Methoprene and Temperature Stimulation of Emergence and Longevity in Adults of Osmia Rufa L. (Megachilidae; Apoidea) During Wintering Period

Abstract

A b s t r a c t 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.

Methoprene, a Juvenile Hormone Analog, Causes Winter Diapause Elimination in Univoltine Bee Species Osmia bicornis L.

“…The most sensitive developmental stage to methoprene application was the 3- The experimental cocooned females were treated topically on the cocoon surface once a day for five consecutive days with 200 µg of methoprene dissolved in 5 µL acetone (Sigma, Sosnowiec, Poland) and cocooned males with 120 µg of methoprene dissolved in 3 µL acetone [24][25][26]. Appropriate volume and concentration of methoprene were prepared according to our previous experience and experiments and based on authors who performed their experiments on Apis mellifera, a honeybee who belongs, similar to Osmia, to the Apoidea superfamily and has similar body weight [18,27,28]. The vehicle control was treated with 5 µL of acetone (female) or 3 µL (male) and the negative control was not treated.…”