The Proteolytic Activity of Diapausing and Newly Hatched Red Mason Bees (Osmia Rufa: Megachilidae)

Abstract

a b s t r a c t osmia rufa is a solitary bee that is used commercially for pollinating crops. The bee enters obligatory diapause as an imago. The activity of proteolytic enzymes during diapause has not been investigated. we studied the proteinase activity on four substrates -casein, haemoglobin, bovine serum albumin (bsa), and gelatine -during diapause (from october to march) and in newly hatched males and females in april. during diapause, greater fluctuations in enzyme activity levels were noted in males than in females, and a significant decrease in male enzyme activity was observed in January and march. male enzymes were most effective in decomposing gelatine; whereas, female enzymes were equally effective in hydrolysing gelatine and bsa. The differences in substrate preferences between male and female enzymes were particularly pronounced in october and in the newly hatched individuals. The levels of gelatinolytic activity likely indicate that a high proportion of proteinases in o. rufa are elastase-like enzymes. They are involved in the digestion and remodelling of proteins with numerous peptide bonds formed by amino acids with short side-chains.

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“…Zaobidna et al [16] observed a similar tendency in the extracts of entire O . rufa bodies for gelatinolytic activities of proteases, whereas Hahn and Denlinger [51] observed increaseed demand for free amino acids–hydrolytic products of proteins–in spring in these bees.…”

“…Increased activities of proteases and their inhibitors were observed in the hemolymph in April, when the insects terminated the diapause, particularly in the females (Figs 2 and 3 ). Zaobidna et al [ 16 ] observed a similar tendency in the extracts of entire O . rufa bodies for gelatinolytic activities of proteases, whereas Hahn and Denlinger [ 51 ] observed increaseed demand for free amino acids–hydrolytic products of proteins–in spring in these bees.…”

“…(2) As one of the main wild-living pollinators, O . rufa provides services for natural and rural ecosystems and is also employed in commercial pollination [ 12 – 16 ]. Protection of pollinating entomofauna is nowadays a major challenge.…”

“…In O . rufa , however, proteolytic and antioxidative activities were studied only in homogenates made of the entire individual bodies and only at the diapause stage [ 8 , 16 , 26 , 27 ] but never in mature, flying, fully active insects that are more exposed to environmental pressure (e.g. pesticides, ultraviolet radiation, ultrasound waves, toxic substances and pathogens).…”