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FASCINATING! Mind-Control Turns Bugs into Zombies (pictures & videos)
Zombie movies have been all the rage recently, but did you know that bugs (insects, and the odd arachnid) are turned into zombies and forced, through some pretty freaky voodoo mind-control, to do some pretty sinister things? I've always been a bug lover, but some of these things really do boggle the mind. I've included videos for most of these, so you don't think I'm making it up!
Emerald Cockroach Wasp - turns cockroaches into willing food for its young!
The emerald cockroach wasp (Ampulex compressa) is a brilliantly-colored green wasp, as its name suggests. The other part of its name tells you what it's also known for—mesmerizing cockroaches and making them willing victims for its voracious grubs!
This is its M.O.: when an emerald cockroach wasp is ready to lay its eggs, it seeks out cockroaches, which are, fortunately for the wasp and unfortunately for us, all too easy to find. It will tackle the cockroach and first sting a specific ganglion (insect nerve cluster) in the cockroach's thorax (center region), temporarily paralyzing its front two legs. This makes it easy for the wasp to make a second sting to a specific spot in its head ganglion that controls the cockroach's escape reflex. Without an escape reflex, the cockroach becomes a willing slave. After snipping off half of the cockroach's antenna and (seriously) drinking the blood out of them, the wasp grabs one of the antenna and leads the zombified cockroach into a burrow, usually underground. The wasp then lays an egg on the cockroach's abdomen, and then packs the burrow with debris so other predators don't come in and walk off with the cockroach.
The egg then hatches into a larva, which bites a hole into the cockroach and sucks out its blood to feed on. Keep in mind the cockroach is still alive and conscious, but has no impulse to run away or fight off the larva! After a few days, the larva digs into the cockroach and eats it from the inside out. It then pupates inside the dead cockroach, and emerges as a new adult wasp, ready to wreak havoc on another unsuspecting cockroach!
Glyptapanteles - turns caterpillars into zombie guards (and food for its larvae!)
Glyptapanteles is another innocuous-looking, but frightening, little wasp. Well, frightening if you're a caterpillar. This wasp attacks caterpillars, laying dozens of little eggs (up to 80, in fact) inside their body. The eggs hatch into larvae that feed off the caterpillar's body fluid, but avoid its organs so the caterpillar stays alive. Then, when the larvae are ready to pupate, they chew a hole into the caterpillar's skin and wriggle out (see the disgusting video below to see this in action)!
Shockingly, the caterpillar is still alive as a bunch of worms burrow out of its skin. One or two larvae stay behind and turn the caterpillar into a zombie. The caterpillar stops feeding, and, instead helps spin protective silk around the pupating larvae, and even fends off potential attackers of the pupae. Eventually, its usefulness gone, the caterpillar starves to death.
Cordyceps fungus turns ants into zombies
One particular type of cordyceps fungus develops an unusual parasitic relationship with ants (other varieties parasitize other insects and arthropods). The fungus, when it infects an ant, begins to affect its nervous system, effectively making it into a zombie. The ant will abandon all normal activity, start acting confused, and make its way up to the top of a tall plant or tree, the fungus instructing it to do so.
When it reaches the top, it will grab onto the plant with a death grip and eventually die. Then the cordyceps fungus will grow out of its head (see pictures!), consuming the poor dead ant's innards, and release its spores. The position at the top of the plant, of course, helps the fungus spread its spores as far and wide as possible.
Other ants will recognize the strange behavior of an infected ant, and will usually grab it and throw the demented ant far away from the colony, knowing that if it stays, it could pose a danger to the whole colony when the fungus emerges from its head.
Hymenoepimecis argyraphaga turns spiders into cocoon-spinning zombies
We've discussed two small, harmless-looking wasps that turn cockroaches and caterpillars into their zombie hosts. Here's another that does the same to a particular Costa Rican orchard spider: the Hymenoepimecis argyraphaga.
This is how it enacts its sinister plan: the female wasp stings the orchard spider, temporarily paralyzing it so it can lay an egg on the spider's abdomen. The egg hatches a larva which feeds on the spider's hemolymph, while the spider continues about its normal business. Then after a week or two, the larva injects the spider with a poison which will change its web-spinning ability drastically. Instead of beautifully patterned webs that it had been spinning, the spider, under the zombie poison of the larva, starts a completely different, sloppy-looking web that is reinforced and will hold a much heavier object--the larva's cocoon.
The larva then kills the spider, digests all of its internal organs and hemolymph, and then pupates while dangling from the reinforced web that the poor zombified spider had built for it before it was offed and eaten.
Why? The pupa needs some protection from scavenging insects such as ants. Dangling from a web is a perfect place for the pupa to develop when it's most defenseless.
Slavemaker ants use "propaganda substances" to turn fool other ants into being their willing slaves!
Slavemaker ants (including Myrmoxenus ravouxi, Formica sanguinea, Rossomyrmex minuchae, and Formica subintegra, among others) are a peculiar variety of ants that must have other ants do work for them. Some species will even die in the presence of food if an enslaved ant doesn't actually feed them! How they're able to turn normally industrious ants into their zombie slaves is really intriguing. In some slavemaking ant species, even some Shakespearean intrigue is involved that would make Macbeth and Hamlet's Claudius proud!
When certain types of slavemaker ants want to take over another ant colony, they use some bioactive substances (specifically specific decyl and dodecyl acetates) that they store in their Dufour's gland, to change the behavior of the soon-to-be-enslaved ants: these ants start to panic and disperse, and often even start attacking their own kind! The host nest in total disarray, unable to mount a defense, becomes easy prey for the slavemaker ants, who typically cart off with the nest's eggs and pupae.
Another clever, but devious, technique is employed by the Ravoux's slavemaker ant (Myrmoxenus ravouxi). In the hubbub of an invasion when the enslaved ants are incapable of mounting a defense, the slavemaker queen will seek out the host queen and literally strangle her to death (sometimes decapitating her in the process). If any of the workers rush to the queen's defense before she's killed, the slavemaker queen will calm them down by stroking their antennae. After the host queen is killed, or possibly during the strangulation, some pheromones (cuticular hydrocarbons) are passed on from the host queen to the slavemaker queen, making the enslaved ants believe that she is their queen.
Myrmeconema neotropicum makes ants turn themselves into bird food!
Myrmeconema neotropicum is a nematode (worm) that uses ants in a really creepy--but cool--way to disperse its eggs far and wide. The black ants that get infected by it do so by eating bird droppings with the eggs in South American jungles. When infected, the ants change in appearance and behavior in the following ways:
- their abdomens turn from black to bright red
- they begin straying farther away from the nest
- they tend to climb up high in trees
- they get more sluggish
- they walk around pointing their bright red abdomens uncharacteristically upward
So what ends up happening? From further away they begin to look like bright red berries...exactly the type of food that birds like! Birds snatch them up and eat them, thereby perpetuating the process.
Spinochordodes tellinii makes grasshoppers and crickets drown themselves!
This is a pretty gruesome worm. It's really gross.
When an unfortunate grasshopper or cricket eats one of this worm's eggs, the egg hatches inside the insect's body and begins to grow. It will carefully do so without killing the insect, avoiding organs and surviving on the insect's hemolymph (its blood). When it reaches maturity, it does something to the insect's brain that impels it to jump into water when it sees a body of water, and drown (grasshoppers and crickets don't normally do this!).
Then, when the grasshopper is dead (sometimes before!), the worm, now 3-4 times as long as the insect, pops out and lives on where it will eventually lay eggs and continue the lifecycle.