TARGET ROLE: Natural pollination using bumblebees is an effective way of increasing profits and reduce labor costs. Bumblebees can increase crop production through more efficient pollination. Many crops are well suited to natural pollination with bumblebees, including; cucumbers, peppers, tomatoes, vegetables, seed crops, strawberries, blueberries, cane berries, melons & squash. Nectar produced by the flowering plants in the greenhouse is not always sufficient for the optimal development of a bumble bee population. For this reason, sugar water is supplied. Depending on the circumstances, the hive may be supplied with additional insulation.
DESCRIPTION: Bumble bees are easily recognized, being large (3/4 inch long) with black and yellow or orangish hair patterns on their abdomens. Queens and workers have pollen baskets on their hind legs. Bumble bees can be distinguished from carpenter bees because of the presence of orangish or yellow hair patterns on the upper surface of the abdomen on the honey bee. Some members of bumble bees (Subfamily Bombinae) in the genus, Psithyrus, are parasites of bumble bees, feeding on larvae.
LIFE CYCLE: New queens emerge during the late summer or early autumn. After mating and feeding to store fat reserves on their bodies for the winter, they will then hibernate. During early spring the following year, the new queens emerge to establish new colonies of their own. However, towards the end of summer or early autumn, again, new queens emerge from the colony she has founded. The rest of the colony, however, including the workers and the original queen, will not survive. All in all then, providing a queen is successful and is not killed by disease, pesticide or predators, she may live for about a year – part of this time being spent in hibernation.
Accounts of how long bumblebees live, do vary between species and studies. For example, Bombus terricola workers were observed to be 13.2 days on average – around 2 weeks. But in other studies, workers were observed to live for up to 41.3 days – about 6 weeks. It is believed that workers engaged in nest duties live longer than bumblebee workers whose main duty is foraging.
These bumblebees are of course more prone to predator attack, and are also exposed to varying weather conditions. It is not unusual to find a bedraggled looking bumblebee needing to rest and revive itself after having been caught in a shower.
RELEASE INSTRUCTIONS: Bee hives can be introduced when the first flowers open. In winter, a minimum of 2 hives per acre is used at the start of a round tomato crop. Follow up by two weekly introductions of approximately one hive per acre. When a crop starts in summer, more hives are needed at the start, minimum 4-5 per acre. It is recommended to place some extra hives in spring when the outdoor vegetation starts to flower, since this flowering makes a proportion of the workers leave the greenhouse
Place the hives (preferably) evenly distributed along the south-side of the main path in the greenhouse in order to have the maximum shade from the crop in summer. The best position is on a horizontal platform (avoid inclination, or else sugar solution may leak). Before opening the flight hole, allow the colonies to calm down a minimum half hour after placing on final position. Whenever possible, open flight hole when vents are closed to prevent loss of workers.
Best at ambient temperatures of 10-30°C/50-86°F. It may be necessary to provide extra shade (e.g. with styrofoam). The sugar solution that is provided with the hive is generally sufficient for the entire life of the colony. Secure the hive so that ants cannot enter it, (i.e. with a barrier of grease or insect glue). Also avoid contact between plants and hive, since this can also be a way for ants to reach the hive. If pollination is required during a longer period, regularly place new hives in the greenhouse.
STRATEGIC CONSIDERATIONS: Close CO2 lines in case they are close to the bumblebee hives. Let the colonies calm down for at least one hour after placement before opening the flight hole. Close and remove the colonies prior to the application of pesticides (if advised so by our consultant). Feed additional pollen in case flowers do not produce sufficient pollen. Adapt introduction schedule prior to heavy blossoming outside the greenhouse in spring. Watch out for continuous high humidities as a result of poor ventilation.