Diapause and aging in solitary bees

Diapause is a physiological state that protects insects from environmental stresses of winter. Diapause also extends the annual lifecycle of insects by many months. But, it remains a question how diapause impacts the cellular age of insects. On the one hand, overwintering conditions are stressful and therefore would be predicted to negatively impact cellular age. On the other hand, diapause is a state of physiological protection that extends lifespan, therefore would be predicted to protect against cellular aging. We examined the relationship between diapause and telomere length, a marker of cellular age. We found that telomere length increased in later life stages and after diapause. When comparing diapausing and nondiapausing phenotypes, we found that nondiapausers had longer telomeres at every life stage. For both diapausers and nondiapausers, telomere length increased after metamorphosis. Activity of the enzyme telomerase, which increases telomere length, was longer in adults, and potentially explains why adults have longer telomeres. Overall, we found evidence to support that diapause has renewing capabilities. However, bees that are preparing for diapause may incur cellular damage. While emergence from diapause may increase telomere length, nondipausers still have longer telomeres as adults than individuals who went through diapause. A future step in this work is to determine how telomere length relates to other aspects of cellular damage, and the potential impacts on lifespan and stress resiliency.