BUMBLE BEE ALTERNATIVE
CONNIE STUBBS, UNIV. OF MAINE

Bumble bees are a very good alternative to honey bees for wild blueberry
pollination. Research conducted by Connie Stubbs and Frank Drummond,
Biolog. Sci. Dept., Univ. of Maine, indicate that the commercially
available bumblebee, Bombus impatiens, is an excellent pollinator of wild
blueberries.

Field observations of the commercial bumblebee and honeybee indicate that
the bumblebee forages on blueberry even in moderately-heavy rain, whereas
the honeybee does not. Bumblebees also start foraging earlier in the
morning and visit flowers at cooler temperatures than honeybees.

Stubbs and Drummond conducted a 3 year study (1996 - 1998), which compared
pollination efficiency at different stocking densities of bumblebees to the
"recom-mended" stocking density of 3 honeybee hives per acre. Stubbs and
Drummond found that stocking bumblebees at 3 colonies per acre produced
significantly higher fruit set than stocking with honeybees. Percentage
fruit set was 73% for Bombus imatiens versus 49% for honeybees. Also
significantly more berries were harvested from counted flowers on marked
stems in fields with bumblebees. The percentage of flowers that produced
harvestable berries was 41% in fields with bumblebees as compared to 26% in
fields with honeybees. Berry weights were similar for the two species.
For bumble-bees, the average berry weight was .48 grams and the average
seeds per berry was 38.7. For honeybees, the average berry weight was .46
grams and average seeds per berry was 39.1.

In 1998, the average price of honeybee hives was $50, which increased from
1995 from $10 - $14 per hive. The bumblebees for field pollination are
sold in units of 4, termed "quads" because each quad contains 4 colonies.
In 1998, the price per bumblebee colony, if purchased in bulk (50 quads or
more), was $70 to $280 per quad.

(Source Univ. of Maine Wild Blueberry Newsletter, Jan., 1999)

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