The increased risk of predation enhances cooperation.
Theory predicts that animals in adverse conditions can decrease individual risks and increase long-term benefits by cooperating with neighbours. However, some empirical studies suggest that animals often focus on short-term benefits, which can reduce the likelihood that they will cooperate with others. In this experimental study, we tested between these two alternatives by evaluating whether increased predation risk (as a correlate of environmental adversity) enhances or diminishes the occurrence of cooperation in mobbing, a common anti-predator behaviour, among breeding pied flycatchers Ficedula hypoleuca. We tested whether birds would join their mobbing neighbours more often and harass a stuffed predator placed near their neighbours' nests more intensely in areas with a higher perceived risk of predation. Our results show that birds attended mobs initiated by their neighbours more often, approached the stuffed predator significantly more closely, and mobbed it at a higher intensity in areas where the perceived risk of predation was experimentally increased. In such high-risk areas, birds also were more often involved in between-pair cooperation. This study demonstrates the positive impact of predation risk on cooperation in breeding songbirds, which might help in explaining the emergence and evolution of cooperation.
Institute of Systematic Biology, University of Daugavpils, 5401 Daugavpils, Latvia. indrikis.krams@biology.lv
Indrikis
I
Krams
Arnis
A
Bērziņs
Tatjana
T
Krama
David
D
Wheatcroft
Kristīne
K
Igaune
Markus J
MJ
Rantala
D000818:Animals; D005075:Biological Evolution; D003299:Cooperative Behavior; D007844:Latvia; D019370:Observation; D046109:Passeriformes / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*; D018709:Statistics, Nonparametric