Audibility Capacity of Mosquitoes
Male mosquitoes have a highly developed sense of hearing, though it is much different from that of humans. Male mosquitoes rely on their sense of hearing for breeding purposes. Because of the link between hearing and mating behavior, as well as their impact on human health, the hearing abilities of mosquitoes has been the subject of much study. The limit of mosquito hearing is approximately 2,000 Hertz.
Mosquitoes are equipped with two feathery antennae on their head, and they use these to hear. The antennae are attached at the base to circular structures called Johnston’s organs. Mosquitoes engage in an active, metabolically driven ...view middle of the document...
When they analyzed the synchronized tone of courting pairs, it was found to be approximately 1,200 Hertz. The researchers investigated the structure of the hearing apparatus, and found that the cells were responsive to frequencies as high as 2,000 Hertz. Mated females were found to be less responsive to the flight tones of males.
Ultrasonic Mosquito Repellents
Some commercial products exist that claim to repel mosquitoes by emitting ultrasonic sounds. Some radio stations also have tried broadcasting these ultrasonic sounds, thus repelling mosquitoes from their listeners. These sounds often are emitted at 15 kilohertz, which is above the upper limit of sensitivity for most adult humans, so it mostly goes unnoticed. Unfortunately, according to a review of 10 field studies by A. Enayati et al., published in a 2010 issue of “The Cochrane Library,” there is no evidence to suggest these devices repel mosquitoes. Bart Knols, advisory board chairperson for the Dutch Malaria Foundation and entomologist, echoed these findings, adding that there was “no scientific evidence whatsoever” to demonstrating the effectiveness of such devices. Knols went further, adding that mosquitoes aren't even repelled by the frequency produced from dragonfly wings. Predators of mosquitoes, dragonflies produce a flight tone of 20 to 170 Hertz, which is much lower than the tones emitted by ultrasonic repellant devices.
Nuguid, Mia Carmela P.
BSEd 3-B Physical Science
Assignment #3 (Dec. 01, 2015)
There are 15 species of hedgehogs, most of which are found in the wild in Africa, Asia and Europe. These little, rodent-like critters are covered in spines, which provide them a great deal of protection. Their eyesight is poor, but their keen hearing and sharp sense of smell help them get by quite well in the world.
No Glasses Necessary
Compared to humans, hedgehogs have poor eyesight. That's OK, however, because...