BOBEK L. (1,2), TOMÁŠEK O. (1,3), KRÁLOVÁ T. (1,2), KOTASOVÁ ADÁMKOVÁ M. (2), ALBRECHT T. (1,3) (1) Ústav biologie obratlovců AV ČR, Brno; (2) Ústav botaniky a zoologie, PřF MU, Brno; (3) Katedra zoologie, PřF UK, Praha Life-history theory posits that amount of energy available for growth, reproduction and survival is limited resulting in allocation trade-off between these components of individual fitness. As a consequence most life-history variation runs along one major axis, so called fast-slow life-history continuum. Compared to slow life-histories, fast life-histories are characterised by fast growth and development rates, high annual reproductive output, low survival and hence short life-spans. Recently, divergent life-histories has been hypothesised to co-evolve with a suite of physiological and behavioural adaptations–so called pace-of-life syndromes. The most studied trait in this regard is the rate of energetic metabolism, which is often used as a characteristics defining species-specific pace of life: fast and slow pace of life is characterised by high and low metabolic rate, respectively. In vertebrates, glucose is one of the main substrates for energy production circulating in the blood, and has been reported to positively correlate with metabolic rate. Therefore, we hypothesise that basal blood glucose concentration (G0) may also be a component of pace-of-life syndromes. To test this idea, we measured basal blood glucose concentrations (G0) in 330 individuals of 30 passerines and tested whether G0 is related to body mass and other life-history traits. Our data revealed significant interspecific differences in G0 with mean values ranging from 9.77 mmol/L to 15.4 mmol/L. Controlling for phylogeny, we found G0 to be negativelly correlated with body mass and migration distance and positivelly with immediate reproductive investment (clutch size and egg mass, but not yearly clutch frequency). These findings support the idea that G0 is an important component of paceof-life syndromes and corroborate findings of previous intraspecific studies reporting that, in contrast to fatty acids, glucose may not be the main fuel for migration. Supported by GAČR projects 17-24782S a 14-36098G.