A floral calendar for bee conservation

  • A Pune scientist has drawn up a floral calendar for beekeeping and conservation.
  • With a bee calendar developed for each district, beekeepers can move their colonies to areas where the bees’ favoured crops and plants are located.
  • Scientist K Lakshmi Rao, who has travelled across India to map the foraging behaviour of bees, says that factors such as climate change, cropping patterns and practices have disturbed bee activity.

Researcher K Lakshmi Rao is habituated to bee stings. And in her quest across India, to understand what whets the appetite of the honeybee (Apis mellifera), she has been at the receiving end of several such nips. The data (and her sting-riddled travel) helped shape a floral calendar for beekeeping, for the conservation of bee colonies in India where honey production has doubled in the last 10 years.

Rao travelled the length and breadth of the country from 2014 to map which crops the bees like best, the seasons during which these plants bloom, their migratory route, the plants’ nectar and pollen content and others such nitty-gritty details as part of a Department of Science and Technology (DST) project.

“Bee visits plants for its food, nectar and pollen and depending on nectar and pollen content they exhibit floral fidelity which means they favour specific pollen and nectar sources over others. They then communicate the message to the colony. So we need to have this information to help beekeepers,” Rao, assistant director, Central Bee Research and Training Institute, Pune, told Mongabay-India.

The Food and Agricultural Organisation of the United Nations defines a floral calendar for beekeeping as a timetable that indicates to the beekeeper the approximate date and duration of the blossoming periods of the important honey and pollen plants in their area.

“It basically shows what kind of flowers are available for the bees from January to December. Using the calendar, farmers and beekeepers can move and place their bee colonies accordingly for efficient nectar and pollen gathering,” Rao said.

Researchers at the apiary in the Sundarbans. Photo courtesy K Lakshmi Rao.


Out of the 87 most important crops that require pollinators for fertilisation to develop fruits and seeds, 62 crops provide pollen or nectar or both to the honeybees. Several oilseed crops of great economic value like sunflower, til, niger, safflower provide both pollen and nectar to honey bees. Likewise pulses, spices and fruit crops also provide forage to bees.

A. mellifera beekeeping is mainly dependent on agricultural crops. Agricultural crops are seasonal and provide bee forage for limited periods. Bee colonies cannot be sustained throughout the year in any cultivated area unless it has an integrated intensive agriculture, agroforestry and social forestry systems. During the gap periods between two crop seasons, bee colonies have to be moved to forest areas, Rao said.

“From the calendar, we can understand the potential of each state to sustain the number of bee colonies. We have compiled and plan to hand out 1000 state-specific copies of floral calendars in each state,” she said, adding the calendar for Uttar Pradesh is under process and she will visit northeastern states next year.

Chasing flowers across states

Explaining the methodology, Rao said the exercise spanned multiple disciplines like agriculture, social forestry, botany and geography. CBRTI representatives in different states helped her out with fieldwork.

“In natural forests, you should know what is the combination of the forest and you should understand what are the rare and which are the dominant species. The forests in northeast India are different from the forests in rest of the country so once I study about them, I plan to travel to northeast India next year,” she clarified.

Rao doled out some interesting bee trivia that helped craft the calendar. Nectar is the carbohydrate source for the honeybees while they get their protein from pollen.

“Only honeybees collect and bring the nectar and pollen to the hive. If the sugar content of nectar goes below 20 percent then they don’t make honey. They use it for own consumption. If the sugar content of the nectar is between 20 to 68 percent then they will make honey,” she said.

Rao recounts that her visit to the Sundarbans was one of the most challenging trips.

“I went to the islands three times because different flowers bloom in different seasons and I need to track them down,” she said with a smile.

The CBRTI apiary in the Sundarbans. Photo courtesy K Lakshmi Rao.


The scientist also advocates the use of pollen as a nutraceutical. “Pollen is available abundantly in our country and is a good source of proteins. Six grams of pollen will provide the same amount of protein as 100 grams of lentils. We can collect an almost equal quantity of pollen as honey from the colonies,” she said.

She said states like Haryana, Uttarakhand, Punjab provide robust raw material for the bees to forage on as the crops and plants flower continuously for nine months.

“Starting from mustard and eucalyptus to litchi and other crops, beekeepers can migrate their colonies as the seasons progresses,” Rao said.

Declining bees, changing crop patterns disturb pollination

But all is not well with the pollinators.

While climate change is linked to potential population decline in bees in many parts of the world, Rao said factors such as changes in cropping patterns and practices like growth of non-native plants have played a key role in disturbing their activities.

“In Punjab, for example, sunflower cultivation used to be a good source of nectar for the bees but now the hybrid variety being sown has poor nectar content and doesn’t find favour with the bees. Similarly, cloned-variants of eucalyptus do not flower,” she said.

Fleshing out the climate change link, Rao said because of drought conditions in Maharashtra beekeepers are forced to move their colonies away.

“Secondly, in states such as Maharashtra because of the increased cultivation of sugarcane crops, the bees are not getting their food. Earlier after sugarcane, they used to grow niger (Guizotia abyssinica) but now that is not happening. Imported plants such as Australian acacia are not good for honey bees,” she rued.

As much as crops are important, Rao said taking care of the bees is equally crucial.

“The bees are prone to diseases so they need to be given proper medicines. Instead, they are giving antibiotics that are reflecting in the honey. Keepers should ensure some nectar is left for the bees’ consumption and they should let them have proper rest. Their health deteriorates if they are constantly making honey,” Rao added.


Banner image: Bees are an important pollinator for many crops of high economic value. Photo by Nikhil Moore/Wikimedia Commons.

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