Cucurbit Genetics Cooperative Report 3:48 (article 28) 1980
Comparison of Squash and Honey Bees as Pollinators of
Vincent J. Tepedino
Utah State University, UMC 53,
Logan, UT 84322
Observations and experiments were conducted to ascertain
if the specialized squash bee Peponopis pruinosa
is superior to the honey bee Apis mellifera as
a pollinator of summer squash, Cucurbita pepo,
var. Italian Black Zucchini. The study site was the Greenville
Farm operated by Utah State University at North Logan, UT.
Natural populations of P. pruinosa have been recorded
there since 1953 and since honey bees are common, it was
not necessary to import hives for experimental purposes.
Three parameters contributing to pollination efficiency
are: 1) the number of visits necessary to achieve pollination,
2) the preference of the bees for staminate or pistillate
flowers, and 3) the average time spent foraging on a flower.
Bagging and controlled visit experiments showed individual
visits to pistillate flowers by each species to be equivalent.
Honey bees display a significant preference for pistillate
flowers; squash bees prefer staminate flowers. Squash bees
work the flowers more rapidly than do honey bees. When all
parameters are considered, there appears to be little difference
between the species as pollinators of squash. However, because
of their earlier diurnal flight periods, squash bees were
responsible for most pollinations before honey bees appeared
in numbers on the plantings.