A viral aphrodisiac. Like, literally – a virus that makes sexytime happen. Then it kills you….

Unfortunately (or maybe fortunately), as NPR reports, it only affects crickets. They get infected, then want to have more sex, spreading the virus to more hosts:

Shelley Adamo and her team at Dalhousie University in Halifax have just discovered a virus that seems to have an effect kind of like that … in crickets. It’s called iridovirus and she stumbled across its aphrodisiac qualities accidentally.

When Adamo’s whole colony of crickets was accidentally infected with the virus (which also turns their guts blue, and kills them within a matter of weeks), she noticed, in passing, that in the days before they died their mating behavior seemed to increase.

Interestingly, the virus also appears to sterilize the crickets — which Adamo points out could be advantageous to the virus, because it means that instead of wasting time and energy producing eggs, the female crickets will continue to mate.

The virus (which is highly contagious) seems to need the crickets to mate. Without the mating, the virus can’t hop from creature to creature. Interestingly, it isn’t actually transmitted through the insemination — instead, the virus seems to pass from one cricket’s antennae into the other’s mouth.

Or, it could even be that the cricket itself, sensing it is sick, does a sort of Hail Mary attempt to spread its genes. Adamo says this behavior has been shown in many animals — insects, birds, even a few mammals — and is called “terminal reproductive investment.”

“When animals sense that they are very ill, they sometimes increase their reproductive output,” Adamo explains. “Basically, because they are about to keel over, they might as well go for gold.”

Whatever the explanation for how it happens, there are cases throughout the animal kingdom, it turns out, in which a virus or parasite influences a creature to mate more. In addition to crickets, the effect’s been shown in moths, ladybugs, midges and, most recently, rats. There’s also a sickness called Dourine — caused by the parasite Trypanosoma equiperdum — which, some scientists say, seems to increase mating behavior in horses.

Kinky.

[via Mr. Steinhoff]