How do animals communicate using sounds? How did animal vocal communication arise and evolve? Exploring a new way to conceptualize animal communication, this new edition moves beyond an earlier ...emphasis on the role of senders in managing receiver behaviour, to examine how receivers' responses influence signalling. It demonstrates the importance of the perceiver role in driving the evolution of communication, for instance in mimicry, and thus shifts the emphasis from a linguistic to a form/function approach to communication. Covering a wide range of animals from frogs to humans, this new edition includes new sections on human prosodic elements in speech, the vocal origins of smiles and laughter and deliberately irritating sounds and is ideal for researchers and students of animal behaviour and in fields such as sensory biology, neuroscience and evolutionary biology.
The evolution of communicative signals involves a major hurdle; signals need to effectively stimulate the sensory systems of their targets. Therefore, sensory specializations of target animals are ...important sources of selection on signal structure. Here we report the discovery of an animal signal that uses a previously unknown communicative modality, infrared radiation or "radiant heat," which capitalizes on the infrared sensory capabilities of the signal's target. California ground squirrels (Spermophilus beecheyi) add an infrared component to their snake-directed tail-flagging signals when confronting infrared-sensitive rattlesnakes (Crotalus oreganus), but tail flag without augmenting infrared emission when confronting infrared-insensitive gopher snakes (Pituophis melanoleucus). Experimental playbacks with a biorobotic squirrel model reveal this signal's communicative function. When the infrared component was added to the tail flagging display of the robotic models, rattlesnakes exhibited a greater shift from predatory to defensive behavior than during control trials in which tail flagging included no infrared component. These findings provide exceptionally strong support for the hypothesis that the sensory systems of signal targets should, in general, channel the evolution of signal structure. Furthermore, the discovery of previously undescribed signaling modalities such as infrared radiation should encourage us to overcome our own human-centered sensory biases and more fully examine the form and diversity of signals in the repertoires of many animal species.
Electricity-generating wind turbines are an attractive energy source because they are renewable and produce no emissions. However, they have at least two potentially damaging ecological effects. ...Their rotating blades are hazardous to raptors which occasionally fly into them. And wind turbines are very noisy when active, a feature that may interfere with the lives of animals beneath them. We studied California ground squirrels (
Spermophilus beecheyi) in the Altamont Pass Wind Resource Area of Northern California. These squirrels emit vocalizations that alert others to the presence of a predator, and so may be forced to compensate for turbine noise by modifying antipredator behavior. We compared the antipredator behavior of squirrels at two sites, one close to and the other far from turbines, and under two conditions, during baseline and playback of conspecific alarm calls. We generated composite two variables using principle components analysis, one representing vigilance and one representing another cautionary antipredator tactic, for further statistical comparisons. Animals at the Turbine site exhibited elevated levels of vigilance and showed increased caution demonstrated in part, by returning to the area near their burrows during alarm calling. We conclude that this site difference is probably caused by the disparity in turbine noise, since predator abundance, group size, and vegetation type and density were similar for the two sites. Though population level impacts of these behavioral differences remain to be explored, our results indicate that behavioral impacts of turbines on wildlife should be considered during future turbine development.
In species with long-term pair relationships, behavioural compatibility between mates could be a significant source of selection among pairs. We explored the relation between behavioural ...compatibility and reproductive success in cockatiels, a socially monogamous species with biparental care and variable compatibility. The mate behavioural compatibility measure, derived from our previous work with these birds, was based on five pair-level variables: proximity, behavioural synchrony, copulation, allopreening responsiveness and total aggression. We operationally defined mates as more compatible when they showed greater proximity, synchrony, allopreening responsiveness and copulation frequencies and lower frequencies of aggression. Using a captive, seminatural population, we tested the following three interrelated hypotheses: (1) pairs with greater behavioural compatibility before breeding should have greater reproductive success; (2) among pairs that laid fertile eggs, pairs with greater behavioural compatibility should show better incubation coordination and (3) pairs with better incubation coordination should hatch more fertile eggs. Our results were consistent with these hypotheses. Pairs that laid eggs had significantly higher behavioural compatibility scores than did those that laid no eggs. Pairs with higher behavioural compatibility scores reared significantly more chicks to independence even after controlling for the effects of pair bond duration and parental age. Among pairs that laid fertile eggs, mates with higher behavioural compatibility scores had greater incubation coordination, measured by periods during which only one parent at a time attended the eggs, and greater hatching success of fertile eggs. Behavioural compatibility between mates in socially monogamous species may have reproductive consequences, and emergent behavioural features of pair relationships may have evolutionary significance.
Extrapair sexual behaviour may facilitate mate switching in monogamous species by allowing individuals to appraise and acquire a different mate. An individual benefits from mate switching if the new ...mate enhances the switcher's reproductive success more than the current mate. Several factors, including mate compatibility, may influence whether another individual represents a better option than the current mate. In a large, communally housed, captive colony of cockatiels,
Nymphicus hollandicus, we tested three related hypotheses. (1) Members of pairs that show low mate behavioural compatibility should be more likely to engage in extrapair sexual behaviour than members of pairs with high mate behavioural compatibility. (2) Individuals that pursue extrapair sexual behaviour should be members of pairs with a high likelihood of reproductive failure. (3) Individuals that engage in extrapair sexual behaviour should later pair with their extrapair partner. We operationally defined pairmate relationships as more compatible when they involved lower within-pair aggression, less distance between mates and greater within-pair allopreening responsiveness, behavioural synchrony and copulation frequency than the opposite pattern of behaviour. Pairs in which neither pair member engaged in extrapair sexual behaviour had significantly higher behavioural compatibility scores than pairs in which at least one member did so. Every individual that engaged in extrapair copulation subsequently re-paired with their extrapair partner. This extrapair copulation and subsequent mate switching effectively dissolved relationships that had poor reproductive prospects and established new, reproductively successful relationships. This result suggests that extrapair sexual behaviour facilitates mate switching in cockatiels, and that behavioural compatibility is important in mate retention and divorce.
Ground squirrels (Spermophilus spp.) have evolved a battery of defences against the rattlesnakes (Crotalus spp.) that have preyed on them for millions of years. The distinctive behavioural reactions ...by these squirrels to rattlesnakes have recently been shown to include self-application of rattlesnake scent-squirrels apply scent by vigorously licking their fur after chewing on shed rattlesnake skins. Here, we present evidence that this behaviour is a novel antipredator defence founded on exploitation of a foreign scent. We tested three functional hypotheses for snake scent application-antipredator, conspecific deterrence and ectoparasite defence-by examining reactions to rattlesnake scent by rattlesnakes, ground squirrels and ectoparasites (fleas). Rattlesnakes were more attracted to ground squirrel scent than to ground squirrel scent mixed with rattlesnake scent or rattlesnake scent alone. However, ground squirrel behaviour and flea host choice were not affected by rattlesnake scent. Thus, ground squirrels can reduce the risk of rattlesnake predation by applying rattlesnake scent to their bodies, potentially as a form of olfactory camouflage. Opportunistic exploitation of heterospecific scents may be widespread; many species self-apply foreign odours, but few such cases have been demonstrated to serve in antipredator defence.
Chemical substances produced by one species are sometimes found on the body of another species. Animals often ingest such foreign substances and sequester them into their integument, but here we ...report a case of direct application of heterospecific substances to the body. California ground squirrels,
Spermophilus beecheyi, and rock squirrels,
Spermophilus variegatus, apply scent derived from their major predator, rattlesnakes,
Crotalus spp., by chewing shed rattlesnake skins and licking their fur. We found that the sequence of body areas licked during application was essentially the same for the two species. We consider three hypotheses regarding the function of this ‘snake scent application’ (SSA): antipredator defence, ectoparasite defence, and conspecific deterrence. To test these hypotheses, we assessed patterns of species and sex/age class differences in application quantity and compared them with patterns reflecting differences in the importance of predation, flea loads and conspecific aggression as sources of selection. We found no species differences in application quantity; however, juveniles and adult females of both species engaged in longer bouts of application than adult males. This pattern of sex/age class differences in SSA supports only the antipredator hypothesis because juveniles are most vulnerable to predation and adult females actively protect their young. We found no evidence to support either the ectoparasite defence or conspecific deterrence hypotheses. Thus, SSA behaviour may be a novel form of chemical defence against predation.
Dale Francis Lott (1933-2004) Owings, Donald H
The American psychologist,
05/2005, Letnik:
60, Številka:
4
Journal Article
Recenzirano
Obituary for Dale Francis Lott (1933-2004). An overview of his life as well as his contributions to the field of Psychology are included. (PsycInfo Database Record (c) 2022 APA, all rights reserved)
California ground squirrels (Spermophilus beecheyi) and northern Pacific rattlesnakes (Crotalus viridus oreganus) have an adversarial relationship. Adults are partially protected by venom resistance ...and harass rattlesnakes in part to defend their more vulnerable offspring. Larger, warmer snakes are more dangerous than smaller colder snakes, and in escalated conflict squirrels could benefit from risk assessment strategies. Rattlesnakes often rattle at harassing squirrels and rattling sounds produce cues related to body size and temperature. In study 1 we played back rattling sounds from snakes that varied in dangerousness and evaluated the roles of sex and parity in squirrel risk assessment strategies. In general, squirrels tail flagged and stood bipedally more, and were slower to reapproach the playback speaker following playbacks of rattling sounds from more dangerous snakes. In comparison with males and nonmothers, mothers were most responsive to rattling sounds and more sensitive to variation in snake dangerousness. Mothers tail flagged more than males and nonmothers, and this behavior tracked variation in snake dangerousness most closely, perhaps reflecting the effects of snake size and temperature on pup vulnerability. These findings suggest that many aspects of squirrel antisnake behavior are governed by their effects on descendant kin. In study 2 we tested the effects of offspring age on mothers’ responses to live rattlesnakes and rattling sounds. According to the offspring value hypothesis, mothers should take more risks in defense of older offspring because they are more likely to survive to reproductive age. By contrast, under the offspring vulnerability hypothesis, older offspring are less vulnerable to predators and thus mothers should take fewer risks. Risk-taking, as measured by behaviors that bring the squirrel close to the snake’s strike range, was either unaffected by or negatively correlated with offspring age. Thus, our findings suggest that whereas offspring value is unimportant in squirrel antisnake behavior, offspring vulnerability may affect maternal defense. We suggest that offspring vulnerability in mammals, in comparison with birds, may play a larger role in parental defense against predators.
Abstract
Pair relationships and their emergent properties represent potentially significant sources of proximate and ultimate influence on mating systems, but the study of such relational factors has ...been rare compared to the volume of literature dedicated to individual-level measures of mate quality. This study assessed variation in the stability of pair relationships in cockatiels (Nymphicus hollandicus) and sought sources for that variation in both the behavior of mated individuals and their compatibility. Pair relationships represent an especially salient aspect of the social system of cockatiels, a socially monogamous species with long-term pairing.In a semi-natural, captive setting, this study compared (1) the social interactions between cockatiel mates to those individuals' interactions with opposite-sex non-mates, (2) the roles of males and females in pair relationships, and (3) the various pairs in their displays of intrapair and extrapair interactions. We also assessed the behavioral features underlying pair relationships by examining the interrelationships among social behaviors within pairs and the degree to which emergent properties structure pair relationships. Interactions between mates, as compared to opposite-sex non-mates, were characterized by closer proximity, greater behavioral synchrony, less aggression, more allopreening, and greater sexual behavior. Males and females displayed little dimorphism in many intrapair and extrapair behaviors; however, males approached and courted their mates more than females did, and males but not females exhibited more intersexual aggression to non-mates than to their mates. Social interactions between mates varied significantly among pairs in ways that reflected variation in the degree of behavioral compatibility between mates. In other words, suites of highly correlated behaviors characterized the interactions between mates such that pairs exhibiting greater affiliative or accordant behaviors exhibited less aggressive or discordant behaviors and vice versa. Emergent properties appeared to play an especially important role in compatibility. By examining significant within-species variation in pair relationships, this study complements the increasing knowledge of mating relationships gained from comparative studies and illustrates the importance of emergent, pair-level behavior in the maintenance of long-term monogamous pair-bonds.
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