November 12, 2013
The Love Lives Of Fence Lizards
A particular breed of lizard has some specific mating desires according to April Flowers’ recent article on redOrbit. Fence lizards, also scientifically known as Sceloporus undulatus, are found in the eastern US and have an interesting relationship between body-color patterning and mating. In fact, in a study of the lizards, they found that male lizards are less amorous to females sporting the blue badges on their throats and abdomens.
See the male lizards have these and use them in courtship displays and aggressive encounters with rival males because the blue badges are linked to testosterone levels. This is pretty typical in animal, birds, and reptiles. The males are usually more brilliant in body-color patterning. This attracts females thus the most brilliantly colored (and often most potent in testosterone) males breed. In fence lizards, the females also have these badges, being dubbed the bearded ladies, which means those females with brighter, more prominent beards have higher testosterone levels.
The research team “captured 24 pregnant females and raised their young in the lab. They paired the lizards off randomly in order to keep track of the amount of time the males spent with each female.” They found that when given a choice, male fence lizards preferred females with less prominent beards. Now, that is not to say that the males would not mate with the more bearded ladies because they did; however, they would choose the more feminine look when able. In other words, the males did not say no to the bearded ladies when there was no other option.
Why is this? Well, Flowers writes, “National Geographic reports that there might be a good evolutionary reason for this preference. The study found that more blandly colored lizards laid more viable eggs — clutches that were heavier and had more nutrients. These females also lay earlier in the season, giving their brood more time to develop and therefore offering an important survival advantage. The males selecting more reproductively fit females are an example of classic sexual selection.”
Okay, but what is particularly interesting about this theory is that the researchers found that 76 percent of female fence lizards sport the beard. That is a vast majority of females. If these bearded ladies are not as reproductively fit, then why are they so dominant? Well, Flowers provides several possibilities:
- Fence lizards’ love lives are in evolutionary flux.
- The bearded ladies have more “brassy” attitudes thus they get their man, so to speak.
- All of the females find the blue beards attractive, so when they mate, their genes pass onto the males.
What a fascinating article with fascinating ideas. Who knew that the love lives of fence lizards could be so titillating? First of all, the fact that the female lizards have such colorful brilliance as the males is interesting since often in the wild, the males will shine, but the females are dull. Think of the cardinal: the male is red and stunning while the female blends in with the trees. She is still beautiful, but in a simpler, more earthy way.
The fence lizard females love those blue beards so much that they themselves sport them. That is great. Secondly, to know that the males prefer females with less blue and more bland yet the vast majority of females are bearded intrigues me. Finally, the speculation about just why the females sport those blue beards also fascinates.
So much to consider, so little time! Now, that’s a good article.
Image Credit: Thinkstock