Diapause survival and post-diapause performance in bumblebee queens (Bombus terrestris)

Diapause survival and post-diapause performance (i.e., if a queen starts to lay eggs) of in total 2210 bumblebee queens (Bombus terrestris) were measu red under different diapause regimes: 5 temperatures (-5, 0, 5, 10 and 15 d egrees C) in combination with 5 durations of exposure (1, 2, 4, 6 and 8 mon ths). The results show that weight at the start of diapause determines to a large extent whether a queen will be able to survive diapause. Queens with a wet weight below 0.6 g prior to diapause did not survive, but for those queens exceeding this threshold a higher pre-diapause weight did not increase the ir post-diapause performance. There was no effect of temperature on diapause survival; 76% of the varianc e in survival could be explained by the duration of the treatment. Neither temperature nor duration of exposure had an effect on post-diapause perform ance. The preoviposition period of the queens that laid eggs was also deter mined. The preoviposition period was affected by both temperature and durat ion of exposure: the preoviposition period decreased with decreasing temper ature but also with increasing duration of the treatment.