ENDOPHYTE-INFECTED AND UNINFECTED FESCUE SEEDS SUPPRESS WHITE-FOOTED MOUSE (PEROMYSCUS-LEUCOPUS) REPRODUCTION

Growth reproduction, circulation, and thermoregulation in domestic liv estock and laboratory rodents are adversely affected by consumption of tissues derived from plants infected with endophytic fungi. Because l ittle Is known about the systemic effects of infected diets on wild ro dent granivores, we conducted a series of laboratory experiments to as sess the effects of consuming endophyte-infected (E+) and uninfected ( E-) seeds of tall fescue (Festuca arundinacea) on reproduction in the white-footed mouse, Peromyscus leucopus. Groups of mice (paired and si ngle-sex) were fed diets of either rodent chow E+, or E-seeds; in seve ral experiments, chow and seeds were ground and mixed in a 1:1 ratio. E- seeds alone suppressed reproductive output compared to chew-fed mic e, bur consumption of E+ seeds did not further reduce reproductive per formance. Furthermore, paired testes mass was more strongly reduced by the presence of seeds in the diet than was the mass of the female rep roductive tract, but reproductive tract mass in both sexes was not fur ther diminished by endophyte consumption. These results suggest that m ales are more sensitive than females to the presence of seed in the di et, and that white-footed mice and related rodent granivores cannot re ly upon a diet of grass seeds alone to support reproduction. Depending upon the dme of year that such seeds are eaten, suppression of breedi ng may be advantageous to consumers.