Great tits detox at the expense of a lower life expectancy

Some males of great tits that faced higher energetic costs during their reproductive phase upregulated the concentration of an enzyme important for detoxifying free radicals. Together with other physiological reactions like the loss of weight and a higher level of stress hormones, harder-working birds compensated higher energetic demands in a way that had no direct consequences for their offspring or their own survival. This is what researchers of the Max Planck Institute for Ornithology have found. However, birds with a higher concentration of the enzyme had a lower overwinter survival. This seems to be the physiological key mediating the trade-off between reproduction and survival. (Mehr in: Pressemitteilungen – idw – Informationsdienst Wissenschaft)