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  • Author: Kamila Dmochowska x
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Kamila Dmochowska, Karol Giejdasz, Monika Fliszkiewicz and Krystyna Żółtowska

Changes in the Antioxidative System of the Red Mason Bee (Osmia Rufa) (Hymenoptera: Megachilidae) Induced by Artificially Elongated Diapause

Osmia rufa as a polylectic insect is used in the pollination of numerous plants. The usefulness of this insect for plant breeders is considerably limited because of the short flight periods of the insects in the natural environment. In order to break this limitation, the wintering period of the insects in cocoons is elongated. The temperature is maintained at 4°C up to the time of plant blooming. This treatment does shortens the lifetime of the insects which may be the result of oxidative stress. Such results led to the examination of the selected components of antioxidative system. These components are: total antioxidative status, content of glutathione and activity of peroxidase and glutathione S-transferase in O. rufa emerged in spring, according to their biological clock, and emerged in summer - after elongated diapause. It was observed that diapause elongation unprofitably influenced the antioxidative system of a bee. A statistically significant decrease in total antioxidative status, and activity of both antioixidative enzymes - peroxidase and glutathione S-transferase, was noted. The changes in the glutathione level in turn, were insignificant. In our opinion, the lower efficiency of antioxidative systems of the red mason bee emerged in summer, may limit their response ability to endo- and exogenous factors influencing oxidative stress. The results of our study are the first publication concerning an antioxidative system in mason bees.

Open access

Ewa A. Zaobidna, Kamila Dmochowska, Regina Frączek, Ewa Dymczyk and Krystyna Żółtowska

Abstract

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.

Open access

Kamila Dmochowska-Ślęzak, Małgorzata Dmitryjuk, Ewa Zaobidna and Krystyna Żółtowska

Abstract

Varroa destructor is a parasitic mite of the Western honey bee. The activity of five antioxidant enzymes of V. destructor were analysed. Glutathione content and total antioxidant status was also evaluated. Our results suggest that antioxidant enzymes constitute the main line of defense against ROS in V. destructor, whereas low-molecular-weight antioxidants play a limited role in the antioxidant system of mites.