Current Projects
Stress and Aging
While the mechanisms of aging and senescence are well described for insects primarily via laboratory studies of Drosophila and other models with simple lifespan-dependent behavioral trajectories, studies linking variation in the onset/duration of potentially lifespan-limiting, metabolically-intensive natural behaviors to the accumulation of cell/tissue damage, the activity of cellular protective mechanisms, functional senescence and longevity are extremely rare. The honey bee is a power model system to test these relationships because we can fully manipulate the pace of honey bee (Apis mellifera) behavioral development and life-time foraging (i.e. flight) effort.
 When we compared young and old foraging worker bees on their first flight of the morning and others at the end of a long day of foraging to those working solely in the hive, we found that young honey bee foragers to express more antioxidants in their flight muscles over the course of a foraging day than age-matched hive bees who seldom fly. But as bees of both behavioral groups age the protective antioxidant response decreases (Williams et al 2008).
Older bees also exhibit decreased flight ability (Vance et al in press). Decreased flight ability may make the bees less efficient fliers and likely increases the risk of predation. Other labs have shown that older bees carry less pollen and nectar as well. All of these factors likely contribute to the long known correlation between earlier onset of foraging behavior and shorter lifespan.
These data suggest rather than simply an outcome of developmental processes, life history stages and lifespan may be the modified by behaviorally induced stresses during the course of the individual’s lifetime and that organisms with longer lifespans may have evolved to better handle cellular stress.
We’re continuing these experiments to look at metabolic expenditure, and evolution of highly metabolic lifestyles. One of the particularly interesting aspects of honey bee life history is that in the right social situation forager bees can return to hive work- in effect becoming behaviorally younger. Future research in the lab will focus on these bees to see if they become younger at the cellular level (as measured by gene expression across the genome using microarrays) as well or if the effects of foraging on the antioxidant response and other cellular measures are permanent.
Endocrine Rhythms and Behavior
 Honey bees foragers exhibit diurnal changes in juvenile hormone, a sesquiterpenoid hormone known to pace the rate of behavioral development. Developing larvae and earlier behavioral stages in adults do not exhibit this rhythm. Additionally these rhythms disappear seasonally. Currently we are focusing on the role of these hormone rhythms and their control.
Elekonich et al 2003 |
