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Showing posts with label Insects. Show all posts
Showing posts with label Insects. Show all posts

Jan 14, 2010

World's loudest insect

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The sound of the cicada love song can be deafening. In fact, it's the loudest song known in the insect world. Some species of cicadas register over 100 decibels when singing. Only males sing, trying to attract females for mating. Cicada calls are species-specific, helping individuals locate their own kind when different kinds of cicadas share the same habitat.

The Mating Call of the Male Cicada
The adult male cicada possesses two ribbed membranes called tymbals, one on each side of its first abdominal segment. By contracting the tymbal muscle, the cicada buckles the membrane inward, producing a loud click. As the membrane snaps back, it clicks again. The two tymbals click alternately.

Air sacs in the hollow abdominal cavity amplify the clicking sounds. The vibration travels through the body to the tympani, which amplify the sound further.

The Cicada Chorus
If a single male cicada can make a noise over 100 decibels, imagine the noise produced when thousands of cicadas sing together. Males aggregate as they sing, creating a cicada chorus. Together, the males sing and fly, landing on sunny branches near the tops of trees.

The Female Response – Wing Flicking
A female cicada that finds a male attractive will respond to his call by doing a maneuver descriptively called the "wing flick." As you might imagine, this involves a brisk movement of the wings. The male can both see and hear the wing flick, and will reply with more clicking of his tymbals. As the duet continues, the male makes his way toward her and begins a new song, called the courtship call.

The Alarm Call
In addition to its mating and courtship calls, the male cicada makes noise when startled. Pick up a male cicada, and you'll probably hear a good example of the cicada shriek. Similar to the mating call, the alarm call adds to the noise of the cicada population.

Dec 1, 2009

Why bugs are attracted to lights?

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Many insects are attracted to light, and some fly right into the light itself. Moths commonly hover around lights and are active at night. This attraction to light is a response called phototaxis.

When insects fly at night they use light sources such as the moon for navigation. Light from a distant source reaches both eyes with the same intensity. This enables the insect to fly in a straight line with both wings beating at the same rate.

If the light is from a closer source such as a candle or lantern, it changes the insect's perception. The light is perceived stronger in one eye than in the other eye. This causes the wing on one side to move faster. The insect then approaches the light in a spiral path, eventually drawing it into the light itself.

One good way to know if an insect is nocturnal is to look at their antennae. Insects with poor eyesight have longer antennae. Many varieties of beetles have poor eyesight. They use their antennae to move around safely at night.

Source: http://www.suite101.com/article.cfm/science_for_kids/11252