A Study Of Infanticidal Behavior Of Reed Vole

Infanticide is the killing of conspecific preweanling yong and is found in many animals, such as spider, reptile, bird, mammal, even in mankind. Much of the early work in this controversial area assumed that infanticide was maladaptive and symptomatic of abnormal or sociopathologic conditions in nature or laboratory. In recently years, however, a prominent new view of infanticide, that is sexual selection hypothesis, has emerged: such behavior can be adaptive and routinely occurs as a reproductive strategy in a variety of animals. Evidence supporting this hypothesis largely consists of inferences derived from witnessed attacks which disappearance of infants in a variety of ptrimates, carnivores and rodents in the field. And in the laboratory this hypothesis is also supported largely by the experiments on rodents, especially house mouse and brown rat. However, there are few reseaches on the infanticidal behavior of reed vole.This study observes the infanticidal behavior of reed vole, Microtus fortis fortis Buchner captured in the fields of Qing Tongxia city, Ningxia Hui Autonomous Region in its different reproductive states.The results shows that males and females voles without sexual experiences all infanticides. And the difference of infanticidal frequence between the males and the females is not significant. Most infanticidal voles immediately attacks pups after noticing them. And they often bite heads of pups and induces victims' death in a short time. After mating, most infanticidal males stops infanticiding and exhibit ignorance or care behavior toward unfamiliar pups. However they do not resume infanticidal behavior after their youngs can live independently. All the infanticdalfemales feed their youngs, even show parental behavior towards unfamiliar pups after parturition. And many females start infanticiding again after their yongs' ablactation.The males stops infanticiding after mating and the females stops infanticiding, so it is impossible for them to kill their youngs. Microtus fortis fortis Buchner is polygamous. Male vole mates with several females, and the parenthoods between male voles and their offsprings are uncertain!. So copulation can inhibit infanticidal behavior of males. On the other hand, Microtus fortis fortis Buchner mainly reproducts in spring and summer. Furthermore, young voles do not mature sexually or remains inactive after reaching seual maturation in the same year they are given to birth, so they will reproduct in the next year. Maybe when pups ablactate, the males are not in their reproductive period. So they do not infanticide even after their pups can live independently, and they will probably infanticide again in the next reproductive period. In contrast to the males, the females infanticide again after their youngs' ablactation. Maybe this is related to the difference of reproductive invest between the males and the females. The females invest much more than the males. So as a reproductive strategy, it is renewed in the females after pups ablactate.