Mating System Variation in Woodhouse's Toad (Bufo woodhousii)

Sexual selection and mating‐system variation was studied in two disjunct populations of Woodhouse's toad (Bufo woodhousii) with dissimilar breeding‐period durations. In spite of the differences in breeding‐period duration, nightly operational sex ratios were roughly equivalent and strongly male biased in both populations, ranging from 0 to 0.5 in the population with a prolonged breeding period, and from 0 to 0.2 in the explosively breeding form. Although operational sex ratios were similar, some males mated with up to three females in the population with an extended breeding period, whereas none of the males mated polygynously in the population with a short breeding season. Two alternative reproductive tactics, satellite and active‐searching behavior, were only exhibited by males under high densities in the population with a short breeding period. In the population with an extended breeding period, male mating success was positively related to call rate, but independent of size or number of nights of participation in chorus activity. Although operational sex ratios were equally low, mating was random by size, number of nights of participation in chorus activity, and call rate for males in the explosively breeding population. 1989 Blackwell Verlag GmbH