scholarly journals Offspring Discrimination Without Recognition: California Towhee Responses to Chick Distress Calls

The Condor ◽  
2007 ◽  
Vol 109 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Lauryn Benedict
Keyword(s):  
Natural Selection ◽  
Decision Rule ◽  
Playback Experiments ◽  
Distress Call ◽  
Parental Fitness ◽  
Vocal Recognition ◽  
Distress Calls ◽  
Individual Offspring ◽  
Fitness Benefits ◽  
Offspring Discrimination

AbstractAbstractAccurate offspring discrimination improves parental fitness by ensuring appropriate parental investment. In colonial avian species, offspring discrimination is often mediated by recognition of individual offspring vocalizations, but spatially segregated species do not necessarily need sophisticated recognition abilities if parents can use alternative information to distinguish offspring from nonoffspring. I experimentally tested the hypothesis that territorial California Towhee (Pipilo crissalis) parents use a location-based decision rule, instead of true vocal recognition of offspring, when deciding whether to respond to chick distress calls. Accurate responses to offspring distress calls should be favored by natural selection because they can have large fitness benefits if parents succeed in chasing away potential nest predators. Responses to nonoffspring, in contrast, may be costly and should not be favored by natural selection. Towhee parents were presented with a series of three playback experiments in which I manipulated the identity of the vocalizing chick, the age of resident chicks, and the location of the distress call broadcast. Parents showed no evidence of individual vocal recognition and no pattern of differential response to distress calls when offspring age differed from that of the calling chick. Parents did, however, exhibit a significant tendency to approach distress calls originating near their offspring more often than distress calls originating elsewhere on their territory. These results provide support for the evolution of an offspring discrimination strategy based on a simple location-based decision rule instead of true vocal recognition.

scholarly journals Responsiveness to conspecific distress calls is influenced by day-roost proximity in bats ( Saccopteryx bilineata )

2016 ◽  
Vol 3 (5) ◽  
pp. 160151 ◽  
Author(s):  
Maria Eckenweber ◽  
Mirjam Knörnschild
Keyword(s):  
Group Composition ◽  
Playback Experiments ◽  
Distress Call ◽  
Social Relevance ◽  
The Social ◽  
Saccopteryx Bilineata ◽  
Distress Calls ◽  
Foraging Site ◽  
Physical Distress ◽  
Mobbing Behaviour

Distress calls signal extreme physical distress, e.g. being caught by a predator. In many bat species, distress calls attract conspecifics. Because bats often occupy perennial day-roosts, they might adapt their responsiveness according to the social relevance in which distress calls are broadcast. Specifically, we hypothesized that conspecific distress calls broadcast within or in proximity to the day-roost would elicit a stronger responsiveness than distress calls broadcast at a foraging site. We analysed the distress calls and conducted playback experiments with the greater sac-winged bat, Saccopteryx bilineata , which occupies perennial day-roosts with a stable social group composition. S. bilineata reacted significantly differently depending on the playback's location. Bats were attracted to distress call playbacks within the day-roost and in proximity to it, but showed no obvious response to distress call playbacks at a foraging site. Hence, the bats adapted their responsiveness towards distress calls depending on the social relevance in which distress calls were broadcast. Distress calls within or in proximity to the day-roost are probably perceived as a greater threat and thus have a higher behavioural relevance than distress calls at foraging sites, either because bats want to assess the predation risk or because they engage in mobbing behaviour.

Larval habitats impose trait-dependent limits on the direction and rate of adult evolution in dragonflies

2021 ◽  
Vol 17 (5) ◽  
pp. 20210023
Author(s):  
Michael P. Moore
Keyword(s):  
Natural Selection ◽  
Comparative Study ◽  
Adult Stage ◽  
Larval Habitat ◽  
Adult Size ◽  
Larval Habitats ◽  
Size Evolution ◽  
Fitness Benefits ◽  
Context Dependent ◽  
Ornament Evolution

Natural selection on juveniles is often invoked as a constraint on adult evolution, but it remains unclear when such restrictions will have their greatest impact. Selection on juveniles could, for example, mainly limit the evolution of adult traits that mostly develop prior to maturity. Alternatively, selection on juveniles might primarily constrain the evolution of adult traits that experience weak or context-dependent selection in the adult stage. Using a comparative study of dragonflies, I tested these hypotheses by examining how a species’ larval habitat was related to the evolution of two adult traits that differ in development and exposure to selection: adult size and male ornamentation. Whereas adult size is fixed at metamorphosis and experiences consistent positive selection in the adult stage, ornaments develop throughout adulthood and provide context-dependent fitness benefits. My results show that species that develop in less stable larval habitats have smaller adult sizes and slower rates of adult size evolution. However, these risky larval habitats do not limit ornament expression or rates of ornament evolution. Selection on juveniles may therefore primarily affect the evolution of adult traits that mostly develop prior to maturity.

scholarly journals The weeping vocalization of the screaming hairy armadillo (Chaetophractus vellerosus), a distress call

2019 ◽  
Vol 100 (5) ◽  
pp. 1427-1435 ◽  
Author(s):  
Juan P Amaya ◽  
Emmanuel Zufiaurre ◽  
Juan I Areta ◽  
Agustín M Abba
Keyword(s):  
High Amplitude ◽  
Physical Stress ◽  
Harmonic Structure ◽  
Vertebrate Species ◽  
Acoustic Features ◽  
Distress Call ◽  
Data Support ◽  
Acoustic Characterization ◽  
Distress Calls

Abstract Distress calls are signals given by individuals experiencing physical stress such as handling by a predator. These calls have been recorded in numerous phylogenetically distant vertebrate species, and share certain acoustic features, such as high amplitude, broadband, and rich harmonic structure. Screaming hairy armadillos (Chaetophractus vellerosus) sometimes give a high-amplitude weeping call when captured by predators or disturbed by humans. We provide an acoustic characterization of this call using recordings of hand-held wild individuals, and test whether it constitutes a distress signal. The weeping call was a harsh, loud, broadband, long sound, composed of five note types: crying, inhaled, inhaled sobbing, exhaled sobbing, and grunt notes. Crying notes were the most common, distinctive, and loudest sounds. The proportion of armadillos that called when disturbed was between nearly five to seven times higher than when treated with care. Likewise, 223 hunters reported armadillos consistently weeping when trapped by dogs, and no weeping was heard in natural undisturbed conditions. Our data support a distress signal role for the weeping call.

Stimuli Eliciting Distress Calls in Adult Passerines and Response of Predators and Birds To Their Broadcast

Behaviour ◽  
1994 ◽  
Vol 131 (1-2) ◽  
pp. 19-37 ◽  
Author(s):  
Michael R. Conover
Keyword(s):  
Short Duration ◽  
Sound Source ◽  
Procyon Lotor ◽  
Molothrus Ater ◽  
The Body ◽  
Distress Call ◽  
Severe Attack ◽  
Passerine Species ◽  
Distress Calls

AbstractThis study examined the response of birds and captive predators to the broadcast of distress calls and the effect of different stimuli on the elicitation ofthese calls. In doing so, this study tested two hypotheses about why adult passerines should distress call when physically constrained: the calls are designed 1) to attract attention, or 2) to startle the predator into releasing the caller. Birds often responded to both interspecific and intraspecific distress calls by approaching the sound source, but they rarely mobbed or engaged in any behavior that would aid the caller in escaping. The playback of a distress call had little effect on most captive opossums (Didelphis marsupialis) and raccoons (Procyon lotor) which were attacking a caged starling (Slurnus vulgaris). However, distress calls startled one opossum and two raccoons and provoked two other raccoons into a more severe attack. Birds only distress called when physically constrained. All passerine species that were tested, except brown-headed cowbirds (Molothrus ater), emitted distress calls, but in no species did every individual call. Distress calls usually were of short duration, interrupted by periods of silence, and paired with struggling behavior. Birds were more likely to distress call when held by the limbs rather than the body or neck, when moved, or when viewing a rapidly approaching object. These results indicate that one function of distress calls for most passerines is to startle the predator, but that other functions also are likely. My results also support the hypothesis that birds approach a distress caller to acquire information about the predator that has captured the caller.

Function of Distress Calls in Least Horseshoe Bats: A Field Study Using Playback Experiments

2019 ◽  
Vol 20 (2) ◽  
pp. 455 ◽  
Author(s):  
Xiu Wu ◽  
Yulan Pang ◽  
Bo Luo ◽  
Man Wang ◽  
Jiang Feng
Keyword(s):  
Field Study ◽  
Playback Experiments ◽  
Distress Calls ◽  
Horseshoe Bats

scholarly journals Grandmothering and natural selection

2010 ◽  
Vol 278 (1704) ◽  
pp. 384-391 ◽  
Author(s):  
A. Friederike Kachel ◽  
L. S. Premo ◽  
Jean-Jacques Hublin
Keyword(s):  
Natural Selection ◽  
Inclusive Fitness ◽  
Human Life ◽  
Reproductive Period ◽  
Age At First Birth ◽  
Weak Selection ◽  
Wide Range ◽  
Grandmother Hypothesis ◽  
Fitness Benefits ◽  
Post Menopausal

Humans are unique among primates in that women regularly outlive their reproductive period by decades. The grandmother hypothesis proposes that natural selection increased the length of the human post-menopausal period—and, thus, extended longevity—as a result of the inclusive fitness benefits of grandmothering. However, it has yet to be demonstrated that the inclusive fitness benefits associated with grandmothering are large enough to warrant this explanation. Here, we show that the inclusive fitness benefits are too small to affect the evolution of longevity under a wide range of conditions in simulated populations. This is due in large part to the relatively weak selection that applies to women near or beyond the end of their reproductive period. However, we find that grandmothers can facilitate the evolution of a shorter reproductive period when their help decreases the weaning age of their matrilineal grandchildren. Because selection favours a shorter reproductive period in the presence of shorter interbirth intervals, this finding holds true for any form of allocare that helps mothers resume cycling more quickly. We conclude that while grandmothering is unlikely to explain human-like longevity, allocare could have played an important role in shaping other unique aspects of human life history, such as a later age at first birth and a shorter female reproductive period.

scholarly journals Spectral entropy of early-life distress calls as an iceberg indicator of chicken welfare

2020 ◽  
Vol 17 (167) ◽  
pp. 20200086 ◽  
Author(s):  
Katherine A. Herborn ◽  
Alan G. McElligott ◽  
Malcolm A. Mitchell ◽  
Victoria Sandilands ◽  
Brett Bradshaw ◽  
...  
Keyword(s):  
Early Life ◽  
Affective State ◽  
High Energy ◽  
Acoustic Parameter ◽  
Broiler Chicks ◽  
Spectral Entropy ◽  
Distress Call ◽  
Livestock Farming ◽  
Acoustic Environment ◽  
Distress Calls

Chicks ( Gallus gallus domesticus ) make a repetitive, high energy ‘distress’ call when stressed. Distress calls are a catch-all response to a range of environmental stressors, and elicit food calling and brooding from hens. Pharmacological and behavioural laboratory studies link expression of this call with negative affective state. As such, there is an a priori expectation that distress calls on farms indicate not only physical, but emotional welfare. Using whole-house recordings on 12 commercial broiler flocks ( n = 25 090–26 510/flock), we show that early life (day 1–4 of placement) distress call rate can be simply and linearly estimated using a single acoustic parameter: spectral entropy. After filtering to remove low-frequency machinery noise, spectral entropy per minute of recording had a correlation of −0.88 with a manual distress call count. In videos collected on days 1–3, age-specific behavioural correlates of distress calling were identified: calling was prevalent (spectral entropy low) when foraging/drinking were high on day 1, but when chicks exhibited thermoregulatory behaviours or were behaviourally asynchronous thereafter. Crucially, spectral entropy was predictive of important commercial and welfare-relevant measures: low median daily spectral entropy predicted low weight gain and high mortality, not only into the next day, but towards the end of production. Further research is required to identify what triggers, and thus could alleviate, distress calling in broiler chicks. However, within the field of precision livestock farming, this work shows the potential for simple descriptors of the overall acoustic environment to be a novel, tractable and real-time ‘iceberg indicator’ of current and future welfare.

Individually distinctive pup vocalizations fail to prevent allo-suckling in grey seals

1999 ◽  
Vol 77 (5) ◽  
pp. 716-723 ◽  
Author(s):  
Susanne McCulloch ◽  
Patrick P Pomeroy ◽  
Peter JB Slater
Keyword(s):  
Breeding Season ◽  
Individual Recognition ◽  
Mutual Recognition ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
Playback Experiments ◽  
Auditory Cues ◽  
Distinctive Features ◽  
Vocal Recognition

In crowded aggregations that occur in breeding colonies, female pinnipeds commonly become separated from their pups and may use spatial, olfactory, or auditory cues to locate them. A system of mutual recognition based on vocalizations is known for otariids. Female phocids are known to use location and olfaction to help identify pups, but evidence for vocal recognition is weak. During the 1997 breeding season on the Isle of May, Scotland, vocalizations were recorded from grey seal, Halichoerus grypus, pups; playback experiments were carried out; and nursing of nonfilial pups was observed. Pup vocalizations were found to be both stereotyped and individually distinctive, features normally associated with a system of individual recognition. However, playback experiments revealed that mothers did not respond more to vocalizations of their own pups than to those of nonfilial pups. Furthermore, seventeen cases of allo-suckling were observed during 68 h of observation on the colony. High densities of animals and frequent separations present challenges to identification of pups by their mothers.

scholarly journals When good mutations go bad: how population size can change the direction of natural selection

2021 ◽  
Author(s):  
Yevgeniy Raynes ◽  
Christina L Burch ◽  
Daniel M Weinreich
Keyword(s):  
Natural Selection ◽  
Population Size ◽  
Underlying Mechanism ◽  
Deleterious Mutations ◽  
Fitness Costs ◽  
Sign Inversion ◽  
Population Sizes ◽  
The Common ◽  
Fitness Benefits ◽  
The Cost

Classical evolutionary theory holds that the efficiency, but not the direction, of natural selection depends on population size. In small populations, drift overwhelms selection, rendering all fitness-affecting mutations selectively neutral. Yet, beneficial mutations never become deleterious and deleterious mutations never become beneficial. Remarkably, several mutations, including in modifiers of recombination and mutation rate, have now been shown to be favored at some population sizes but disfavored at others, challenging established theory. Previously, we have designated this phenomenon sign inversion. Here we show that, unlike selected mutations in the classical framework, mutations susceptible to sign inversion confer both fitness costs and fitness benefits, that vary among their carriers. Furthermore, all such mutations can be classified based on whether their effects differ between or within mutant lineages. Using computer simulations, we demonstrate that both between-lineage and within-lineage variability can cause sign inversion and elucidate the common underlying mechanism. Our results confirm that variability in the sign of selective effects is necessary for sign inversion, which occurs because drift overwhelms selection on carriers bearing the cost and carriers enjoying the benefit at different population sizes.

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