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David R. Tarpy - One of the best experts on this subject based on the ideXlab platform.
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Honey Bee (Apis mellifera) Queen Reproductive Potential Affects Queen Mandibular Gland Pheromone Composition and Worker Retinue Response
2016Co-Authors: Juliana Rangel, Katalin Böröczky, Coby Schal, David R. TarpyAbstract:Reproductive division of labor is one of the defining traits of honey bees (Apis mellifera), with non-reproductive tasks being performed by Workers while a single queen normally monopolizes reproduction. The decentralized organization of a honey bee colony is maintained in large part by a bouquet of queen-produced pheromones, the distribution of which is facilitated by contact among Workers throughout the hive. Previous studies have shown that the developmental fate of honey bee queens is highly plastic, with queens raised from younger Worker larvae exhibiting higher measures of reproductive potential compared to queens raised from Older Worker larvae. We investigated differences in the chemical composition of the mandibular glands and attractiveness to Workers of “high-quality” queens (i.e., raised from first instar Worker larvae; more queen-like) and “low-quality” queens (i.e., raised from third instar Worker larvae; more Worker-like). We characterized the chemical profiles of the mandibular glands of high-quality queens and low-quality queens using GC-MS and used the Worker retinue response as a measure of the attractiveness to Workers of high-quality queens vs. low-quality queens. We found that queen quality affected the chemical profiles of mandibular gland contents differently across years, showing significant differences in the production of the queen mandibular pheromone (“QMP”) components HVA and 9-HDA in 2010, but no significant differences of any glandular compound in 2012. We also found that Workers were significantly more attracted to high-quality queens than to low-quality queens in 2012, possibly because of increased attractiveness of their mandibular gland chemical profiles. Our results indicate that the age at which honey bee larvae enter the “queen-specific” developmental pathway influences the chemical composition of queen mandibular glands and Worker behavior. However, these changes are not consistent across years, suggesting that other external factors may play important roles in modulating queen quality.
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the effects of honey bee apis mellifera l queen reproductive potential on colony growth
Insectes Sociaux, 2013Co-Authors: Juliana Rangel, J. J. Keller, David R. TarpyAbstract:Reproduction in species of eusocial insects is monopolized by one or a few individuals, while the remaining colony tasks are performed by the Worker caste. This reproductive division of labor is exemplified by honey bees (Apis mellifera L.), in which a single, polyandrous queen is the sole colony member that lays fertilized eggs. Previous work has revealed that the developmental fate of honey bee queens is highly plastic, with queens raised from younger Worker larvae exhibiting higher measures in several aspects of reproductive potential compared to queens raised from Older Worker larvae. Here, we investigated the effects of queen reproductive potential (“quality”) on the growth and winter survival of newly established honey bee colonies. We did so by comparing the growth of colonies headed by “high-quality” queens (i.e., those raised from young Worker larvae, which are more queen-like morphologically) to those headed by “low-quality” queens (i.e., those raised from Older Worker larvae, which are more Worker-like morphologically). We confirmed that queens reared from young Worker larvae were significantly larger in size than queens reared from old Worker larvae. We also found a significant positive effect of queen grafting age on a colony’s production of Worker comb, drone comb, and stored food (honey and pollen), although we did not find a statistically significant difference in the production of Worker and drone brood, Worker population, and colony weight. Our results provide evidence that in honey bees, queen developmental plasticity influences several important measures of colony fitness. Thus, the present study supports the idea that a honey bee colony can be viewed (at least in part) as the expanded phenotype of its queen, and thus selection acting predominantly at the colony level can be congruent with that at the individual level.
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Experimentally induced variation in the physical reproductive potential and mating success in honey bee queens
Insectes Sociaux, 2011Co-Authors: David R. Tarpy, J. J. Keller, Joel R. Caren, Deborah A. DelaneyAbstract:In honeybee colonies, reproduction is monopolized by the queen while her daughter Workers are facultatively sterile. Caste determination is a consequence of environmental conditions during development, during which female larvae may become either queens or Workers depending on their larval diet. This bipotency introduces significant variation in the reproductive potential of queen bees, with queens raised from young Worker larvae exhibiting high reproductive potential and queens raised from Older Worker larvae exhibiting lower reproductive potential. We verify that low-quality queens are indeed produced from Older Worker larvae, as measured morphometrically (e.g., body size) and by stored sperm counts. We also show, for the first time, that low-quality queens mate with significantly fewer males, which significantly influences the resultant intracolony genetic diversity of the Worker force of their future colonies. These results demonstrate a reproductive continuum of honeybee queens and provide insights into the reproductive constraints of social insects.
Zeng, Zhi Jiang - One of the best experts on this subject based on the ideXlab platform.
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Making a queen : an epigenetic analysis of the robustness of the honeybee (Apis mellifera) queen developmental pathway
'Wiley', 2017Co-Authors: He, Xu Jiang, Zhou, Lin Bin, Pan, Qi Zhong, Barron, Andrew B, Wei Yu Yan, Zeng, Zhi JiangAbstract:Specialized castes are considered a key reason for the evolutionary and ecological success of the social insect lifestyle. The most essential caste distinction is between the fertile queen and the sterile Workers. Honeybee (Apis mellifera) Workers and queens are not genetically distinct, rather these different phenotypes are the result of epigenetically regulated divergent developmental pathways. This is an important phenomenon in understanding the evolution of social insect societies. Here, we studied the genomic regulation of the Worker and queen developmental pathways, and the robustness of the pathways by transplanting eggs or young larvae to queen cells. Queens could be successfully reared from Worker larvae transplanted up to 3 days age, but queens reared from Older Worker larvae had decreased queen body size and weight compared with queens from transplanted eggs. Gene expression analysis showed that queens raised from Worker larvae differed from queens raised from eggs in the expression of genes involved in the immune system, caste differentiation, body development and longevity. DNA methylation levels were also higher in 3-day-old queen larvae raised from Worker larvae compared with that raised from transplanted eggs identifying a possible mechanism stabilizing the two developmental paths. We propose that environmental (nutrition and space) changes induced by the commercial rearing practice result in a suboptimal queen phenotype via epigenetic processes, which may potentially contribute to the evolution of queen–Worker dimorphism. This also has potentially contributed to the global increase in honeybee colony failure rates.10 page(s
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Data from: Making a queen: an epigenetic analysis of the robustness of the honey bee (Apis mellifera) queen developmental pathway
2016Co-Authors: He, Xu Jiang, Zhou, Lin Bin, Pan, Qi Zhong, Barron, Andrew B, Wei Yu Yan, Zeng, Zhi JiangAbstract:Specialized castes are considered a key reason for the evolutionary and ecological success of the social insect lifestyle. The most essential caste distinction is between the fertile queen and the sterile Workers. Honeybee (Apis mellifera) Workers and queens are not genetically distinct, rather these different phenotypes are the result of epigenetically regulated divergent developmental pathways. This is an important phenomenon in understanding the evolution of social insect societies. Here, we studied the genomic regulation of the Worker and queen developmental pathways, and the robustness of the pathways by transplanting eggs or young larvae to queen cells. Queens could be successfully reared from Worker larvae transplanted up to 3 days age, but queens reared from Older Worker larvae had decreased queen body size and weight compared with queens from transplanted eggs. Gene expression analysis showed that queens raised from Worker larvae differed from queens raised from eggs in the expression of genes involved in the immune system, caste differentiation, body development and longevity. DNA methylation levels were also higher in 3-day-old queen larvae raised from Worker larvae compared with that raised from transplanted eggs identifying a possible mechanism stabilizing the two developmental paths. We propose that environmental (nutrition and space) changes induced by the commercial rearing practice result in a suboptimal queen phenotype via epigenetic processes, which may potentially contribute to the evolution of queen–Worker dimorphism. This also has potentially contributed to the global increase in honeybee colony failure rates
Joanna N Lahey - One of the best experts on this subject based on the ideXlab platform.
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age women and hiring an experimental study
Journal of Human Resources, 2008Co-Authors: Joanna N LaheyAbstract:As baby boomers reach retirement age, demographic pressures on public programs may cause policy makers to cut benefits and encourage employment at later ages. But how much demand exists for Older Workers? This paper reports on a field experiment to determine hiring conditions for Older women in entry-level jobs in two cities. A younger Worker is more than 40 percent more likely to be offered an interview than is an Older Worker. No evidence is found to support taste-based discrimination as a reason for this differential, and some suggestive evidence is found to support statistical discrimination.
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age women and hiring an experimental study
National Bureau of Economic Research, 2005Co-Authors: Joanna N LaheyAbstract:As the baby boom cohort reaches retirement age, demographic pressures on public programs such as social security may cause policy makers to cut benefits and encourage employment at later ages. This paper reports on a labor market experiment to determine the hiring conditions for Older women in entry-level jobs in Boston, MA and St. Petersburg, FL. Differential interviewing by age is found for these jobs. A younger Worker is more than 40% more likely to be offered an interview than an Older Worker. No evidence is found to support taste-based discrimination as a reason for this differential and some suggestive evidence is found to support statistical discrimination.
Shaoze Yan - One of the best experts on this subject based on the ideXlab platform.
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a quick tongue Older honey bees dip nectar faster to compensate for mouthpart structure deterioration
The Journal of Experimental Biology, 2019Co-Authors: Yue Chen, Yunqiang Yang, Matthew S Lehnert, Shaoze YanAbstract:ABSTRACT The western honey bee, Apis mellifera L. (Hymenoptera), is arguably the most important pollinator worldwide. While feeding, A. mellifera uses a rapid back-and-forth motion with its brush-like mouthparts to probe pools and films of nectar. Because of the physical forces experienced by the mouthparts during the feeding process, we hypothesized that the mouthparts acquire wear or damage over time, which is paradoxical, because it is the Older Worker bees that are tasked with foraging for nectar and pollen. Here, we show that the average length of the setae (brush-like structures) on the glossa decreases with honey bee age, particularly when feeding on high-viscosity sucrose solutions. The nectar intake rate, however, remains nearly constant regardless of age or setae length (0.39±0.03 μg s−1 for honey bees fed a 45% sucrose solution and 0.48±0.05 μg s−1 for those fed a 35% sucrose solution). Observations of the feeding process with high-speed video recording revealed that the Older honey bees with shorter setae dip nectar at a higher frequency. We propose a liquid transport model to calculate the nectar intake rate, energy intake rate and the power to overcome viscous drag. Theoretical analysis indicates that A. mellifera with shorter glossal setae can compensate both nectar and energy intake rates by increasing dipping frequency. The altered feeding behavior provides insight into how A. mellifera, and perhaps other insects with similar feeding mechanisms, can maintain a consistent fluid uptake rate, despite having damaged mouthparts.
Kelly Simon - One of the best experts on this subject based on the ideXlab platform.
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The need for fresh blood: understanding organizational age inequality through a vampiric lens
'SAGE Publications', 2015Co-Authors: Riach K., Kelly SimonAbstract:YesThis article argues that Older age inequality within and across working life is the result of vampiric forms and structures constitutive of contemporary organizing. Rather than assuming ageism occurs against a backdrop of neutral organizational processes and practices, the article denaturalizes (and in the process super-naturalizes) organizational orientations of ageing through three vampiric aspects: (un)dying, regeneration and neophilia. These dimensions are used to illustrate how workplace narratives and logics normalize and perpetuate the systematic denigration of the ageing organizational subject. Through our analysis it is argued that Older Workers are positioned as inevitable ‘sacrificial objects’ of the all-consuming immortal organization. To challenge this, the article explicitly draws on the vampire and the vampiric in literature and popular culture to consider the possibility of subverting existing notions of the ‘Older Worker’ in order to confront and challenge the subtle and persistent monstrous discourses that shape organizational life
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The need for fresh blood: understanding organizational age inequality through a vampiric lens
'SAGE Publications', 2013Co-Authors: Riach Kathleen, Kelly SimonAbstract:This article argues that Older age inequality within and across working life is the result of vampiric forms and structures constitutive of contemporary organizing. Rather than assuming ageism occurs against a backdrop of neutral organizational processes and practices, the article denaturalizes (and in the process super-naturalizes) organizational orientations of ageing through three vampiric aspects: (un)dying, regeneration and neophilia. These dimensions are used to illustrate how workplace narratives and logics normalize and perpetuate the systematic denigration of the ageing organizational subject. Through our analysis it is argued that Older Workers are positioned as inevitable ‘sacrificial objects’ of the all-consuming immortal organization. To challenge this, the article explicitly draws on the vampire and the vampiric in literature and popular culture to consider the possibility of subverting existing notions of the ‘Older Worker’ in order to confront and challenge the subtle and persistent monstrous discourses that shape organizational life
