Bombus terrestris: Difference between revisions
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{{italic title}}{{Taxobox |
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| name = ''Bombus terrestris'' |
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| image = Bumblebee October 2007-3a.jpg |
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| image_width = 240px |
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| regnum = [[Animal]]ia |
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| phylum = [[Arthropod]]a |
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| classis = [[Insect]]a |
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| ordo = [[Hymenoptera]] |
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| familia = [[Apidae]] |
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| subfamilia = [[Apinae]] |
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| genus = ''[[Bombus]]'' |
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| species = '''''B. terrestris''''' |
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| binomial = ''Bombus terrestris'' |
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| binomial_authority = ([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]) |
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|subgenus = ''[[List of world bumblebee species#Bombus sensu stricto|Bombus]]''}} |
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'''''Bombus terrestris''''', the '''buff-tailed bumblebee''' or '''large earth bumblebee,''' is one of the most numerous [[bumblebee]] [[species]] in [[Europe]]. In addition, ''Bombus terrestris'' is the largest of the European bumblebee species.<ref name ="bee">{{citation|url=http://www.bumblebee.org/key.htm |title=Bumblebee species |accessdate=4 October 2014 }}</ref> It is one of the main species used in greenhouse [[pollination]], and consequently, can be found in many countries and areas where it is not native, such as [[Tasmania]] for example.<ref name ="Semmens">{{cite journal | author = Semmens, T.D., E. Turner, and R. Buttermore. |title = ''Bombus terrestris'' (L.) (Hymenoptera: Apidae) now established in Tasmania | journal = Australian Journal of Entomology | year = 1993 | volume = 32 | issue = 4| pages =346}}</ref> Moreover, it is a [[Eusociality|eusocial]] insect that is characterized by unique [[Hymenopteran]] sex ratios, where male drones dominate most colonies. The queen of ''B. terrestris'' is often highly dominant over her colony, and exhibits behaviors such as altering the sex ratio in her favor over the workers and controlling queen larval development with pheromones. However, after aggression breaks out in the nest, the workers can usually gain control of the nest and restart the colony cycle. The queen is [[monandrous]] and only mates with one male after leaving the nest, despite the potential genetic benefits from [[Polyandry in nature|polyandrous]] mating. ''B. terrestris'' demonstrates noteworthy learning tactics with flower color and diverse foraging behaviors. They have also been implicated in a number of bee [[pathology]] studies investigating bee parasites and viruses. |
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==Taxonomy and phylogenetics== |
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''B. terrestris'' is part of the order [[Hymenoptera]], which is composed of ants, bees, wasps, and [[Sawfly|sawflies]]. The family [[Apidae]] specifically consists of bees. It is also part of the subfamily [[Apinae]], which includes most species of bees. There are 14 tribe lineages within [[Apinae]], and ''B. terrestris'' is in the bumblebee tribe, [[Bombini]]. It is in the genus ''[[Bombus]]'', which consists entirely of bumblebees, and the subgenus ''Bombus sensu stricto''. This subgenus contains closely related species such as ''[[Bombus affinis]]'', ''[[Bombus cryptarum]]'', ''[[Bombus franklini]]'', ''[[Bombus ignitus]]'', ''[[White-tailed bumblebee|Bombus lucorum]]'', ''[[Bombus magnus]]'', ''[[Western bumblebee|Bombus occidentalis]]'', and ''[[Bombus terricola]]''. There are nine recognised subspecies: ''B. terrestris africanus, B. terrestris audax, B. terrestris calabricus, B. terrestris canariensis, B. terrestris dalmatinus, B. terrestris lusitanicus, B. terrestris sassaricus, B. terrestris terrestris and B. terrestris xanthopus,'' each with a distinctive colouration scheme.<ref>{{Cite journal|title = An overview of the Bombus terrestris (L. 1758) subspecies (Hymenoptera: Apidae)|url = http://dx.doi.org/10.1080/00379271.2008.10697559|journal = Annales de la Société entomologique de France (N.S.)|date = 2008-01-01|issn = 0037-9271|pages = 243–250|volume = 44|issue = 2|doi = 10.1080/00379271.2008.10697559|first = Pierre|last = Rasmont|first2 = Audrey|last2 = Coppee|first3 = Denis|last3 = Michez|first4 = Thibaut De|last4 = Meulemeester}}</ref> |
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[[File:Dunkle Erdhummel (Bombus terrestris) ventral.jpg|thumb|left|Ventral view of ''B. terrestris'']] |
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==Description and identification== |
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''B. terrestris'' are pollen-storing bees that generally feed and forage on nectar and pollen.<ref name = "Goulson">{{cite journal | author = Goulson, D., J. Peat, J. C. Stout, J. Tucker, B. Darvill, L. C. Derwent, and W. O. H. Hughes | year = 2002 | title = Can alloethism in workers of the bumblebee, Bombus terrestris, be explained in terms of foraging efficiency? | journal = Animal Behaviour | volume = 64 | pages = 123–130}}</ref> The queen is between 20–22 mm long, males range from 14–16 mm, and workers from 11–17 mm. The latter are characterized by their white-ended abdomens, and look just like workers of the white-tailed bumblebee, ''[[Bombus lucorum|B. lucorum]]'', a close relative, apart from the yellowish bands of ''B. terrestris'' being darker in direct comparison. The queens of ''B. terrestris'' have the namesake [[buff (colour)|buff]]-white [[abdomen]] tip ("tail"); this area is white like in the workers in ''[[White-tailed bumblebee|B. lucorum]].''<ref name ="bee"/> ''B. terrestris'' are unique compared to other bees in that their caste of workers exhibit a wide variation in worker size, with [[thorax]] sizes ranging from 2.3 to 6.9 mm in length and masses ranging from 68 to 754 mg.<ref name = "Goulson"/> |
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==Distribution and habitat== |
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''B. terrestris'' is most commonly found throughout Europe and generally occupies temperate climates. Because it can survive in a wide variety of habitats, there are populations in the [[near East]], the Mediterranean Islands, and Northern Africa as well.<ref name="Widmer">{{cite journal |author = 10. Widmer, A., P. Schmid-Hempel, and A. Estoup, and A. Scholl|year = 1998|title = Population genetic structure and colonization history of Bombus terrestris s.l. (Hymenoptera: Apidae) from the Canary Islands and Madeira|journal = Heredity|volume = 81|pages = 563–572}}</ref> Additionally, after being introduced as a greenhouse pollinator in nonnative countries, this bee is now considered an [[invasive species]] in many of these countries, including Japan, Chile, Argentina, and Tasmania.<ref name= "Semmens"/><ref name = "Inoue">{{cite journal |author =Inoue, M.K., J. Yokoyama, and I. Washitani | year = 2008 | title = Displacement of Japanese native bumblebees by the recently introduced ''Bombus terrestris'' (L.) (Hymenoptera: Apidae) | journal = Journal of Insect Conservation | volume = 12 | pages = 135–146 }}</ref><ref name = "Torretta">{{cite journal| author = Torretta, J.A., D. Medan, and A. H. Abrahamovich| year = 2006 | title = First record of the invasive bumblebee ''Bombus terrestris'' (L.) (Hymenoptera, Apidae) in Argentina| journal = Transactions of the American Entomological Society| volume = 132| issue = 3 & 4|pages = 285–289}}</ref> Nests are usually found underground, such as in abandoned rodent dens.<ref name = "Inoue"/><ref name = "Dornhaus">{{cite journal | author = Dornhaus, A. and L. Chittka | year = 2001 | title = Food alert in bumblebees (''Bombus terrestris''): possible mechanisms and evolutionary implications | journal = Behavioral Ecology and Sociobiology | volume = 50 | pages = 570–576}}</ref> Colonies form comb-like nest structures with egg cells each containing several eggs. The queen will layer these egg cells on top of one another. Colonies produce between 300-400 bees on average, with a large variation in the number of workers.<ref name="Duchateau">{{cite journal |author = Duchateau, M. J. and H. H. W. Velthuis|year = 1988|title = Development and reproductive strategies in Bombus terrestris colonies|journal = [[Behavior]]|volume = 107|issue = |pages = 186–207}}</ref> |
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==Colony structure== |
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=== Social castes === |
=== Social castes === |
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Like in most social bees'','' there are three main social caste divisions in ''B. terrestris.'' This ensures a division of labor and efficient colony functioning. Queens |
Like in most social bees'','' there are three main social caste divisions in ''B. terrestris.'' This ensures a division of labor and efficient colony functioning. Queens become the main female individual to reproduce in a future colony. Her sole responsibility is to lay eggs after she founds a nest. This fate is determined for larvae that receive more food, have longer [[instar]] stages and higher levels of [[juvenile hormone]] [[biosynthesis]]. <ref>{{Cite journal|title = Caste Determination in Bombus terrestris: Differences in Development and Rates of JH Biosynthesis between Queen and Worker Larvae|url = http://www.sciencedirect.com/science/article/pii/S0022191096001060|journal = Journal of Insect Physiology|date = 1997-04-01|pages = 373-381|volume = 43|issue = 4|doi = 10.1016/S0022-1910(96)00106-0|first = JONATHAN|last = CNAANI|first2 = DAVID W|last2 = BORST|first3 = Z. -Y|last3 = HUANG|first4 = GENE E|last4 = ROBINSON|first5 = ABRAHAM|last5 = HEFETZ}}</ref> Workers, an entirely female caste, mainly forage for food, defend the colony, and tend to the growing larvae. They are usually sterile for most of the colony cycle and do not raise their own young. Unlike queens and workers, which develop from fertilized [[Ploidy|diploid]] eggs, drones, or male bees, are born from unfertilized, [[Ploidy|haploid]] eggs. Drones leave the colony shortly after reaching adulthood to find a mate outside the nest. This is their sole role in the colony. |
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=== Life cycle === |
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A solitary queen hatched from her abandoned colony initiates the colony cycle when she mates with a male and finds a nest. She will stay in this nest over winter and then will lay a small batch of [[Ploidy|diploid]] eggs in the spring. Once these hatch, she tends the larvae, feeding them with nectar and pollen. When the larvae are grown, they [[pupate]], and about two weeks later, the first workers emerge. This is known as the initiation phase of the colony.<ref name="Duchateau"/> Workers will forage for nectar and pollen for the colony and tend later generations of larvae. The workers are smaller than the queen, and only live for a few weeks. The foraging range and frequency of workers depends on the quality and distribution of available food, but most workers forage within a few hundred meters of their nest.<ref>{{cite journal | author = Stephan Wolf & Robin F. A. Moritz | title = Foraging distance in ''Bombus terrestris'' L. (Hymenoptera: Apidae) | journal =[[Apidologie]] | volume = 39 | issue = 4 | pages = 419–427 | publisher = EDP Sciences | year = 2008 | url = http://www.apidologie.org/articles/apido/abs/2008/04/m07103/m07103.html |doi=10.1051/apido:2008020}}</ref> |
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This first phase can last a variable amount of time in ''B. terrestris'', after which the switch point is reached, and the queen begins to lay some unfertilized eggs, which develop into males.<ref name="Duchateau"/> When the male drones emerge from the nest, they do not return, foraging only for themselves. They seek out new queens and mate with them. Remaining diploid eggs receive extra food and pupate to become new queens. The queen can use [[pheromone]]s to discourage the workers' inclination to invest more in these larvae, thereby ensuring that not too many become queens. The colony persists until the competition point is reached, when workers begin egg laying. At this point, outright aggression among workers and between the queen and workers begins. This is a predictable time point that occurs about 30 days into the colony cycle.<ref name="Duchateau"/> |
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Usually, the worker-queen conflict will force the queen out and the new workers will become queenless. A "false queen" might take control of the colony for a short period.<ref name = "Honk">{{cite journal | author = van Honk, C. and P. Hogeweg | year = 1981 | title = The ontogeny of the social structure in a captive Bombus terrestris colony | journal = Behavioral Ecology and Sociobiology | volume = 9 | issue = 2 | pages = 111–119}}</ref> The colony cycle starts again when the newly hatched queens leave the nest in search of a mate and a nest for themselves in order to start a new colony. |
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==Reproductive behavior== |
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===Mating system=== |
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''B. terrestris'' is thought to be a singly mating species. This is not unusual for social insect queens, but it also true that mating with several males ([[polyandry]]) has potential genetic benefits.<ref name = "Baer">{{cite journal | author = Baer, B. and P. Schmid-Hempel | year = 2001 | title = Unexpected consequences of polyandry for parasitism and fitness in the bumblebee, ''Bombus terrestris'' | journal = Evolution | volume = 55 | issue = 8 | pages = 1639–1643 }}</ref> The lack of multiple matings by ''B. terrestris'' queens may be partly due to male interference. ''B. terrestris'' males plug the female's sexual tract with a sticky secretion during mating, which appears to reduce the female's ability to successfully mate with other males for several days.<ref>{{cite journal | author=Annette Sauter, Mark J. F. Brown, Boris Baer & Paul Schmid-Hempel | year=2001 |title=Males of social insects can prevent queens from multiple mating |journal=[[Proceedings of the Royal Society B]] |volume=268 |issue=1475 |pages=1449–1454 |doi=10.1098/rspb.2001.1680 |pmid=11454287 |pmc=1088762}}</ref> Mating with multiple males may also reduce hibernation success and fitness of the queen over the winter, likely due to some component of the sperm. <ref>{{Cite journal|title = Sperm influences female hibernation success, survival and fitness in the bumble-bee Bombus terrestris|url = http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634972/|journal = Proceedings of the Royal Society B: Biological Sciences|date = 2005-02-07|issn = 0962-8452|pmc = 1634972|pmid = 15705558|pages = 319-323|volume = 272|issue = 1560|doi = 10.1098/rspb.2004.2958|first = Boris|last = Baer|first2 = Paul|last2 = Schmid-Hempel}}</ref> While there may be genetic fitness benefits in colony [[heterogeneity]] from a polyandrous mating system, bumblebees are also likely to be [[monandrous]] due to social constraints and risks associated with multiple matings. Finding multiple mates might be energetically costly and expose the queen to higher predation risks. Additionally, while queens may prefer multiple matings to ensure more genetic variability and viable offspring, the queen-worker conflict dictates that workers will be more apt to raise larvae from a single male.<ref name = "Baer"/> This is due to [[haplodiploidy]] in [[Hymenoptera]]n social insects in which males (drones) are haploid and females (workers and queens) are diploid. This confers greater genetic similarity between sister workers (relatedness of 0.75) than between mother and offspring (relatedness of 0.5), making [[kin selection]] stronger between sisters. This selective force would be reduced if workers were the offspring of multiple males, which might lead to increased conflict in the nest. |
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[[File:Bombus terrestris queen face HC1.jpg|thumb|''B. terrestris'' queen]] |
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===Worker egg laying=== |
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In addition to the queen, the workers can lay eggs for the colony brood. Since workers do not mate, all of their eggs are haploid and will develop into drones. There are multiple factors that determine whether a worker bee will become reproductively active. Workers born early in the first brood are more likely to become egg layers due to their increased size and age, which allows more time for ovarian development. Workers usually have to be at least 30 days old to become an egg layer. Individuals that spend less time foraging and more time near the queen are also more likely to become reproductive. Lastly, due to intense competition for the opportunity to reproduce, older workers often harass the queen by attacking her and buzzing loudly. Once this point is reached the colony is usually abandoned.<ref name = "van Honk">{{cite journal | author = van Honk, C.G.J., P.F. Roseler, H.H.W. Velthuis, and J.C. Hoogeveen | year = 1981 | title = Factors influencing the egg laying of workers in a captive ''Bombus terrestris'' colony | journal = Behavioral Ecology and Sociobiology | volume = 9 | pages = 9–14}}</ref> |
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===Sex ratios=== |
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Due to the variability in the switch point of ''B. terrestris'' colonies, there are varying levels of sex ratios among nests. Early-switching colonies have a much smaller number of future queens compared to males (1:17.4), which may give them a competitive advantage in mating with later emerging queens. Late-switching colonies have fewer males and a more even sex ratio of 1:1:3, thus indicating the queen's control over her colony (she prefers a 1:1 ratio, since she is equally related to both sons and daughters). On the other hand, workers prefer a 3:1 ratio, as they are more related to each other than to their mother. Although early and late switching colonies are usually balanced equally in numbers in the population, the overall demographic in one study was found to be male biased, resulting in an overall sex ratio of 1:4 (female to males).<ref name="Duchateau"/> However, most studies show that this balance of bimodal sex determination between early and late-switching colonies creates the queen's preferred 1:1 sex ratio in ''B. terrestris'' populations.<ref name = "Bourke">{{cite journal | author = Bourke, A.F.G. and F.L.W. Ratnieks | year = 2001 | title = Kin-selected conflict in the bumble-bee ''Bombus terrestris'' (Hymenoptera: Apidae) | journal = Proceedings of the Royal Society of London B | volume = 268 | pages = 347–355}}</ref> This is unusual for monogamous social insects, which usually have a 3:1 sex ratio indicative of worker colony control. ''B. terrestris'' often does not conform to standard predictions of sex ratios based on evolutionary theory and haplodiploid theory. |
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===Reproductive suppression=== |
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====Queen suppression==== |
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Queen bees can control [[oogenesis]] in worker bees via [[juvenile hormone]] (JH), which regulates egg development. Among queenless ''B. terrestris'' workers, the corpus allata, which secretes JH, was noticeably enlarged compared to queenright workers. JH concentrations were also higher in the [[hemolymph]] of queenless workers. This suggests that the presence of a queen is enough to prevent workers from laying eggs, which helps her maintain genetic control over her colony's brood. The mechanism through which the queen induces this behavior is likely through pheromones.<ref>{{cite journal | author = Roseler, P. F. | year= 1977 | title = Juvenile hormone control of oogenesis in bumblebee workers, ''B. terrestris'' | journal = Journal of Insect Physiology | volume = 23 | pages = 985–992}}</ref> |
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====Worker suppression==== |
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While the queen controls much of the egg laying and larval development in the colony, it is likely that workers play a much bigger role in controlling egg laying than previously thought. Dominant workers will often inhibit younger workers from laying eggs.<ref name = "van Honk"/><ref name = "Bloch">{{cite journal | author = Bloch, G. and A. Hefetz | year = 1999 | title = Regulation of reproduction by dominant workers in bumblebee (''Bombus terrestris'') queen right colonies | journal = Behavioral Ecology and Sociobiology | volume = 45 | pages = 125–135}}</ref> Workers have low levels of JH and ovarian development during the early stages of the colony cycle and also after the competition point. Workers introduced into queenright and queenless colonies experience similar levels of inhibition from fellow workers during the competition point, indicating the key role of worker policing of fellow nest mates later in the colony cycle. This suggests that worker reproductive development will be highest between early development and the competition point in the colony.<ref name = "Bloch"/> |
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==Kin selection== |
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[[File:Courgette bloem met gewone aardhommel (Cucurbita pepo and Bombus terristris).jpg |thumb|Queen and worker on ''[[Cucurbita pepo]]'' flower]] |
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===Worker-queen conflict=== |
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Conflict is expected between queen and workers over the sex ratio and reproduction of males in the colony, especially in monandrous colonies where workers are more related to their own sons and nephews than to their brothers.<ref name = "Bloch"/> In early-switching colonies, workers might start laying eggs when they know it will be in their own genetic interests, perhaps from a cue that indicates the switch point has been reached and the queen is now laying [[Ploidy|haploid]] eggs. This might be delayed, because sex can only be differentiated in mature larvae by workers. In late-switching colonies (where the competition point still occurs at the same time in the cycle), workers may start laying eggs when they detect a change in the queen’s pheromone that indicate larvae are developing into new queens.<ref name = "Bourke"/> Thus, the outcome of this conflict is mediated through the dominance of the queen and the information available to the workers. While it is assumed that queens usually win this conflict, it is still unclear because some studies have indicated that up to 80% of males are produced by workers.<ref name = "van Honk"/> These asymmetries in the timing of egg lying and dominance in ''B. terrestris'' might explain why it often does not conform to predicted sex ratios and kin-selection hypotheses. |
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===Worker-worker conflict=== |
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Although ''B. terrestris'' workers are most directly in competition with the queen for egg laying opportunities, they will still inhibit their sisters from laying eggs in order to have their own sons. This is beneficial to them because they will share more genes with their own son (.5) rather than their nephews (.375).<ref name = "Bloch"/> However, kin theory states that in monandrous colonies, workers will be most closely related to each other, so they should spend the most time raising the queen's young, which are their full sisters. This likely reduces worker-egg laying and worker policing, but it is still prevalent in ''B. terrestris'', again indicating how this bumblebee often does not conform to standard kin selection theories for social insects. Worker policing is most common in polyandrous colonies, where sisters can be as removed from one another as they would be from a brother. This increases competition for egg laying and worker policing since nephews are more distantly related to each sister than in singly mated colonies. More research will likely need to be done in order to elucidate the underlying conflict in ''B. terrestris'' colonies. |
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==Social and foraging behavior== |
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===Dominance hierarchy=== |
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Workers start out at the bottom of the dominance hierarchy in the social colony. As they age, they move closer to the position of queen. Queen-side workers are often egg layers and interact more frequently with the queen. This social position may pay off later, after the competition point is reached. When the queen is overthrown by the aggression of the workers, the most dominant worker will have the best likelihood of contributing more eggs to the colony brood and will perhaps climb to the position of “false queen.” The queen appears to maintain a constant distance of social dominance from her workers at all points in the cycle, suggesting that she is displaced by the sheer number of workers later in the cycle.<ref name = "Honk"/> |
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===Foraging behavior=== |
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''B. terrestris'' generally forage on a large variety of flower species. Their highest activity is in the morning, with their peak time being noted at around 7-8 am. This is likely because it gets progressively warmer in the afternoon, and foragers prefer ambient temperatures of around 25°C during nectar and pollen collection. <ref>{{Cite journal|title = Effect of temperature on the foraging activity of Bombus terrestris L. (Hymenoptera: Apidae) on greenhouse hot pepper (Capsicum annuum L.)|url = https://www.jstage.jst.go.jp/article/aez/38/3/38_3_275/_article|journal = Applied Entomology and Zoology|date = 2003-01-01|pages = 275-280|volume = 38|issue = 3|doi = 10.1303/aez.2003.275|first = Yong Jung|last = Kwon|first2 = Shafqat|last2 = Saeed}}</ref> |
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====Alloethism==== |
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''B. terrestris'' bees exhibit alloethism, where different sized bees perform different tasks, in foraging behavior. Larger bees are more often found foraging outside the nest and will return to the nest with larger amounts of nectar and pollen. It is possible that larger bees might be able to withstand greater temperature variation, avoid predation, and travel larger distances making them selectively advantageous. Distinct social roles based on [[Morphology (biology)|morphology]] might also be beneficial for individuals of the colonies, by making the colony operate more efficiently. Small bees can be reared more cheaply and kept for in-nest tasks, while only some larvae will be fed enough to become large foraging bees.<ref name = "Goulson"/> |
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[[File:Bombus terrestris01.jpg|thumb|''B. terrestris'' foraging]] |
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====Food alert==== |
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Individuals who return from the nest after a foraging run often recruit other bees in the colony to leave the nest and search for food. In ''B. terrestris'', successful foragers will return to the nest and run around frantically and without a measurable pattern, unlike the ritualized dance of the honeybee. Although the mechanism by which this recruitment strategy functions is unclear, it is hypothesized that running around likely spreads a pheromone that encourages other bees to exit and forage by indicating the location and odor of food nearby.<ref name ="Dornhaus"/> Bee colonies that have lower food reserves, or honeypots, will be more reactive to foraging pheromones. If the colony already has ample food stores, workers will likely be less sensitive to pheromones in order save time and energy when food collection is not necessary. <ref>{{Cite journal|title = Colony Nutritional Status Modulates Worker Responses to Foraging Recruitment Pheromone in the Bumblebee Bombus terrestris|url = http://www.jstor.org/stable/40295227|journal = Behavioral Ecology and Sociobiology|date = 2008-10-01|pages = 1919-1926|volume = 62|issue = 12|first = Mathieu|last = Molet|first2 = Lars|last2 = Chittka|first3 = Ralph J.|last3 = Stelzer|first4 = Sebastian|last4 = Streit|first5 = Nigel E.|last5 = Raine}}</ref> |
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====Homing ability==== |
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''B. terrestris'' has an impressive homing range, where bees displaced from their nests can relocate the colony from up to 9.8 km away. However, the return often takes several days, indicating ''B. terrestris'' might be utilizing familiar foliage and natural landmarks to find the nest. This may be a tedious process if an individual is outside the conventional foraging range of the nest.<ref>{{cite journal |author = Goulson, D. and J. Stout | year = 2001 | title = Homing ability of the bumblebee ''Bombus terrestris'' (Hymenoptera: Apidae) | journal = Apidologie | volume = 32 | pages = 105–111}}</ref> Another study indicated that these bees can navigate their way back to the nest from a distance as far away as {{convert|13|km|mi|abbr=on}}, although most forage within 5 km of their nest.<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/5215022.stm |title=Homing instinct of bees surprises |publisher=[[BBC News]] |date=July 26, 2006 |author=Louisa Cheung}}</ref> One [[mark and recapture]] study found their average foraging distance to be approximately 663 m.<ref>{{cite journal | author = Walther-Hellwig, K. and R. Frankl | year = 1999 | title = Foraging distances of ''Bombus muscorum'', ''Bombus lapidarius'', and ''Bombus terrestris'' (Hymenoptera, Apidae) | journal = Journal of Insect Behavior | volume = 13 | issue =2 | pages =2000}}</ref> Male bees have also been found to have longer flight ranges than worker bees, likely because they move farther away from the nest to find mates. Males have flight distances of anywhere from 2.6-9.9 km. If males also contribute to [[pollination]], this might increase previously predicted pollen flow ranges based on worker flight behavior.<ref>{{cite journal| author = Kraus, F.B., S. Wolf, R.F.A. Moritz|year = 2009| title = Male flight distance and population substructure in the bumblebee ''Bombus terrestris''| journal = Journal of Animal Ecology | volume = 78 |pages = 247–252}}</ref> |
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===Learning=== |
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Bumblebees and honey bees are extremely influenced by an innate preference for blue and yellow color. When they have no training, they will often just visit flowers that naturally attract them. However, it is generally thought that bees will learn to visit more nectar rewarding flowers after experience associates the reward with the color of the petals. This has been demonstrated in ''B. terrestris,'' where bees trained on artificially colored flowers will pick a similar color to the one they were trained with when tested with an array of flower choices. If individuals were tested with flower colors significantly different than from what they were trained with, they just visited flowers most closely aligned with their innate color preferences.<ref>{{cite journal | author = Gumbert, A | year = 2000 | title = Color choices by bumble bees (''Bombus terrestris''): Innate preferences and generalization after learning | journal = Behavioral Ecology and Sociobiology | volume = 48 | issue = 1 | pages = 36–43 }}</ref> In addition to identifying specific colors for foraging purposes, it has also been shown that young worker bees have to learn complex motor skills in order to efficiently collect nectar and pollen from flowers. These skills might take several days to develop, as memory does not always hold perfectly on a day-to-day basis, sometimes deteriorating overnight.<ref>{{cite journal |author = Raine, N.E. and L. Chittka | year = 2007 | title = Pollen foraging: learning a complex motor skill by bumblebees (''Bombus terrestris'') | journal = Naturwissenschaften | volume = 94 | pages = 459–464 }}</ref> It is worth noting that even within a species different populations have varying levels of innate blue preference and exhibit intraspecific variation in learning rate during association tasks. This is true of two subspecies of ''B. terrestris'', ''B. terrestris dalmatinus'' and ''B. terrestris audax.'' <ref>{{Cite journal|title = A Population Comparison of the Strength and Persistence of Innate Colour Preference and Learning Speed in the Bumblebee Bombus terrestris|url = http://www.jstor.org/stable/40295468|journal = Behavioral Ecology and Sociobiology|date = 2009-06-01|pages = 1207-1218|volume = 63|issue = 8|first = Thomas C.|last = Ings|first2 = Nigel E.|last2 = Raine|first3 = Lars|last3 = Chittka}}</ref> |
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====Limitations on foraging precision==== |
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While bees are highly adept at discrimination tasks, they are still limited by the magnitude of difference needed in hue to properly carry out these tests. Error rates of color recognition decrease in ''B. terrestris'' when flower pigments are closer together on the color spectrum. This might have damaging effects on pollination efficiency if bees visit different flower species with similar, but distinct colors, which can only be mediated if the flowers have unique shapes.<ref>{{cite journal |author = Dyer, A.G. and L. Chittka | year = 2004 | title = Biological significance of distinguishing between similar colours in spectrally variable illumination: bumblebees (''Bombus terrestris'') as a case study | journal = Journal of Comparative Physiology A | volume = 190 | pages = 105–114}}</ref> |
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====Social learning==== |
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While bees often forage alone, experiments demonstrate that young foragers might learn what flowers provide the most nectar more quickly when foraging with older workers. ''B. terrestris'' individuals have a faster learning curve for visiting unfamiliar, yet rewarding flowers, when they can see a conspecific foraging on the same species.<ref>{{cite journal | author = Leadbeater, E. and L. Chittka | year = 2007 | title = The dynamics of social learning in an insect model, the bumblebee (''Bombus terrestris'') | journal = Behavioral Ecology and Sociobiology | volume = 61 | issue = 11 | pages = 1789–1796}}</ref> The discovery of this type of associative learning is a novel insight into bee behavior and may supplement learning via color reward association. |
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[[File:Bombus terrestris 00001.png|thumb|left]] |
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==Parasites and disease== |
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=== Brood parasites === |
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''B. terrestris'' is parasitized by ''[[Bombus bohemicus|B. bohemicus]]'', a [[Brood parasite|brood-parasitic]] [[Cuckoo bee]] that invades ''B. terrestris'' hives and takes over reproductive dominance from the host queen, laying its own eggs that will be cared for by host workers.<ref>Kreuter, Kirsten; Elfi Bunk (November 23, 2011). "How the social parasitic bumblebee Bombus bohemicus sneaks into power of reproduction". ''Behavioral Ecology and Sociobiology'' '''66''' (3): 475–486. doi:10.1007/s00265-011-1294-z. Retrieved 21 September 2015.</ref> Another brood parasite is the bee [[Vestal cuckoo bumblebee|''B. vestalis'']]''.'' Both of these are distributed in various regions of Europe. The difference between ''B. bohemicus'' and ''B. vestalis'' is that the former parasitizes several bumble bee species while ''B. vestalis'' exclusively parasitizes ''B. terrestris.''<ref>{{Cite journal|title = Specialist Bombus vestalis and generalist Bombus bohemicus use different odour cues to find their host Bombus terrestris|url = http://www.sciencedirect.com/science/article/pii/S0003347210001867|journal = Animal Behaviour|date = 2010-08-01|pages = 297–302|volume = 80|issue = 2|doi = 10.1016/j.anbehav.2010.05.010|first = Kirsten|last = Kreuter|first2 = Robert|last2 = Twele|first3 = Wittko|last3 = Francke|first4 = Manfred|last4 = Ayasse}}</ref> |
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===Effects of foraging on resistance=== |
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Foraging is considered energetically costly and it is possible that individuals that spend more time foraging suffer costs to their overall fitness. For example,'' B. terrestris'' is often vulnerable to parasitism by [[Conopidae|conopid flies]] in Central Europe, and it has been hypothesized that foragers might suffer higher incidences of parasites due to the increased metabolic costs of flying. This was demonstrated in a population in which foraging workers had significantly lower levels of encapsulation of an experimental parasitic egg when compared to non-foraging workers. This suggests that foragers have compromised immune systems due to increased energetic expenses and might be predisposed to fly parasites.<ref>{{cite journal | author = Konig, C. and P. Schmid-Hempel | year = 1995 | title = Foraging and immunocompetence in workers of the bumblebee, Bombus terrestris L. | journal = Proceedings of the Royal Society of London B | volume = 260 | pages = 225–227}}</ref> |
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===Effects of polyandry on resistance=== |
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While ''B. terrestris'' is a singly mating species, a polyandrous system would potentially be beneficial because it would be possible to attain greater genetic variability for resistance against disease. Accordingly, artificially increasing the number of mates a ''B. terrestris'' queen obtains through artificial insemination has shown that the increased genetic variability in her offspring confers greater resistance to the most common bumblebee parasite, ''[[Crithidia]] bombi.'' <ref name = "Baer"/> However, the average reproductive success between one and multiple matings is not linear. Queens that mated once and mated four times had a higher fitness than those that mated twice.<ref name = "Baer"/> This suggests that there might be a fitness barrier to increased matings, which might be why colonies are usually monandrous. |
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===Immunocompetence=== |
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Surprisingly, the [[immunocompetence]], as measured by the ability to encapsulate a novel [[antigen]], does not vary based on the local environment. Experimental studies demonstrate that ''B. terrestris'' have equal levels of encapsulation in poor and stable environments.<ref name ="Schmid">{{cite journal | author = Schmid-Hempel, R. and P. Schmid-Hempel | year = 1998 | title = Colony performance and immunocompetence of a social insect, ''B. terrestris'', in poor and variable environments | journal = Functional Ecology | volume = 22 | pages = 22–30}}</ref> This is unexpected, because [[Immune system|immunity]] should be compromised in conditions where food supply is low in order to save energy. Perhaps encapsulation represents an invariable trait of bumblebees, or immunity is far too complex to characterize solely based on measurements of encapsulation. |
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===Threats from disease=== |
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[[File:Deformed Wing Virus in worker bee.JPG |thumb|Honeybee infected with deformed wing virus]] |
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[[Deformed wing virus]] (DMV) is normally a [[Apis mellifera|honey bee]] pathogen that results in reduced and crumpled wings, making those individuals inviable. This virus is thought to have spread to ''B. terrestris,'' and in 2004, as many as 10% of queen bees bred commercially in Europe were found dead with deformed wings. This was confirmed as DMV when ''B. terrestris'' colonies tested positive for the presence of DMV [[RNA]]. This could indicate that DMV is a broad range pathogen among bees, or perhaps it has recently been infecting new hosts after transmission from [[honey bee]]s.<ref>{{cite journal | author = Genersch, E., C. Yue, I. Fries, J. R. de Miranda | year = 2006 | title = Detection of Deformed wing virus, a honey bee viral pathogen, in bumble bees (''Bombus terrestris'' and ''Bombus pascuorum'') with wing deformities | journal = Journal of Insect Pathology | volume = 91 | pages = 61–63}}</ref> |
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==Environmental concerns== |
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===Invasive species=== |
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While native to Europe, ''B. terrestris'' has been introduced as a greenhouse pollinator into many foreign ecosystems. The presence of ''B. terrestris'' is becoming an ecological concern in many communities in which it is not native. It is classified as an "invasive alien species" in Japan.<ref name="Matsumura"/> For example, ''B. terrestris'' has a large niche overlap with local Japanese bee species in terms of flower resources and nest sites. ''B. terrestris'' queens competing for local underground nest sites are displacing ''B. hypocrita sapporoensis''. However, ''B. pseudobaicalensis'', which visits similar flowers but only forms nests above ground, has not seen a rapid decline in population numbers.<ref name = "Inoue"/> |
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In 2008, the Australian government banned the live import of ''B. terrestris'' into Australia on the grounds that it would present a significant risk of becoming a feral species and thereby present a threat to native fauna and flora.<ref>{{cite web | last = | first = | authorlink = Minister for the Environment, Heritage and the Arts | coauthors = | title = Bumblebee rejected for live import | work = | publisher = Australian Government | date = 26 October 2008 | url = http://www.environment.gov.au/minister/garrett/2008/mr20081026.html| doi = | accessdate = 1 January 2009 }}</ref> In 2004, this bumblebee was classified as a 'Key Threatening Process' by the Scientific Committee of the New South Wales Department of Environment.<ref>{{cite web |author= Paul Adam | authorlink = | coauthors = | title = Introduction of the large earth bumblebee, ''Bombus terrestris'' - key threatening process listing | work = | publisher = NSW Government | date = February 2004 | url = http://www.environment.nsw.gov.au/determinations/BombusTerrestrisKtpDeclaration.htm | doi = | accessdate = 1 January 2009 }}</ref> |
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This species was introduced to Chile in 1998. It has since crossed into Argentina, and is spreading at about 275 km per year. Its spread has been detrimental to populations of ''[[Bombus dahlbomii]]'', which is the only bumblebee species native to southern South America (Patagonia, Southern Chile and Argentina).<ref name=one>{{cite journal|last1=Polidori|first1=C|last2=Nieves-Aldrey|first2=JL|title=Comparative flight morphology in queens of invasive and native Patagonian bumblebees (Hymenoptera: Bombus)|journal=Elsevier|date=2014|volume=338|issue=2|pages=126–33|pmid=25499798|doi=10.1016/j.crvi.2014.11.001}}</ref> ''Bombus terrestris'' populations facilitated such massive and immediate population decline of ''[[Bombus dahlbomii]]'' through competition and pathogen introduction/spillover.<ref name="one"/><ref name=rufford>{{cite journal|last1=Arbetman|first1=Marina|last2=Meeus|first2=Ivan|last3=Morales|first3=Carolina|title=Alien parasite hitchhikes to Patagonia on invasive bumblebee|journal=Biological Invasions|date=2006|volume=8|issue=1|pages=489|doi=10.1007/s10530-012-0311-0|url=http://www.rufford.org/files/Biol%20Invasions%20DOI%2010.1007s10530-012-0311-0_0.pdf}}</ref> ''[[Bombus ruderatus]]'', a bee previously introduced in 1982, is also seriously affected. The cause is thought to be the parasite ''[[Apicystis bombi]]'', an organism carried by the buff-tails, but which has no adverse effect on that species.<ref>{{cite journal | last= Goulson | first= Dave | year=2013 | title= Argentinian invasion! | journal= Buzzword | volume= 21 |issue = | pages= 17–18 | url = |format = | doi = }}</ref> |
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===Colony development in changing environments=== |
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In [[Temperate climate|temperate]] areas, variable climates and environmental conditions occur during changing seasons. Lack of available food due to these unpredictable circumstances can often negatively affect colony growth, reproduction, and resistance to parasites. In poor environments with limited food, the few workers born are smaller than average. However, it appears that ''B. terrestris'' is well adapted to a changing environment, considering colony growth is higher under variable feeding conditions than under stable feeding conditions. Workers and reproductives are also heavier with a variable food supply when compared to stable food availability. This might indicate an adaptive strategy of increased provisioning to save for days it is hard to find food.<ref name ="Schmid"/> |
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===Pesticide exposure=== |
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In their 2014 study published in ''[[Functional Ecology]]'' researchers using [[Radio-frequency identification|Radio-Frequency Identification (]]RFID) tagging technology on the bees, found that a sublethal exposure to either a [[neonicotinoid]] ([[imidacloprid]]) and/or a [[pyrethroid]] (?-[[cyhalothrin]]) over a four-week period caused an impairment of the bumblebee's ability to [[forage]].<ref name="Gill_Raine_2014">{{cite journal |journal=Functional Ecology |title=Chronic impairment of bumblebee natural foraging behaviour induced by sublethal pesticide exposure |first1=Richard J. |last1=Gill |first2=Nigel E. |last2=Raine |date=7 July 2014 |accessdate=4 October 2014 |doi=10.1111/1365-2435.12292 }}</ref> Research published in 2015 showed that bees prefer solutions containing [[Neonicotinoid|neonicotinoids]], even though the consumption of these pesticides caused them to eat less food overall. This work implies that treating flowering crops with such pesticides presents a sizeable hazard to foraging bees.<ref name="Neonicotinoids">{{cite journal|last=Kessler|first=Sebastien C|coauthors=et al|date=7 May 2015|title=Bees prefer foods containing neonicotinoid pesticides|journal=Nature|publisher=Macmillan Publishing Ltd|volume=521|pages= 74–76|issn= 0028-0836|url=http://www.nature.com/nature/journal/v521/n7550/full/nature14414.html}}</ref> |
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==Human importance== |
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===Commercial Use=== |
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Since 1987, ''B. terrestris'' has been bred commercially for use as a pollinator in European greenhouse crops, particularly tomatoes—a task which was previously carried out by human hand.<ref name="Matsumura">{{cite journal|last=Matsumura|first=Chizuru |author2=Jun Yokoyama|author3=Izumi Wasitani|date=August 2004|title=Invasion Status and Potential Ecological Impacts of an Invasive Alien Bumblebee, Bombus terrestris L. (Hymenoptera: Apidae) Naturalized in Southern Hokkaido, Japan|journal=Global Environmental Research|publisher=AIRIES|pages=51–66|url=http://www.airies.or.jp/publication/ger/pdf/08-01-06.pdf}}</ref><ref>{{cite web|url=http://www.koppert.com/Pollination/?snsrc=aws_af0698a370efeb5d62f7ead745f106678343564925&snkw=pollination&gclid=COib-bPopqsCFesLtAodzl_7zw|title=Natural pollination|last=Anon|work=Koppert Biological Systems|publisher=Koppert B.V.|accessdate=18 September 2011}}</ref> ''B. terrestris'' has been commercially reared in New Zealand since the early 1990s,<ref>Velthuis, H. H. W. and van Doorn, A. (April 2004) 'The breeding, commercialization and economic value of bumblebees.' in B. M. Freitas and J. O. P. Pereira (eds) ''Solitary Bees Conservation, Rearing and Management for Pollination.'' Federal University of Ceara, Brasil, pp. 135-149</ref><ref>http://biobees.co.nz/biology.html</ref> and is now used in at least North Africa, Japan, Korea, and Russia, with the global trade in bumblebee colonies probably exceeding 1 million nests per year.<ref>[[Dave Goulson]] (2010). "Bumblebees. Behaviour, Ecology and Conservation" Oxford University Press.</ref> In Korea, however, some have chosen ''[[Bombus ignitus]]'' over the already established commercial pollinator, ''Bombus terrestris'', for fear of competition or genetic contamination by mating with native bumblebee species.<ref>{{Cite journal|url = |title = Temperature and humidity favorable for colony development of the indoor-reared bumblebee, Bombus ignitus|last = Joo Yoon|first = Hyung|date = April 2002|journal = Applied Entomology and Zoology|doi = |pmid = |access-date = }}</ref> Also, there has been a ban on importing ''B. terrestris'' into North America which resulted in higher interest in other species like ''[[Common eastern bumblebee|B. impatiens]]'' in North America''.''<ref>"Bumblebees : Behaviour, Ecology, and Conservation". ''web.a.ebscohost.com''. Retrieved 2015-09-26.</ref> |
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Nonetheless, ''B. terrestris'' are key commercial pollinators in Europe, which has driven researchers to investigate the influence of agricultural land on the foraging and survival of this species. [[Monoculture]] reduces biodiversity in farmland areas, and likely decreases the number of flowering species bees can forage on. ''B. terrestris'' consequently exhibits greater nest growth in suburban areas than in farmland, because local suburban gardens promote more plant diversity for bees to feed from. Agriculture has a profound impact on many bumblebees, and is causing widespread decline in several species. However, ''B. terrestris'' is still widespread, likely because it can forage at very long distances, making it less sensitive to changes in [[biodiversity]] and the environment.<ref>{{cite journal | author = Goulson, D., W.O.H. Hughes, L.C. Derwent, and J.C. Stout | year = 2002 | title = Colony growth of the bumblebee, ''Bombus terrestris'', in improved and conventional agricultural and suburban habitats | journal = Oecologia | volume = 130 | pages = 267–273}}</ref> |
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==References== |
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{{reflist|2}} |
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==External links== |
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{{Commons|Bombus terrestris}} |
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{{Wikispecies|Bombus terrestris}} |
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* [http://www.aussiebee.com.au/bumblebeeharm.html ''What Harm Could Exotic Bumblebees Do in Australia?''] - a report by Australian Native Bee Research Centre |
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[[Category:Bumblebees]] |
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[[Category:Pollinators]] |
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[[Category:Hymenoptera of Europe]] |
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[[Category:Invasive insect species]] |
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[[Category:Insects described in 1758]] |
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Revision as of 18:05, 12 November 2015
Social castes
Like in most social bees, there are three main social caste divisions in B. terrestris. This ensures a division of labor and efficient colony functioning. Queens become the main female individual to reproduce in a future colony. Her sole responsibility is to lay eggs after she founds a nest. This fate is determined for larvae that receive more food, have longer instar stages and higher levels of juvenile hormone biosynthesis. [1] Workers, an entirely female caste, mainly forage for food, defend the colony, and tend to the growing larvae. They are usually sterile for most of the colony cycle and do not raise their own young. Unlike queens and workers, which develop from fertilized diploid eggs, drones, or male bees, are born from unfertilized, haploid eggs. Drones leave the colony shortly after reaching adulthood to find a mate outside the nest. This is their sole role in the colony.
- ^ CNAANI, JONATHAN; BORST, DAVID W; HUANG, Z. -Y; ROBINSON, GENE E; HEFETZ, ABRAHAM (1997-04-01). "Caste Determination in Bombus terrestris: Differences in Development and Rates of JH Biosynthesis between Queen and Worker Larvae". Journal of Insect Physiology. 43 (4): 373–381. doi:10.1016/S0022-1910(96)00106-0.