杏吧原创

EVER got an electric shock after walking across a new carpet? Houseflies have
a similar problem, and it could prove their undoing. 杏吧原创s have now worked
out how to exploit the phenomenon to build an environmentally friendly
flytrap.

Houseflies tend to become positively charged, losing electrons through
friction as they walk across certain insulating surfaces such as PVC or
polythene. 鈥淭his means they can attract and pick up negatively charged dust
particles,鈥� says Daniel McGonigle of the University of Southampton, who is
studying this 鈥渢riboelectric鈥� effect in flies. The flytrap he鈥檚 developing with
colleague Chris Jackson exploits the fact that spores of the common fly-killing
fungus Metarhizium anisopliae are naturally negatively charged. Their
trap consists of a pheromone lure that entices the flies onto a walkway made of
a material that gives them a positive charge. The walkway leads to a receptacle
containing the fungal spores, which become attached to the victim before it
flies away.

The fungus spreads through the fly鈥檚 body and kills it within about 10 days.
During this time, the insect is highly infectious and passes on the fungus to
other flies. 鈥淪o you can control the pests without having to spray wide areas
with insecticide, which is generally nasty stuff,鈥� says McGonigle.

But John Chubb, an expert on electrostatics based in Cheltenham,
Gloucestershire, predicts that the flytrap will have problems outside the lab.
He says warm and humid weather might dissipate the charge on the spores in the
trap. 鈥淚t might work, but I鈥檓 a little sceptical,鈥� he says.