Abstract:
Senescence or ageing in invertebrates is only partly unscrambled. Up to now five
different theories deal with explaining the biology of ageing. Most likely physiology, genetic
predestination and the impact of the environment form the image of ageing in individuals and
groups. Social insects, especially the honeybee Apis mellifera, present the best model system
to study developmentally related ageing, because high phenotypic plasticity makes the worker
caste useful to dissolve remaining questions. Here, we used long-lived winter honeybee
workers and measured transcriptional changes of 14 antioxidative enzymes, immunity and
ageing-related (Insulin/insulin-like growth factor signalling-pathway) genes at two time
points during hibernation. Additionally, the bees received a bacterial infection to see ageing
and infection associated immunity changes. Gene expression levels for each group of target
genes revealed that ageing had a much higher impact than the bacterial infections, notably for
immunity related genes. Antimicrobial peptide and antioxidative enzyme genes were
significantly up-regulated in aged worker honeybees independent of bacterial infections.
Vitellogenin and IlP-1, known ageing markers, were contrary regulated with increasing
vitellogenin levels during ageing. The increased antioxidative enzyme and antimicrobial
peptide gene expression may have a positive and also protective effect during ageing in
hibernating worker honeybees.
