Pity the poor peacock. He can truss himself up in iridescent blues and greens built of billions of intricate, light-catching nanostructures in the feather barbules; he can fan his train of tail feathers that open their hundred eyes to a peahen like an adoring audience; he can coo, bob his head, and shiver so that he positively glimmers like blue bonfire in the forest; and still, the female — who isn’t even that hot — can sniff and walk away. He is the product of millions of years of sexual selection for extravagance, and possesses the most spectacular, show-stopping plumage in the world, but he is far from irresistible. Having seen plenty of peacocks in my life, nowadays I’m more intrigued by the peahens and their discerning gaze. So frustratingly fickle! So charmingly coy! It’s that pickiness that has undoubtedly driven the male to such desperate majesty.
Who hasn’t felt a little like a peacock at times, trying their best to be noticed by the object of their affection and falling short no matter what? What am I doing wrong?, I’ve asked myself. What am I missing? What could she possibly be looking for? I find myself sympathizing with the peacock and his unrequited attempts at winning love on the zoo lawn, coldly rebuffed time after time until he’ll display for any toddler in a pair of brown overalls. Because peacocks look more or less equally fantastic to us, we can’t imagine why a female chooses one and not another. Some guys just don’t have it, the biologists tell us, after a peahen takes a pass on a shimmering fountain of male grandeur. Not wanting to guess the mind of a peahen, they throw up their hands and decline to say what “it” is. That certain something that captures the peahen’s heart. That je ne sais quoi.
Well, to hell with that! Je veux savoir “quoi”! If the peacock can look like that and still get shot down in flames, unless it possesses that je ne sais quoi, I think I speak for males of all species when I say I sure as hell want to know what the “quoi” is.
Instead of a peacock, let’s talk about its simpler, arachnid analogue, the Peacock Spider. I recently discovered this charming little guy via the famous and fabulous Myrmecos blog, the hot place to be for gorgeous insect photos and bug scuttlebutt. Like its namesake, the Australian peacock spider females are dun and its males garish, with an amazing technicolor dream-abdomen that fans out like a peacock’s tail. Like the bird, the peacock spider male does a display dance for the cautious and picky female, though his involves waving his third pair of legs in the air as if to say, “Hey, baby! Hey! Over here!”
A note on spider vision: despite having eight (and occasionally a mere six or four) eyes, most spiders rely on them very little. Among spiders who spin webs, the most important sense is, perhaps unsurprisingly, touch; they sense vibrations extremely well, but their eyes are used primarily to detect differences in light and dark. However, the jumping spiders (Salticidae) such as the peacock spider actively chase their prey. Therefore, they are usually diurnal and all have excellent vision; their depth perception helps them leap twenty times their body length with astounding accuracy, and their color vision extends into the ultraviolet, which is invisible to us. (Many jumping spiders have tetrachromatic color vision; they have four color-detecting cone cells where we only have Red, Blue, and Green.) So the peacock spider’s diurnal lifestyle gave rise to its visual courtship displays, and part of that je ne sais quoi that makes some spiders more attractive than others might have to do with an ultraviolet aura we cannot even perceive.
Is that the case? We don’t know. But there is someone working on it! Her name is Madeline Girard, a biologist at UC Berkeley, and she is using laser vibrometry, microspectrophotometry, and other things you and I have never heard of and probably cannot hope to understand, just to figure out which component of the peacock spider’s display is the most effective one. Ms. Girard believes that the answer is not one trait, but a combination of traits. I will be checking in with her as her research progresses. Let’s all wish her luck and hope she comes to some helpful conclusions about the origins of male peacock spider panache.
The idea that it is not one trait but a combination of traits seems logical to me. After all, a peacock isn’t judged solely on its feathers, though that ultraviolet aura might once again play a part, and the peahen does judge the male based on the number of eyespots on the tail. But technique, duration, and size all play a part. (Amiright, ladies?) She also judges him on the frequency of displays; there is a positive correlation between how often the male shakes a tailfeather and how often he gets some tail. Sexiness, and the precious genes for sexiness that that sexiness implies, isn’t just in the fancy plumage, but in the good physical health to be able to flaunt them often. Just showing you’re willing to work hard to win her goes a long way towards proving your worth. So here’s a note to all the displaying males out there, bird and spider and human alike: Don’t worry if your plumage doesn’t impress the ladies right away. In the end, persistence pays off.