Wind generated by an attacking bat: anemometric measurements and detection by the praying mantis cercal system

Triblehorn, Jeffrey D.; Yager, David D.

doi:10.1242/jeb.02132

Cited by 16 publications

(17 citation statements)

References 38 publications

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“…Quantitatively, bats dropped twice as many deafened mantids with functioning cercal systems compared to deafened mantids with deactivated systems. Mantids have, on average, 75·ms between detection of bat-generated wind and capture to escape from a bat (Triblehorn and Yager, 2006). It is unlikely that this is enough time for the mantis to perform a maneuver that will cause the bat to completely miss its target, but may allow the mantis to alter its flight path sufficiently to cause the bat to drop the mantis without damage, resulting in a successful escape.…”

Section: Effectiveness Of the Mantis Wind-evoked Responsementioning

confidence: 99%

“…Many insects possess a wind-sensitive cercal system capable of detecting the air currents generated by an approaching bat. However, there is some question whether an insect would have enough time after initially detecting the wind generated by an approaching bat to perform an effective evasive response [around 75·ms for mantids (Triblehorn and Yager, 2006)]. …”

Section: Introductionmentioning

confidence: 99%

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Free-flight encounters between praying mantids (Parasphendale agrionina) and bats (Eptesicus fuscus)

Triblehorn

Ghose

Bohn

et al. 2008

Journal of Experimental Biology

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SUMMARYThrough staged free-flight encounters between echolocating bats and praying mantids, we examined the effectiveness of two potential predator-evasion behaviors mediated by different sensory modalities: (1) power dive responses triggered by bat echolocation detected by the mantis ultrasound-sensitive auditory system, and (2) ʻlast-ditchʼ maneuvers triggered by batgenerated wind detected by the mantis cercal system. Hearing mantids escaped more often than deafened mantids (76% vs 34%, respectively; hearing conveyed 42% advantage). Hearing mantis escape rates decreased when bat attack sequences contained very rapid increases in pulse repetition rates (escape rates <40% for transition slopes >16·p.p.s.·10·ms ) could circumvent mantis/insect auditory defenses. However, echolocation attack sequences containing such transitions occurred in only 15% of the trials. Since mantis ultrasound-mediated responses are not 100% effective, cercalmediated evasive behaviors triggered by bat-generated wind could be beneficial as a backup/secondary system. Although deafened mantids with functioning cerci did not escape more often than deafened mantids with deactivated cerci (35% vs 32%, respectively), bats dropped mantids with functioning cerci twice as frequently as mantids with deactivated cerci. This latter result was not statistically reliable due to small sample sizes, since this study was not designed to fully evaluate this result. It is an interesting observation that warrants further investigation, however, especially since these dropped mantids always survived the encounter.

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Section: Effectiveness Of the Mantis Wind-evoked Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Free-flight encounters between praying mantids (Parasphendale agrionina) and bats (Eptesicus fuscus)

Triblehorn

Ghose

Bohn

et al. 2008

Journal of Experimental Biology

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“…We used a wide range of air current velocities (0.014 -0.56 m/s) and durations (20 -1,000 ms), which cover the velocities and durations given for singing crickets (Kämper 1984) and for disturbance effects by approaching predators (Dupuy et al 2012;Gnatzy and Heußlein 1986;Gnatzy and Kämper 1990;Triblehorn and Yager 2006). The stimuli used here were a uniform onset of bulk air movement toward the cerci, from the back to the front of the animal, which does not represent the natural situation.…”

Section: Discussionmentioning

confidence: 99%

Impact of cercal air currents on singing motor pattern generation in the cricket (Gryllus bimaculatusDeGeer)

Jacob

Hedwig

2015

Journal of Neurophysiology

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Jacob PF, Hedwig B. Impact of cercal air currents on singing motor pattern generation in the cricket (Gryllus bimaculatus DeGeer). J Neurophysiol 114: 2649 -2660, 2015. First published September 2, 2015; doi:10.1152/jn.00669.2015.-The cercal system of crickets detects low-frequency air currents produced by approaching predators and self-generated air currents during singing, which may provide sensory feedback to the singing motor network. We analyzed the effect of cercal stimulation on singing motor pattern generation to reveal the response of a singing interneuron to predator-like signals and to elucidate the possible role of self-generated air currents during singing. In fictive singing males, we recorded an interneuron of the singing network while applying air currents to the cerci; additionally, we analyzed the effect of abolishing the cercal system in freely singing males. In fictively singing crickets, the effect of short air stimuli is either to terminate prematurely or to lengthen the interchirp interval, depending on their phase in the chirp cycle. Within our stimulation paradigm, air stimuli of different velocities and durations always elicited an inhibitory postsynaptic potential in the singing interneuron. Current injection in the singing interneuron elicited singing motor activity, even during the air current-evoked inhibitory input from the cercal pathway. The disruptive effects of air stimuli on the fictive singing pattern and the inhibitory response of the singing interneuron point toward the cercal system being involved in initiating avoidance responses in singing crickets, according to the established role of cerci in a predator escape pathway. After abolishing the activity of the cercal system, the timing of natural singing activity was not significantly altered. Our study provides no evidence that selfgenerated cercal sensory activity has a feedback function for singing motor pattern generation. cercal sensory system; air stimulus; singing central pattern generator interneuron; escape response TERRESTRIAL ANIMALS are constantly subjected to air currents, which, among others, can be of atmospheric origin, produced by approaching predators and conspecifics, or self-generated.Crickets, cockroaches, and locusts detect air currents through the cerci, two appendages at the rear of the abdomen (Edwards and Palka 1974) that carry up to 2,000 mechanosensitive filiform hairs (Chiba et al. 1992). Each filiform hair is innervated by a single sensory neuron, which makes synaptic connections with ascending interneurons, like the giant interneurons (GIs), in the terminal abdominal ganglion (TAG; Edwards and Palka 1974). Stimulation of the cercal pathway with salient air currents as generated by predators triggers escape responses and aggressive and freezing reactions and alters the singing behavior in male crickets (Baba and Shimozawa 1997;Dambach et al. 1983;Kohstall-Schnell and Gras 1994;Lewkiewicz and Zuk 2004;Matsuura et al. 2002). Air currents directed to the cerci evoke silencing responses in singing ...

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“…[2], [3], [4]). Laboratory and field studies suggest that in addition to listening to echolocation calls, the praying mantis Parasphendale agrionina may also make use of the wind-sensitive cercal organ for the detection of wind that is generated by an attacking bat [5], [6]. This suggests the cercal organ of insects suffering from bat predation as an additional sensory system for bat detection.…”

Section: Introductionmentioning

confidence: 99%

The Cercal Organ May Provide Singing Tettigoniids a Backup Sensory System for the Detection of Eavesdropping Bats

et al. 2010

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Conspicuous signals, such as the calling songs of tettigoniids, are intended to attract mates but may also unintentionally attract predators. Among them bats that listen to prey-generated sounds constitute a predation pressure for many acoustically communicating insects as well as frogs. As an adaptation to protect against bat predation many insect species evolved auditory sensitivity to bat-emitted echolocation signals. Recently, the European mouse-eared bat species Myotis myotis and M. blythii oxygnathus were found to eavesdrop on calling songs of the tettigoniid Tettigonia cantans. These gleaning bats emit rather faint echolocation signals when approaching prey and singing insects may have difficulty detecting acoustic predator-related signals. The aim of this study was to determine (1) if loud self-generated sound produced by European tettigoniids impairs the detection of pulsed ultrasound and (2) if wind-sensors on the cercal organ function as a sensory backup system for bat detection in tettigoniids. We addressed these questions by combining a behavioral approach to study the response of two European tettigoniid species to pulsed ultrasound, together with an electrophysiological approach to record the activity of wind-sensitive interneurons during real attacks of the European mouse-eared bat species Myotis myotis. Results showed that singing T. cantans males did not respond to sequences of ultrasound pulses, whereas singing T. viridissima did respond with predominantly brief song pauses when ultrasound pulses fell into silent intervals or were coincident with the production of soft hemi-syllables. This result, however, strongly depended on ambient temperature with a lower probability for song interruption observable at 21°C compared to 28°C. Using extracellular recordings, dorsal giant interneurons of tettigoniids were shown to fire regular bursts in response to attacking bats. Between the first response of wind-sensitive interneurons and contact, a mean time lag of 860 ms was found. This time interval corresponds to a bat-to-prey distance of ca. 72 cm. This result demonstrates the efficiency of the cercal system of tettigoniids in detecting attacking bats and suggests this sensory system to be particularly valuable for singing insects that are targeted by eavesdropping bats.

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Wind generated by an attacking bat: anemometric measurements and detection by the praying mantis cercal system

Cited by 16 publications

References 38 publications

Free-flight encounters between praying mantids (Parasphendale agrionina) and bats (Eptesicus fuscus)

Free-flight encounters between praying mantids (Parasphendale agrionina) and bats (Eptesicus fuscus)

Impact of cercal air currents on singing motor pattern generation in the cricket (Gryllus bimaculatusDeGeer)

The Cercal Organ May Provide Singing Tettigoniids a Backup Sensory System for the Detection of Eavesdropping Bats

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