hide
Free keywords:
Carduelis chloris; behaviour; predator escape response; virus infection; Sindbis virus
Abstract:
The fitness effects of parasites on their hosts are often unknown. For most
avian viruses, no records of clinical disease have been associated with
infections. In this study we tested if birds would alter their behaviour during
an infection with an avian virus that naturally occurs in passerines. We
measured spontaneous locomotion activity and take-off performance of
Common Greenfinches Carduelis chloris at the peak of infection with the
Sindbis virus (Togaviridae, Alphavirus). We found that virus-treated birds
had lower locomotion activity than saline-treated birds the third day after
the injection. When exposed to a simulated predator attack, virus-treated
birds reduced their take-off speed from before to after treatment, whereas
saline-treated birds did the opposite. This difference between treatments in
change in flight speed from before to after treatment was only detected in
the evenings, when the birds were heavy. Furthermore, virus-treated birds
increased in body mass from before to after treatment, whereas saline-treated
birds did the opposite. Our results suggest that the infection with Sindbis
virus is accompanied by energetic or pathological costs, and that infected
birds accounted for these cost by reducing locomotion activity while
increasing their energy intake. Down-regulating important behaviours such
as take-off flight speed may have implications for the chances of survival
of infected birds.
