Meadow Vole Essay

Prairie voles are monogamous organisms where both parents are involved in rearing their young. Meadow voles, a closely related species, are polygamous where the mother is the only parent involved in rearing the young. Lim et al. (2004) determined that dopamine and vasopressin are key hormones in regulating social behaviors. Elevated levels of vasopressin V1a receptor (V1aR) was discovered to cause the differences in behavioral differences between the prairie vole and the meadow vole. Dopamine receptors were determined to not differ in the two species, but it is necessary for V1aR modified meadow voles to display partner preferences (Lim et al. 2004).
V1aR was expressed in the ventral palladium of meadow voles through viral vector-mediated
The first control (control-vp) was injected with a vector that expressed lacZ in the ventral palladium. The second control (control-other) was given a viral injection to a different part of the brain. The tested group (V1aR-vp) was injected in the ventral palladium with a vector that expressed V1aR (Lim et al. 2004). The three groups placed in a pen with a sole female for 24 hours before being moved to a new pen with the same female and a new female for three hours. After studying the time spent with each female, it was determined that the males in the V1aR-vp group chose to spend time with the original female vole than the newly introduced female. Lim et al. (2004) determined that the treatments given to the control groups had no effects on the social behaviors of the voles because these males had no preference to either of the introduced females. It was determined that partner preference was the cause of the additional time spent with the first female rather than just an affiliative behavior because the control groups spent less overall time huddling whereas the V1aR-vp group spent equal amounts of times with the second introduced female as the control groups (Lim et al.