A cockroach and a jewel wasp are locked in battle—but not for long. The wasp latches onto the cockroach, arches its body, and inserts its sting precisely into a cluster of nerves in the cockroach's thorax.
The exuding venom temporarily paralyzes the cockroach's front legs. She then stings his brain, where her venom inhibits his fight-or-flight response. From here on, the cockroach is basically a zombie.
The wasp cuts the cockroach's antennae in half,
uses the broken pieces as a straw to feed its blood-like hemolymph, then carries it to an underground lair. She lays an egg on her prey and carefully seals the bill, which becomes the nursery for her offspring.
Over the following weeks, its larva hatches, burrows into a cockroach, eats it alive, pupates in its corpse, and emerges as an abnormal adult. This grim story is just one example of parasitoidism, an evolutionary strategy used by most wasps.
As the parasites develop, they feed on other animals, usually killing their hosts in the process. In fact, these insects are about to be met by wasps—each in a uniquely terrifying way. This wasp targets the ladybug by laying an egg inside its body.
When the larva hatches, it eats the beetle's body fat. It eventually emerges, but Ladybug's duty is not fulfilled. It is now semi-paralyzed, possibly due to a viral infection given to it by Kandi. The larva spins a cocoon between its legs, and the still alive but fascinated beetle stands guard.
When a predatory lacewing larva approaches,
the ladybug twitches, scaring it off. Many other creatures avoid the ladybug entirely because of its bright coloration, which advertises its toxicity. After a week, an adult wasp emerges, leaving behind the corpse of its helpless helper.
Then there is the small but fierce crypt keeper wasp, which targets the larvae of such leaves. Gallworm larvae are also parasitic, but in a more herbivorous sense. It is feeding on this oak tree, which is locked in a closet on one of its branches. Soon, he has company.
The crypt keeper wasp adds her eggs to the mix. Leaf blight develops, and eventually begins to chew its way through, as it usually does. But it makes a smaller hole than usual and gets stuck.
The crypt keeper larva feeds on the gall carcass, pupates inside, then crawls out of the dead wasp's head to make its debut. The final victim is this caterpillar. Fluttering in the cool night air, an owl would have become a moth, but a few weeks ago, developing in its egg, this wasp laid an egg of its own.
The caterpillar emerged and began to grow.
And in a process called polyembryony, the wasp divides within itself repeatedly. But other types of wasps also lay their eggs on caterpillars. Real children realize this and further develop into two separate castes.
What was a single egg becomes thousands of larvae:
some of them are reproductive, others are soldiers. The caterpillar is now both a wasp buffet and a battlefield. As the reproductive larvae eat their own innards, the soldiers kill other parasites.
Reproductive larvae develop into adults and the soldiers die within the host. Needless to say, the result for Caterpillar is... pretty bad. This was just a glimpse into the thriving province of parasitic wasps. Some work underwater to find their hosts.
Others are hyperparasitoids, whose prey are other parasitoid wasps. Scientists are still uncovering these creatures. They can be difficult to collect and very small: the world's smallest known insect is a microscopic wasp that parasitizes bark beetle eggs.
Although much remains unknown, some researchers suspect that parasitic shrews are among the most diverse animal groups—perhaps the most diverse.
Wasps have been perfecting their brand of parasitism for some 247 million years, all to give their offspring the best chance at life.
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