Brood pheromone suppresses physiology of extreme longevity in honeybees (Apis mellifera)

Abstract

SUMMARYHoneybee (Apis mellifera) society is characterized by a helper caste of essentially sterile female bees called workers. Workers show striking changes in lifespan that correlate with changes in colony demography. When rearing sibling sisters (brood), workers survive for 3-6 weeks. When brood rearing declines, worker lifespan is 20 weeks or longer. Insects can survive unfavorable periods on endogenous stores of protein and lipid. The glyco-lipoprotein vitellogenin extends worker bee lifespan by functioning in free radical defense, immunity and behavioral control. Workers use vitellogenin in brood food synthesis, and the metabolic cost of brood rearing (nurse load) may consume vitellogenin stores and reduce worker longevity. Yet, in addition to consuming resources, brood secretes a primer pheromone that affects worker physiology and behavior. Odors and odor perception can influence invertebrate longevity but it is unknown whether brood pheromone modulates vitellogenin stores and survival. We address this question with a 2-factorial experiment where 12 colonies are exposed to combinations of absence vs presence of brood and brood pheromone. Over an age-course of 24 days, we monitor the amount of vitellogenin stored in workers' fat body (adipose tissue). Thereafter, we track colony survival for 200 days. We demonstrate that brood rearing reduces worker vitellogenin stores and colony long-term survival. Yet also, we establish that the effects can result solely from exposure to brood pheromone. These findings indicate that molecular systems of extreme lifespan regulation are integrated with the sensory system of honeybees to respond to variation in a primer pheromone secreted from larvae. Supplementary material available online at

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

“…To allow possible between-treatment variation in each protein band to count equally toward the analysis, independent of bee per se, we therefore used a variance normalisation by calculating a z-score for each band. Similar to the approach of Smedal et al (Smedal et al, 2009), the normalised data were analysed by a main-effects ANOVA with bee coded as a random factor and blot and lane included to control technical error variance. Fisher's least significant difference (LSD) test was used for post hoc comparisons.…”

Vitellogenin Recognizes Cell Damage through Membrane Binding and Shields Living Cells from Reactive Oxygen Species

“…The Antibody, Gels, and Western Blots-The polyclonal Vg antibody produced in rabbit (Pacific Immunology, Ramona, CA) has been tested before (29,31,33). This antibody was used for all imaging and Western blotting.…”

“…Histology-Dissection, tissue preparation, and immunohistochemistry were largely performed as described previously (29). In brief, tissue samples of mature nest bees (age Ͻ27 days) were fixed in paraformaldehyde (4% in PBS), embedded in London Resin White (Electron Microscopy Science, Hatfield, PA), and cut with a Reichert Jung ultra-microtome (Leica, Wetzlar, Germany; section thickness, 1-2 m).…”

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Reproduction, social behavior, and aging trajectories in honeybee workers

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