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05-22-03
How Many Bugs Could a Bug Zapper
Zap?
The approach of the lazy, hazy, crazy days of summer is always accompanied
by booming sales of bug-killing devices. That's because the hot summer
nights and days are perfect for cold-blooded insects. Lots of insects
mean lots of human encounters with insects. And that translates into human
attempts to kill insects.
For centuries, we humans have brushed, swatted and stomped the six-legged
creatures that get in our way. Since World War II and the development
of insecticides, we have added chemicals to our bug-killing arsenal. Killing
insects has become as much of a summer ritual as lemonade, suntan lotion
and family vacations.
We like to kill insects so much so that we invest our hard-earned money--millions
of dollars each year--on products to help do the job. An old-fashioned
flyswatter still works, but in today's high-tech society we would rather
use gizmos and gadgets.
One of those gadgets is the electric bug zapper. Bug zappers are based
on the attraction of night-flying insects to light, especially ultraviolet
light. And when the insect arrives at the light, it gets electrocuted
or zapped!
Exactly why some insects are attracted to light is debated by scientists.
Most agree that artificial lights interfere with insect night behavior.
One theory is based on the idea that night-flying insects navigate according
to light from the moon or stars. Another idea is that insects fly to holes
on the horizon, such as between trees, which have a higher light intensity.
Either way, artificial lights foul up the system.
Entomologists have used this attraction to light to capture insects in
traps. Such traps use a light and a series of vertical fins over a funnel
that lead to a container. The insects headed to the light get diverted
into the container. The traps can be used to collect insects to gain specimens,
to determine presence of species or to estimate populations.
Bug zappers work in the same way, except the insects are killed by the
electric grid. How well do bug zappers work to eliminate unwanted insects?
Hold on to your hat. They don't! No research to date has shown that light
traps help reduce damage caused by insects.
But wait a cotton-pickin' minute. How can killing all those insects not
help out, even just a little bit, in the battle of the bugs? Think about
it this way. Most of the insects killed by the light trap aren't pests.
They are insects that just happen to be attracted to the light.
To be sure, some of the insects killed in the trap are pests. For instance,
June bugs. These insects lay eggs that develop into white grubs in the
lawn. But the problem is that the light trap attracts more beetles than
it ends up killing. The result is that more beetles end up laying eggs
in the vicinity of the trap than would have had the trap not been there.
So while some beetles are killed, more grubs are found in the lawn.
What about mosquitoes? Some mosquitoes are killed by light traps, but,
unfortunately, male mosquitoes are more likely to be attracted to light
than are female mosquitoes. And it is those biting female mosquitoes that
we really want to kill. In addition, several species of midges are also
killed in light traps. Midges resemble mosquitoes but don't bite. So a
light trap does not eliminate a biting mosquito problem.
So how many bugs does a bug zapper zap? Thousands per night on warm summer
days. But remember, you aren't solving any insect problems by using a
bug zapper. You just feel better for having killed a few thousand bugs!
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