Territorial intrusion risk and antipredator behaviour: a mathematical model

In territorial animals that hide to avoid predators, a predatory attack cre ates a conflict because a hiding animal cannot defend its territory from co nspecific intruders. When intruders are persistent, a past conspecific intr usion informs a territorial resident that future intrusions by the same ani mal are likely: Using a mathematical model, I examine the effects that past territorial intrusions call have on antipredator behaviour. Past territori al intrusions rarely affect a resident animal's time to hide (the optimal b ehaviour is to hide as soon as the predator initiates its attack). In contr ast, past intrusions should shorten the length of time during which territo ry holders remain in hiding, with the magnitude of this effect depending on the time of the predator's attack, the re-intruder's pattern of return, an d the intrusion rates of other conspecifics. The results of the model show that we need more information on patterns of re-intruders' behaviour, and e mphasize that a similar functional explanation could underlie other behavio ural changes following territorial and/or aggressive encounters (such as wi nner/loser effects or changes in display frequency and territorial vigilanc e). Differences between my findings and those from previous studies suggest that the trade-off between antipredator behaviour and territorial defence can involve different costs from the trade-off between antipredator behavio ur and foraging.