In the wild, frog romance is a raucous affair. When it\u2019s time to mate, the female Eastern gray tree frog makes her way to the pond, when there could be hundreds of potential suitors, each calling to her in loud chirps that have different audible characteristics.<\/p>\n
In this nighttime chorus, the male aims to charm the female with his particular call. But what makes a call \u201cattractive\u201d?<\/p>\n
On this episode of Curious Campus, we talk with two researchers who specialize in amphibian communication \u2013 how frogs message each other and then decide how to respond.<\/p>\n
Gerlinde H\u00f6ebel is an associate professor in biological sciences in 51ÁÔÆæ\u2019s College of Letters & Science. Michael Reichert is an assistant professor of integrative biology in the College of Arts and Sciences at Oklahoma State University.<\/p>\n
Below, they answer some questions about mating calls. Listen to the full show at W51ÁÔÆæ.com or on your favorite podcast app.<\/p>\n
Reichert: There could be hundreds of males out there calling on a good night. It\u2019s very dense and very loud. So, it\u2019s quite a challenge for the female to distinguish between them and try to find the male whose call she prefers.<\/p>\n
And we know that females tend to have preferences for certain types of call characteristics. And so, what we are trying to determine is why they have these preferences and also how they manage to then find these mates within the very chaotic chorus.<\/p>\n
Reichert: The pond is going to have far more males on a given night than females. If males are able to attract a female, then they\u2019re going to be able to pass along their genes to the next generation. Most females are only going to mate once a summer, but the males could be out there pretty much every night.<\/p>\n
H\u00f6ebel: Female frogs generally only come to the pond when they\u2019re ready to mate \u2013 that\u2019s when they already have a clutch formed, which can consist of hundreds or thousands of eggs. So that requires a lot of energy. It\u2019s really, really hard to do. So many females may only have the energy to produce one clutch a year, and maybe only once in a lifetime because so many of them just don\u2019t live very long. Most of them we collect are only a year old. That\u2019s because many get eaten. Frogs are a very important component of the food chain.<\/p>\n
H\u00f6ebel: We started by trying to find the characteristics that, on average, most females like best. Now we\u2019re interested in individual female preferences. And we\u2019re really surprised how variable those are. Even for things like call duration. Turns out, there\u2019s a sizable minority of females that don\u2019t think long calls are so hot. We\u2019ve found that almost half the female population we\u2019ve tested think that really fast calls are ugly. But others really love it. So the fact that some females have preferences that are complete opposites blew me away.<\/p>\n
H\u00f6ebel: The diversity in female preferences does relieve the pressure on males and keeps the variation of male calls alive because then everybody has some chance of success.<\/p>\n
Reichert: Sexual selection and natural selection are very powerful. Natural selection includes things that influence survival, like camouflage, but sexual selection is for attracting mates. Most of the things we find interesting about animals \u2013 their bright colors, impressive tails or the sounds they make \u2013 these are features related to mate attraction. And they have evolved because they allowed individuals to be more successful at attracting mates.<\/p>\n