A previously unknown population of vampire moths has been found in Siberia. And in a twist worthy of a Halloween horror movie, entomologists say the bloodsuckers may have evolved from a purely fruit-eating species. Only slight variations in wing patterns distinguish the Russian population from a widely distributed moth species, Calyptra thalictri, in central and southern Europe known to feed only on fruit. When the Russian moths were experimentally offered human hands this summer, the insects drilled their hook-and-barb-lined tongues under the skin and sucked blood. Entomologist Jennifer Zaspel at the University of Florida in Gainesville said the discovery suggests...