Bees can suffer serious effects from toxic chemicals in their environments. These include various synthetic chemicals,[1] particularly insecticides, as well as a variety of naturally occurring chemicals from plants, such as ethanol resulting from the fermentation of organic materials. Bee intoxication can result from exposure to ethanol from fermented nectar, ripe fruits, and manmade and natural chemicals in the environment.[2][3]
The effects of alcohol on bees are sufficiently similar to the effects of alcohol on humans that honey bees have been used as models of human ethanol intoxication.[4] The metabolism of bees and humans is sufficiently different that bees can safely collect nectars from plants that contain compounds toxic to humans. The honey produced by bees from these toxic nectars can be poisonous if consumed by humans.
Natural processes can also introduce toxic substances into nontoxic honey produced from nontoxic nectar. Microorganisms in honey can convert some of the sugars in honey to ethanol. This process of ethanol fermentation is intentionally harnessed to produce the alcoholic beverage called mead from fermented honey.
The introduction of certain chemical substances—such as ethanol or pesticides or defensive toxic biochemicals produced by plants—to a bee's environment can cause the bee to display abnormal or unusual behavior and disorientation. In sufficient quantities, such chemicals can poison and even kill the bee. The effects of alcohol on bees have long been recognized. For example, John Cumming described the effect in an 1864 publication on beekeeping.[5]
When bees become intoxicated from ethanol consumption or poisoned with other chemicals, their balance is affected, and they are wobbly when they walk. Charles Abramson's group at Oklahoma State University has put inebriated bees on running wheels, where they exhibit locomotion difficulties. They also put honey bees in shuttle-boxes that used a stimulus to encourage the bees to move, and found that they were less mobile as they became more intoxicated.[6]
A temulent bee is more likely to stick out its tongue, or proboscis. Inebriated bees spend more time flying. If a bee is sufficiently intoxicated, it will just lie on its back and wiggle its legs. Inebriated bees typically have many more flying accidents as well. Some bees that consume ethanol become too inebriated to find their way back to the hive, and will die as a result.[6] Bozic et al. (2006) found that alcohol consumption by honeybees disrupts foraging and social behaviors, and has some similar effects to poisoning with insecticides.[7] Some bees become more aggressive after consuming alcohol.[8]
Exposure to alcohol can have a prolonged effect on bees, lasting as long as 48 hours.[9] This phenomenon is also observed in fruit flies[10] and is connected to the neurotransmitter octopamine in fruit flies, which is also present in bees.[11]
Bees as ethanol inebriation models
In 1999, research by David Sandeman led to the realization that bee inebriation models are potentially valuable for understanding vertebrate and even human ethanol intoxication:
"Advances over the past three decades in our understanding of nervous systems are impressive and come from a multifaceted approach to the study of both vertebrate and invertebrate animals. An almost unexpected by-product of the parallel investigation of vertebrate and invertebrate nervous systems that is explored in this article is the emergent view of an intricate web of evolutionary homology and convergence exhibited in the structure and function of the nervous systems of these two large, paraphyletic groups of animals."[12]
The behavior of honey bees intoxicated by ethanol is being studied by scientists at Ohio State University, Oklahoma State University, University of Ljubljana in Slovenia, and other sites as a potential model of the effects of alcohol on humans. At the Oklahoma State University, for example, Abramson's research found significant correlations between the reactions of bees and other vertebrates to ethanol exposure:
"The purpose of this experiment was to test the feasibility of creating an animal model of ethanol consumption using social insects.... The experiments on consumption, locomotion, and learning suggest that exposure to ethanol influences behavior of honey bees similarly to that observed in experiments with analogous vertebrates."[6]
It has thus been found that "the honey bee nervous system is similar to that of vertebrates".[13][14] These similarities are pronounced enough to even make it possible to derive information on the functioning of human brains from how bees react to certain chemicals. Julie Mustard, a researcher at Ohio State, explained that:
"On the molecular level, the brains of honey bees and humans work the same. Knowing how chronic alcohol use affects genes and proteins in the honey bee brain may help us eventually understand how alcoholism affects memory and behavior in humans, as well as the molecular basis of addiction."[13][15]
The evaluation of a bee model for ethanol inebriation of vertebrates has just begun, but appears to be promising. The bees are fed ethanol solutions and their behavior observed.[6] Researchers place the bees in tiny harnesses, and feed them varying concentrations of alcohol introduced into sugar solutions.[6][13] Tests of locomotion, foraging, social interaction and aggressiveness are performed. Mustard has noted that "Alcohol affects bees and humans in similar ways—it impairs motor functioning along with learning and memory processing."[13][15] The interaction of bees with antabuse (disulfiram, a common medication administered as a treatment for alcoholism) has been tested as well.[16]
Bee exposure to other toxic and inebriating chemicals
Bees[17][18] can be severely and even fatally affected by pesticides,[19][20] fertilizers,[21][22][23] copper sulfate (more lethal than spinosad),[24][22] and other chemicals that man has introduced into the environment.[1] They can appear inebriated and dizzy, and even die. This is serious because it has substantial economic consequences for agriculture.
This problem has been the object of growing concern. For example, researchers at the University of Hohenheim are studying how bees can be poisoned by exposure to seed disinfectants.[25] In France, the Ministry of Agriculture commissioned an expert group, the Scientific and Technical Committee for the Multifactorial Study on Bees (CST), to study the intoxicating and sometimes fatal effects of chemicals used in agriculture on bees.[26] Researchers at the Bee Research Institute and the Department of Food Chemistry and Analysis in the Czech Republic have pondered the intoxicating effects of various chemicals used to treat winter rapeseed crops.[27]Romania suffered a severe case of widespread bee intoxication and extensive bee mortality from deltamethrin in 2002.[28] The United States Environmental Protection Agency (EPA) even has published standards for testing chemicals for bee intoxication.[29]
Natural compounds
Bees and other Hymenoptera can also be substantially affected by natural compounds in the environment besides ethanol. For example, Dariusz L. Szlachetko of the Department of Plant Taxonomy and Nature Conservation, Gdańsk University observed wasps in Poland acting in a very sleepy (possibly inebriated) manner after eating nectar derived from the North American orchid Neottia.[30]
Detzel and Wink (1993) published an extensive review of 63 types of plant allelochemicals (alkaloids, terpenes, glycosides, etc.) and their effects on bees when consumed. It was found that 39 chemical compounds repelled bees (primarily alkaloids, coumarins, and saponins) and three terpene compounds attracted bees. They report that 17 out of 29 allelochemicals are toxic at some levels (especially alkaloids, saponins, cardiac glycosides and cyanogenic glycosides).[31]
Various plants are known to have pollen which is toxic to honey bees, in some cases killing the adults (e.g., Toxicoscordion), in other cases creating a problem only when passed to the brood (e.g., Heliconia). Other plants which have toxic pollen are Spathodea campanulata and Ochroma lagopus. Both the pollen and nectar of the California Buckeye (Aesculus californica) are toxic to honeybees,[32] and it is thought that other members of the Buckeye family are also.
Some plants reportedly rely on using intoxicating chemicals to produce inebriated bees, and use this inebriation as part of their reproductive strategy. One plant that some claim uses this mechanism is the South American bucket orchid (Coryanthes sp.), an epiphyte. The bucket orchid attracts male euglossine bees with its scent, derived from a variety of aromatic compounds. The bees store these compounds in specialized spongy pouches inside their swollen hind legs, as they appear to use the scent (or derivatives thereof) in order to attract females.
The flower is constructed in such a way as to make the surface almost impossible to cling to, with smooth, downward-pointing hairs; the bees commonly slip and fall into the fluid in the bucket, and the only navigable route out is a narrow, constricting passage that either glues a "pollinium" (a pollen sack) on their body (if the flower has not yet been visited) or removes any pollinium that is there (if the flower has already been visited). The passageway constricts after a bee has entered, and holds it there for a few minutes, allowing the glue to dry and securing the pollinium. It has been suggested that this process involves "inebriation" of the bees,[33][34][35][36] but this effect has never been confirmed.
In this way, the bucket orchid passes its pollen from flower to flower. This mechanism is almost but not quite species specific, as it is possible for a few closely related bees to pollinate any given species of orchid, as long as the bees are similar in size and are attracted by the same compounds.[37]
Van der Pijl and Dodson (1966) observed that bees of the genera Eulaema and Xylocopa exhibit symptoms of inebriation after consuming nectar from the orchids Sobralia violacea and Sobralia rosea.[38][39] The Gongora horichiana orchid was suspected by Lanau (1992) of producing pheromones like a female euglossine bee[40] and even somewhat resembles a female euglossine bee shape, using these characteristics to spread its pollen:
"A hapless male bee, blind drunk with the flower's overpowering pheromones, might well mistake a toadstool for a suitable mate, but the flower has made at least a modest attempt at recreating a beelike gestalt."[41]
This seems unlikely, given that no one has ever documented that female euglossines produce pheromones; male euglossines produce pheromones using the chemicals they collect from orchids, and these pheromones attract females, rather than the converse, as Cullina (2004) suggests.[41]
Toxic plant honey
A number of plants produce alkaloids which can taint honey made from their flowers.
Grayanotoxin
Some substances which are toxic to humans have no effect on bees. If bees obtain their nectar from certain flowers, the resulting honey can be psychoactive, or even toxic to humans, but innocuous to bees and their larvae.[42][43] Poisoning from this honey is called mad honey disease.
Accidental intoxication of humans by mad honey has been well documented by several Classical authors, notably Xenophon, while the deliberate use of such honey as a medicine and intoxicant (even hallucinogen) is still practiced by the Gurung tribe of Nepal, who have a long tradition of hazardous cliff-climbing to wrest the precious commodity from the nests of Apis laboriosa, the giant Himalayan honeybee. The honey thus collected by the Gurung owes its inebriating properties to the nectar which the giant bees gather from a deep red-flowered species of Rhododendron, which, in turn, owes its toxicity to the compound grayanotoxin, widespread in the plant family Ericaceae, to which the genus Rhododendron belongs.[44][additional citation(s) needed]
Tutu
The New Zealand native plant Tutu produces poisonous honey, due to the toxin tutin.[citation needed]
Tecoma stans
The Tecoma stans plant is unique because although it is nontoxic itself, its honey from its flowers is poisonous nonetheless.[45][46]
Opium
Morphine-containing honey has been reported in areas where opium poppy cultivation is widespread.[47]
Ethanol
Honey, can ferment, and produce ethanol. Animals, such as birds, that have consumed honey fermented in the sun can be found incapable of flight or other normal movement.[48] Sometimes honey is fermented intentionally to produce mead, an alcoholic beverage made of honey, water, and yeast. The word for "drunk" in classical Greek is sometimes translated as "honey-intoxicated"[49] and indeed the shared Indo-European antiquity of such a conception is enshrined in the names of at least two (euhemerised) goddesses of personified intoxication: the Irish Medb (see also Maeve (Irish name) ) and the Indian Madhavi of the Mahabharata (- see page Yayati), cognate with the English word mead and the Russian word for bear медведь ( – medved – literally 'honey-eater').[50]
1 2 Tosi, Simone; Costa, Cecilia; Vesco, Umberto; Quaglia, Giancarlo; Guido, Giovanni (2018). "A survey of honey bee-collected pollen reveals widespread contamination by agricultural pesticides". Science of the Total Environment. 615: 208–218. doi:10.1016/j.scitotenv.2017.09.226. PMID28968582. S2CID19956612.
↑ Of course, other creatures are not immune to the effects of alcohol:
Many of us have noticed that bees or yellow jackets cannot fly well after having drunk the juice of overripe fruits or berries; bears have been seen to stagger and fall down after eating fermented honey; and birds often crash or fly haphazardly while intoxicated on ethanol that occurs naturally as free-floating microorganisms convert vegetable carbohydrates to [alcohol] (Warren K. Bickel; Richard J. DeGrandpre (1996). Drug Policy and Human Nature: Psychological Perspectives On The Prevention, Management, and Treatment of Illicit Drug Abuse. Springer. ISBN978-0-306-45241-3.)
↑ Fruit flies and other insects also exhibit symptoms of ethanol intoxication (Heberlein, Ulrike; Wolf, Fred W.; Rothenfluh, Adrian; Guarnieri, Douglas J. (2004). "Molecular Genetic Analysis of Ethanol Intoxication in Drosophila melanogaster". Integrative and Comparative Biology. 44 (4): 269–274. CiteSeerX10.1.1.536.262. doi:10.1093/icb/44.4.269. PMID21676709. S2CID14762870.)
1 2 3 4 5 Abramson, Charles I.; Stone, Sherril M.; Ortez, Richard A.; Luccardi, Alessandra; Vann, Kyla L.; Hanig, Kate D.; Rice, Justin (August 2000). "The Development of an Ethanol Model Using Social Insects I: Behavior Studies of the Honey Bee (Apis mellifera L.)". Alcoholism: Clinical and Experimental Research. 24 (8): 1153–1166. doi:10.1111/j.1530-0277.2000.tb02078.x. PMID10968652.
↑ Bozic, Janko; Abramson, Charles I.; Bedencic, Mateja (April 2006). "Reduced ability of ethanol drinkers for social communication in honeybees (Apis mellifera carnica Poll.)". Alcohol. 38 (3): 179–183. doi:10.1016/j.alcohol.2006.01.005. PMID16905444.
↑ Abramson CI, Place AJ, Aquino IS, Fernandez A (June 2004). "Development of an ethanol model using social insects: IV. Influence of ethanol on the aggression of Africanized honey bees (Apis mellifera L.)". Psychol Rep. 94 (3 Pt 2): 1107–15. doi:10.2466/pr0.94.3c.1107-1115. PMID15362379. S2CID24341827.
↑ Happy Hour Bees , Mythology and Mead, Carolyn Smagalski, BellaOnline, The Voice of Women, 2007 describes a prolonged effect from ethanol consumption by honey bees as similar to a "hangover".
1 2 Entomology Postdoctoral researcher Dr. Julie Mustard, Ohio State University
↑ Abramson CI, Fellows GW, Browne BL, Lawson A, Ortiz RA (April 2003). "Development of an ethanol model using social insects: II. Effect of Antabuse on consumatory responses and learned behavior of the honey bee (Apis mellifera L.)". Psychol Rep. 92 (2): 365–78. doi:10.2466/PR0.92.2.365-378. PMID12785614.
↑ Pierre Jolivet (1998). Interrelationship Between Insects and Plants. CRC Press. p.192. ISBN978-1-57444-052-2. The first hymenopteran to visit has difficulties coping with the rostrellum but the later ones to arrive easily escape, soaked, drunk, and often having completed their pollinating function.
↑ Lunau, Klaus (June 1992). "Evolutionary aspects of perfume collection in male euglossine bees (Hymenoptera) and of nest deception in bee-pollinated flowers". Chemoecology. 3 (2): 65–73. Bibcode:1992Checo...3...65L. doi:10.1007/BF01245884. ISSN0937-7409. S2CID26259242. speculated that the chemicals produced by the bucket orchid mimic bee pheromones.
1 2 William Cullina (2004). Understanding Orchids: An Uncomplicated Guide to Growing the World's Most Exotic Plants. Boston: Houghton Mifflin. p.180. ISBN978-0-618-26326-4.
↑ Anand, Mukul; Basavaraju, R. (January 2021). "A review on phytochemistry and pharmacological uses of Tecoma stans (L.) Juss. ex Kunth". Journal of Ethnopharmacology. 265: 113270. doi:10.1016/j.jep.2020.113270. PMID32822823.
Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are currently considered a clade, called Anthophila. There are over 20,000 known species of bees in seven recognized biological families. Some species – including honey bees, bumblebees, and stingless bees – live socially in colonies while most species (>90%) – including mason bees, carpenter bees, leafcutter bees, and sweat bees – are solitary.
A honey bee is a eusocial flying insect within the genus Apis of the bee clade, all native to mainland Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosmopolitan distribution of honey bees, introducing multiple subspecies into South America, North America, and Australia.
A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains.
A bumblebee is any of over 250 species in the genus Bombus, part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related genera are known from fossils. They are found primarily in higher altitudes or latitudes in the Northern Hemisphere, although they are also found in South America, where a few lowland tropical species have been identified. European bumblebees have also been introduced to New Zealand and Tasmania. Female bumblebees can sting repeatedly, but generally ignore humans and other animals.
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example beetles or butterflies; birds, and bats; water; wind; and even plants themselves. Pollinating animals travel from plant to plant carrying pollen on their bodies in a vital interaction that allows the transfer of genetic material critical to the reproductive system of most flowering plants. When self-pollination occurs within a closed flower. Pollination often occurs within a species. When pollination occurs between species, it can produce hybrid offspring in nature and in plant breeding work.
Grayanotoxins are a group of closely related neurotoxins named after Leucothoe grayana, a plant native to Japan originally named for 19th century American botanist Asa Gray. Grayanotoxin I is also known as andromedotoxin, acetylandromedol, rhodotoxin and asebotoxin. Grayanotoxins are produced by Rhododendron species and other plants in the family Ericaceae. Honey made from the nectar and so containing pollen of these plants also contains grayanotoxins and is commonly referred to as mad honey.
Pollination of fruit trees is required to produce seeds with surrounding fruit. It is the process of moving pollen from the anther to the stigma, either in the same flower or in another flower. Some tree species, including many fruit trees, do not produce fruit from self-pollination, so pollinizer trees are planted in orchards.
Pollination management is the horticultural practices that accomplish or enhance pollination of a crop, to improve yield or quality, by understanding of the particular crop's pollination needs, and by knowledgeable management of pollenizers, pollinators, and pollination conditions.
A worker bee is any female bee that lacks the reproductive capacity of the colony's queen bee and carries out the majority of tasks needed for the functioning of the hive. While worker bees are present in all eusocial bee species, the term is rarely used for bees other than honey bees, particularly the European honey bee. Worker bees of this variety are responsible for approximately 80% of the world's crop pollination services.
Bee pollen, also known as bee bread and ambrosia, is a ball or pellet of field-gathered flower pollen packed by worker honeybees, and used as the primary food source for the hive. It consists of simple sugars, protein, minerals and vitamins, fatty acids, and a small percentage of other components. Bee pollen is stored in brood cells, mixed with saliva, and sealed with a drop of honey. Bee pollen is harvested as food for humans and marketed as having various, but yet unproven, health benefits.
Pesticides vary in their effects on bees. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other areas around it. Systemic pesticides, on the other hand, are usually incorporated into the soil or onto seeds and move up into the stem, leaves, nectar, and pollen of plants.
Zoophily, or zoogamy, is a form of pollination whereby pollen is transferred by animals, usually by invertebrates but in some cases vertebrates, particularly birds and bats, but also by other animals. Zoophilous species frequently have evolved mechanisms to make themselves more appealing to the particular type of pollinator, e.g. brightly colored or scented flowers, nectar, and appealing shapes and patterns. These plant-animal relationships are often mutually beneficial because of the food source provided in exchange for pollination.
The tribe Euglossini, in the subfamily Apinae, commonly known as orchid bees or euglossine bees, are the only group of corbiculate bees whose non-parasitic members do not all possess eusocial behavior.
Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has been used as a pesticide since the late 1700s. Clothianidin and other neonicotinoids act on the central nervous system of insects as an agonist of nAChR, the same receptor as acetylcholine, the neurotransmitter that stimulates and activating post-synaptic acetylcholine receptors but not inhibiting AChE. Clothianidin and other neonicotinoids were developed to last longer than nicotine, which is more toxic and which breaks down too quickly in the environment.
The western honey bee or European honey bee is the most common of the 7–12 species of honey bees worldwide. The genus name Apis is Latin for "bee", and mellifera is the Latin for "honey-bearing" or "honey carrying", referring to the species' production of honey.
Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. While such disappearances have occurred sporadically throughout the history of apiculture, and have been known by various names, the syndrome was renamed colony collapse disorder in early 2007 in conjunction with a drastic rise in reports of disappearances of western honey bee colonies in North America. Beekeepers in most European countries had observed a similar phenomenon since 1998, especially in Southern and Western Europe; the Northern Ireland Assembly received reports of a decline greater than 50%. The phenomenon became more global when it affected some Asian and African countries as well. From 1990 to 2021, the United Nation’s FAO calculated that the worldwide number of honeybee colonies increased 47%, reaching 102 million.
Flower constancy or pollinator constancy is the tendency of individual pollinators to exclusively visit certain flower species or morphs within a species, bypassing other available flower species that could potentially contain more nectar. This type of foraging behavior puts selective pressures on floral traits in a process called pollinator-mediated selection. Flower constancy is different from other types of insect specialization such as innate preferences for certain colors or flower types, or the tendency of pollinators to visit the most rewarding and abundant flowers.
Eulaema meriana is a large-bodied bee species in the tribe Euglossini, otherwise known as the orchid bees. The species is a solitary bee and is native to tropical Central and South America. The male collects fragrances from orchid flowers, which it stores in hollows in its hind legs. Orchids can be deceptive by mimicking the form of a female and her sex pheromone, thus luring male bees or wasps. Pollination will take place as the males attempt to mate with the labellum, or the tip petal of the flower. Male E. meriana are territorial and have a particular perch on a tree trunk where it displays to attract a female. After mating, the female builds a nest with urn-shaped cells made with mud, feces, and plant resin, and provisions these with nectar and pollen before laying an egg in each. These bees also have complex foraging and wing buzzing behaviors and are part of a mimicry complex.
Euglossa cordata is a primitively eusocial orchid bee of the American tropics. The species is known for its green body color and ability to fly distances of over 50 km. Males mostly disperse and leave their home nests, while females have been observed to possess philopatric behavior. Because of this, sightings are rare and little is known about the species. However, it has been observed that adults who pollinate certain species of orchids will become intoxicated during the pollination.
Euglossa imperialis is a bee species in the family Apidae. It is considered to be one of the most important pollinators to many Neotropical orchid species in mainland tropical America. It is also one of the most common non-parasitic euglossine species in lowland Panama. E. imperialis, unlike many other bee species, is not a social bee in the sense that there is no apparent morphological or physiological division within the species to distinguish individual bees to be part of a worker or reproductive caste.
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