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Karol Giejdasz and Monika Fliszkiewicz

Abstract

The red mason bee (Osmia rufa L.) is a univoltine solitary species of the Osmia genus. This bee is reared on a commercial scale and used as a managed alternative pollinator. We intended that the results of our study would improve the management of this bee so as to synchronise their flying period with the blooming of crops. In the spring, we moved newly occupied nests of the red mason bee to a laboratory and placed them in incubators. Immature development was examined at three constant temperatures, 20°C, 25°C, and 30°C. Selected nests were opened to monitor the subsequent developmental stages. The remaining bees were wintered in nests stored at cool temperature (4°C). In April, we removed the insects from the nests and began incubation at 25°C to establish the emergence time of adult individuals. To determine the survival rate of adult bees, we moved the emerged specimens to cages, where they were fed and kept until death. Temperature increase generally reduced immature development time. But this tendency was not observed in the prepupal stage. During ontogeny the highest mortality rate was observed in wintering adult insects at developmental temperatures of 25°C and 30°C. Bees developing at constant temperatures emerged faster during spring incubation in comparison to those developing in natural conditions. Constant developmental temperatures decreased the survival rate of females as post-emergence adult insects. The survival rate of males was lower at the developmental temperature of 30°C.

Open access

Karol Giejdasz and Oskar Wasielewski

Abstract

In this study methoprene, a juvenile hormone analogues, was tested as a factor that stimulates the end of diapause, bee activation and emergence. In addition, the survival of bees was checked when combined with an application of methoprene. The experimental activation of wintering bees was carried out once a month between December and March, Three groups of bee cocoons were selected for each activation term: treated with either methoprene or acetone as vehicle control and untreated as controls. After the applications were finished the cocoons were incubated at temperature 26°C. The emerged adult males and females were then kept in the laboratory and fed sucrose solution to evaluate the longevity of bees. The application of juvenile hormone analogue reduced the emergence time of adult bees in December, February and March. The rate of emergence presented in the form of cumulative percentage of emerged adult bees indicated that the bees treated with methoprene started to emerge 1-2 days earlier than bees from acetone and control groups and finished emergence 2-5 days earlier too. Methopren application did not reduce the longevity of the bees after emergence. Moreover, the median longevity of these females was higher than untreated in December and February.

Open access

Karol Giejdasz and Oskar Wasielewski

Abstract

This study discusses the longevity and emergence rate of O. rufa males and females after an extended wintering period in artificial conditions. Experimental activation of the wintering bees was carried out every fifteen days, starting at the end of March and finishing at the beginning of June (25 March, 9 April, 24 April, 9 May, 24 May, 8 June). In our study, the shortest emergence time (5 days) was observed in females that overwintered for at least 220 days and were activated at the beginning of May or later. Their mean emergence time in the last three terms was similar and ranged from 4.6 to 5.1 days. Prolonged wintering increased female emergence dynamics in May and June. Half of the emerged males in our study lived up to 28 days when activated during the first term, and up to 15 days when activated during the last one. In females, half of the bees lived up to 64 and 20 days, respectively.

Open access

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

Karol Giejdasz, Monika Fliszkiewicz, Andrea Bednárová and Natraj Krishnan

Abstract

The red mason bee Osmia rufa is a solitary bee belonging to the family Megachilidae, and is prone to nest in aggregations. Each female builds a nest separately in pre-existing cavities such as holes in wood and walls or empty plant stems. This is done by successively setting the cells in a linear series. In this study, we elucidate the nesting behavior and the reproductive potential of a single O. rufa female. The reproductive potential of nesting females was evaluated after the offspring finished development. We observed that an individual female may colonize up to five nest tubes and build 5-34 cells in them (16 on an average). During the nesting time the number of cells decreased with the sequence of nest tubes colonized by one female, which built a maximum of 11 cells in the first occupied nest and 5 cells in the last (fifth nest). Our observations indicated that 40% of nesting females colonized one nest tube as compared to 7% colonizing five nest tubes. Furthermore, in subsequent nest tubes the number of cells with freshly emerged females gradually decreased which was the reverse with males. Thus, the sex ratio (proportion of male and female offspring) may change during the nesting period. The female offspring predominated in the first two nesting tubes, while in the subsequent three tubes male offspring dominated. We also cataloged different causes of reduction in abundance of offspring in O. rufa females such as parasitization or problem associated with moulting.