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. 2013 Jul 24;8(7):e69819.
doi: 10.1371/journal.pone.0069819. Print 2013.

Pollination services provided by bees in pumpkin fields supplemented with either Apis mellifera or Bombus impatiens or not supplemented

Jessica D Petersen  1 , Stephen Reiners, Brian A Nault
Affiliations

Pollination services provided by bees in pumpkin fields supplemented with either Apis mellifera or Bombus impatiens or not supplemented

Jessica D Petersen et al. PLoS One. .

Abstract

Pollinators provide an important service in many crops. Managed honey bees (Apis mellifera L.) are used to supplement pollination services provided by wild bees with the assumption that they will enhance pollination, fruit set and crop yield beyond the levels provided by the wild bees. Recent declines in managed honey bee populations have stimulated interest in finding alternative managed pollinators to service crops. In the eastern U.S., managed hives of the native common eastern bumble bee (Bombus impatiens Cresson) may be an excellent choice. To examine this issue, a comprehensive 2-yr study was conducted to compare fruit yield and bee visits to flowers in pumpkin (Cucurbita pepo L.) fields that were either supplemented with A. mellifera hives, B. impatiens hives or were not supplemented. We compared pumpkin yield, A. mellifera flower visitation frequency and B. impatiens flower visitation frequency between treatments. Results indicated that supplementing pumpkin fields with either A. mellifera or B. impatiens hives did not increase their visitation to pumpkin flowers or fruit yield compared with those that were not supplemented. Next, the relationship between frequency of pumpkin flower visitation by the most prominent bee species (Peponapis pruinosa (Say), B. impatiens and A. mellifera) and fruit yield was determined across all pumpkin fields sampled. Fruit yield increased as the frequency of flower visits by A. mellifera and B. impatiens increased in 2011 and 2012, respectively. These results suggest that supplementation with managed bees may not improve pumpkin production and that A. mellifera and B. impatiens are important pollinators of pumpkin in our system.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Relationship between fruit weight and viable seeds.
Fruit weight was positively correlated with the number of viable seeds (y = 0.86+0.01×, R2 = 0.75, P<0.001). Gray bands represent 95% confidence limits.
Figure 2
Figure 2. Effects of bee supplementation on fruit yield.
Pumpkin fruit yield (average fruit weight per plant ± SEM) was not statistically significantly different among the treatments (F 2,39 = 0.27, P = 0.77).
Figure 3
Figure 3. Effects of bee supplementation on flower visitation frequency.
Mean (±SEM) Bombus impatiens visitation frequency to pumpkin flowers in fields supplemented with B. impatiens, or Apis mellifera did not differ significantly from visitation frequency in control fields (A). Both years are combined here for simplicity. Mean (±SEM) A. mellifera visitation frequency to pumpkin flowers in fields supplemented with B. impatiens, or A. mellifera did not differ significantly from visitation frequency to flowers in control fields (B).
Figure 4
Figure 4. Relationship between yield and bee visitation frequency.
Relationship between fruit yield and flower visitation frequency by Apis mellifera in 2011 (y = 5.02+11.53×) (A), and Bombus impatiens in 2012 (y = 4.11+19.82×) (B). Supplementation treatment (circle = A. mellifera supplementation, triangle = B. impatiens supplementation, square = nonsupplemented) was illustrated to show the lack of pattern among treatment groups, reinforcing that the point that fruit yield was not influenced by supplementation with managed bees. Supplementation treatment was not included as a factor in these regressions.
Figure 5
Figure 5. B. impatiens visits to pumpkin flowers increases in warmer years.
Average accumulated growing degree days (AGGD), base 10°C from seven weather stations, starting January 1 through May 1, June 1, July 1 and August 1 for 2008 and 2009 (A), and 2011 and 2012 (B). Significant paired t-test results are indicated with an asterisk (*) above the column (P<0.05). In all significant pair-wise comparisons, 2008 and 2012, where B. impatiens visits to pumpkin flowers were greatest, were warmer than 2009 and 2011 respectively.
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References

    1. Klein AM, Vaissiere BE, Cane JH, Steffan-Dewenter I, Cunningham SA, et al. (2007) Importance of pollinators in changing landscapes for world crops. Proc R Soc B Biol Sci 274: 303–313. - PMC - PubMed
    1. Losey J, Vaughan M (2006) The economic value of ecological services provided by insects. Bioscience 56: 311–323.
    1. Aizen MA, Garibaldi LA, Cunningham SA, Klein AM (2008) Long-term global trends in crop yield and production reveal no current pollination shortage but increasing pollinator dependency. Curr Biol 18: 1572–1575. - PubMed
    1. Aizen MA, Garibaldi LA, Cunningham SA, Klein AM (2009) How much does agriculture depend on pollinators? Lessons from long-term trends in crop production. Ann Bot 103: 1579–1588. - PMC - PubMed
    1. Garibaldi LA, Aizen MA, Klein AM, Cunningham SA, Harder LD (2011) Global growth and stability in agricultural yield decrease with dependence on pollinator services. Proc Natl Acad Sci USA 108: 5909–5914. - PMC - PubMed

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