title: Lifespan behavioural and neural resilience in a social insect.
abstract: Analyses of senescence in social species are important to understanding how group living influences the evolution of ageing in society members. Social insects exhibit remarkable lifespan polyphenisms and division of labour, presenting excellent opportunities to test hypotheses concerning ageing and behaviour. Senescence patterns in other taxa suggest that behavioural performance in ageing workers would decrease in association with declining brain functions. Using the ant Pheidole dentata as a model, we found that 120-day-old minor workers, having completed 86% of their laboratory lifespan, showed no decrease in sensorimotor functions underscoring complex tasks such as alloparenting and foraging. Collaterally, we found no age-associated increases in apoptosis in functionally specialized brain compartments or decreases in synaptic densities in the mushroom bodies, regions associated with integrative processing. Furthermore, brain titres of serotonin and dopamine--neuromodulators that could negatively impact behaviour through age-related declines--increased in old workers. Unimpaired task performance appears to be based on the maintenance of brain functions supporting olfaction and motor coordination independent of age. Our study is the first to comprehensively assess lifespan task performance and its neurobiological correlates and identify constancy in behavioural performance and the absence of significant age-related neural declines.
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA ygiraldo@bu.edu.
authors.forename: Ysabel Milton
authors.initials: YM
authors.lastname: Giraldo
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: J Frances
authors.initials: JF
authors.lastname: Kamhi
authors.affiliation: Research Center on Animal Cognition, CNRS, Toulouse 31062 Cedex 9, France Research Center on Animal Cognition, Université de Toulouse, Toulouse 31062 Cedex 9, France.
authors.forename: Vincent
authors.identifier: http://orcid.org/0000-0002-3605-6351
authors.initials: V
authors.lastname: Fourcassié
authors.affiliation: Research Center on Animal Cognition, CNRS, Toulouse 31062 Cedex 9, France Research Center on Animal Cognition, Université de Toulouse, Toulouse 31062 Cedex 9, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Moreau
authors.affiliation: College of Marine and Environmental Science, James Cook University, Townsville 4811, Australia.
authors.forename: Simon K A
authors.identifier: http://orcid.org/0000-0001-8870-1933
authors.initials: SK
authors.lastname: Robson
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: Adina
authors.initials: A
authors.lastname: Rusakov
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Wimberly
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: Alexandria
authors.initials: A
authors.lastname: Diloreto
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: Adrianna
authors.initials: A
authors.lastname: Kordek
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: James F A
authors.initials: JF
authors.lastname: Traniello
mesh_terms: D000375:Aging; D000818:Animals; D001000:Ants / Q000502:physiology*; D017209:Apoptosis; D001522:Behavior, Animal; D001921:Brain / Q000166:cytology / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D008136:Longevity; D024521:Mushroom Bodies / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism; D012919:Social Behavior
chemical_list: D012701:Serotonin; D004298:Dopamine
keywords: ants; biogenic amines; neurodegeneration; senescence; task performance