Feature
A honeybee colony commonly contains 20,000 to 60,000 worker bees . Compare this to our tiny native stingless bees – Trigona sp . – whose colonies only reach 7,000 at most . Not only are such native bees harder to manage , you would need 7 – 9 colonies to replace a single honeybee hive .
variety to guarantee fruit set . Trees may still produce a few fruit with wind and visits by other insects , but bees are essential to get a commercial crop .
While flies , beetles , or other bee species can also pollinate flowers , honeybees truly reign supreme . This is because their furry bodies pick up and distribute pollen as they forage ; the prickly bodies of flies and smooth carapaces of beetles are far less efficient .
Bees are also extraordinarily active . One study found that honeybees foraging on plum trees visited nine flowers per minute , and 27 flowers per tree 1 . Only flowers that received at least three visits from honeybees formed fruit , with around 31 % of such flowers developing into a plum .
Managing bees
Bees collect both nectar and pollen . However , they usually collect only one of these at a time – they very rarely collect both at once . Nectar is food for bees , while pollen is food for the larvae .
The sugar content in nectar can range from only 5 % to 50 %. Unsurprisingly , the higher the sugar content , the more strongly bees will be attracted . The nectar content of flowers varies a lot depending on circumstances , including tree health and flower age .
Bees that aim to gather pollen visit young blossom . It is these flowers that really need their services , as the stigma ( female part ) of the flower must be fertilised . Stonefruit flowers only remain receptive to pollen for about three days after they first open – a relatively short window of opportunity for both tree and farmer .
Manipulating the colony so that bees actively seek out fresh pollen enhances fruit set . For example , trials using “ pollen catchers ” on hives , which rob incoming bees of much of their load , increased the amount of time bees spent foraging for pollen .
Unfortunately , stonefruit blossom is not a particularly good source of either nectar or pollen . If bees have better options they will go to them instead . For this reason , it is important to consider what else is flowering when the orchard blooms .
Inter-row plants and adjacent areas of native bushland that flower at different times can help keep wild bees and other pollinators fed , thus maintaining a base population in the area . For example , orchards next to rainforest areas have been shown to have better rates of pollination than orchards that are isolated from such natural refuges 2 .
1
Benachour K , Louadi K . 2013 . Inventory of insect visitors , foraging behavior and pollination efficiency of honeybees on plum in the Constantine area Algeria . Af . Entomol . 21:354-361 .
2
Blanch KR , Ludwig JA , Cunningham SA . 2006 . Proximity to rainforest enhances pollination and fruit set in orchards . J . App . Ecol . 43:1182-1187 . summerfruit . com . au December 2016 | Australian Stonefruit Grower 15