BREEDING BIOLOGIES, POLLINATORS, AND SEED BEETLES OF TWO PRAIRIE-CLOVERS, DALEA ORNATA AND DALEA SEARLSIAE (FABACEAE: AMORPHEAE), FROM THE INTERMOUNTAIN WEST, USA

摘要

Two prairie-clovers, Dalea ornata (Douglas ex Hook.) Eaton & J. Wright and Dalea searlsiae (A. Gray) Barneby, are perennial forbs found sporadically in the U.S. Intermountain West. Their seed is desirable for use in rangeland restoration. We experimentally characterized the breeding biologies of D. ornata and D. searlsiae in a common garden, surveyed their pollinator guilds, and sampled their seed predators. The 2 Dalea species, being primarily xenogamous, have comparable pollination requirements. For flowers manually pollinated with outcross pollen, an average of 42% of D. ornata flowers and 39% of D. searlsiae flowers yielded plump large seeds filled with endosperm. Both species proved to be self-compatible, but far fewer seeds resulted from either manual pollination with self-pollen (11% seed set for D. ornata and 7% for D. searlsiae) or unassisted autogamy (5% and 6% seed set, respectively). Limited surveys of the prairie-clovers' pollinator guilds in ruderal or cheatgrass-infested habitats revealed sparse visitation solely by wild bees, primarily of the genera Anthidium, Colletes, Bombus, Eucera, and Melissodes. Beetles (Acanthoscelides oregonensis Johnson and Apion amaurum Kissinger) infested seed sampled from 18 of 25 D. ornata populations across a 3-state region. Productive farming of the seed of these prairie-clovers for rangeland restoration in the western United States will require supplementation of bees for pollination and exclusion of seed beetles.