Social context, stress, and plasticity of aging

Abstract

SummaryPositive social contact is an important factor in healthy aging, but our understanding of how social interactions influence senescence is incomplete. As life expectancy continues to increase because of reduced death rates among elderly, the beneficial role of social relationships is emerging as a cross-cutting theme in research on aging and healthspan. There is a need to improve knowledge on how behavior shapes, and is shaped by, the social environment, as well as needs to identify and study biological mechanisms that can translate differences in the social aspects of behavioral efforts, relationships, and stress reactivity (the general physiological and behavioral response-pattern to harmful, dangerous or unpleasant situations) into variation in aging. Honey bees (Apis mellifera) provide a genetic model in sociobiology, behavioral neuroscience, and gerontology that is uniquely sensitive to social exchange. Different behavioral contact between these social insects can shorten or extend lifespan more than 10-fold, and some aspects of their senescence are reversed by social cues that trigger aged individuals to express youthful repertoires of behavior. Here, I summarize how variation in social interactions contributes to this plasticity of aging and explain how beneficial and detrimental roles of social relationships can be traced from environmental and biological effects on honey bee physiology and behavior, to the expression of recovery-related plasticity, stress reactivity, and survival during old age. This system provides intriguing opportunities for research on aging.

Lifespan behavioural and neural resilience in a social insect

“…Eusociality has had profound consequences for the evolution of behavioural development, immune function and genetic regulation of ageing [17,18,19]. Social interactions appear to mediate metabolic homeostasis and affect mortality rates [74].…”

“…Few studies have examined the influence of sociality on ageing and life history [11][12][13], and little is understood about cognitive decline and neurobiological changes accompanying senescence in social animals, apart from humans [12,[14][15][16]. Social insects have striking lifespan polyphenisms [17][18][19][20]: queens often live more than a decade, whereas workers may live only several months [21], indicating that the differentiation of reproductive and sterile castes has had profound effects on senescence, which may be influenced by the social organization of colony labour. The relationship of task performance to age-related changes in the worker brain, however, is not well understood.…”

Flight restriction prevents associative learning deficits but not changes in brain protein-adduct formation during honeybee ageing

“…Based on this study alone, it cannot be firmly excluded that MDA-protein adduct levels were not influenced by factors other than rain and access to flight. For instance, we did not control for any non-foraging behavior or social factors such as the activity level of individual bees and their location in the hive (Riessberger and Crailsheim, 1997;Stabentheiner et al, 2010;Amdam, 2010). Still, in light of apparent discrepancies from the oxidative stress theory of ageing in previous studies with D. melanogaster (Cook-Wiens and Grotewiel, 2002) and rats (Ogonovszky et al, 2005), it is nonetheless plausible that long foraging experience in honeybee workers induces learning impairment through mechanisms that do not directly involve oxidative stress or that an acclimatisation response to foraging activity can enhance protection toward lipid peroxidation and resulting levels of protein damage.…”

Insulin-like peptides (AmILP1 and AmILP2) differentially affect female caste development in the honey bee (Apis mellifera)

“…Additionally, low levels of AmILP1 transcripts in the fat body of adult bees are linked to high blood sugar levels (Wang et al, 2012). In contrast, the regulation and function of AmILP2 is less well understood as AmILP2 expression does not consistently respond to factors as AmILP1 does in adult honey bees (Amdam, 2011;Wheeler et al, 2006).…”