Cypripedium fasciculatum, the Clustered lady’s slipper orchid is one of three endemic Cypripedium species in the Western United States whose pollination mechanisms, until now have been unknown. The Northwest Forest Plan designated C. fasciculatum a ‘Survey and Manage’ species. Therefore, information on the pollinators of C. fasciculatum could aid land managers involved in the preservation and/or management of Cypripedium habitat. This research sought to determine the pollinator(s) of C. fasciculatum, and to understand the floral phenology of C. fasciculatum as it relates to pollination. In 1999, insect activity, floral phenology and pollen removal were monitored at two southwestern Oregon Cypripedium sites. This study is the first to document a pollinator of C. fasciculatum and represents the first record of parasitic diapriid wasps as pollinators. Diapriids parasitize dipteran hosts including fungus gnats (Sciaridae) which were the most prevalent insects collected in the study sites. The relationships between diapriids, their insect host(s) and C. fasciculatum will be addressed in future research.

Key words: Cypripedium fasciculatum, diapriid wasps, pollination, rare orchid