In a previous entry on this blog I wrote about parasitoid wasps and their amazing life cycle that went on to horrify Charles Darwin and inspire the reproductive cycle of one of the most famous movie monsters, the creature from Alien.
Recently I came by some very interesting information about a species of parasitoid wasps called Copidosoma.
Looking at that tiny wasp shows nothing that makes it any different from the other wasps that I've covered, yet there is a reason why I'm dedicating a whole separated entry to it.
Most parasitoid wasps lay many eggs inside a host but not this one, it usually lays one or two eggs. One carries the genes for a female while the other for a male.
At first everything seems normal, then suddenly something unexpected happens, the eggs produce more than one embryos, hundrets to be exact resulting in a developmental phenomenon called "polyembryony". The wasps in each egg are absolutely identical, they are clones.
Some of the embryos develop faster than the others and emerge first, they are called soldiers. With a sleek and long body they posses deadly sharp mandibles which they need for exactly one reason - to kill.
This photo shows the difference bewteen the soldier (left) and a regular larva (right).
The soldiers' only purpose is to murder any other wasp larvae inside the host that isn't from the same egg as them, that way other wasps can't infest the host even if they are from the same species.
The larvae that hatch later look nothing like their clone siblings, they are fatter and lack any offensive mandibles, what they do have is a great hunger and the ability to reproduce once they reach adulthood unlike the soldiers who are sterile and only serve as guards.
These larvae start to feed on their host's body fluids so they can enter their next phase of growing up to be wasps themselves.
A parasitized caterpillar, the wasp's larvae can be seen inside it.
I did mention that sometimes the eggs are two, each one produces either males or females only. What's remarkable is that once the male larvae hatch the soldiers start butchering them. The cause for that is that since their hosts live separated by great distances the more female wasps produced the higher the chances of them succeeding in finding a proper host, while only few males are needed for mating purposes only.
I'm sure there's more we can learn about these amazing animals as they are poorly studied.
If you want to learn more about parasitoid wasps check out my earlier entry on the matter: http://www.narutoforums.com/blog.php?b=18756
I hope you enjoyed this trip to the astonishing microworld! Stay tuned for any future entries and interesting facts.
Up until now I've only been sharing information about arthropods but there are many other animals with fascinating life cycles, now it's time for me to present to you two organisms that affect their hosts in not only dramatic but also unbelievable ways.
I'll start with a tiny worm called Nematomorpha but is also known as horsehair worm due to it's appearance.
The adult worm is not a parasite, it's free living but their larvae are parasites.
Once they enter their host's body they start feeding but do not damage it.
They reach size which is times more than the host's body size and as soon as they start maturing something very peculiar happens.
The species which infect crickets and grasshoppers affect the brain of their victim and make it jump in any water nearby after which the host drowns and the worm finally emerges to start it's life as an adult.
It's interesting to mention that experiments show that when the host is taken out of the water after the worm has left it's body it once again seeks and jumps into the water which shows that whatever manipulation the worm has done on it's brain is permanent.
The video shown bellow shows a worm emerging the moment it's host is in contact with water.
Now I would like to introduce to you another worm who's effect on the host is not only interesting but also very appetizing.
The worm is travels inside birds' intestines and drop to the ground inside the feces which are then collected by ants.
Infected ant, notice the red abdomen.
When entering the ant's body the eggs turn their abdomen red thus making it look like a berry which attracts birds which otherwise don't show any interest in eating ants.
I need to be exact, the creature I'm about to present to you is not exactly a crab but still a crustacean.
Say hello to Cymothoa exigua.
I expect that this first image of the creature is shocking for some but let us examine exactly why this crustacean is so fascinating.
As you may have noticed this animal spends most of it's time inside the mouth of a fish but exactly what does it do in there? Well C. exigua is the first and for now only parasite that replaces a part of the body of it's host.
This parasite first enters the fish through the gills and then attaches itself to the base of the tongue, it then begins to draw blood until the tongue eventually atrophy. When the tongue is finally gone the female attaches herself as the fish's new tongue.
The fish begins to use the parasite as a regular tongue.
This creature has gained some popularity which eventually even led to a horror movie.
The poster for the movie.
And since I don't want to leave you with a bad taste in your mouth (no pun intended), enjoy this hilarious cartoon about the friendly parasite.
Intelligence is the last thing to come to mind for most people when discussing arthropods but the truth is that in the microworld of the crawlers there is someone who is as cunning as a lion, despite being only a few millimeters.
One group of spiders has always been compared to big cats because of their way of active hunting unlike other spiders who rely on their web and vibrations to catch prey. Widely known as jumping spiders (Salticidae), they rely on their eyesight which is very peculiar for a spider, indeed these spiders are considered to be one of the most evolved arthropods with a vision second only to the mantis shrimp.
Notice the big eyes on the front.
As I mentioned what makes these spiders different is the fact that they are active hunters and stalk their prey much like the big cats.
A jumping spider attacking a bee.
One species of jumping spiders is known for another astonishing feat, if we would replace the dinosaurs in Jurassic Park with arthropods then Portia would most definately play the role of the raptors. With a vision similar to that of some mammals and exceeding the visual capabilities of a dragonfly Portia is a deadly predator in the microworld.
But it's not her eyesight that makes her special, it's her brain.
For a creature that is smaller than a fingernail, Portia achieves something that no other arthropod can, she can use strategies in order to catch her prey. One of the reasons for developing such abilities is the fact that she hunts other spiders, some many times bigger than her, others capable of subduing spiders as well (the spitting spiders, who are also hunting other spiders, are often preyed upon by Portia).
The strategies that Portia uses vary from imitating a caught insect in the web or a male spider to remembering her surroundings and using the best route to her prey. The fact that a creature with such a minuscule brain can remember routes and create strategies which include loosing sight of the her prey for some time is absolutely amazing and unique to Portia.
Often she takes a lot of time stalking her prey and using her enviornment so she can surprise even other jumping spiders.
To better understand the thought process of this spider imagine that you have two computers with a different connection, both can download the same picture but the one with a slower connection will take more time. The same way the brain inside Portia, due to it's size and the fact that a large portion is used to process what she sees, requires more time than that of a small mammal in order to come up with a suitable strategy based on the surrounding.
Portia is also a master of camouflage moving slowly and carefully calculating every step.
So next time you see a jumping spider consider that it can see you too and that there is a spider than can think rather than rely on pure instincts.
Portia may be small but she indeed a clever girl.
Nature has always been creative when it comes to reproduction, in a previous post I analysed the gruesome reproductive cycle of parasitoid wasps, surely there can't be an even more bizzare way for an organism to breed.
Or is there?
We are all familiar with the little crustaceans known as barnacles (or Cirripedia), they appear all over the world in the seas and oceans. A lot can be said about those creatures, they have an unusual anatomy for an arthropod and have challenged even Darwin, almost driving him insane.
But there is one barnacle species that has such a peculiar reproductive cycle which makes them deserve the title of gender benders.
Known by the ironically charming name Sacculina, this creature parasitises crabs and other crustacean.
The mature form of this species is so unlike any other arthropod that scientists were able to identify it as a barnacle only by it's larval form.
The larva searches for it's host and when it finds it it injects only a soft part of it's body, completely discarding the rest.
Now inside Sacculina's blob-like body begins to grow like a cancer, spreading "branches" all over the internal organs of the host, even the eyes are entangled.
While other crabs are beginning to prepare for mating the host continues eating completely uninterested in finding a mate.
In full control a sac-shaped part of Sacculina's body emerges from the crab's underside where normally the eggs are positioned. It is time for the parasite to do what it has been preparing for all this time.
Sacculina's blob-like body can be seen showing from the crab's abdomen.
The host crab moves to the water, lifts it's pincers up in the air, raises it's underside and begins to shake it's body. That is normally how crabs release their eggs in the water, however instead of it's own eggs the host actually releases the eggs inside Sacculina's body that is showing from the crab. The parasite's life cycle is complete.
But this is not what makes this animal so extraordinary, there is more.
What happens when Sacculina ends up inside a male crab that doesn't have the natural instincts of releasing eggs?
The parasite has the answer, it releases hormones inside the male crab's body making it act and even look like a female crab. Yes, that's right, it changes the host's gender in order to achieve it's breeding cycle.
Sacculina is truly nature's most bizzare gender bender.
Our planet is teeming with life, from the smallest microorganisms to the gigantic whales inhabiting the oceans. Provided with millions of years and a favourable enviornment, evolution has produced incredible and often bizzare organisms that look more like a product of science fiction than a real part of the nature we claim to know and understand.
I would like to introduce to you a creature that has captured my interest since early childhood, a creature that still holds mysteries that even the brightest minds can only wish to unravel. Usually no bigger than a few millimeters, this creature has succeeded into acomplishing tasks that most would consider impossible or higly unlikely. This animal is known as parasitoid wasps.
But wat is a parasitoid? Is it a parasite? Well not quite, a parasitoid is a creature that spends a significant portion of it's life cycle on or inside a certain host and unlike most parasites it eventually kills and usually consumes it's host.
Many organisms are parasitoids but some arthropods, especially insects, have reached astonishing feats as parasitoids. One specific group of animals have become the experts in this field. Most people think of wasps as social animals quite similar to bees but the fact is that the majority of wasps are solitary creatures that parasitise on other animals. Usually they are so small that are unnoticable with the naked eye. So what can be so fascinating about these little wasps?
First of all their life cycle is worthy of a horror movie.
The adult wasp finds it's host by different means depending on the species, in some cases the plants that are attacked by a caterpillar release chemicals that attract the exact species that use the caterpillar as a host! What follows is the wasp inserting it's ovipositor into the host and injecting it's eggs inside it.
As seen here:
Usually the host's immune system should be enough to irradicate the eggs but the wasp has yet another amazing trick, polydnavirus!
What is polydnavirus (PDV)?
In a few words, millions of years ago parasitoid wasps assimilated a virus to use against their host's immune system, keeping the eggs intact.
The next step of their life cycle is simple, the eggs hatch and the newly born larvae start to feed on their host's fluids and non-vital organs keeping it alive throughout the whole process until the time they have to break out.
This video shows that stage of their development:
As you may have noticed after watching the video, in some cases the host remains alive after the wasp larvae leave it's body. Here is where the most amazing ability of the parasitoid wasps can be seen! The heavily injured host protects the same larvae that fed on it's organs and eventually broke out. Recent research has shown that one or two larvae remain inside the host controlling it into protecting the rest of the larvae, how this is achieved and how it is decided on which larvae to stay inside is still uknown.
Another video that shows the zombified host being controlled by the wasp larvae:
Truly remarkable creatures!
The tiniest known insect to man is also a parasitoid wasp that parasitises other insects eggs. They are 0.139 mm (139 μm) in length and posses a fully functional brain capable of complex processing.
There are species of parasitoid wasps that parasitise on spiders making them create a chaotic web rather than the well-organised web we are used to expect.
And ofcourse the more known jewel wasp that is famous for it's ability to sting inside the cockroach's brain in the precise point to turn it into a helpless slave that is later dragged by the antennae inside a nest where it will provide food for the wasp's young.
Really I can go all day and night writing and talking about how amazing parasitoid wasps are and if you don't think the same way after reading the facts then don't expect anything in nature to ever surprise you more than this.
I thank those who had the patience to read all the information and watch the videos I had to provide. I really hope you enjoyed it and that it opened your eyes to a world where the impossible is often proved possible by the most unnoticable and truly alien creatures.
If it hasn't crossed your mind until now the life cycle of the famous Xenomorph creatures from the Alien series is inspired by parasitoid wasps as well as other insects. This link provides enough information on the subject coming from the actual creators of the Alien concept.
I came across a really detailed video of parasitoid wasps emerging from their unfortunate host that I would like to share.
I must warn you it's really not for the faint of heart!
Expect further updates as new information becomes available.
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