The various factors influencing stable isotope
discrimination by animals involves some uncertainty
in the use of this method for ecological
research and calls for more defined laboratory
experiments. In this study we investigate the
effects of food depletion (i.e. starvation) and
quality (i.e. C/N ratio of fungal diet) on
N
and
13
C/
12
C stable isotope fractionation in the
Collembola Protaphorura fimata. Additionally, the
influence of different life stages is assessed. Food
quality likely will alter consumption rates and
nutritional status in Collembola. Starvation
strongly affects their metabolism by changing the
ratio of anabolic to catabolic processes and
similarly different life stages will alter the balance
between metabolic pathways. Thus, starvation,
food quality and life stage are expected to affect
the fractionation of stable isotopes in Collembola
which may result in patterns not related to the
consumed diet.
15
N/
14