The mechanisms that some viruses employ to infect their hosts could easily be characterized as "clever." There exists a virus, for instance, that makes caterpillars climb treetops, where they die and scatter virus-infected particles into the environment below. Rabies is another good example, because making a host bite other mammals is an excellent way to ensure that the virus gets passed on. But for the most part, these viruses aren't transmitted through sexual contact. So, the news that a virus that infects crickets during copulation also makes them want to have more sex is pretty remarkable. And, as Metro News reports, the virus doesn't just make crickets mate, it also renders them unable to reproduce.
The body cavity was swollen and bluish in color
Shelley Adamo, a biologist at Dalhousie University in Canada, first discovered the virus, called IIV-6/CrIV, when a few of the crickets housed in her laboratory stopped laying eggs. Concerned, she decided to open one of the female crickets that had become infertile. What she found was "shocking," she told Metro News, because the body cavity that usually houses the female's eggs was now swollen and bluish in color. "This female was not a little sick, she was a lot sick," Adamo said. Further research, published in The Journal of Experimental Biology, revealed that males were also affected. Their sperm, Adamo said, had become too slow to be of any use.
What the researcher found even more striking, however, was that the crickets were also mating more frequently than before. Moreover, the virus wasn't preventing them from moving or eating normally.
The crickets just spend a lot of time mating
Adamo thinks that the virus increases the crickets' desire to mate in order to spread more quickly through a population. And the insects' otherwise normal behavior hints that the virus might also affect their genomes by severing the signaling pathways that activate the immune system. "It's forcing the host to make viral proteins and suppressing the expression of immune-related proteins," Adamo told Metro News. So instead of becoming lethargic and eating less, the crickets just end up spending a lot of time mating.
The researchers admit that they don't know very much about how the virus works. But further research could yield interesting human applications. After all, human STDs are also largely asymptomatic, so they might suppress our immune systems in much the same way. If researchers can figure out exactly how this cricket virus does its dirty work, scientists might be able to develop therapies that can awaken human immune systems during STD infections — and help us fight back.