High duty cycle echolocation and prey detection by bats

Lazure, Louis; Fenton, M. Brock

doi:10.1242/jeb.048967

Cited by 54 publications

(60 citation statements)

References 46 publications

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“…HDC bats may also be more readily attracted to fluttering targets than LDC bats (Goldman and Henson, 1977;Lazure and Fenton, 2011). In these respects, HDC echolocators differ from LDC echolocators.…”

Section: Hdc Echolocationmentioning

confidence: 99%

“…Some Kerivoula and Murina spp. detect flutter, but the cues they use remain unknown (Lazure and Fenton, 2011).…”

Section: Evolution Of Hdc Echolocationmentioning

confidence: 99%

Section: Advantages Of Hdc Echolocationmentioning

confidence: 99%

“…Some Kerivoula and Murina spp. detect flutter, but the cues they use remain unknown (Lazure and Fenton, 2011).Temporal overlap between outgoing sounds and returning echoes is an important feature of HDC echolocation. In P. parnellii, the beginning of the approach phase is signalled by an increase in pulse duration resulting in prominent pulse-echo overlap (Novick and Vaisnys, 1964).…”

mentioning

confidence: 99%

“…By monitoring echolocation calls at the same time, researchers can compare the responses of HDC and LDC echolocators, and identify other strategies that bats may use to detect fluttering targets [e.g. LDC bats in the genera Murina and Kerivoula (Lazure and Fenton, 2011)].Second, compared with LDC bats, HDC bats should be better able to exploit wingbeat signatures of fluttering insects and be more likely to show selective foraging. This prediction can be tested by identifying and comparing the diversity of insect prey in the diets of sympatric HDC and LDC bats.…”

mentioning

confidence: 99%

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Evolution of high duty cycle echolocation in bats

Fenton

Faure

Ratcliffe

2012

Journal of Experimental Biology

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112

129

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SummaryDuty cycle describes the relative ʻon timeʼ of a periodic signal. In bats, we argue that high duty cycle (HDC) echolocation was selected for and evolved from low duty cycle (LDC) echolocation because increasing call duty cycle enhanced the ability of echolocating bats to detect, lock onto and track fluttering insects. Most echolocators (most bats and all birds and odontocete cetaceans) use LDC echolocation, separating pulse and echo in time to avoid forward masking. They emit short duration, broadband, downward frequency modulated (FM) signals separated by relatively long periods of silence. In contrast, bats using HDC echolocation emit long duration, narrowband calls dominated by a single constant frequency (CF) separated by relatively short periods of silence. HDC bats separate pulse and echo in frequency by exploiting information contained in Doppler-shifted echoes arising from their movements relative to background objects and their prey. HDC echolocators are particularly sensitive to amplitude and frequency glints generated by the wings of fluttering insects. We hypothesize that narrowband/CF calls produced at high duty cycle, and combined with neurobiological specializations for processing Doppler-shifted echoes, were essential to the evolution of HDC echolocation because they allowed bats to detect, lock onto and track fluttering targets. This advantage was especially important in habitats with dense vegetation that produce overlapping, time-smeared echoes (i.e. background acoustic clutter). We make four specific, testable predictions arising from this hypothesis.Key words: Chiroptera, calling behaviour, signal design, Yinpterochiroptera, Yangochiroptera, flutter detection, Doppler shift compensation. Fig.1A-C). For the purpose of this paper, we define LDC bats as those producing signals with a duration <25% of their signal period during the search phase of echolocation. Most LDC bats produce echolocation calls with their larynx, although a handful of species in the family Pteropodidae use tongue clicks (Griffin et al., 1958;Yovel et al., 2010).HDC bats avoid auditory masking by separating pulse and echo in frequency, allowing them to broadcast calls and receive echoes at the same time (Schuller, 1974;Schuller, 1977). HDC bats take advantage of information contained in Doppler-shifted echoes generated by the relative movements of bat and target, including acoustic glints generated by the wingbeats of fluttering insects. Echolocation calls of HDC bats consist of a long CF component followed by a brief, downward FM sweep. In some species, the initial portion of the call also contains a short, upward FM sweep (Henson et al., 1987; Jones and Rayner, 1989). Narrowband calls of HDC bats are typically multi-harmonic with the highest signal energy in the second acoustic element (Pye and Roberts, 1970;Schnitzler and Denzinger, 2011). HDC bats emit long duration calls (e.g. 10 to >50ms) relative to their call period ( Fig.1D-F). We operationally define HDC bats as those whose signal durations are ≥25% of...

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Section: Hdc Echolocationmentioning

confidence: 99%

“…Some Kerivoula and Murina spp. detect flutter, but the cues they use remain unknown (Lazure and Fenton, 2011).…”

Section: Evolution Of Hdc Echolocationmentioning

confidence: 99%

Section: Advantages Of Hdc Echolocationmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Evolution of high duty cycle echolocation in bats

Fenton

Faure

Ratcliffe

2012

Journal of Experimental Biology

Self Cite

112

129

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The Biosonar System of Bats

Sillar

Picton

Heitler

2016

The Neuroethology of Predation and Escape

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Unique Turbinal Morphology in Horseshoe Bats (Chiroptera: Rhinolophidae)

Curtis

Simmons

2016

The Anatomical Record

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The mammalian nasal fossa contains a set of delicate and often structurally complex bones called turbinals. Turbinals and associated mucosae function in regulating respiratory heat and water loss, increasing surface area for olfactory tissue, and directing airflow within the nasal fossa. We used high-resolution micro-CT scanning to investigate a unique maxilloturbinal morphology in 37 species from the bat family Rhinolophidae, which we compared with those of families Hipposideridae, Megadermatidae, and Pteropodidae. Rhinolophids exhibit numerous structural modifications along the nasopharyngeal tract associated with emission of high duty cycle echolocation calls via the nostrils. In rhinolophids, we found that the maxilloturbinals and a portion of ethmoturbinal I form a pair of strand-like bony structures on each side of the nasal chamber. These structures project anteriorly from the transverse lamina and complete a hairpin turn to project posteriorly down the nasopharyngeal duct, and vary in length among species. The strand-like maxilloturbinals in Rhinolophidae were not observed in our outgroups and represent a synapomorphy for this family, and are unique in form among mammals. Within Rhinolophidae, maxilloturbinal size and cross-sectional shape were correlated with phylogeny. We hypothesize that strand-shaped maxilloturbinals may function to reduce respiratory heat and water loss without greatly impacting echolocation call transmission since they provide increased mucosal surface area for heat and moisture exchange but occupy minimal space. Alternatively, they may play a role in transmission of echolocation calls since they are located directly along the path sound travels between the larynx and nostrils during call emission. Anat Rec, 300:309-325,

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High duty cycle echolocation and prey detection by bats

Cited by 54 publications

References 46 publications

Evolution of high duty cycle echolocation in bats

Evolution of high duty cycle echolocation in bats

The Biosonar System of Bats

Unique Turbinal Morphology in Horseshoe Bats (Chiroptera: Rhinolophidae)

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