Influence of brood, vent screening, and time of year on honey bee (Hymenoptera: Apidae) pollination and fruit quality of greenhouse tomatoes.
Greenhouse tomatoes, Lycopersicon esculentum Miller (Solanaceae), are autogamous, but facilitated pollination results in increased fruit size and set. Previous research examining honey bee pollination in greenhouse tomato crops established that fruit quality resulting from honey bee visitation is often comparable to bumble bees (Bombus spp.) and significantly better than in flowers that receive no facilitated pollination. However, management alternatives have not been studied to improve tomato fruit quality when honey bees are the only pollination option available for the high-value greenhouse industry. We investigated whether the quantity of brood (eggs, larvae, and pupae) in a honey bee colony in the winter and screening on greenhouse vents in the summer would encourage honey bee foraging on tomato flowers. We also established the influence of time of year on the potential for honey bees to be effective pollinating agents. We constructed small honey bee colonies full of naive forager bees with either two frames of brood ("brood colonies") or two empty frames ("no-brood") and compared total fruit set and the number of tomato seeds resulting from fruit potentially visited by honey bees in each of these treatments to bagged flowers that received no facilitated pollination. There was no significant difference in the quality of fruit resulting from honey bees from "brood" and "no-brood" colonies. However, these fruits produced significantly more seeds than bagged flowers restricted from facilitated pollination. Honey bees from brood and no-brood colonies also resulted in 98% fruit set compared with 80% fruit set in bagged flowers that received no facilitated pollination. During the summer, the number of seeds per fruit did not differ significantly between unbagged flowers potentially visited by honey bees in screened greenhouses and unscreened greenhouses and bagged flowers that received no facilitated pollination. However, time of year did have a significant influence on the quality of fruit produced by honey bees compared with flowers that received no facilitated pollination, because no difference in seed number was observed between the treatments after mid-April. The results from this study demonstrate that the management of brood levels and vent screening cannot be used to improve the quality of fruit resulting from honey bee pollination and that honey bees can be a feasible greenhouse pollination alternative only during the winter.
Department of Biological Sciences, Simon Fraser University, 8888 University Dr., Burnaby, British Columbia, Canada. sholly@uoguelpha.ca
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Sabara
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Gillespie
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Winston
D000383:Agriculture / Q000379:methods*; D000818:Animals; D001516:Bees / Q000254:growth & development / Q000502:physiology*; D035264:Flowers / Q000502:physiology; D005638:Fruit / Q000254:growth & development*; D018551:Solanum lycopersicum / Q000254:growth & development*; D011058:Pollen / Q000502:physiology*; D011786:Quality Control; D012621:Seasons