title: Early life stress affects mortality rate more than social behavior, gene expression or oxidative damage in honey bee workers.
abstract: Early life stressors can affect aging and life expectancy in positive or negative ways. Individuals can adjust their behavior and molecular physiology based on early life experiences but relatively few studies have connected such mechanisms to demographic patterns in social organisms. Sociality buffers individuals from environmental influences and it is unclear how much early life stress affects later life history. Workers of the honey bee (Apis mellifera L.) were exposed to two stressors, Varroa parasitism and Paraquat exposure, early in life. Consequences were measured at the molecular, behavioral, and demographic level. While treatments did not significantly affect levels of oxidative damage, expression of select genes, and titers of the common deformed wing virus, most of these measures were affected by age. Some of the age effects, such as declining levels of deformed wing virus and oxidative damage, were opposite to our predictions but may be explained by demographic selection. Further analyses suggested some influences of worker behavior on mortality and indicated weak treatment effects on behavior. The latter effects were inconsistent among the two experiments. However, mortality rate was consistently reduced by Varroa mite stress during development. Thus, mortality was more responsive to early life stress than our other response variables. The lack of treatment effects on these measures may be due to the social organization of honey bees that buffers the individual from the impact of stressful developmental conditions.
authors.affiliation: Department of of Biology, 312 Eberhart Building, The University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27402, USA. Electronic address: olav_rueppell@uncg.edu.
authors.forename: Olav
authors.initials: O
authors.lastname: Rueppell
authors.affiliation: Department of of Biology, 312 Eberhart Building, The University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27402, USA.
authors.forename: Babak
authors.initials: B
authors.lastname: Yousefi
authors.affiliation: Department of of Biology, 312 Eberhart Building, The University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27402, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Collazo
authors.affiliation: Department of of Biology, 312 Eberhart Building, The University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27402, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Smith
mesh_terms: D000818:Animals; D001516:Bees / Q000235:genetics / Q000469:parasitology / Q000502:physiology*; D004781:Environmental Exposure / Q000009:adverse effects; D015870:Gene Expression; D006540:Herbicides / Q000633:toxicity; D008018:Life Cycle Stages; D016015:Logistic Models; D008136:Longevity; D008925:Mites; D018384:Oxidative Stress; D010269:Paraquat / Q000633:toxicity; D012919:Social Behavior
chemical_list: D006540:Herbicides; D010269:Paraquat
keywords: Developmental stress; Parasitism; Pesticide; Predictive behavioral demography; Social evolution