Consequences of multiple simultaneous opportunities to exploit others’ efforts on free riding

Individuals within a group do not all act in the same way: typically the investors (or producers) put efforts into producing resources while the free riders (or scroungers) benefit from these resources without contributing. In behavioural ecology, the prevalence of free riders can be predicted by a well-known game-theoretical model -the Producer-Scrounger (PS) model- where group members have the options to either search for resources (producers) or exploit the efforts of others (scroungers). The PS model has received some empirical support, but its predictions, surprisingly, are based on the strict assumption that only one resource can be exploited at a time. Yet, multiple simultaneous opportunities to exploit others’ efforts should frequently occur in nature. Here, we combine analytic and simulation approaches to explore the effect of multiple simultaneous scrounging opportunities on tactic use. Our analyses demonstrate that scrounging rates should increase with the number of simultane...