This is the continuation from the series LANGUAGE OF ANIMALS-
If you haven't read the first part yet, you can click in the given link :https://penyourthoughts24x.wixsite.com/pendownthoughts/post/language-of-animals-part-1
There comes the rainy season and along with the petrichor, we have a whole lot of frogs croaking everywhere.
We all know why, right?
Because this is the time they mate!!
Also remember hearing crickets making a hell lot of noise at night, especially in summer?
What might be just noise to you is actually music to them.
Yes, crickets sing!
Let's peep into how acoustic signaling systems are subject to strong pressures of sexual selection!
Frogs🐸🐸🐸
Each frog species produces distinctive calls that facilitate pre-mating reproductive isolation and thus speciation.
In many terrestrial species, a chorus of simultaneously calling males attracts females to breeding sites; reproductive females then "choose" and locate one male, using distinctive acoustic cues. Males compete with each other vocally and sometimes physically as well.
While most of the more than 5,000 frog species worldwide have eardrums that are flat on the side of the head, two frog species-Huia cavitympanum of Borneo & Odorrana tormota of China have eardrums recessed in the side of the skull, similar to mammals.
What is amazing is that these two frog species can thus produce & detect ultrasounds to avoid the interference of sound that is produced by rushing water in the lower-frequency range!
Well, there is also a significant point of difference between both these species!
The frogs in China produce very loud calls that are, at the same time, both audible and ultrasonic. In Borneo, however, the Huia cavitympanum produces some sounds that are purely ultrasonic!
Now, what about deaf-mute frogs?
They can't just be an evolutionary mistake!
The stubfoot toads, like many harlequin frogs, don’t have an external tympanum or a vocal sac.
Their calls(consisting mostly of a series of clicks)have an average volume of 72 decibels at a distance of 1 metre, which is quite feeble compared to 87-113dB. calls of other similar-sized frogs.
-This is covered up by the fact that these male stubfoot toads set up territories only 2 to 4 metres apart, so their neighbours’ calls should be audible!
-In the absence of a decent pair of ears, the toad may have turned much of its body into a listening device with the sound being absorbed through their skin & lungs.
Crickets🦗🦗🦗
Crickets sing to attract mates,
● to promote copulation, and
● in aggressive interactions with rivals.
Only males sing.
A sexually receptive female, upon hearing the “calling song” of a conspecific male walks or flies towards the sound source, a behavior known as phonotaxis. Once the male and female come into physical contact the male switches to a distinct signal, “courtship song”, which is part of a multimodal display that entices the female to mate. Males also sing “rivalry songs” during and, more typically, after winning, aggressive encounters with rivals.
How do they do this?
-Crickets sing by scraping the hardened edge (plectrum) of one fore-wing against a row of cuticular teeth (file) on the underside of the other wing. The resulting vibrations are filtered and amplified by resonant structures on the wings, resulting in the loud, musical tones that characterize cricket songs.
-Each scissoring movement of the two wings produces a single note or sound pulse, which consists of a series of harmonically related frequency components.
-In calling songs, the dominant frequency is usually the lowest harmonic (fundamental frequency) and, depending on the species, is generally in the range 3-8 kHz.
Courtship songs of many species contain two types of note:
● some, generally of low amplitude, that are dominated by the same fundamental frequency as calling song; and
● others, generally much louder, in which a higher harmonic is dominant.
The songs of different species are distinguished both by sound frequency and by the temporal pattern, or rhythm, with which the individual notes are produced.
So, the next time you hear them, you know someone is busy wooing their lady love.
image source- google