Honesty and Handicaps in Communication
Much of the recent research on communication in behavioral ecology has addressed the issue of whether signals are honest in the context of mate choice, resource defense, and predator-prey interactions. There are examples of communication involving deceit (such as the mimicry example mentioned above), but the wider issue is the selection signalers and receivers exert on one another. When signalers and receivers have conflicting interests, the result is likely to be a coevolutionary arms race. Two such instances are potential prey signaling to deter predators from attacking and females using male signals to choose the best mate. Selection should favor signals that best achieve signalers' interests, even at the expense of receivers; therefore signals are unlikely to be honest. However, selection should also favor receivers adept at gathering information in their best interests. Such a co-evolutionary arms race seems likely to result in signals that are 'honest on average'.
One way it is thought that signal honesty can be ensured if signals are costly. This idea is usually referred to as the handicap principle, where handicap means the conspicuous cost of the signal, that is, resources used for the signal that might otherwise have increased signaler fitness. A hypothetical example would be the energy used to produce a call indicating a larger than actual body size - energy that could otherwise have been used to grow a larger body. The debate about the role of handicaps in communications is outside the scope of this article.
signaling underlying such cooperation are still under study, but are likely to be important to the functioning of cooperation. When the signaler is a different species from the receiver, the lack of genetic relatedness may be the factor favoring cooperation and the associated signaling. Examples include the cleaner fish found on reefs that closely approach other, generally much larger species (clients) quite capable of eating the cleaner. However, the cleaner only approaches a client closely after an exchange of signals to indicate that the larger species is a client and not a predator. Recent research suggests that the signals also allow the client to minimize the risk that a cleaner will bite rather than clean.
The long-range advertising signals in most signal modalities contain information on species identity. Such information is valuable to conservation efforts because such signals and signaling activity allow species to be identified and their abundance to be estimated. This application is particularly well developed for birds, allowing species to be identified, and counted even at night or when they are hidden by dense vegetation. If birds can be individually identified, then detailed information on survival, habitat use, and immigration rates can be collected. Most bird vocalizations are naturally individually distinctive and techniques have been developed to gather such information as a noninvasive alternative to catching and marking.
The persistence of communication even when signalers differ from receivers in benefits (i.e., there is a large payoff asymmetry) is a topic of current interest in behavioral ecology. Two factors that allow communication to persist despite payoff asymmetries are the rarity of the signal and the genetic relatedness of signaler and receiver.
Extreme payoff asymmetries are found when the signal is rare and communication occurs between species. For example, edible mimics are thought to gain protection from predators by resembling inedible or dangerous prey (models) only when mimics are rare relative to models.
Extremes of relatedness often characterize striking examples of cooperation and its associated signaling. For example, individuals of the same species sometimes cooperate in locating distant food sources through signals such as the dance language of honeybees and the pheromone trails of ants. Often such social insects are very close genetic relatives. Other examples of cooperation include foregoing reproduction to help a close relative reproduce (e.g., social insects, naked mole rats). The details of the
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