9th October 05:52
Article: Parasites brainwash grasshoppers into death dive
Parasites brainwash grasshoppers into death dive
12:02 31 August 2005
A parasitic worm that makes the grasshopper it invades jump into water and
commit suicide does so by chemically influencing its brain, a study of the
insects' proteins reveal.
The parasitic Nematomorph hairworm (Spinochordodes tellinii) develops inside
land-dwelling grasshoppers and crickets until the time comes for the worm to
transform into an aquatic adult. Somehow mature hairworms brainwash their
hosts into behaving in way they never usually would - causing them to seek
out and plunge into water.
Once in the water the mature hairworms - which are three to four times
longer that their hosts when extended - emerge and swim away to find a mate,
leaving their host dead or dying in the water. David Biron, one of the study
team at IRD in Montpellier, France, notes that other parasites can also
manipulate their hosts' behaviour: "'Enslaver' fungi make their insect hosts
die perched in a position that favours the dispersal of spores by the wind,
But the "mechanisms underlying this intriguing parasitic strategy remain
poorly understood, generally", he says.
Now Biron and his colleagues have shown that the worm brainwashes the
grasshopper by producing proteins which directly and indirectly affect the
grasshopper's central nervous system.
Full Text at NewScientist
Robert Karl Stonjek