OSMIA (HYMENOPTERA, MEGACHILIDAE) DIVERSITY AT A SITE IN CENTRAL COASTAL CALIFORNIA

Thirty species of the megachilid bee genus Osmia were recorded at a re search reservation in central coastal California during two survey per iods: 1937-43 and 1987-92. Diversity remained constant at 23 species b etween surveys. However, cumulative diversity increased from 23 to 30 species. The total number of species at this geographic locale is rela tively high when compared with nine other surveys but is most typical of diversities found at other montane, mid-elevation latitudes. Differ ences between study periods suggest that long-term surveys are require d to accurately assess species diversity.