Nature’s Strangest Mating Rituals

October 28, 2015 | Sarah Tse

Male peacock spider (Maratus volans)
Photo credit: Jurgen Otto/Flickr (CC BY-SA 2.0)

Male animals practice some truly bizarre courtship rituals, all in the name of love — or rather, sex.

In every domain of life, males go to great lengths to grab the attention of females. Examples of absurd displays can be found throughout the animal world, as well as at the local bar. Given that reproduction drives all life, it’s no surprise that evolution has devised some pretty wild techniques to help guys score.

The throat fan of the Jamaican Gray Lizard (Anolis lineatopus) appears to glow when light passes through it from the back.
These translucent dewlaps catch the light in a way that just screams, ‘Pick me!’ Photo credit: Manuel Leal, Division of Biological Sciences

Jamaican Gray lizards seem to have it relatively easy. A recent study published in Functional Ecology analyzes their use of translucent flaps of skin on their necks, called dewlaps, to catch the eye of a cruising female. In the shady forests they inhabit, these dewlaps actually appear to glow by both reflecting and transmitting light. Extending their radiant dewlaps, combined with bobbing their heads up and down, helps these small lizards stand out from their visually noisy surroundings.

But Jamaican Gray lizards look pretty drab compared to other male mating displays. You’re probably familiar with peacocks, but have you ever seen a peacock spider strut his stuff? Male peacock spiders certainly live up to their name: to attract a female, they raise their vividly-colored abdomens and extend a pair of white-fringed flaps. On top of that, they wave their legs back and forth in an elaborate dance that’s simply irresistible to female arachnids. The dance of the male peacock spider is especially desperate because he risks being devoured by his prospective mate if she gets bored.

This dance is fueled by both arousal and mortal fear. Video credit: Peacockspiderman/Youtube

Other males rely on performance more than good looks to impress females. In many bird species, a female will only choose a male who has constructed a nest that passes inspection. The bowerbird takes this to the next level by spending hours arranging a complex tower of sticks decorated with whatever trinkets he thinks may appeal to his lady love, from snail shells to butterfly wings to poker chips.

 A male satin bowerbird (Ptilonorhynchus violaceus) builds its bower with blue things collected
The male bowerbird arranges his treasures like a path of rose petals leading to the honeymoon suite. Photo credit: Summ/Wikipedia (CC BY-SA 3.0)

These and other examples of courting rituals may seem a bit unfair for the gentlemen—why do they have to do all the work? As always, it all comes down to evolution. Females bear most of the grunt-work in reproduction, as they have to produce eggs full of nutrients that are energetically costly. As such, they want to pick a male who will maximize the return on their investment, by either providing for her and the kids or contributing superb sperm. She judges his appearance and mating efforts to determine whether he has good genes and survival skills.

Males, on the other hand, have plenty of energetically cheap sperm to spare, so their reproductive strategy is to get with as many females as possible, and to prevent other males from mating. Thus, the sexual dimorphism, or physical differences between the sexes, drives an intense rivalry between males. Some males even go so far as to stop their mates from hooking up with other males afterwards. Male roundworms do this by producing seminal fluid that actually shortens the life of the female after she has produced offspring, which removes her from the mating pool for other males.

On the other end of the spectrum, male anglerfish barely lift a finger to attract females. In the deep sea, anglerfish are so rare that even finding another one requires Herculean effort. So the males have evolved to conserve all their energy towards finding females: they’re born much smaller than females, often without fully developed jaws or digestive systems. But what they do have are huge eyes and a fine-tuned sense of smell, which helps them detect their glowing partners and any pheromones she may release in the deep, dark waters they inhabit.

Several species of anglerfish
Seven species of Anglerfish: a good-looking bunch. Photo credit: Masaki Miya et al./Wikipedia (CC BY 2.0). Images have been rearranged from original.

Once a male locates a female, the fun begins. He bites her skin near the pelvic region and releases an enzyme that dissolves the skin surrounding his mouth and her wound, fusing their bodies together and effectively turning him into a parasite. Now he’s set for life; he receives nutrients from her through their shared blood vessels, while providing sperm whenever she’s ready to mate. It makes evolutionary sense since neither of them are likely to find another mate, so they have better chances of reproducing more than once if they stick together—literally. It’s an incredibly creepy relationship, but their devotion to each other is sweet and inspiring.

Of course, human courtship rituals provide the most intriguing subjects of study. We can find the above behaviors, plus many more outlandish ones, replicated throughout our species—whether it’s excessive pruning and bodybuilding at the gym, or spending extravagant amounts of money on sleek new cars. But ladies, next time you’re about to crush some guy’s pathetic pick-up line, you should at least be grateful he’s not literally leeching off of you.

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