Pest Management Professional, October 2012

technicalities CoCkroaChes T he light comes on and dozens to thousands of cockroaches scatter When we see it we know its a good day to be in the bug business Because these insects are nocturnal most people conclude the running and scattering is caused by the introduction of the bright light But if we set up a night vision camera wed see cockroaches are on the move before anyone approaches the switch How do they know were coming Motion detectors Two really cool appendages called cerci on the back of the cockroach body are organs designed to detect movement in the air around the animal giving it a primitive early warning system When the air pressure in a room changes this can occur when someone enters a room or when the heating ventilation and air conditioning HVAC system turns on or off an air current is created the cerci detect the change and suddenly the roach is on the move We just dont see it until the light comes on You might notice some of the roaches remain still when the light comes on Those behind an object might not feel the air movement as quickly so they dont start to run immediately Once the insect is in motion we see how fast these pests really move An American roach Periplaneta americana was clocked by researchers at University of California Berkley moving at 59 in per second In human terms thats equivalent to about 35 mph This might not sound fast but if you consider the size of the animal vs the distance it covers its a phenomenal rate In his book Insect Lives Stories of Mystery and Romance From a Hidden World Harvard University Press paperback edition 2002 naturalist David George Gordon reports this distance is 10 times the number a human can cover during the same time period He also explains the American cockroach is three times faster than the cheetah when compared on a size scale basis The German roach Blattella germanica is slower clocking in at 12 in per second Built for speed How do its legs keep a cockroach moving at these speeds without falling over Look closely and youll see amazing coordination The cockroach normally moves three legs at a time the first and third on one side and the second on the other creating a tripod that supports the body evenly at all times Because the body is in a state of balance it can stop moving at any given time without falling over To run the insect simply speeds up the coordinated movement of the legs Some cockroach species such as the brown banded roach Supella longipalpa have been observed using their wings as an airfoil When running theyll spread them out like an aircraft wing The air current lifts the body front and the roach runs on its back two legs So good luck sneaking up on these little guys Once they feel your presence theyre off two or three legs at a time pmp You can contact Meek international technical and training director for Orkin at fmeek@ rollins com Frank Meek Columnist The american cockroach is about three times faster than the cheetah when compared on a size scale basis run roach run Australian cockroach Periplaneta australasiae with the cerci circled Photo Frank Meek Orkin LLC www mypmp net Pest Management Professional October 2012 125