The costs and benefits of ecological information

Date

2007-08

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Abstract

Information makes the world more predictable. Therefore, gaining information about the environment can reduce uncertainty in the decision making of foragers. However, acquiring information about the environment may be costly if it causes an animal to divert attention away from other fitness related activities. One such cost is that of increasing apprehension (multitasking). Apprehension occurs when a forger diverts its attention away from gaining information about resource patches to assessing predation risk. Here I present a study that quantified the cost of apprehension on the foraging ability of hispid cotton rats. I quantified the ability of cotton rats to forage efficiently and assess resource heterogeneity (patchiness) over a distance gradient that represents increasing predation risk. I provide evidence that apprehension does affect cotton rats’ ability to forage efficiently and in their assessment of patchiness. Although the increase in apprehension did reduce foraging efficiency in cotton rats, the benefit of being aware of predator presence and the potential risk of predation presumably outweighed that cost.

Eavesdropping (the use of information contained within a signal by an unintended receiver) for information contained within the communication and signals of other individuals (including heterospecifics) can often be beneficial. One source of information that may be acquired is through eavesdropping on signals (alarm calls) of conspecifics and heterospecifics. Alarm calls provide information about the presence of a potential predator. Thus, eavesdropping can potentially increase survival if an informed individual better manages the tradeoff between risks and safety. I present a study that quantified the ability of hispid cotton rats (eavesdropper) to change their perceived risk of predation when presented with information contained within heterospecific vocalizations, including the alarm and contact calls of blue jays, red-tailed hawk calls, American robin songs, and a silent control. I provide evidence that cotton rats (1) eavesdrop on the alarm vocalizations of blue jays and (2) increase their perceived risk of predation during jay alarms but not jay contact calls. There was no evidence that the direct cue of predator presence (hawk call) influences cotton rats’ perceived risk of predation. Eavesdropping behavior and the change in the perceived risk of predation potentially provides a benefit to the cotton rats as they balance the costs of predation risks and the benefits of foraging.

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Keywords

Ecological information

Citation