A1 Refereed original research article in a scientific journal
The effect of overwintering temperature on the body energy reserves and phenoloxidase activity of bumblebee Bombus lucorum queens
Authors: S.-R. Vesterlund, T. M. Lilley, T. van Ooik, J. Sorvari
Publisher: SPRINGER BASEL AG
Publishing place: Basel
Publication year: 2014
Journal: Insectes Sociaux
Journal name in source: INSECTES SOCIAUX
Journal acronym: INSECT SOC
Volume: 61
Issue: 3
First page : 265
Last page: 272
Number of pages: 8
ISSN: 0020-1812
DOI: https://doi.org/10.1007/s00040-014-0351-9
Warming winters and changes in species composition related to the estimated global warming may cause a threat to bumblebees adapted to cold winters. During the overwintering period, their intermediary and respiratory metabolism decreases but metabolism remains responsive to temperature. The effect of temperature on diapause survival, phenoloxidase (PO) activity, and energy expenditure of the white-tailed bumblebee (Bombus lucorum) after a 4-month diapause were studied by manipulating the diapause temperature. Two overwintering temperatures were used, cold (1.8 A degrees C) and warm (9 A degrees C). Body fat content was used as an estimate of the remaining energy resources and PO activity as an immune function parameter of overwintering bumblebee queens. The baseline levels of PO activity were used to measure the differences in B. lucorum queen responses after overwintering in either temperature. We found a 0.4 g pre-diapause threshold weight of survival in B. lucorum. Large queens had more fat left and a higher PO activity compared to small ones after overwintering in warm conditions, but in the cold there was no effect of size on the remaining fat in the fat body of queens or their PO activity. The observed difference in energy usage appears to relate to normal size-dependent metabolism and variation in energy allocation between basic metabolism and immune functions.