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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Insect Genetics and Biochemistry Research » Research » Publications at this Location » Publication #347396

Title: Mechanisms of increased lifespan in hypoxia in the alfalfa leafcutting bee, Megachile rotundata

item GREENLEE, KENDRA - North Dakota State University
item BOWSHER, JULIA - North Dakota State University
item HEIDINGER, BRITT - North Dakota State University
item Rinehart, Joseph - Joe
item Yocum, George

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2017
Publication Date: 11/5/2017
Citation: Greenlee, K.J., Bowsher, J., Heidinger, B., Rinehart, J.P., Yocum, G.D. 2017. Mechanisms of increased lifespan in hypoxia in the alfalfa leafcutting bee, Megachile rotundata [abstract]. Entomological Society of America Annual Meeting. Denver, CO. November 5-8, 2017. Poster D3283.

Interpretive Summary: .

Technical Abstract: Genetic variation accounts for a small amount of variation in lifespan, while environmental stressors are strong predictors. Hypoxia is an environmental stress that increases longevity in some contexts, but the mechanisms remain poorly understood. In the bee Megachile rotundata, lifespan doubles upon rearing in hypoxia. We hypothesized that hypoxia increases longevity by limiting telomere loss from reactive oxygen species (ROS). Prepupal bees were maintained in 10, 21, or 24% oxygen for 9 months. Each month, two subsets of bees were removed, prepupal bees were divided and either immediately frozen or reared to adulthood and frozen. Similar to our previous findings, all bees had extended lifespans compared to bees reared normally, but bees exposed to hypoxia had higher survival (74%) after 9 months in 10% oxygen compared to those stored in hyperoxia (14%)or normoxia (41%). Because they survived better than bees in normoxia or hyperoxia, we predicted that bees in hypoxic conditions would have reduced telomere loss rates, lower levels of ROS, and/or higher levels of telomerase activity than bees exposed to normoxia. However, we found no effect of oxygen on telomere length. Interestingly, telomeres were significantly longer in adults compared to prepupae. We also measured total antioxidant activity and lipid peroxidation and found no differences among treatments from either prepupal or adult bees, indicating that reduced oxidative stress is not the mechanism for increased longevity. Together, these data suggest that hypoxia initiates an alternate protective pathway, possibly involving hypoxia inducible factor, that increases lifespan in these bees.