| Summary: | 'Golden Delicious' winter squash (GDWS), Cucurbita maxima Duchesne,
provides significant amounts of pollen (24 mg) and nectar (236 μl), but with a low
reward of 14% nectar sugar. The quantity of nectar produced per GDWS flower
differed between sites and floral sex. The GDWS male flowers had 25% higher
sugar concentration than female flowers. There was no statistical difference in the
percent of nectar sugars per flower between sites, but the interaction between site
and floral sex was statistically significant for the amount of nectar and percent of
nectar sugars. Pollen production per flower differed significantly between sites
with the most productive site producing 27% more, and 45% more than the other
sites.
Pollination efficiency of honeybees and bumble bees was assessed with
field cages (1.8x1.8x1.8 m). No significant differences were found except for the
interaction between the bee treatment and year on number of fruit per cage. This
significant difference reflects the increase in fruit number produced by honey bees
in 1997.
The effect of distance from honey bee hives on fruit and seed quality was
tested, and found significant only for B- and C-seeds weight, which were both less
in the plots farthest from the nearest group of honey bee hives. Placement of honey
bee hives in fields of ≤120 ha appears not to be critical for adequate pollination of
GDWS. Other pollinators (excluding honey bees) were frequent visitors to the
squash flowers studied here - for example, Bombus spp., Megachilids, Halictids,
etc. These other pollinators, mostly bumble bees, accounted for 3.55% of all bee
visits.
Honey bees visited proportionately more female flowers in the morning,
and progressively switched to the more abundant male flowers in the afternoon.
This bias differed by site and year. Bumble bees visited proportionally slightly
more male GDWS flowers than did female flowers and did it in a similar rate
throughout the day. From 15 minute observations each hour of individual female
GDWS flower, we calculated that they received approximately 80 honey bee visits
per day. === Graduation date: 2001
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