. It won’t kill you, but you may wish you were dead. The venom is a neurotoxin that can cause temporary paralysis of the part of the body that was bitten too.

An indigenous people of Brazil, the Sateré-Mawé, use the bullet ant bite in an initiation rite for warriors. That’s how much the ant’s bite hurts.

Finally, let’s learn about an insect with a terrifying name, the assassin bug. There are a lot of assassin bug species throughout the world, and while they sound scary, they can’t actually kill you. Their bite might hurt, but compared to a bullet ant bite, pffft. Easy peasy. But the white-spotted assassin bug of Africa does something the bullet ant only wishes it could do. If something disturbs a white-spotted assassin bug, it can spit venom. And if any of the venom gets into your eyes, it can temporarily blind you.

Assassin bugs mostly eat other insects. Some specialize in hunting spiders, some in hunting bedbugs or cockroaches. The assassin bug has a strong proboscis, or rostrum, that it uses to stab its prey and inject venom containing digestive enzymes. The venom paralyzes the insect and the digestive enzymes liquefy its insides. The assassin bug slurps up the liquefied insect insides. But if a predator attacks the assassin bug, it will inject a different kind of venom that causes intense localized pain and kills off the tissue around the injection site. No other insects are known to produce two different types of venom.

Some people keep assassin bugs as pets. What is wrong with those people?

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Thanks for listening!