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Adult vampire bats produce contact calls when isolated: acoustic variation by species, population, colony, and individual.

Carter GG, Logsdon R, Arnold BD, Menchaca A, Medellin RA - PLoS ONE (2012)

Bottom Line: We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively.Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups.This result is consistent with, but not sufficient evidence of, vocal convergence in groups.

View Article: PubMed Central - PubMed

Affiliation: Biological Sciences, University of Maryland, College Park, Maryland, United States of America. gcarter@umd.edu

ABSTRACT

Background: Bat pups produce individually distinct isolation calls to facilitate maternal recognition. Increasing evidence suggests that, in group-living bat species, adults often use similar calls to maintain contact. We investigated if isolated adults from all three species of the highly cooperative vampire bats (Phyllostomidae: Desmodontinae) would produce vocally distinct contact calls when physically isolated.

Methods/principal findings: We assessed variation in contact calls recorded from isolated captive and wild-caught adult common vampire bats (Desmodus rotundus), white-winged vampire bats (Diaemus youngi) and hairy-legged vampire bats (Diphylla ecaudata). We compared species-typical contact call structure, and used information theory and permuted discriminate function analyses to examine call structure variation, and to determine if the individuality of contact calls is encoded by different call features across species and populations. We found that isolated adult vampire bats produce contact calls that vary by species, population, colony, and individual. However, much variation occurred within a single context and individual. We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively. Contact calls from a captive colony of Desmodus were less individually distinct than calls from wild-caught Desmodus from different colonies. Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups. This result is consistent with, but not sufficient evidence of, vocal convergence in groups.

Conclusion: Our results show that adult vampire bats of all three species produce highly variable contact calls when isolated. Contact calls contain sufficient information for vocal discrimination, but also possess more intra-individual variation than is required for the sole purpose of identifying individuals.

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Related in: MedlinePlus

Spectrograms of calls from a common, white-winged, and hairy-legged vampire bat.Shown are a contact call (a), echolocation pulse (b), and portion of distress call (c) from a common vampire bat (Desmodus rotundus); double-note contact call (d), echolocation pulse (e), and portion of distress call (f) from a white-winged vampire bat (Diaemus youngi); contact call (g), echolocation pulse (h) and portion of a distress call (i) from a hairy-legged vampire bat (Diphylla ecaudata). Distress calls are often produced by captured bats.
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pone-0038791-g001: Spectrograms of calls from a common, white-winged, and hairy-legged vampire bat.Shown are a contact call (a), echolocation pulse (b), and portion of distress call (c) from a common vampire bat (Desmodus rotundus); double-note contact call (d), echolocation pulse (e), and portion of distress call (f) from a white-winged vampire bat (Diaemus youngi); contact call (g), echolocation pulse (h) and portion of a distress call (i) from a hairy-legged vampire bat (Diphylla ecaudata). Distress calls are often produced by captured bats.

Mentions: The observation that social calls can mediate parental care [12], colonial roosting [16]–[18], group foraging [37], and collision avoidance [38] suggests that complex communication might mediate other cooperative social behaviors. Common vampire bats Desmodus rotundus show fission-fusion dynamics [12], [39], and possess the most cooperative social lives known among bats [12], [40]–[42]. Desmodus in Costa Rica roost in groups of 8–20 adults, which split apart and recombine, due to roost switching [39]. Females maintain long-term roosting affiliations that are largely independent of relatedness and last up to 12 years [12]. This species has been observed to survive 15+ years in the wild [43], with records twice as long in captivity [12], [44]. Such long-term social bonds involve cooperative behaviors such as allogrooming and regurgitated food sharing [39]–[41]. Unlike Desmodus, the social structures of the other two vampire species, the white-winged vampire bat (Diaemus youngi) and hairy-legged vampire bat (Diphylla ecaudata), have not been well studied in a natural context. However, all three species (Figure 1) are known to participate in social grooming and cooperative food sharing through regurgitation [13], [40], [45].


Adult vampire bats produce contact calls when isolated: acoustic variation by species, population, colony, and individual.

Carter GG, Logsdon R, Arnold BD, Menchaca A, Medellin RA - PLoS ONE (2012)

Spectrograms of calls from a common, white-winged, and hairy-legged vampire bat.Shown are a contact call (a), echolocation pulse (b), and portion of distress call (c) from a common vampire bat (Desmodus rotundus); double-note contact call (d), echolocation pulse (e), and portion of distress call (f) from a white-winged vampire bat (Diaemus youngi); contact call (g), echolocation pulse (h) and portion of a distress call (i) from a hairy-legged vampire bat (Diphylla ecaudata). Distress calls are often produced by captured bats.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375292&req=5

pone-0038791-g001: Spectrograms of calls from a common, white-winged, and hairy-legged vampire bat.Shown are a contact call (a), echolocation pulse (b), and portion of distress call (c) from a common vampire bat (Desmodus rotundus); double-note contact call (d), echolocation pulse (e), and portion of distress call (f) from a white-winged vampire bat (Diaemus youngi); contact call (g), echolocation pulse (h) and portion of a distress call (i) from a hairy-legged vampire bat (Diphylla ecaudata). Distress calls are often produced by captured bats.
Mentions: The observation that social calls can mediate parental care [12], colonial roosting [16]–[18], group foraging [37], and collision avoidance [38] suggests that complex communication might mediate other cooperative social behaviors. Common vampire bats Desmodus rotundus show fission-fusion dynamics [12], [39], and possess the most cooperative social lives known among bats [12], [40]–[42]. Desmodus in Costa Rica roost in groups of 8–20 adults, which split apart and recombine, due to roost switching [39]. Females maintain long-term roosting affiliations that are largely independent of relatedness and last up to 12 years [12]. This species has been observed to survive 15+ years in the wild [43], with records twice as long in captivity [12], [44]. Such long-term social bonds involve cooperative behaviors such as allogrooming and regurgitated food sharing [39]–[41]. Unlike Desmodus, the social structures of the other two vampire species, the white-winged vampire bat (Diaemus youngi) and hairy-legged vampire bat (Diphylla ecaudata), have not been well studied in a natural context. However, all three species (Figure 1) are known to participate in social grooming and cooperative food sharing through regurgitation [13], [40], [45].

Bottom Line: We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively.Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups.This result is consistent with, but not sufficient evidence of, vocal convergence in groups.

View Article: PubMed Central - PubMed

Affiliation: Biological Sciences, University of Maryland, College Park, Maryland, United States of America. gcarter@umd.edu

ABSTRACT

Background: Bat pups produce individually distinct isolation calls to facilitate maternal recognition. Increasing evidence suggests that, in group-living bat species, adults often use similar calls to maintain contact. We investigated if isolated adults from all three species of the highly cooperative vampire bats (Phyllostomidae: Desmodontinae) would produce vocally distinct contact calls when physically isolated.

Methods/principal findings: We assessed variation in contact calls recorded from isolated captive and wild-caught adult common vampire bats (Desmodus rotundus), white-winged vampire bats (Diaemus youngi) and hairy-legged vampire bats (Diphylla ecaudata). We compared species-typical contact call structure, and used information theory and permuted discriminate function analyses to examine call structure variation, and to determine if the individuality of contact calls is encoded by different call features across species and populations. We found that isolated adult vampire bats produce contact calls that vary by species, population, colony, and individual. However, much variation occurred within a single context and individual. We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively. Contact calls from a captive colony of Desmodus were less individually distinct than calls from wild-caught Desmodus from different colonies. Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups. This result is consistent with, but not sufficient evidence of, vocal convergence in groups.

Conclusion: Our results show that adult vampire bats of all three species produce highly variable contact calls when isolated. Contact calls contain sufficient information for vocal discrimination, but also possess more intra-individual variation than is required for the sole purpose of identifying individuals.

Show MeSH
Related in: MedlinePlus