The antioxidant system in diapausing and active red mason bee Osmia bicornis

The red mason bee Osmia bicornisL. (Hymenoptera: Megachilidae) belongs to a group of insects that undergo an obligatory diapause in the imago stage. Red mason bees (O. bicornis) consume oxygen during overwintering diapause, and reactive oxygen species can be produced despite substantial inhibition of metabolism. These are first studies to investigate the antioxidant system in diapausing red mason bees and to compare the antioxidant systems of overwintering and active imagines. The present study analyzes total antioxidant status, glutathione and ascorbic acid levels, and the activity of superoxide dismutase, catalase and peroxidase in overwintering (October to March) and active (April) female and male O. bicornis. Diapause phases (prediapause, diapause and post-diapause) cannot be distinguished based on the parameters of the antioxidant system of the bees. During overwintering, a significant decrease is noted only in ascorbic acid content. The remaining antioxidants remain fairly stable, which indicates the absence of oxidative stress in diapausing specimens. The analyzed parameters distinguish diapausing bees from active insects. Excluding total antioxidant status, the evaluated parameters are significantly higher in active individuals than in overwintering specimens. Sex-related differences are found only for catalase, the level of which is consistently higher in males than in females.