ONLY FOR TODAY SPECIAL PRICE!! Scare mosquitoes with ultrasonic sounds! Keep this application in background for keep mosquitoes and all others small insect far away from you. Many insects have good ultrasonic hearing and most of these are nocturnal insects listening for echolocating bats. This includes many groups of moths, beetles, praying mantids and lacewings. Upon hearing a bat the insects will make evasive manoeuvres to escape being caught by the bat. Ultrasonic frequencies trigger a reflex action in the noctuid moth that cause it to drop a few inches in its flight to evade attack.
Tiger moths also emit clicks which may disturb bats' echolocation, but may also in other cases evade being eaten by advertising the fact that they are poisonous by emitting sound.
Ultrasound generator/speaker systems are sold with claims that they frighten away rodents and insects, but there is no scientific evidence that the devices work. From wikipedia.