Long frog love cries attract females and enemies
Scientists at the University of Texas can now explain in a little more detail the risks and rewards of two song variants with which male Túngara frogs wanting to mate advertise themselves as a worthwhile sexual object: The frogs rely either on a short, repeated, frequency-modulated whimper or an increasingly longer song of whimpers with short interspersed "chak" sounds to attract female frogs willing to mate.
Females are always more interested in the longer arias - but at the same time more predators and bloodsuckers locate the persistently shrill frogman. The frog researchers led by Michael Ryan therefore initially concluded that only particularly fit males could afford the associated life-threatening onslaught - which is why only fit males sing long instead of short, and at the same time provide quality-conscious females with an audible predicate indication that hungry bloodsuckers and predators simply take append.
In fact, their meticulous investigations did not provide any clear indication of a higher quality of the Lang singers, the scientists report: On average, the males were neither larger nor heavier or he althier - they were simply eaten more often.
As the researchers state, the longer calls are used more frequently when males are in the company of rivals: the competition forces the frogs on johns' feet to use longer songs to reduce their chances of finding a female and at the same time the risk of enemy contact. At the same time, a longer song for hungry frog eaters is a signal for a higher density of prey, according to Ryan and Co: The predators and parasites follow the whimpering not because of the quality, but because of the quantity of the local singing community. (yo)