The Ultimate Body Invaders

In the world of Nature, every organisms are trying very hard to win the game of survival. In order to win the game, some come up with an extraordinary method---to invade another kind and manipulate the host to create a condition favoring the survival of the invaders, while putting the hosts in great danger. The following are 5 ultimate body invaders that adopt the unique mechanism to ensure the survival of their species. 

Cordyceps 

Cordyceps invaded host. 

Cordyceps are fungi from the genus ascomycete fungi, among which there are a lot of different species. The fungus parasites on insects and different species parasites on different hosts. As the cordyceps fungus infects an insect host, its mycelium (fungus part) replaces the host's body tissues. The fruiting body of the fungus will eventually puncture the host body and protrude out to allow the release of ascospores (spores). Many of the times, during the development stage, the fungus manipulate its host such as controlling the insect to climb up a plant and attaches itself there before it dies, ensuring optimal dispersal of the spores of the fungus. Some cordyceps genus are proven to have medicinal properties.  

Paragordius tricuspidatus

Parasitic worm emerging out of cricket.

Paragordius tricuspidatus is well-known for manipulating behaviour of its cricket host. The eggs of this parasitic worms are laid at the river edges where the crickets reside. The microscopic size eggs are ingested by accident by the crickets, and hatch within. The larvae of the worm get nourishment from the host and grow, eventually filling the entire body cavity of the cricket. They can grow up to 10 - 15cm in lengths.  Upon maturation, the parasitic worms are ready to exit the hosts, the worms will induce an abnormal behavior to the cricket hosts --- to jump into the water. Most of the crickets will drown, while some will survive and lead a normal life after the excision of the parasites. After which, the worms will slither out and find its mating partners. The manipulation in behaviours are believed to be cause by a release of proteins that affect the Central Nervous System (CNS) of the crickets.  

Dinocampus coccinellae

Paralyzed ladybug guarding cocoons

Dinocampus coccinellae is a species of wasp that parasites on Ladybug. The female wasp lays one egg in the soft abdomen of the ladybug. After the egg hatches, the larva starts to consume the ladybug's eggs, then the gonads and the body of their host. However the ladybug host is still alive. When the parasites are ready to emerge, they paralyze the ladybug and tunnel out of its body. Then the parasites pupate in a cocoon attaching to the leg of the living ladybug, The ladybug's occasional twitching ward off any potential preys of the parasites,  making the ladybug the "bodyguard" of its parasites. A few days later, the wasps will emerge from the coccoon. 1 out of 4 ladybugs will recover from the paralysis and come back to health after all the cocoons have emptied.  

Leucochloridium paradoxum

Snail with infection.

Leucochloridium paradoxum, a kind of parasitic flatworm, infects a snail and alters the original behaviors and appearance of the snail; after which increasing the chances of the snail being eaten by a bird which is the next and final host of the parasite. To do so, the parasite resides into the translucent eye-stalks (preferably left one) of the snail, altering the normal eye-stalks into yellow-greenish stripes, inducing caterpillar mimicry. Birds do not usually snack on snail, however the altered eye-stalks of the snail, resembling a caterpillar results in birds mistakenly consuming the infected snails. The parasites also cause the snail to be more visible to the birds by making the snails stay under the sunlight instead of hiding in the shade.   

Myrmeconema neotropicum

Normal ants.

Infected ant with red gaster raise up high to mimic wild-berries. 

Myrmeconema neotropicum is tetradonematid nematode parasite that induce berries mimicry in tropical ants. The parasites mate and lay eggs inside the gasters (the hindmost abdomen) of the ants. The infected ants will develop bright red, egg-filled gasters that resemble red berries available in tropical forest. The parasites also cause the weakening of the exoskeleton linking the gasters to the rest of the body of the infected ants. The infected ants will walk with their gasters raise up high, allowing birds to mistaken them as wild berries and pick up the gasters which detach easily from the ant.The parasite eggs will be passed in the birds' dropping and later collected by the tropical ants again.  

Meet the Alien In Deep Sea

Anglerfish is a type of very rare creature living in the deep sea. In most Anglerfish species, there is a long filament protruding out above the fish's eyes, at the tip of the filament there is an irregular growth of flesh (looks like a bulb, called esca). The long filament can move in all directions, while the esca acts as a bait to lure prey to the Anglerfish. When the prey is close enough, the Anglerfish will open its huge jaws and devour the prey whole! The Anglerfish can swallow a prey that is twice its own body size.

In some species of Anglerfish that lives deep under the sea where sunlight is scarce, the esca will emit light due to symbiosis with bacteria. The bacteria enters the esca, starts to multiply rapidly till their collective glow is bright enough to attract other fishes to become the prey of Anglerfish.

Here comes the interesting part, the reproduction of Anglerfish. As Anglerfish is extremely rare, it is very difficult to find a mating partner. In order not to become extinct, the Anglerfish has a very distinct way of reproduction.

At birth, the males are born with well developed olfactory organs (sensory system for smell). When the male Anglerfish mature, its digestive system starts failing, resulting in not able to feed independently. As a result, before the male dies from failure of digestive system, it has to find a female using its powerful olfactory organ. The male can detect pheromones from a mature female using its olfactory organ. So what will happen after the male found his mating partner?

After the male found a female, the male will bite into the female's skin, and digest the skin of his mouth and her body using a type of enzyme secreted. This will enable the couple to fuse with each other to the blood vessel level. The male then degenerates into a pair of gonads that parasites on the female. The gonads (male) release sperm in response to the hormones in the female's bloodstream signalling eggs release. This ensure that, whenever the female is ready to spawn, there will be sperm available to fertilise the eggs.

One of the species of Anglerfish, the little thing protruding

out at the back of the fish is the male that fused with the female

For the Anglerfish, the males reduce to parasites on females after maturation. The males are deemed to sacrifice in the reproduction system in this species, in order to ensure the survival of the species of Anglerfish.