Effect Of Mating And Temperature Acclimation On The Diapause Nutrients Of Bumble Bee Queens(Bombus Terrestris)

Bumble bees are important social pollinators that play an important role in agricultural development and greenhouse pollination services.The life cycle of bumble bee undergoes two main stages: the diapause stage,when the queen has mated and is alone,and the colony development stage.Queen diapause is one of the most important stages of bumble bees’ life cycle and is crucial for the queen’s survival and colony development.Bumble bee queens are fasted,i.e.,they do not consume any food during diapause and their energy requirements depend mainly on the nutrient accumulation during prediapause.However,the queen’s nutrient reserve during prediapause could be influenced by mating and temperature.In this study,we used the bumble bee Bombus terrestris queen as experimental material.We investigated the effect of mating behavior on nutrient accumulation during prediapause by comparing the nutrient reserves of mated queens with virgin queens.In addition,we also investigated the effect of temperature acclimation on the cold resistance and survivability of queens during diapause by comparing the main nutrient reserves of queens after acclimation at different temperatures during prediapause and the energy consumption during diapause.The main study results of this study were as follows:(1)Effect of mating behavior on nutrient reserves of bumble bee queens during prediapauseWe used 6-day-old mated and virgin queens reared for 3,6 and 9 days,respectively,to compared differences in body weight gain,free water content,total fat content,fat body weight,and protein,lipid and total sugar concentrations in the fat body of mated and virgin queens during prediapause.Results showed that mated queens had significantly higher(P<0.05)the body weight gain,total fat content,fat body weight,and lipid concentrations in the fat body than virgin queens during prediapause,while total sugar concentrations were not significantly different(P>0.05).The free water content and protein concentrations in the fat body of queens only significantly differed at the 6th days after mating behavior,i.e.,the free water content of mated queens was significantly lower(P<0.05)than that of virgin queens,while the protein concentrations in the fat body were significantly higher(P<0.05)than that of virgin queens.In conclusion,the mating behavior stimulated development of fat body of queens,and that there was a close relationship between mating behavior and the lipid reserves of queens during prediapause.(2)Effect of temperature acclimation on nutrient reserves of bumble bee queen during prediapause and energy consumption during diapauseWe used 6-day-old mated queens undergoing acclimation at 3 temperatures(10,15 and25°C)and 3 times(3,6 and 9 days)to compared the differences in reserves of major nutrients(free water content,total fat content,protein,lipid and total sugar concentrations in the fat body)of queens during prediapause,the temperature of acclimation for 6 days during prediapause on the energy consumption of queens during 3 months of diapause.Stepwise regression analysis revealed that total sugars concentrations,free water,and lipids concentrations were much more affected by temperature than protein concentrations(P<0.05).The acclimation temperature and acclimation time had an interactive effect on free water content and total sugar concentration in the fat body of queens during prediapause.Lower temperature acclimation significantly increased(P<0.05)free water,total fat content and lipid concentrations in the fat body accumulation by queens during prediapause,while higher temperature acclimation significantly increased(P<0.05)protein concentrations and total sugar concentrations in the fat body accumulation by queens during prediapause.The temperature acclimation for 6 days during prediapause on the queen survival rate was not significantly different(P>0.05)after 3 months of diapause.Moreover,lower temperature acclimation reduced protein,lipid,and total sugar consumption by queens during diapause.In conclusion,low-temperature acclimation increases queens of lipids accumulation during prediapause and reduces the nutritional consumption of queens during diapause.Lowtemperature acclimation during prediapause could benefit queens to increase reserves of major nutrient lipids during diapause.