South Africa- The well-established theory, which states that females instinctively prefer older males, is proven to be untrue by Professor Verburgt of the University of Pretoria. Female crickets have a preference for songs of younger males, Verburgt concludes.
He recorded the mating songs of 25 young and old male field crickets and analyzed them by length and frequency. The difference between the mating songs corresponded with the difference in age in such a way that younger males serenades were longer and at the same time, louder. To find which of the two the female cricket had a preference for, the researchers first had to create an average old and an average young serenade by mixing the recordings. They then used two audio-speakers to play the different serenades which let to the discovery that female crickets had a distinct preference for serenades with high energetic quality, which were the characteristic of the of young crickets’ serenades. Based on this, Verburgt concludes that age related degradation makes males less attractive for females; the muscles needed for the production of sound become weaker with age the sperm ages rapidly. Clearly older males are not always preferred by females.
Verburgt, L., Ferreira, M., & Ferguson, J. (2011). Male field cricket song reflects age, allowing females to prefer young males Animal Behaviour, 81 (1), 19-29 DOI: 10.1016/j.anbehav.2010.09.010