Let's start a little series on plants and pollinators, and see where that takes us. I can't guarantee I'll be able to identify all of the pollinators, but maybe some kind folks will identify and comment.
In this case, I believe this Sitka valerian is being visited by a hoverfly, a fairly common pollinator of plants. While population declines in pollinator groups such as bees and vertebrates get some press, the conservation status and potential effect of a decline in dipterans (flies and mosquitoes) is poorly understood (see: Kearns, C.A. 2001. North American dipteran pollinators: assessing their value and conservation status. Conservation Ecology 5(1): 5). Unfortunately, that likely isn't going to change soon, if this quote from the discussion section of that paper remains true:
"An attempt to document the conservation status of fly pollinators in North America reveals the need for further basic research into fly pollination systems, and into the natural fluctuations in dipteran abundance. The main impediment to implementing any of the large-scale studies recommended is that intensive collecting efforts produce large numbers of species that require identification. Fly species identifications are often difficult, and the number of fly taxonomists is limited."
Sitka valerian is native to western North America, where it is typically a plant of mid- to high-elevations in moist meadows and open subalpine forest. In some areas of the Thynne Mountain, where this photograph was taken, it was the dominant herbaceous species. Plants of Southern Interior British Columbia notes that First Nations groups often used the plant as a medicine or disinfectant.