Thursday, October 28, 2021

Swarms!

Cartoon woman screaming

In keeping with my October theme of creepy critters, I’m bringing you swarms. The sheer number of swarming animals is not just creepy, it’s deeply unsettling for most people. The feeling is such a profound part of the human psyche that swarms even surface in religious teachings – there are the biblical plagues in the Old Testament and the Miracle of the Gulls in Mormonism.

Swarming can be found throughout the animal world, among all types of creatures in the air, on land, and in the sea. The reason behind much of this behavior is still a mystery, but scientists have figured out why some occur. One strong impetus for swarms is the search for food. This is the case for the largest swarms on earth, locusts, and for the daily swarms of bats as they leave their caves in search of food. In the ocean, swarms of sardines and krill will trigger other swarms of animals seeking to feed on them. Swarms born of swarms. Despite drawing predatory attention, animals of all kinds swarm for protection from predators. While some members of the swarm may be picked off, the individual still has an improved chance for survival in a large group. This is the old “safety in numbers” logic. Swarms can be also created by climate, seasonal, or environmental changes. We see this in migratory patterns or the simple business of moving to a new house (which causes swarming in bees and ants). Lastly, swarms are set off by the biological imperative to reproduce. In virtually every part of the natural world there are animals seeking love in large groups.

Locusts eating corn corn off the stalk

The effects of swarms are mostly confined to the animals involved, with some important exceptions. Locusts, for instance, cause massive destruction to the environment and decimate food resources wherever they go. Last year (2020) residents of East Africa were beset by a massive swarm that spanned nearly 930 square miles and contained an estimated 200 billion insects. By far the largest swarms on earth, locust swarms have the ability to drastically alter life wherever they go. According to this article, the conditions that locusts need to thrive (dry weather followed by torrential rain) is becoming more common due to climate change. Also, swarming locusts are biologically compelled to reproduce faster and eat more while swarming. So, there’s every reason to believe that these swarms will only continue to grow in frequency and size. Which could become a hazard for life worldwide. Luckily, there are smart people working hard on solutions, including this one that turns locusts into animal feed. 

A mass of grey-brown millipedes
If you read my centipede blog, you know how I feel about centipedes and millipedes (not a fan of those squirmy legs), so millipede swarms are super-duper creepy to me. Apparently driven by an irresistible food source, millipedes in Senegal pile on top of each other to get at it (see the video here). In Japan, millipedes swarm in large enough numbers to stop train traffic. Scientists have now determined that these poisonous creatures are part of a brood cycle that emerges every eight years, similar to the life cycle of cicada.

Swarming red crabs by a roadwayOne of the most incredible swarms on the planet is the march of the Red Crabs of Christmas Island. This small island is off the northwest coast of Australia and has a population of 2,000. People, that is. Its crab population is 40,000,000. Every year at this time (October-November), the crabs march from their homes in the forest down to the beach for a festival of breeding and nothing stops them. Their relentless march is annoying and messy (especially when thousands lie dead on roadways), but Christmas Island inhabitants have learned how to live with them. Among other concessions to the crabs, they’ve built tunnels under roadways for the crabs to use. For more on this cool phenomenon, including what invasive species is threatening it, check out this article

A swarm of female sea turtles coming onto the beach from the sea.
Speaking of crabs, if you who don’t like swimming in the ocean because you don’t know what’s underneath you, you should not look at the video of this next swarm. While researching something else entirely off the coast of Panama, scientists discovered a massive swarm of Tuna Crabs moving along the bottom. According to this video, they say there are thousands of crabs in the horde, but it looks like zillions to me. Cool…and creepy.

Right up the coast from the Tuna Crab swarm is Costa Rica, home to large populations of Olive Ridley Sea Turtles. In the Ostional National Wildlife Refuge females of this species swarm the beach to lay their eggs. Their swarm is known as a mass arrival and happens every month. In November 2016 biologist, Vanessa Bézy captured something special on her drone camera – a swarm of hundreds of thousands of turtles; the largest swarm ever filmed. Why there were so many remains a mystery, but it is a spectacular sight. Protecting these turtles continues to be a high priority to environmentalists. Learn more (and see the amazing video) from National Geographic.

Drosophila melanogaster fruit flies mating

Most people would consider fruit flies to be annoying but otherwise unremarkable. But, as it turns out, those little fliers carry big secrets. It seems they are into free love and they swarm to get in on the action. Their urge to reproduce turns them into sex-crazed, orgy-loving little beasties. According to this article, their initial one-on-one heterosexual coupling escalates into an extended session of group sex. There’s more, but I’ll be discreet and let you read it for yourself. 

Monarch butterflies create epic and beautiful swarms as they migrate to and from their winter homes in the mountains of Mexico. Much of their travels are still a mystery, but we do know that they number in the millions (150,000,000 or more) once they arrive. Here is a video done by National Geographic using a fake hummingbird camera to get up close without disturbing them. It’s amazing. And, this video, lets you hear how sounds there. 

A man in white clothes stands by some trees next to a river. The trees are covered in spider webs.
And then there are the spider swarms. And for many people, these are the creepiest of all. In the fall months here in the Southwest, male tarantulas leave their burrows and take to the roads in search of lady tarantulas. They number in the hundreds, and even thousands, as they venture out (here’s more from Marfa, Texas). While the tarantulas we see in our country are generally harmless to people, there are others that are more problematic. Case in point: Australian Diving Tarantulas (yes, they go underwater). These guys have a particularly strong venom that can severely sicken a person. And, in 2015 (for reasons unknown), roughly 25,000 of these spiders swarmed the little town of Maningrada, Australia. That must have been a very scary scene, even for the bravest of spider-lovers.  Another truly frightening spider swarm happed in 2011 in Pakistan and, to be honest, this is where my love of nature crashes right into my tapped-down arachnophobia. That year, after unprecedented flooding, the arachnid population moved to high ground. Specifically, into trees. Once there, they set up house and spun webs. Tree after tree was covered in webs in which millions of 2-inch spiders lived. Altogether too much for me. 

A swarm of deadly jellyfish moving through the water.

Here’s wishing you a happy, creepy Halloween… and if you come across a swarm, get out of the way. 

Submitted by Pam


Tuesday, October 19, 2021

Vampires Are Everywhere

A cartoon Dracula peeking around a corner and waving hello.
We humans have an interesting relationship with vampires. On the one hand, we have created a whole genre of creatures to horrify, titillate and entertain ourselves. We like the über creepy Nosferatu type vampire, and we like sexy dreamer Twilight type vampires. We like them all. But, while we may like fictional vampires, we revile the animal most closely associated with vampires - vampire bats. For as much as we love fake vampires, it seems people just don’t like to think about real-life vampires. Nevertheless, we are surrounded by them on a daily basis.  

Most of the common insects that plague people are bloodsuckers. There are mosquitoes, bed bugs, various flies and fleas, ticks and leeches. And I probably missed a few. These insects represent a staggering disease toll taken on the human population. For instance, mosquitoes continue kill more people than any other animal and fleas helped spread the Black Death that tried to wipe out Europe in the mid-1300s. Not all blood-feeding insects are dangerous to humans, but the ones that are a threat are super dangerous to humans. 

Vampire Bat

There are a surprising number of vampires hiding amongst us in the animal kingdom. For various evolutionary reasons, these animals have adapted to use blood as a food source. Here are some you may not be familiar with, and all have just as much creep cred as any old flying bat:

Dracula Ants (Adetomyrma venatrix) – 

A close-up of a Dracula ant
These rare ants are from Madagascar and are endangered, which is just one of the things that are unusual about them (most ant species thrive spectacularly). Perhaps part of their problem is that they are horrible parents – they’ve earned their common name by their habit of sucking the blood of their young. More specifically, they poke holes in their larvae and slurp up the hemolymph (ant blood) therein. Scientists say this does not harm the larvae, but I remain unconvinced. These ants will also consume the larvae entirely if the colony runs out of food, which is undeniably harmful. Other interesting facts about this insect are that their workers are blind and that they have the fastest animal movement on record – they can snap their mandibles at speeds of up to 200 mph (more on that here).

Vampire Moths (Calyptra spp) – 

A beige Vampire Moth sitting on a person's finger and looking directly into the camera.
While people are busy swatting at mosquitoes or running from bats, they may fall victim to a seemingly harmless little moth – because who’s afraid of a moth? You might want to be, because it seems that the males of these moths have branched out from piercing into fruit and sucking out the juice to piercing into mammals and sucking out the blood. And they don’t bite and run like most mosquitoes do, some will stay on their host for up to 50 minutes! Scientists have not determined definitely why the moths drink blood and why only the males do it, but it is believed it adds something beneficial to their sperm. Vampire moths are fairly widespread across the globe and are not specific in their choices of host animals, but the feeding habits of all the species have not been well documented yet. Which means that you may or may not be in danger of getting bitten by a moth seeking male enhancement. More on these bite-y little things here (including a video that shows their drilling technique while feeding). 

Surprisingly (at least to me)  there are a number of birds that are vampires. And not big and scary-looking ones like vultures (who only ingest blood incidentally while they feed on carrion). These vampires are more seemingly-sweet creatures hiding gruesome tendencies. Bird vampires appear to have evolved from being parasite-eaters to supplementing parasites with doses of blood. It is easy to see how a tick eater could morph into a direct blood drinker.  
Tristan Thrush eating a dead bird. Photo by Brian Gatwicke

Vampire Finch (Geospiza difficilis septentrionalis) and Tristan Thrush (Turdus eremita) - 

From the nursery of evolution, the Galapagos Islands, these two birds have a varied diet, including the blood of other birds. With limited food resources on the islands, it seems only sensible to get whatever you can from whatever you can. Here’s a video of a Vampire Finch sourcing a Boobie bird's blood. A picture of  the Vampire Finch preying on a Boobie won Wildlife Photographer of the Year for Thomas P. Peschak in 2018 - see it here. The Tristan Thrush is another island-based bird with the same blood-sucking habit. In this case, they occasionally like to suck on penguin blood, but it's not a major source of nutrition. They are expert scavengers  and will find food wherever it presents itself. For instance, they will pull other birds out of their burrows, peck them to death and eat them. These guys are brutal - but survivors.  

Oxpecker bird drinking from a wound. Photo by Ian White on Flickr.
Oxpecker Bird (Buphagus spp) – 

These African birds don’t mess around with other birds, they go straight for some of the largest mammals on Earth. They ride around on the backs of buffaloes, giraffes and the like and clean off parasites. But they want blood as much as parasites and will not hesitate to create or reopen wounds to get what they want. These birds can be major pests to their hosts and possibly dangerous to the weakest ones. Here’s video that shows them feeding on, and squabbling over, a buffalo’s blood.  


Looking into the mouth of a Lamprey.
I’ve saved the worst for last in this list of blood-lovers – the Lamprey. For me, the horror factor of these animals is way above and beyond any fictional monster. These fish have thrived and remained unchanged for 360 million years partly because they have pared down to simple sucking machines. They have no jaws or scales; they are simply an elongated body with a suction-cup mouth full of hook-like teeth in circular rows. They are parasites and live to find a host fish to latch onto and live off its blood. The creepiness factor for these fish is really ratcheted up when you see them in the large, squirmy masses they congregate in. Their design may be efficient, but I do not want to ever be in any water that they are in (and they live in fresh and salty water worldwide!). This article has a great video with some close-ups of the mouth, which should explain why I find them so freaky.

Either share your blood willingly or watch your back closely; there are plenty of things that want a piece of you. 

A vampire creature holding a bat and saying "Your wife has a beautiful neck".

Take Care.

Submitted by Pam


Wednesday, October 13, 2021

Centipedes Creep Me Out

A large back and yellow centipede crawling out of a grey tennis shoe with white bottoms. There is a white pair next to it.
I live in a place where rattlesnakes, scorpions and tarantulas are common, and they do not bother me at all. But the other day I came across a centipede and that triggered some kind of primeval revulsion in me. They always do - it’s all those little legs and all that squirming around…..I just can’t. I know I’m not alone in this (here are some interesting thoughts as to just why we find them so gross), so I really don’t understand how these arthropods have managed to avoid being part of Halloween lore of creepy creatures. I‘m adding them to my list for sure. So, in celebration of their Halloween, here’s a little something about these creepy crawlers.

A view of a black and yellow centipede from the side.
First of all, there are centipedes and there are millipedes, and while they are both pretty yucky, they have some interesting differences. As their names imply, centipedes have fewer legs than millipedes – one per body segment as opposed to two. Although millipedes have twice as many legs, they are slow-moving burrowers, while centipedes scurry around rapidly. This difference in their movements is down to centipedes being carnivorous and predatory while millipedes feed on decaying organic matter and roots in soil. Millipedes are generally considered beneficial creatures (albeit still creepy), while centipedes are the ones who have venom and can (and will) bite. For more on their differences, check out this article

An upside-down yellow-orange centipede. The segmented body, legs, head and antenna are on display.

Let’s talk about those legs: First of all,  the word “centipede” would indicate one hundred legs with that the root word of “cent” while “millipede” would indicate one thousand, but that is not accurate. According to this article, centipedes have up to 382, while millipedes have between 40 and 400. Also, they don’t start out with all they end up with – they grow additional legs as they mature. And they can drop a leg to escape a predator (like some lizards do with their tails) and grow it back later. They have an abundance of legs, but they actually use different ones for specific purposes. For instance, centipedes carry their venom in the two legs right by their heads (these forcipules are legs and fangs all in one and are unique to centipedes). They jump on their prey and insert the venom while using some of their legs to completely encircle their victim. Meanwhile, other legs are maintaining their grip on whatever surface the centipedes are hunting from.

a grey and black centipede in a den wrapped around a horde of white baby centipedes.
Often the creepiest things about the animal world are the mating rituals therein (and, yes, I include humans in this statement), and centipedes are no exception. Except that it appears their genders don’t even want to be near each other; they have developed reproduction without copulation. In most centipede species, males create a web that they deposit their sperm in, after which  females get into it and absorb the sperm to fertilize their eggs. Depending on the species, the females then either deposit their eggs in the ground and leave or stick around to care for and protect their offspring.


A blue and yellow South African centipede amongst dirt and pebbles.
There are somewhere around 3,300 species of centipedes in the world, and they come in an array of colors and sizes. Centipedes are generally black or dark, reddish-brown with yellow legs, but they can also be orange, blue, yellow or purple in parts (check out this Google search to see some of them). If they weren’t so darn creepy, some varieties could be considered pretty (and probably are by people more tolerant than I).

A house centipede in a white sink next to a drain.
One of the most common varieties of centipedes is the House Centipede. These guys are small, look like a combination between a spider and a centipede, and are often found lurking in drains. If you come across one don't kill it; it's busy hunting insects that you really don't want in your house like roaches, flies and termites. While House Centipedes are pretty common, on the other end of the centipede spectrum is the uncommon Waterfall Centipede (Scolopendra cataracta). These natives of Southeast Asia were not even discovered by scientists until 2001. Despite their large size (about 8 inches), they stayed off the radar because they prefer to hide and hunt in and under water - especially around waterfalls. These elusive centipedes can run along the bottom underwater, which is definitely creepy. Here's more on them. 

A male Oriental Pied Hornbill sitting on a branch with a centipede in its mouth.

If small centipedes can cause visceral reactions, large ones are the stuff of nightmares. And they can
get really big. The winner for being the largest is the Peruvian Giant Yellow-Leg Centipede 
(Scolopendra gigantea). This intimidating creature can grow as long as 12 inches and can easily take down prey more than fifteen times its size. These guys seem to be fearless (which makes them even more intimidating) – scientists have observed them hanging from ceilings in caves while feasting on bats. These centipedes are native to South America and the Caribbean, but they have been introduced to the world at large for the pet trade. Needless to say, keeping these large venomous animals is not a great idea. When it comes to centipedes this large, the bite can not only cause all sorts of problems, it can also be fatal. For more on keeping centipedes (including the pertinent warnings), check out this article. And if you want to see a man (unwisely) handling a ginormous centipede, here’s a video

A beige centipede lunging out of the dirt and striking a fish swimming by.

One more thing: Even if you find centipedes as creepy as I do, please don’t kill them just because you don’t like the way they look. They have their spot in the ecosystem and have the right to live happy centipede lives.

Take Care.

Submitted by Pam


 


Tuesday, October 5, 2021

What’s This Bug? Wait - That’s A Bug?

Hawk Moth caterpillar in its snake disguise. It's hanging of a brown branch in front of a black background.
This feisty little creature would be the hands-down winner in any Halloween costume contest. Although it does a heck of a job disguising itself as a snake, it is really a Hawk Moth (Hemeroplanes triptolemus) caterpillar. Commonly known as Snake Mimic Caterpillars, these caterpillars can be found in the rainforests of Central and South America and are undisputed masters in the art of mimicry. 

A green Hawk Moth caterpillar on a twig.Many animals use mimicry to defend themselves from predators, or to better position themselves in the food chain (here’s a short yet comprehensive list). Some animals have developed super-sneaky ways to use mimicry to get themselves close to their preferred prey, but insects use these tricks primarily to protect themselves from predators. Caterpillars, especially, are extremely creative in their costuming (they are, after all, a favorite snack for many other creatures). The Hawk Moth caterpillar is an excellent example of this; it is pretty non-descript in its adult form, but as a caterpillar it can transform into a dramatically scary-looking pit viper.

A brownish-grey patterned Hawk Moth adult on a green leaf.
So, how does a caterpillar turn into a snake? With a little bit of puffing up and flopping over. When the Hawk Moth caterpillar feels threatened it will drop the front part of its body off the branch or leaf it’s on and expose its underside. This action allows them to display an underside with faux snakeskin and eyespots that actually appear to glisten. To complete the masquerade, the caterpillar will puff out its head to mimic the triangular head of a venomous snake. And if that’s not enough, they sometimes lunge as if they’re about to strike. The use of eyespots and snake mimicry as a defense strategy is very effective (even if they do make comically short snakes) and, according to this research, it even works in areas where tree-dwelling snakes are rare. It seems caterpillar predators like birds and lizards are well aware that they are prey to snakes and take no chances with anything that might be a snake.

A closeup of a Hawk Moth caterpillar's snake face.
If you want to get a better look at how this snake disguise works, I have a couple videos for you to check out. In this one, if you look closely at the head of the “snake”, you can see the little bitty caterpillar legs between the fake eyes and this video shows a caterpillar transforming itself. You can see how the head of the caterpillar becomes the nose and part of the mouth of the snake. Cool stuff

A green cartoon snake wiggling back and forth.
If you are planning a show-stopper Halloween costume, keep in mind that these caterpillars have set a very high standard in costuming. But, if you can come up with something that is even a fraction as convincing as their snake disguise, you may win the day.

Take Care.
Submitted by Pam..





























Take Care.

Submitted by Pam






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