Effect of indomethacin-treated wheat on a wild population of montane voles

Semiweekly mark and recapture livetrapping was conducted July-October 1985 to determine the effectiveness of wheat treated with indomethacin, a prostaglandin synthetase inhibitor, to control the productivity of a wild population of montane voles (Microtus montanus) in southeastern Idaho. Before treatment, control (C) and experimental (E) groups, each on ca 0.3 ha, were statistically equal in population size (x̄ ± SD; C = 50 ± 21, E = 45 ± 14), adult female: male ratio (C = 1: 0.8, E = 1:0.7), juvenile: adult ratio (C = 0.16:1, E = 0.13:1), number of juveniles per 100 females (x̄ ± SD; C = 27 ± 8, E = 21 ± 18), and percentage of pregnant females (x̄ ± SD; C = 44 ± 10, E = 46 ± 17). After the 15-week experiment all population categories were unchanged for the control group and significantly (P ≤.05) lower for the experimental group, which ended with a final population of (x̄ ± SD) 17 ± 6, with 7 ± 21 juveniles per 100 females and an 11 ± 14% pregnancy rate.