Dying Alone: Not Getting Laid Could Kill You Quicker

Getting laid is supposed to kill you. Or at least be more likely to kill you quicker than not getting laid. It's not always the hep C kind of risky, but sex and the whole process around it can be precarious in all kinds of ways for all kinds of creatures. Some spiders in particular seek out sex in ways that make them more susceptible to be offed by predators, like tarantulas in the American Southwest taking to the open desert during mating season. Australian locusts face a ten percent chance of dying the worst death imaginable while seeking mates: being paralyzed by a wasp and having its still-living body used as an incubation chamber for the wasp's eggs. That's just a sampling. There's all of the extra energy an organism wastes too. Our horny spider is also burning precious calories out there seeking love.

A study out in today's issue of Science magazine has some rather surprising and possibly frustrating news for common reproductive wisdom. The basic result is this: Fruit flies that sensed the sexual pheromones of potential mates but were unable to, you know, do it, were more likely to live shorter lives. The simple explanation is that, sans mating, they lost both their fat stores and their resistance to starvation, while experiencing an increase in stress. In the fruit fly world, these things mean you're probably gonna die soon, or at least sooner.

"It was really quite bad for the flies to perceive the females in the environment but not get anything out of it," Scott D. Pletcher, the study's senior author, told me yesterday. "Forty percent reduction in lifespan. It’s what caused us to keep looking at it. The effect was much larger than we can induce otherwise. Expecting sex without any sexual reward was detrimental to their health and cut their lives short."

Understand that this result was weird. Not getting any should make you safer as a creature on Earth: You're less exposed to danger while using less energy. Basically, selfishness should be safer than procreation, as weird as it is to think of refusing sex as selfish. But it is, or at least it's a certain strain of selfishness. Evolution has made tweaks as such to override that variety of selfishness, not just in making sex feel really awesome, but in terms of applying costs to not having sex in terms of longevity and health.

"These data may provide the first direct evidence that aging and physiology are influenced by how the brain processes expectations and rewards," Pletcher added in the study's accompanying materials. "In this case, sexual rewards specifically promoted healthy aging."

It's possible, however, to generalize this sort of behavior outside of sexual rewards/frustration. "Are there other things that can work like mating does?" Pletcher continued in our interview. "I can’t say for sure but one of the things that seems to be coming to light is that these mechanisms are related to just general reward. In our case, that seems to be relating to mating reward. These mechanisms that make us feel good and that reinforce animal behavior have roots in many different types of inputs. Work that was not done by [our team] but by another lab found that when males courted females and were rejected, they strongly preferred alcohol."

In a previous study, Pletcher showed that it's possible to speed up aging by presenting fruit flies with only the smell of food, and not the food itself.

"[The research] says there are many ways to satisfy a craving for a reward, and this is sort of the basis for addiction," Pletcher added. "You can get addicted to cocaine, but we’re also susceptible to many other things, [like] gambling. Gambling can produce those same reward mechanisms. Mating is just one of many different mechanisms by which we can cause these kinds of positively reinforcing behaviors."

Again, we're only talking about fruit flies at this point. Sex, we know well enough, has many different sorts of health benefits and you should be doing it right now. But a study like this using sex pheromones and longevity factors is yet to materialize for human beings. "Humans are out of my realm, but demographers have recognized for many years that a person’s social environment—whether they’re married or not, the nature of their friendships—these are things that have big effects on how healthy you are and how long you live," Pletcher explained. "But no one has really come up with a mechanism of how that could work. So I’m hoping that these results would give the human biologists some sense of what they could test."

@everydayelk