Our Better Nature: Mating Is Wild

Meeting romantic partners has always been fraught with issues like the fear of rejection and maybe angst over an ill-timed acne outbreak. With over half of U.S. couples having met online, singles have more potential mates from which to choose, although having too many options can itself cause stress.

At first glance, wild animals have it easy when it comes to finding mates. When female spongy moths are in the mood, they just release a few molecules of sex pheromone, and guy moths flock to them, eager to please. No dating profiles needed. And when a male white-tailed deer encounters a female during her estrus or heat cycle, she’ll hook up with him even if he doesn’t take her to a nice restaurant first. Sounds refreshingly simple compared to our modern dating scene.

The downside for spongy moths is that within a few days, they all die. Most of their lives are spent as caterpillars, and their adult-phase romances are fleeting. For deer, the bucks get free-range sex for about two straight months, after which they’re celibate until the next fall.

While many species are all about hookups, what seems like emotional intimacy can be found in nature, too. Male and female great blue herons pair up exclusively all season, both helping to build the nest and feed the young, and the couple will coo and touch bills affectionately. However, these love-birds break up once their chicks are grown, finding new mates the following year.

Such troubles are petty when you consider the dangers of sexual cannibalism. Female black widow spiders and praying mantises often eat their male suitors right after, or even in the midst of, the mating process. The list of animals that lunch while they love includes a few snake species, notably the green anaconda, as well as scorpions.

Biologists don’t agree on what drives sexual cannibalism. Bizarrely, “mistaken identity” is on the list of possibilities. I suppose if Ms. Mantis swipes right on Mr. Hunk, and Mr. Mediocre shows up instead, that might set her off.

There’s also sexual parasitism, which is equally enticing. Anglerfish, with their needle-sharp teeth and weird fishing poles sprouting from their heads, are creepy by nature. Though many species ply shallow waters and have safe, if boring, sex, deep-sea anglerfish (found between roughly 800 to 8,000 feet down) have a mating ritual that’s beyond horrific.

For ages, only female deep-sea anglerfish were found. The missing-male puzzle resolved when a female turned up with her mate (males are much smaller than females) melded to her like a giant zit. This fusion-mating process was actually filmed in 2018. Here’s the scene: After the usual small-talk (I assume), the male anglerfish bites into the female’s underside and holds on. The female gradually absorbs the male, integrating his blood vessels so that he gets free nourishment. Whether in a state of intimate bliss or abject terror, he slowly melts into her until nothing’s left but his sperm factory, which becomes a permanent sex organ of the female, allowing her to lay fertilized eggs at will.

But males don’t always get the short end of the stick, so to speak. There are at least two kinds of spiders where males occasionally eat older females (I guess cougars don’t fare well in those species). Mating also doesn’t go well for female bed bugs, who actively avoid males. These nasty bugs mate through traumatic insemination, which is exactly what it sounds like. Male bed bugs inseminate females right into their body cavities after puncturing them, resulting in female injury and some deaths.

On the species level, sex is worth the numerous risks and costs because it leads to genetic recombination (in addition to offspring). Advantages include a more diverse, and thus more adaptable, genome. A new adaptation may help a species adjust to changing conditions, or allow it to exploit a novel food source.

All the same, quite a few species “decided” the fuss and muss of locating (and surviving) a mate was too much bother, and went to an asexual family plan where mothers make female babies from unfertilized eggs. It’s a clever trick called parthenogenesis (PG), meaning “virgin creation.” The term has the same root as the Parthenon, the ancient Greek temple dedicated to the goddess Athena Parthenos, or “Athena the Virgin.”

For a species, one of the benefits of PG is that critters can multiply a lot faster than through sexual reproduction, and by so doing, can take advantage of new habitats or food sources more quickly than their competitors. A number of insect species are parthenogenic, especially crop pests like aphids and scale insects. The list of animals known to make babies through PG includes some lizards, turtles, snakes, sharks, and at least one bird.

The downside of PG is that without genetic recombination, the only variety in the genome is from mutations caused by damage to DNA from chemicals, UV rays, or other factors. Parthenogenic species are less likely to successfully adapt to big changes brought by wildfires, floods, or the sudden loss of a favored food.

Given some of nature’s wild options for linking up with a mate, I’ll take the risk of duplicity and disappointment in online dating any time. Now if I can just learn how to photoshop my yearbook picture onto Hugh Jackman’s body for my dating profile, I’m sure I’ll get loads of hits.