Research shows that two widely touted devices are worthless at best and, in one case at least, probably harmful. There are far better uses for your money.
Butterfly hibernation boxes. I am sorry to disappoint you about these ""butterfly roosts'' because nature stores sell them and I usually wish them well. Unfortunately the evidence indicates that they simply do not work as advertised. As Suse Greenstone, who monitored seven boxes for several seasons, remarks, ""So far, no butterflies, but spiders love them.'' (Spiders aren't all that bad after all, but I doubt that those who purchase the boxes are interested in their well being.)
A more ambitious test was carried out for Pennsylvania State University by David Wisniewski. He set out fifty boxes along woodland trails where mourning cloaks and other overwintering butterflies had been observed. After the first winter all he found was spider silk in eight of the boxes. The next year provided much more information: spider silk in 26 boxes, abandoned umbrella wasp nests in 7, cluster flies in 3, gypsy moths in 2, stink bugs in 2, ants in 1 and white-footed mice in another. Eight were empty; none had been used by butterflies -- a perfect record of sorts.
Are they used for roosting? Perhaps, but butterflies generally shelter under leaves and twigs, hanging with wings down, their slim profile offering little target for wind or rain.
If you want to protect butterflies, you would be wiser to plant a butterfly garden or stack your woodpile loosely.
(Claire Hagen Dole, editor of ""Butterfly Gardeners' Quarterly'', provided the information I have cited. Ms. Dole tells me that she will forward a sample issue of this informative publication to anyone who sends her a stamped, 32 cent, self-addressed business envelope at NABA, 4 Delaware Road, Morristown, NJ 07960.)
Electronic bug killers or repellers. The most common of these devices is a major contributor to suburban noise. Known as the bug zapper, it certainly kills as those loud sizzles attest. Its yellow glow attracts insects to a wire grid that electrocutes them. And if you don't accept the sound as evidence of its effectiveness, just look beneath the zapper at the piles of fried bugs.
Sounds good. Clear the air of those pesky mosquitoes and the backyards of our homes built in area swamps will be enjoyable once again.
Unfortunately evidence does not support these advertising claims either. Entomologists have sorted through thousands of dead insects collected under these devices and found virtually no female mosquitoes. (Needing protein for egg development, females are the ones that bite; males sip nectar from flowers.) On the other hand the entomologists found an overwhelming proportion of ""good bugs'': honeybees and predatory insects that prey on garden pests including mosquitoes.
But perhaps the most telling criticism of these devices is the experience cited by one entomologist who visited a factory where they were assembled. He came across a storeroom whose shelves were lined with chemical pesticides. ""Are these for comparative tests?'' he asked. ""Oh, no,'' his guide told him, ""we use them to get rid of the bugs around our buildings.''
But what about ultrasonic devices? Colorado is one of the few states that requires manufacturers to prove claims about their products before they are registered. In his evaluation of these ultrasonic devices and garlic based repellents for the state, entomologist Whitney Cranshaw says, ""Usually, the efficacy data submitted fails any reasonable scientific test.''
And now, as the News reported several weeks ago, we hear that bug zappers spray insect-carried, harmful bacteria in all directions.
So save your money.