Ovary growth and protein levels in ovary and fat body during adult-wintering period in the red mason bee, Osmia rufa

Abstract

Winter months are supposed to be a crucial period for the development of the reproductive system, especially ovaries, in Osmia rufa females. During 7 months of the wintering period (from September till March), the length and width of terminal oocytes and protein concentrations in ovary and fat body tissue extracts of red mason bee females, O. rufa, were studied. Our observations indicate statistically significant differences in the size of terminal oocytes for three different periods of over-wintering

Overwintering strategies in the red mason solitary bee—physiological correlates of midgut metabolic activity and turnover of nutrient reserves in females of Osmia bicornis

“…This could be due to the release of vitellogenins into the hemolymph, leading to a depletion of proteins in the former and an increase in the latter. This correlates with the significant increase in size of the ovaries and oocytes during overwintering (Wasielewski et al 2011a). This pattern was strongly correlated with the pattern of protease activity in the midgut.…”

“…After diapause termination, the protein concentration continuously increased and was the highest in March, before emergence. In contrast, in fat body tissue, our previous work indicated that during overwintering the protein content rapidly decreased, especially after winter months indicative of a rapid utilization and mobilization of these reserves (Wasielewski et al 2011a). This could be due to the release of vitellogenins into the hemolymph, leading to a depletion of proteins in the former and an increase in the latter.…”

“…Most information about the precise timing of diapause initiation, maintenance, and termination is available on a spring-flying solitary bee from North America Osmia lignaria Bosch et al 2010). However, the precise timing of entering diapause, its maintenance and diapause termination is different in O. bicornis (Wasielewski et al 2011a). Based on the classification of the eco-physiological phases of insect diapause (Kostál 2006), we determined that O. bicornis enters diapause in November and diapause termination occurs at the end of January.…”

Effect of Temperature Treatment during Development ofOsmia rufaL., on Mortality, Emergence and Longevity of Adults

“…The fact that fewer parasites were found in nests of bees developing at higher temperatures might be an effect of parasite developmental forms being less tolerant to temperature. In Polish climatic conditions, real diapause in Osmia rufa begins in early October (Wasielewski et al, 2011), which means that the emergence on 8 April occurred after 180 days of wintering. This date was adopted as the beginning of the second phase of the experiment, since in nature Osmia rufa appears in late March and early April (Wójtowski, 1979).…”

“…Reproductive diapause is characterised by the cessation of ovary development, and by body fat hypertrophy (Hondelmann & Poehling, 2007). In the red mason bee, marked inhibition of ovary development and depletion of fat body resources is observed between October and January (Wasielewski et al, 2011). After this period it is possible to manipulate the duration of the wintering period by treating cocoons with high or low temperatures (Giejdasz & Wilkaniec,1998).…”