Abstract:
Many cranberry growers on the Oregon coast are well aware that good pollination is necessary for quality fruit set. Multiple
visits to the flower deliver more pollen, which can increase the percentage fruit set, number of seeds per berry, and mature
berry weight. The better a bee is at delivering pollen to the flower, the fewer the number of visits required for adequate
pollination. Typically growers rent hives of the European honeybee for cranberry pollination. However, honeybees have
exhibited a general preference for lotus, gorse, other weeds and native plants over cranberry flowers. As a result, growers
must bring in enough hives to saturate the surrounding area so that at least some of the honeybees will have no choice but to
forage in cranberry beds. In addition, honeybees forage primarily in fair weather. Multiple studies have shown (and many
people have observed) that honeybees will retreat to their hives once it begins to rain. Often, they will retreat even when the
skies become overcast, which is not ideal behavior for working in stormy coastal weather. Further, with the recent concerns
about Colony Collapse Disorder, attack by mites and other diseases, the supply of available hives has decreased. This
shortage brings to light the need for an alternate pollinator—a native species that is not susceptible to the ills of honeybees.
In the Pacific Northwest, there are over 200 species of native bees. Those species native to Oregon are acclimated to Oregon
weather. Several species of bumblebees begin foraging hours before honeybees are active, and cease foraging at dusk when
the honeybees have already been inactive for an hour or two. The advantages of having bees forage longer hours are
obvious—the more time they spend foraging, the more flowers they will pollinate. In addition, Oregon's native bee species are
often sighted foraging when it is drizzling while the warm-weather preferring honeybees are in their hives.
Currently, little is known about the number and diversity of bee species present on the southern Oregon coast. This information
is required for determining whether a better pollinator than honey bees is available for cranberries. By determining which
species are present during bloom it will be possible to select a species that flies during bloom, and one that is also loyal to
cranberries.
