Soybean and Bees

Table 5. Differences on yield components of soybeans due to presence or absence of bees.
Treatment Total beans (n) Filled pods (n) Thrashed beans (n) Empty pods (%)
Bees 782*** 332*** 664* 15.7**
No bees 643 276 577 18.6
Open field 889 386 813 10.7
*, **,*** Bees/no bees comparison significantly different at the 0.2, 0.1, and 0.05 levels, respectively.
Source: Erickson, 1976.
In Kansas, yield in soybeans cv. Forrest grown in cages containing bees were 20% greater
than in cages without bees (Kettle and Taylor, 1979). Yield increases in two varieties tested
over 3 years in Delaware ranged from 2.2% to 16.0% in cages with honeybees versus cages
without bees (Mason, 1979). Sheppard et al. (1979) found out that honeybee populations
that appear adequate for hybrid seed production have been achieved by stocking soybean
fields with one hive per 0.72 hectare.
Jung (2014) found no differences on the yield among field open soybeans or caged soybeans
(with and without honeybees inside the cage), but caged experiments conducted by Erickson
et al. (1978) in Arkansas and Missouri, resulted in up to 16% increase on the yields when
honeybees were introduced in the cages.
In North Parana, Southern Brazil, Chiari et al. (2005, 2008) evaluated the effect of the honeybee
pollination on production and quality of soybean seeds, concluding that seed production
was higher in covered areas with honeybee colonies (51%) and uncovered areas (58%) than
in covered areas without honeybee colonies. The pod number in covered treatment with
honeybees was 61% higher as compared with the covered treatment without honeybees.
However, the average weight of 100 seeds was larger in the area covered without honeybees.
The study of Chiari et al. (2008), established that the soybean yields in the covered area with
honeybees (2.757 kg/ha) and in the uncovered area (2.828 kg/ha) were higher than in the
covered area without honeybees (2.000 kg/ha). The number of pods/plant was greater in the
covered area with honeybees (38) and in the uncovered area (32) as compared to the covered
area without honeybees (21), but no difference was found for the seed weight or its germination.
In Ceará, Northeastern Brazil, Milfont et al. (2013) refer increments in soybean yield of 18.1%,
comparing open area with free access to wild pollinators, plus introduction of honeybees,
as compared to caged pollinate-free soybeans. When honeybees were not introduced in the
88 SoybeAn and bees