Territory defence in poison frogs: experience pays off

[Translate to English:] Allobates femoralis Männchen rufen lautstark um den Besitz ihres Territoriums anzuzeigen. Foto © Elena Haeler

[Translate to English:] Allobates femoralis Männchen rufen lautstark um den Besitz ihres Territoriums anzuzeigen. Foto © Elena Haeler  1

Experience makes the difference. That’s the main finding of a recently published study led by a research team from the Vetmeduni Vienna on the territory defence behaviour of Allobates femoralis, a small species of poison frog that is widespread across Amazonia. Contrary to the assumption that the speed of response would affect the accuracy of the defensive attack, the researchers found that age, and thus experience in territory defence, is the relevant factor determining the animal’s success.

Male poison frogs are highly territorial and fiercely repel calling intruders from their territory. These territorial defence attacks must be conducted cautiously, as they are energetically costly and bear the risk of own injury or of accidentally targeting the wrong individual – for example, a potential mating partner. Yet contrary to previous assumptions, a quicker response is not associated with a higher number of erroneous attacks. Rather, the age of the animal is decisive. As study director Eva Ringler from the Messerli Research Institute of Vetmeduni Vienna says, “Younger frogs are more likely to make erroneous attacks than older ones, suggesting that experience plays an essential role in identifying and distinguishing rival individuals in a territorial context.”

Of benefit: wait and observe

Serving as background to the study is the fact that many behavioural processes in animals are affected by a trade-off between speed and accuracy. Animals that spend more time gathering information before a behavioural response have lower error rates than faster-acting individuals. This so-called speed–accuracy trade-off implies that speed and accuracy cannot be maximised simultaneously in decision-making. This compromise affects many behavioural patterns, such as predator avoidance, foraging strategies and nest site selection. However, very little is known about the speed–accuracy trade-off affecting territorial behaviour.

Experience makes attacks more successful

In their study, the researchers investigated the speed–accuracy trade-off in the context of male territoriality during the breeding season in the poison frog Allobates femoralis. In their experiment, the research team presented the frogs being studied with the acoustic playback of a call of an invisible “threatening” intruder together with a visible “non-threatening” intruder represented by a frog model simulating a female or non-calling male. “Contrary to our prediction, neither reaction time nor approach speed of the tested frogs determined the likelihood of erroneous attacks on the frog model. However, younger individuals were more likely to attack the non-threatening model than older ones,” says Ringler.

Attacks generally carried out with great caution

The researchers assume that older A. femoralis individuals are more experienced and therefore might already have learned to visually distinguish between threatening intruders and non-threatening individuals, as well as between males and females. Another important finding is that the relatively low attack rate of less than 20 percent is in line with the general assumption that fighting is energetically costly and involves the risk of injury.

To the english press release, the scientific article and the press photo 2

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