Honeybee starvation

Honey bee starvation is a problem for bees and beekeepers. Starvation may be caused by unfavorable weather, disease, long distance transportation or depleting food reserve. Over-harvesting of honey (and the lack of supplemental feeding) is the foremost cause for scarcity as bees are not left with enough of a honey store, though weather, disease, and disturbance can also cause problems. Backyard beekeepers face more colony losses in the winter than in the summer, but for commercial beekeepers there is not much variation in loss by season. Starvation may be avoided by effective monitoring of hives and disease prevention measures. Starvation can amplify the toxic effect of pesticides bees are exposed to.[1]

Background

Backyard beekeepers produce 40% of all honey worldwide. Beehive management issues resulting in colony losses are a major concern for backyard beekeepers. According to a 2014–15 national survey, backyard beekeepers lost 52% and commercial beekeepers lost 32% of colonies. Backyard beekeepers face more colony losses in the winter than in the summer, but for commercial beekeepers there is not much variation in loss by season.[2] Roughly 22% of backyard beekeepers have identified starvation as one of the main causes for colony losses.[3] Honey bee starvation is an especially challenging problem for beginning beekeepers. Starvation may be caused by unfavorable weather, disease, long distance transportation or depleting food reserve. Starvation may be avoided by effective monitoring of hives and disease prevention measures.

Causes

Food scarcity

Over-harvesting of honey (and the lack of supplemental feeding) is the foremost cause for scarcity. Bees are not left with enough of a honey store.[4] Weather changes and extremes, available food reserve and presence of brood are factors that influence the speed at which food store depletes. It could just take a day or two of food scarcity to kill an entire hive.

Weather

In the Winter, honeybees cluster around the queen and brood to keep them warm.[5] It is believed that an outer layer of bees called mantle bees keep the cluster packed and warm. Also an inner layer of worker bees move around and shiver to produce warmth.[6] Even if food is available in a far corner of the hive or in another frame, it may be too cold for the bees to leave the cluster to reach the food.[7] This leads to starvation and death.

Early Spring can be misleading in terms of knowing honey level in hive. A couple of cold nights in Spring can prevent the bees from foraging and beekeepers may not realise if the bees have been able to store enough to get through those days.[5] Throughout Spring, colonies are likely to become densely populated.

In Summer, huge amount of honey is necessary for the big population of bees. Rainy days can wash out nectar and pollen from flowers and hungry bees may run out of food.

In the Fall, sudden drops in temperature are the major reasons for starvation.

Diseases

Diseases like Nosema ceranae impact the digestive tract of the bees. This could lead to starvation even in the presence of food sources.[8]

Transportation

Millions of bees are transported each year to California and other parts of the USA to pollinate crops such as almonds.[9] Bee hives are transported cross-country in trucks nonstop or with little break.[10] Bees are severely stressed from confinement, heat, weather changes and sudden change in their daily tasks. While on the road for two to three days, it is difficult for the truck driver or the beekeeper to check on the temperature and food level in the hives. Proper nutrition of the bees is affected and there is high risk of bees starving to death on the road trip. One study points to impaired food gland development in migratory bees resulting in improper feeding of brood.[11] North Carolina State University news states that providing bees access to huge amount of food while on road may ease stress due to transportation [12]

Migratory bees are usually released in a very large farm for a few weeks to pollinate a single crop. Long term diet of one type of nectar makes the bee vulnerable to diseases. Recent studies have shown that the lifespan of migratory bees are less than that of stationary bees.[13]

Symptoms

A drop in the hive activity level is the primary indicator that food reserve may have depleted. In Summer, weight of the hive may also be used to suspect lack of honey.

Starvation increases pesticide effects

Lack of food reduces the ability of bees to resist to pesticide intoxication. A recent study showed that starvation (or poor food quality) synergistically amplifies the adverse toxic effect of pesticides.[1]

Preventive steps

Feeding bees

While harvesting honey, it is essential to leave enough of a store of honey for times when bees are not able to forage. It might still become necessary to feed bees. During feeding, it is important to follow recommendations about what to feed, how to feed and how often.[14]

Suitable food for bees

Bees can be fed water and sugar syrup in summer and fall. In the winter, syrup would freeze. Therefore, dry sugar is preferred.[15] Harvested honey made by the bees can also be fed back. It is important to make sure honey comes from disease-free bees, although in practice, this is impossible, as every beehive carries some disease.[16]

It is also essential to look at how starved the bees are. If the bees are dying, thin sugar syrup should be directly sprinkled on the bees as they will not be able to fly or process hard candy. In about an hour, this should help save their lives. Further, they can be fed syrup and candy using feeders.

Precautions while feeding

Hive needs to be ventilated in winter time.[17] Hives may need to be closed to prevent food robbery from outside foragers.[18]

Feeding frequency

While there are generic weight recommendations available, frequency and amount of food to feed vary for each hive. Depending on the weather conditions, configuration and population in hive, a beekeeper needs to decide how much to feed and when to feed.[19] It is best to seek recommendations from experienced beekeepers in the locality.

Hive monitoring

It is crucial to monitor food reserve in the hive, temperature and hive activity especially in harsh weather conditions.

Manual monitoring

Manual inspection is the most common method to date. It is a tedious process for beekeepers and intrusive for bees. It is necessary to monitor regularly to identify any issues with feeding and food bank. Balancing the two is a challenge for beekeepers. This is more of a problem on cold and rainy days. The only way to tackle this is to make good predictions based on hyperlocal information.[20][21]

A lot of information is available from beekeeper associations and social media networks. Mobile apps like Bee Safe![22] can predict and alert how much to feed and when to feed based on weather conditions and hive feed cycles.

Electronic monitoring systems

Electronic monitoring systems can be an effective tool for the beekeeper to ensure bees do not starve.[23] These monitors gather a lot of data about a hive such as temperature, vibrations etc. The downside of existing electronic monitors is the high cost and need for processing vast amounts of data to derive any use from it. Reasonable pricing and improvisations to get an alert based on the hive configurations are necessary before backyard keepers can use these monitors efficiently to know when to feed.

See also

References

  1. Tosi, Simone; Nieh, James C.; Sgolastra, Fabio; Cabbri, Riccardo; Medrzycki, Piotr (2017). "Neonicotinoid pesticides and nutritional stress synergistically reduce survival in honey bees". Proceedings of the Royal Society B: Biological Sciences. 284 (1869): 20171711. doi:10.1098/rspb.2017.1711. PMC 5745400. PMID 29263280.
  2. Lee, K.V.; Steinhauer, N.; Rennich, K.; et al. (2015). "A national survey of managed honey bee 2013–2014 annual colony losses in the USA". Apidologie. 46 (3): 292. doi:10.1007/s13592-015-0356-z.
  3. Kulhanek, K; Steinhauer N; et al. (2017). "A national survey of managed honey bee 2015–2016 annual colony losses in the USA". Journal of Apicultural Research.
  4. Eric (2010-03-31). "What honeybee starvation looks like in a beehive – DIY Living". GardenFork.TV. Retrieved 2017-01-10.
  5. "Starving Bees". Pollinator.com. Retrieved 2017-01-10.
  6. Anton Stabentheiner; Helga Pressl; Thomas Papst; Norbert Hrassnigg; Karl Crailsheim (2003). "Endothermic heat production in honeybee winter clusters". Journal of Experimental Biology. 206 (2): 353–358. doi:10.1242/jeb.00082. PMID 12477904.
  7. "Why so many starving bees?". Honey Bee Suite. 2011-04-25. Retrieved 2017-01-10.
  8. "Nosema ceranae: Kiss of Death or Much Ado about Nothing? @ Scientific Beekeeping". Scientificbeekeeping.com. 2011-02-23. Retrieved 2017-01-10.
  9. "The Mind-Boggling Math of Migratory Beekeeping". Scientific American. 2013-09-01. Retrieved 2017-01-10.
  10. "Hive Drive | Overdrive – Owner Operators Trucking Magazine". Overdriveonline.com. 2005-04-07. Retrieved 2017-01-10.
  11. Kiheung Ahn; Xianbing Xie; Joseph Riddle; Jeff Pettis; Zachary Y. Huang (2012). "Effects of Long Distance Transportation on Honey Bee Physiology". Psyche. 2012: 1–9. doi:10.1155/2012/193029.
  12. "Nutrition Matters: Stress From Migratory Beekeeping May Be Eased by Access to Food | NC State News | NC State University". News.ncsu.edu. 2016-08-24. Retrieved 2017-01-10.
  13. Simone-Finstrom, M.; et al. (2016). "Migratory management and environmental conditions affect lifespan and oxidative stress in honey bees". Sci. Rep. 6: 32023. Bibcode:2016NatSR...632023S. doi:10.1038/srep32023. PMC 4995521. PMID 27554200.
  14. "Winter feeding of honey bees". Honey Bee Suite. 2010-08-13. Retrieved 2017-01-10.
  15. Dave Cushman. "Emergency feeding of bees". Dave-cushman.net. Retrieved 2017-01-10.
  16. "Feeding honey bee colonies to prevent starvation | Compliance and management | Honey bees | Livestock | Agriculture | Agriculture Victoria". Agriculture.vic.gov.au. Retrieved 2017-01-10.
  17. "the winter cluster of honey bees". Westmtnapiary.com. Retrieved 2017-01-10.
  18. "Beekeeping feeding". Bushfarms.com. Retrieved 2017-01-10.
  19. "Bee sugar syrup feed recipe – 1:1, 2:1" (PDF). Uncledavesenterprise.com. Retrieved 2017-01-10.
  20. "Beehive Inspection – Amazing Bees | Beekeeper Section". Beekeepers.amazingbees.com.au. 2016-12-31. Retrieved 2017-01-10.
  21. Chernak, Susan (2016-12-03). "Bee-Centered Beekeeping: Part III". Keeping Backyard Bees. Retrieved 2017-01-10.
  22. "??". D2wuvg8krwnvon.cloudfront.net. Retrieved 2017-01-10.
  23. "Can tech keep the world's bees buzzing?". BBC News. 2016-09-22. Retrieved 2017-01-10.
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