Bombus terrestris

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'''''Bombus terrestris''''', the '''buff-tailed bumblebee''' or '''large earth bumblebee''', is one of the most numerous [[bumblebee]] [[species]] in [[Europe]]. It is one of the main species used in greenhouse [[pollination]], and so can be found in many countries and areas where it is not native, such as [[Tasmania]].{{cite journal |author1=Semmens, T.D. |author2=E. Turner |author3=R. Buttermore. |name-list-style=amp |title = ''Bombus terrestris'' (L.) (Hymenoptera: Apidae) now established in Tasmania | journal = Australian Journal of Entomology | year = 1993 | volume = 32 | issue = 4| page =346 | doi=10.1111/j.1440-6055.1993.tb00598.x| doi-access =free }} Moreover, it is a [[Eusociality|eusocial]] [[insect]] with an overlap of generations, a division of labour, and cooperative brood care. The queen is [[monogamy in animals|monogamous]] which means she mates with only one male. ''B. terrestris'' workers learn flower colours and forage efficiently.

'''''Bombus terrestris''''', the '''buff-tailed bumblebee''' or '''large earth bumblebee''', is one of the most numerous [[bumblebee]] [[species]] in [[Europe]]. It is one of the main species used in greenhouse [[pollination]], and so can be found in many countries and areas where it is not native, such as [[Tasmania]].{{cite journal |author1=Semmens, T.D. |author2=E. Turner |author3=R. Buttermore. |name-list-style=amp |title = ''Bombus terrestris'' (L.) (Hymenoptera: Apidae) now established in Tasmania | journal = Australian Journal of Entomology | year = 1993 | volume = 32 | issue = 4| page =346 | doi=10.1111/j.1440-6055.1993.tb00598.x| doi-access =free }} Moreover, it is a [[Eusociality|eusocial]] [[insect]] with an overlap of generations, a division of labour, and cooperative brood care. The queen is [[monogamy in animals|monogamous]], which means she mates with only one male. ''B. terrestris'' workers learn flower colours and forage efficiently.

== Taxonomy and phylogenetics ==

== Taxonomy and phylogenetics ==

This first phase can last a variable amount of time in ''B. terrestris'', after which a switch point is reached, and the queen begins to lay some unfertilized eggs, which develop into males. When the male drones emerge from the nest, they do not return, foraging only for themselves. They seek out emerging queens and mate with them. The remaining diploid eggs hatch into larvae that 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 resolution of this worker/queen conflict can be complex and is discussed below. The colony persists until fall in temperate zones and then workers begin to lay unfertilized eggs that if they mature will become males. 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 in very temperate climates.

This first phase can last a variable amount of time in ''B. terrestris'', after which a switch point is reached, and the queen begins to lay some unfertilized eggs, which develop into males. When the male drones emerge from the nest, they do not return, foraging only for themselves. They seek out emerging queens and mate with them. The remaining diploid eggs hatch into larvae that 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 resolution of this worker/queen conflict can be complex and is discussed below. The colony persists until fall in temperate zones and then workers begin to lay unfertilized eggs that if they mature will become males. 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 in very temperate climates.

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.{{cite journal |author1=van Honk C. |author2= P. Hogeweg |name-list-style=amp | 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 | doi=10.1007/bf00293582|bibcode= 1981BEcoS...9..111V |s2cid= 39669241 }} The newly emerged queens sometimes act as workers and help to raise another brood of queens. During this time they daily leave the nest looking for food, during which time they may mate. Eventually they find a site to dig a "hibernaculum" where they will hibernate until the next spring, when they emerge, seek food — primarily to build up their ovaries — and soon seek a site to found a new nest. (In warmer climates they may skip the hibernation stage.) Almost always the old colony will have died out, and if the site is free of parasites one of the new queens will return and reuse that site.

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.{{cite journal |author1=van Honk C. |author2= P. Hogeweg |name-list-style=amp | 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 | doi=10.1007/bf00293582|bibcode= 1981BEcoS...9..111V |s2cid= 39669241 }} The newly emerged queens sometimes act as workers and help to raise another brood of queens. During this time they daily leave the nest looking for food, during which time they may mate. Eventually they find a site to dig a "hibernaculum" where they will hibernate until the next spring, when they emerge, seek food — primarily to build up their ovaries — and soon seek a site to found a new nest. (In warmer climates they may skip the hibernation stage.) Almost always the old colony will have died out, and if the site is free of parasites one of the new queens will return and reuse that site.

==Reproductive behavior==

==Reproductive behavior==

[[File:Courgette bloem met gewone aardhommel (Cucurbita pepo and Bombus terristris).jpg |thumb|Queen and worker on ''[[Cucurbita pepo]]'' flower]]

[[File:Courgette bloem met gewone aardhommel (Cucurbita pepo and Bombus terristris).jpg |thumb|Queen and worker on ''[[Cucurbita pepo]]'' flower]]

===Worker-queen conflict===

===Worker–queen conflict===

Conflict is expected between the 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. 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 haploid eggs. 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. 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. 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, although worker bees are more closely related to their nephews (0.375) than to their brothers (0.25) and kinship selection would lead workers to favor their sons over nephews, and nephews over brothers.

Conflict is expected between the 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. 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 haploid eggs. 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. 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. 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, although worker bees are more closely related to their nephews (0.375) than to their brothers (0.25) and kinship selection would lead workers to favor their sons over nephews, and nephews over brothers.

===Worker-worker conflict===

===Worker–worker conflict===

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 sons (.5) rather than their nephews (.375). However, kin theory states that in monandrous colonies, workers will be most closely related to their sisters (0.75) but are more closely related to their sons (0.50) than to their nephews (0.375) and least of all to their brothers (0.25), and would accordingly devote their resources.

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 sons (.5) rather than their nephews (.375). However, kin theory states that in monandrous colonies, workers will be most closely related to their sisters (0.75) but are more closely related to their sons (0.50) than to their nephews (0.375) and least of all to their brothers (0.25), and would accordingly devote their resources.

===Foraging behavior===

===Foraging behavior===

''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.{{Cite journal|title = Effect of temperature on the foraging activity of Bombus terrestris L. (Hymenoptera: Apidae) on greenhouse hot pepper (Capsicum annuum L.)|journal = Applied Entomology and Zoology|date = 2003-01-01|pages = 275–280|volume = 38|issue = 3|doi = 10.1303/aez.2003.275|first1 = Yong Jung|last1 = Kwon|first2 = Shafqat|last2 = Saeed|doi-access = free| bibcode=2003AppEZ..38..275K }}

''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.{{Cite journal|title = Effect of temperature on the foraging activity of Bombus terrestris L. (Hymenoptera: Apidae) on greenhouse hot pepper (Capsicum annuum L.)|journal = Applied Entomology and Zoology|date = 2003-01-01|pages = 275–280|volume = 38|issue = 3|doi = 10.1303/aez.2003.275|first1 = Yong Jung|last1 = Kwon|first2 = Shafqat|last2 = Saeed|doi-access = free| bibcode=2003AppEZ..38..275K }}

''B. terrestris'' bees exhibit alloethism, which is where different sized bees perform different tasks. This kind of behavior can be seen most often in foraging activities. 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.

''B. terrestris'' bees exhibit alloethism, which is where different sized bees perform different tasks. This kind of behavior can be seen most often in foraging activities. 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.

=== Parasites ===

=== Parasites ===

''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.{{cite journal |last1=Kreuter |first1=Kirsten |last2=Bunk |first2=Elfi |last3=Lückemeyer |first3=Anna |last4=Twele |first4=Robert |last5=Francke |first5=Wittko |last6=Ayasse |first6=Manfred |title=How the social parasitic bumblebee Bombus bohemicus sneaks into power of reproduction |journal=Behavioral Ecology and Sociobiology |date=March 2012 |volume=66 |issue=3 |pages=475–486 |doi=10.1007/s00265-011-1294-z |bibcode=2012BEcoS..66..475K |s2cid=7124725 }} 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''.{{cite journal |last1=Kreuter |first1=Kirsten |last2=Twele |first2=Robert |last3=Francke |first3=Wittko |last4=Ayasse |first4=Manfred |title=Specialist Bombus vestalis and generalist Bombus bohemicus use different odour cues to find their host Bombus terrestris |journal=Animal Behaviour |date=August 2010 |volume=80 |issue=2 |pages=297–302 |doi=10.1016/j.anbehav.2010.05.010 |s2cid=140212119 }}

''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.{{cite journal |last1=Kreuter |first1=Kirsten |last2=Bunk |first2=Elfi |last3=Lückemeyer |first3=Anna |last4=Twele |first4=Robert |last5=Francke |first5=Wittko |last6=Ayasse |first6=Manfred |title=How the social parasitic bumblebee Bombus bohemicus sneaks into power of reproduction |journal=Behavioral Ecology and Sociobiology |date=March 2012 |volume=66 |issue=3 |pages=475–486 |doi=10.1007/s00265-011-1294-z |bibcode=2012BEcoS..66..475K |s2cid=7124725 }} 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''.{{cite journal |last1=Kreuter |first1=Kirsten |last2=Twele |first2=Robert |last3=Francke |first3=Wittko |last4=Ayasse |first4=Manfred |title=Specialist Bombus vestalis and generalist Bombus bohemicus use different odour cues to find their host Bombus terrestris |journal=Animal Behaviour |date=August 2010 |volume=80 |issue=2 |pages=297–302 |doi=10.1016/j.anbehav.2010.05.010 |s2cid=140212119 }}

A common microsporidian parasite that infects the gut of various bumblebee species, including ''B. terrestris'', is ''[[Nosema bombi]]''. It can cause a creeping disease and is detrimental to the fitness of its bumblebee host.Paul Schmid-Hempel (1998). "Parasites in Social Insects" Princeton University Press. A study by Manlik et al. (2017) showed that ''N. bombi'' infection prevalence varies widely over time, and is associated with [[mitochondrial DNA]] genotypes in ''B. terrestris''.{{cite journal |author1=Oliver Manlik |author2=Regula Schmid-Hempel |author3=Paul Schmid-Hempel |name-list-style=amp |year=2017 |title=Parasite infection of specific host genotypes relates to changes in prevalence in two natural populations of bumblebees |journal=[[Infection, Genetics and Evolution]] |volume=56 |pages=125–132 |doi=10.1016/j.meegid.2017.11.019 |pmid=29155285 |bibcode=2017InfGE..56..125M |hdl=1959.4/unsworks_48026 |hdl-access=free }}

A common microsporidian parasite that infects the gut of various bumblebee species, including ''B. terrestris'', is ''[[Nosema bombi]]''. It can cause a creeping disease and is detrimental to the fitness of its bumblebee host.Paul Schmid-Hempel (1998). "Parasites in Social Insects" Princeton University Press. A study by Manlik et al. (2017) showed that ''N. bombi'' infection prevalence varies widely over time, and is associated with [[mitochondrial DNA]] genotypes in ''B. terrestris''.{{cite journal |author1=Oliver Manlik |author2=Regula Schmid-Hempel |author3=Paul Schmid-Hempel |name-list-style=amp |year=2017 |title=Parasite infection of specific host genotypes relates to changes in prevalence in two natural populations of bumblebees |journal=[[Infection, Genetics and Evolution]] |volume=56 |pages=125–132 |doi=10.1016/j.meegid.2017.11.019 |pmid=29155285 |bibcode=2017InfGE..56..125M |hdl=1959.4/unsworks_48026 |hdl-access=free }}

===Pesticide exposure===

===Pesticide exposure===

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]].{{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 |doi=10.1111/1365-2435.12292 |volume=28 |issue=6 |pages=1459–1471|doi-access=free |bibcode=2014FuEco..28.1459G }} Research published in 2015 showed that bees prefer solutions containing 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.{{cite journal |last1=Kessler |first1=Sébastien C. |last2=Tiedeken |first2=Erin Jo |last3=Simcock |first3=Kerry L. |last4=Derveau |first4=Sophie |last5=Mitchell |first5=Jessica |last6=Softley |first6=Samantha |last7=Radcliffe |first7=Amy |last8=Stout |first8=Jane C. |last9=Wright |first9=Geraldine A. |title=Bees prefer foods containing neonicotinoid pesticides |journal=Nature |date=7 May 2015 |volume=521 |issue=7550 |pages=74–76 |doi=10.1038/nature14414 |pmid=25901684 |pmc=4772122 |bibcode=2015Natur.521...74K }}

In their 2014 study published in ''[[Functional Ecology]]'' researchers using [[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]].{{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 |doi=10.1111/1365-2435.12292 |volume=28 |issue=6 |pages=1459–1471|doi-access=free |bibcode=2014FuEco..28.1459G }} Research published in 2015 showed that bees prefer solutions containing 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.{{cite journal |last1=Kessler |first1=Sébastien C. |last2=Tiedeken |first2=Erin Jo |last3=Simcock |first3=Kerry L. |last4=Derveau |first4=Sophie |last5=Mitchell |first5=Jessica |last6=Softley |first6=Samantha |last7=Radcliffe |first7=Amy |last8=Stout |first8=Jane C. |last9=Wright |first9=Geraldine A. |title=Bees prefer foods containing neonicotinoid pesticides |journal=Nature |date=7 May 2015 |volume=521 |issue=7550 |pages=74–76 |doi=10.1038/nature14414 |pmid=25901684 |pmc=4772122 |bibcode=2015Natur.521...74K }}

==Human importance==

==Human importance==