Analysis: the carefully choreographed movement tells other bees where to go to find pollen within five kilometres of the hive
Bees provide pollination to virtually every fruit and vegetable plant thus playing a crucial role in agricultural food production and wild plant diversity and conservation. They are also an important source of income for beekeepers and this contributes to the economic value of rural areas (there are an estimated 3,000 beekeepers in Ireland).
However, human activity is causing dramatic declines in insects. A recent study in the Biological Conservation journal reported that 40% of insect species could be gone in a few decades and that the world is witnessing the "largest extinction event on the earth". The main factors affecting the health of bees are biological (diseases, parasites invasive species etc chemical (pesticides etc), environmental (landscape fragmentation and modern agricultural landscapes), climate and hive management.
Some bee species including honey bees, bumblebees, and stingless bees live socially in colonies. Of course, all bees are important and a lot of them are under threat in Ireland as are our solitary bees. We are familiar with small and generally brown European honey bees (Apis mellifera - Apis is Latin for "bee", and mellifera for "honey-bearing) and they're the most valuable pollinator economically of agricultural crops worldwide.
From RTÉ Radio 1's Drivetime, Úna Fitzpatrick from the National Biodiversity Data Centre on how local councils can lead the way in saving bees
The Varroa mite is one of the most serious problems affecting honey bee health. Its effect has been so severe that in many regions honey bees would have been virtually wiped out if not treated regularly. Small hive beetle (SHB) is another big challenge as the larval stage of the SHB life cycle causes the majority of damage to active hives by burrowing into combs, eating brood, honey and pollen. Whilst feeding. the larvae also carry a yeast species (Kodamaea ohmeri) which contaminates the honey causing it to ferment. Chalkbrood (fungal disease) and Nosema (a microsporidian under the classification of fungus) attacks the gut of the bees and are the other major threats to the bee population around the world.
Traditional practices in the bee industry are laborious physical inspection that greatly disturbs bees and hinders the growth of the hive colony. Minimally intrusive monitoring sensors would therefore be extremely advantageous to bee health and beekeepers. Our research at the MiCRA Biodiagnostics Technology Gateway at Technological University Dublin has seen the development of various industry applications to monitor the beehive health and status, stress level and to understand the colony characteristics, queen laying and much more information.
Throughout the winter, an average hive has about 10,000 bees in residence and this will increase to around 50,000 in mid-summer. Right now, the bees are busy spring-cleaning the hives and removing excrement and dead bees. A few sunny spring days will see them tentatively emerge and have the hive ready for the queen bee to start laying in excess of 1,000 eggs per day - the highest rate of eggs per day that I have seen in the literature is about 2,000.
From RTÉ Archives, a profile of beekeeper Jess Cobb from Bridgetown, Co Wexford for On the Land in 1962
As the colony increases in size, the bees will go outside to find pollen and nectar to feed the new arrivals. The beehive food larders are now low after the winter and the main food source is the honey which the beekeeper has deliberately not removed at harvest time. It takes thousands of visits to flowers by bees to produce a jar of honey. During the summer, bees make a beeline for pollen and can travel up to five kilometres from the hive. They are very democratic in their search which will take in allotments, weedy corners, fancy gardens, fruit plants, vegetable plants, dandelions and even the flower decorating your cocktail glass.
It’s harder for bees to find good patches of flowers in the summer because agricultural intensification means fewer wildflowers and foraging becomes more challenging. To overcome this, bees have developed an ability to tell other hive members exactly where they sourced the pollen. The honey bee in the hive performs a carefully choreographed "waggle dance" which instructs the rest of the hive members where to fly to find pollen. If a scout makes a promising find, she will fill the saddle bag-like pollen sacs on her legs and communicate the good news of the find by dancing on return to the hive. It's a bit like if one of us won the Lotto.
The waggle dance is GPS for bees. Based on the figure 8, the bee scout moves at an angle, waggles, reverses direction and waggles some more. This communicates three things. First, she indicates the direction of the flowers in relation to the sun. The hive's honeycombs are built vertically, so straight up means toward the sun, down means away from the sun and so on. The second indicator is distance: she waggles her abdomen rapidly and the more she waggles, the further the distance. Finally, she identifies the type of flower and the pollen she has collected provides a scent cue for the others to smell for.
Why do honeybees do the waggle dance?
The decoding of the waggle dance was undertaken by Professor Karl von Frisch, the Austrian ethologist who received the Nobel Prize in 1973. A recent study, published in Science Advances, revealed that bees are smart, have incredibly powerful brains for their size and are able to add, subtract and complete basic mathematical problems with a success rate of up to 75%.
However, unless we change our ways and current practices, insects as a whole will soon go down the path of extinction. Keeping the bees dancing is great for bees, plants and pollination and the honey harvesting industry and economy.
The views expressed here are those of the author and do not represent or reflect the views of RTÉ