Sunday, June 08, 2008

Parasitic Wasps

Lately I have been posting on my favorite science stories of the week (or every other week as it may be). A few that have come out in the last few weeks has me thinking that I might want to focus some of my studies on bugs. I am not sure that's such a great idea for someone who is allergic to bees! Anyway, here are two fascinating stories about wasps. Both were provided by one of my favorite sciency blogs - Not Exactly Rocket Science.

The first story, Parasitic wasp turns caterpillars into head-banging bodyguards, involves a Glyptapanteles wasp that attacks a particular type of caterpillar (Thyrinteina leucocerae). As many wasps do, this wasp lays its eggs inside of the host. The larvae then eat their host from the inside out before breaking through the skin. The caterpillar lives on and the larvae stay nearby.  When ever a predator to the larvae arrives, the caterpillar violently swings its head at the intruder.  The caterpillar eventually dies, but not before the larvae have transformed into adults. The researchers proved that the caterpillar decreased the death rate by 50%! While they aren't sure of the exact method, a top hypothesis is that a few larvae remain in the caterpillar controlling its functions for the good of the others. Wow.

The second story, The wasp that walks cockroaches, is similarly amazing. Here a female Jewel Wasp (Ampulex compressa), upon finding a cockroach stings it twice, once to immobilize and once to inject venom into its brain.  The venom doesn't paralyze the roach.  The wasp then grabs the antennae for the roach and walks it like a dog back to its nest.  It then lays an egg inside the living host.  The researchers have been studying what the mechanism is to accomplish this feat.  They have proven that the venom doesn't interfere with motor skills or the ability to fly. It appears to affect the signaling mechanism in the brain. The cockroach can recover from the venom, but not before the egg hatches and it is eaten from the inside out.

Apparently humans aren't the most exploitative creatures in nature as previously thought.

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