Sociality, Hierarchy, Health Comparative Biodemography: A Collection of Papers (2014) / Chapter Skim
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12 Hierarchy and Connectedness as Determinants of Health and Longevity in Social Insects--Brian Johnson and James R. Carey
12 Hierarchy and Connectedness as Determinants of Health and Longevity in Social Insects--Brian Johnson and James R. Carey
Pages 269-294
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From page 269... ...
Because of the paucity of information on how social factors, including networks and hierarchies, affect health and longevity in social species in general and humans in particular, our broad goal of this paper is to describe a general research framework for answering questions concerned with sociality and health based on the use of social insects in general and the honey bee (Apis melifera) in particular.
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From page 270... ...
. The various levels of social organization are thus classified according to combinations of these cooperative behaviors including subsocial, colonial, communal, cooperatively breeding, and usocial.
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From page 271... ...
. The honey bee hive consists of a single queen, multiple drones and from 10,000 to 40,000 workers.
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From page 272... ...
For example, queen honey bees are capable of living 3-5 years but honey bee workers only live 6-8 weeks. This is remarkable because the queens do not differ genetically from workers -- they are produced through workers constructing special "queen cells" (Seeley, 1995)
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From page 273... ...
have a shorter adult lifespan than either queens or workers (Wilson, 1971; Hölldobler, 1990) , mother queens live much longer than workers in all eusocial insects (Keller and Genoud, 1997; Keller, 1998)
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From page 274... ...
The evolution of adult provisioning by social insects enabled pre-adults to grow rapidly towards adult competence under the protection of parental care. This provisioning not only prolongs pre-adult (larval)
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Extensive parental care increases life span to 1 year; larval and pupal mortality reduced to near zero; this fosters reduction in birth rate; allows females to invest more resource for their own maintenance and for rearing of their offspring (lifespans range 60-365 days)
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From page 276... ...
Thus subsocial behavior may be an outcome of extended longevity rather than vice versa. Sociality Provides Insurance-based Survival Advantages In many facultatively eusocial insects, offspring need continuous care during development, but the life expectancy of adult caregivers is shorter than the developmental period.
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From page 277... ...
. SOCIAL INSECTS: MOLECULAR MODELS OF AGING Operational Framework We consider the two basic conceptual frameworks for understanding aging in all organisms including social insects -- accumulated damage and adaptive senescence (Finch, 1990)
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From page 278... ...
Genes that show positive relationships with aging in other insects, such as vitellogenin (the yolk protein) , can show the opposite pattern in social insects such as the honey bee (Amdam et al., 2007)
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(2007) tested the potential for this hypothesis to explain lifespan variation between honey bee queens and workers.
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From page 280... ...
The authors interpreted these results as supporting the notion that ROS production in the flight muscles contributes to functional senescence in foragers; however, it is unclear that a cause-and-effect connection was made, as no damage was detected and older foragers had high antioxidant capacity even if they had no ability to increase it further. Nevertheless, it is the case that high ROS production in forager honey bees is a good context
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From page 281... ...
Adaptive Senescence Adaptive Aging Worker honey bees have been the focus of much work on adaptive senescence. In short, honey bee workers in the spring and summer have a complex system of division of labor in which workers exhibit different physiological states (castes)
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From page 282... ...
Hence, it provides a context to study aging due to molecular damage controlling for the effects of adaptive senescence. Aging Reversal Bees that have entered the last of the developmental phases that characterize adult development, the foraging caste, can be induced to revert to the nursing phase by simply removing all the young bees from the nest (Huang and Robinson, 1996)
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From page 283... ...
(2007) also found that overage nurses do experience senescence, in that they are less able to handle physiological stresses, such as heat and oxidative damage (relative to younger nurses)
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suggests that such a capacity is possible. Senescence and Immunity: Health in Older Workers Disposable Castes: Downregulation of Immunity in the Honey Bee?
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From page 285... ...
The basic hypothesis could perhaps be expressed as the immune machinery is turned off at the transition to foraging, and then a process of senescence erodes the functional properties of the system. In these first studies, the circulating level of functional hemocytes was taken as a proxy for the functional properties of the entire insect immune system.
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From page 286... ...
With respect to the number of functional hemocytes, Wilson-Rich (2008) found no decline in the number of functional hemocytes with age in honey bees.
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From page 287... ...
Hence, it can be quite problematic to infer function from studies of gene expression alone. The initial studies by Amdam and others that suggested that Vg is the linchpin underlying functional senescence in honey bees oversimplify the biology of developmental polyphenism in bees.
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From page 288... ...
. They map out the phenotypic and genetic architectures of food storage and foraging behavior and show how they are linked through broad epistasis and pleiotropy affecting a reproductive regulatory net work that influences foraging behavior, a major determinant of honey bee health and longevity.
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From page 289... ...
Even though the history of health studies in social insects and particularly in honey bees extends back well over a century with investigations focused mostly on various brood diseases (e.g., foul brood) or parasites (e.g., Varroa mite)
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. Lifetime learning by foraging honey bees.
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From page 291... ...
. Extended longevity of queen honey bees compared to workers is associated with peroxidation-resistant membranes.
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(2012) DNA methylation changes elicited by social stimuli in the brains of worker honey bees.
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From page 293... ...
. Nutritional status influences socially regulated foraging ontogeny in honey bees.
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