Parasite Keeps Host Alive

Parasites are survivors. Take the Wolbachia bacterium for example. It kills male Trichogramma wasps (pictured), which causes a problem. When the male wasp dies, so does the bacteria. But this bacterium is very clever. Scientists have observed that Wolbachia, once inside the wasp egg, can feminize a male embryo, turning it into a female and assuring that both host and parasite live on.