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Hügel T, Goerlitz HR. Light might suppress both types of sound-evoked antipredator flight in moths. Ecol Evol 2020; 10:13134-13142. [PMID: 33304523 PMCID: PMC7713931 DOI: 10.1002/ece3.6904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 11/29/2022] Open
Abstract
Urbanization exposes wild animals to increased levels of light, affecting particularly nocturnal animals. Artificial light at night might shift the balance of predator-prey interactions, for example, of nocturnal echolocating bats and eared moths. Moths exposed to light show less last-ditch maneuvers in response to attacking close-by bats. In contrast, the extent to which negative phonotaxis, moths' first line of defense against distant bats, is affected by light is unclear. Here, we aimed to quantify the overall effect of light on both types of sound-evoked antipredator flight, last-ditch maneuvers and negative phonotaxis. We caught moths at two light traps, which were alternately equipped with loudspeakers that presented ultrasonic playbacks to simulate hunting bats. The light field was omnidirectional to attract moths equally from all directions. In contrast, the sound field was directional and thus, depending on the moth's approach direction, elicited either only negative phonotaxis, or negative phonotaxis and last-ditch maneuvers. We did not observe an effect of sound playback on the number of caught moths, suggesting that light might suppress both types of antipredator flight, as either type would have caused a decline in the number of caught moths. As control, we confirmed that our playback was able to elicit evasive flight in moths in a dark flight room. Showing no effect of a treatment, however, is difficult. We discuss potential alternative explanations for our results, and call for further studies to investigate how light interferes with animal behavior.
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Affiliation(s)
- Theresa Hügel
- Acoustic and Functional EcologyMax Planck Institute for OrnithologySeewiesenGermany
| | - Holger R. Goerlitz
- Acoustic and Functional EcologyMax Planck Institute for OrnithologySeewiesenGermany
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2
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Hügel T, Goerlitz HR. Species‐specific strategies increase unpredictability of escape flight in eared moths. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Theresa Hügel
- Acoustic and Functional Ecology Group Max Planck Institute for Ornithology Seewiesen Germany
| | - Holger R. Goerlitz
- Acoustic and Functional Ecology Group Max Planck Institute for Ornithology Seewiesen Germany
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3
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Symes LB, Martinson SJ, Hoeger LO, Page RA, ter Hofstede HM. From Understory to Canopy: In situ Behavior of Neotropical Forest Katydids in Response to Bat Echolocation Calls. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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4
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Early erratic flight response of the lucerne moth to the quiet echolocation calls of distant bats. PLoS One 2018; 13:e0202679. [PMID: 30125318 PMCID: PMC6101402 DOI: 10.1371/journal.pone.0202679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 08/07/2018] [Indexed: 11/19/2022] Open
Abstract
Nocturnal insects have evolved ultrasound-sensitive hearing in response to predation pressures from echolocating insectivorous bats. Flying tympanate moths take various evasive actions when they detect bat cries, including turning away, performing a steering/zigzagging flight and ceasing flight. In general, infrequent ultrasonic pulses with low sound intensities that are emitted by distant bats evoke slight turns, whereas frequent and loud ultrasonic pulses of nearby bats evoke erratic or rapid unpredictable changes in the flight path of a moth. Flight cessation, which is a freezing response that causes the moth to passively dive (drop) to the ground, is considered the ultimate last-ditch evasive behaviour against approaching bats where there is a high predation threat. Here, we found that the crambid moth Nomophila nearctica never performed passive dives in response to frequent and loud ultrasonic pulses of >60 dB sound pressure level (SPL) that simulated the attacking echolocation call sequence of the predominant sympatric insectivorous bat Eptesicus fuscus, but rather turned away or flew erratically, regardless of the temporal structure of the stimulus. Consequently, N. nearctica is likely to survive predation by bats by taking early evasive action even when it detects the echolocation calls of sympatric bats hunting other insects at a distance. Since aerially hawking bats can track and catch erratically flying moths after targeting their prey, this early escape strategy may be common among night-flying tympanate insects.
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Thevenon H, Pfuhl G. Discrepancies in the spiking threshold and frequency sensitivity of nocturnal moths explainable by biases in the canonical auditory stimulation method. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172404. [PMID: 29765685 PMCID: PMC5936950 DOI: 10.1098/rsos.172404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
The auditory stimulation method used in experiments on moth A cell(s) is generally believed to be adequate to characterize the encoding of bat echolocation signals. The stimulation method hosts, though, several biases. Their compounded effects can explain a range of discrepancies between the reported electrophysiological recordings and significantly alter the current interpretation. To test the hypothesis that the bias may significantly alter our current understanding of the moth's auditory transducer characteristics, papers using the same auditory stimulation method and reporting on either spiking threshold or spiking activity of the moth's A cells were analysed. The consistency of the reported data was assessed. A range of corrections issued from best practices and theoretical background were applied to the data in an attempt to re-interpret the data. We found that it is not possible to apply a posteriori corrections to all data and bias. However the corrected data indicate that the A cell's spiking may (i) be independent of the repetition rate, (ii) be maximum when detecting long and low-intensity pulses and (iii) steadily reduce as the bat closes on the moth. These observations raise the possibility that a fixed action pattern drives the moths' erratic evasive manoeuvres until the final moment. In-depth investigations of the potential bias also suggest that the auditory transducer's response may be constant for a larger frequency range than thought so far, and provide clues to explain the negative taxis in response to the searching bats' calls detection.
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6
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Gordon SD, Ter Hofstede HM. The influence of bat echolocation call duration and timing on auditory encoding of predator distance in noctuoid moths. ACTA ACUST UNITED AC 2018; 221:221/6/jeb171561. [PMID: 29567831 DOI: 10.1242/jeb.171561] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/24/2018] [Indexed: 11/20/2022]
Abstract
Animals co-occur with multiple predators, making sensory systems that can encode information about diverse predators advantageous. Moths in the families Noctuidae and Erebidae have ears with two auditory receptor cells (A1 and A2) used to detect the echolocation calls of predatory bats. Bat communities contain species that vary in echolocation call duration, and the dynamic range of A1 is limited by the duration of sound, suggesting that A1 provides less information about bats with shorter echolocation calls. To test this hypothesis, we obtained intensity-response functions for both receptor cells across many moth species for sound pulse durations representing the range of echolocation call durations produced by bat species in northeastern North America. We found that the threshold and dynamic range of both cells varied with sound pulse duration. The number of A1 action potentials per sound pulse increases linearly with increasing amplitude for long-duration pulses, saturating near the A2 threshold. For short sound pulses, however, A1 saturates with only a few action potentials per pulse at amplitudes far lower than the A2 threshold for both single sound pulses and pulse sequences typical of searching or approaching bats. Neural adaptation was only evident in response to approaching bat sequences at high amplitudes, not search-phase sequences. These results show that, for short echolocation calls, a large range of sound levels cannot be coded by moth auditory receptor activity, resulting in no information about the distance of a bat, although differences in activity between ears might provide information about direction.
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Affiliation(s)
- Shira D Gordon
- Dartmouth College, Department of Biological Sciences, 78 College Street, Hanover, NH 03755, USA
| | - Hannah M Ter Hofstede
- Dartmouth College, Department of Biological Sciences, 78 College Street, Hanover, NH 03755, USA
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7
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Ter Hofstede HM, Ratcliffe JM. Evolutionary escalation: the bat-moth arms race. ACTA ACUST UNITED AC 2017; 219:1589-602. [PMID: 27252453 DOI: 10.1242/jeb.086686] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Echolocation in bats and high-frequency hearing in their insect prey make bats and insects an ideal system for studying the sensory ecology and neuroethology of predator-prey interactions. Here, we review the evolutionary history of bats and eared insects, focusing on the insect order Lepidoptera, and consider the evidence for antipredator adaptations and predator counter-adaptations. Ears evolved in a remarkable number of body locations across insects, with the original selection pressure for ears differing between groups. Although cause and effect are difficult to determine, correlations between hearing and life history strategies in moths provide evidence for how these two variables influence each other. We consider life history variables such as size, sex, circadian and seasonal activity patterns, geographic range and the composition of sympatric bat communities. We also review hypotheses on the neural basis for anti-predator behaviours (such as evasive flight and sound production) in moths. It is assumed that these prey adaptations would select for counter-adaptations in predatory bats. We suggest two levels of support for classifying bat traits as counter-adaptations: traits that allow bats to eat more eared prey than expected based on their availability in the environment provide a low level of support for counter-adaptations, whereas traits that have no other plausible explanation for their origination and maintenance than capturing defended prey constitute a high level of support. Specific predator counter-adaptations include calling at frequencies outside the sensitivity range of most eared prey, changing the pattern and frequency of echolocation calls during prey pursuit, and quiet, or 'stealth', echolocation.
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Affiliation(s)
- Hannah M Ter Hofstede
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - John M Ratcliffe
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, Canada L5L 1C6
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Cobo-Cuan A, Kössl M, Mora EC. Hearing diversity in moths confronting a neotropical bat assemblage. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:707-715. [PMID: 28421281 DOI: 10.1007/s00359-017-1170-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 02/20/2017] [Accepted: 04/04/2017] [Indexed: 11/30/2022]
Abstract
The tympanal ear is an evolutionary acquisition which helps moths survive predation from bats. The greater diversity of bats and echolocation strategies in the Neotropics compared with temperate zones would be expected to impose different sensory requirements on the neotropical moths. However, even given some variability among moth assemblages, the frequencies of best hearing of moths from different climate zones studied to date have been roughly the same: between 20 and 60 kHz. We have analyzed the auditory characteristics of tympanate moths from Cuba, a neotropical island with high levels of bat diversity and a high incidence of echolocation frequencies above those commonly at the upper limit of moths' hearing sensitivity. Moths of the superfamilies Noctuoidea, Geometroidea and Pyraloidea were examined. Audiograms were determined by non-invasively measuring distortion-product otoacoustic emissions. We also quantified the frequency spectrum of the echolocation sounds to which this moth community is exposed. The hearing ranges of moths in our study showed best frequencies between 36 and 94 kHz. High sensitivity to frequencies above 50 kHz suggests that the auditory sensitivity of moths is suited to the sounds used by sympatric echolocating bat fauna. Biodiversity characterizes predators and prey in the Neotropics, but the bat-moth acoustic interaction keeps spectrally matched.
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Affiliation(s)
- Ariadna Cobo-Cuan
- Research Group in Bioacoustics and Neuroethology, Faculty of Biology, University of Havana, 25 St. 455, Vedado, 10400, Havana, Cuba. .,Department of Integrative Biology and Physiology, University of California Los Angeles, 612 Charles E. Young Drive East, Los Angeles, CA, 90095, USA.
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, J.W. Goethe Universität Frankfurt, Max von Laue Strasse 13, 60438, Frankfurt Am Main, Germany
| | - Emanuel C Mora
- Research Group in Bioacoustics and Neuroethology, Faculty of Biology, University of Havana, 25 St. 455, Vedado, 10400, Havana, Cuba
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Nakano R, Mason AC. Hearing sensitivity is more relevant to acoustic conspicuousness than to mechanical constraints in crambid moths. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blw029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Ntelezos A, Guarato F, Windmill JFC. The anti-bat strategy of ultrasound absorption: the wings of nocturnal moths (Bombycoidea: Saturniidae) absorb more ultrasound than the wings of diurnal moths (Chalcosiinae: Zygaenoidea: Zygaenidae). Biol Open 2017; 6:109-117. [PMID: 27913454 PMCID: PMC5278430 DOI: 10.1242/bio.021782] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The selection pressure from echolocating bats has driven the development of a diverse range of anti-bat strategies in insects. For instance, several studies have proposed that the wings of some moths absorb a large portion of the sound energy contained in a bat's ultrasonic cry; as a result, the bat receives a dampened echo, and the moth becomes invisible to the bat. To test the hypothesis that greater exposure to bat predation drives the development of higher ultrasound absorbance, we used a small reverberation chamber to measure the ultrasound absorbance of the wings of nocturnal (Bombycoidea: Saturniidae) and diurnal moths (Chalcosiinae: Zygaenoidea: Zygaenidae). The absorption factor of the nocturnal saturniids peaks significantly higher than the absorption factor of the diurnal chalcosiines. However, the wings of the chalcosiines absorb more ultrasound than the wings of some diurnal butterflies. Following a phylogenetic analysis on the character state of diurnality/ nocturnality in the Zygaenidae, we propose that diurnality in the Chalcosiinae is plesiomorphic (retained); hence, the absorbance of their wings is probably not a vestigial trait from an ancestral, nocturnal form but an adaptation to bat activity that overlaps their own. On a within-species level, females of the saturniids Argema mittrei and Samia cynthia ricini have significantly higher absorption factors than the males. In the female S. c. ricini, the higher absorption factor corresponds to a detection distance by bats that is at best 20-30% shorter than that of the male. Summary: Moth wings partly absorb the ultrasonic calls of bats to reduce predation. Different moths fly at night or day, and this work compares their absorption of ultrasound.
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Affiliation(s)
- Athanasios Ntelezos
- Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
| | - Francesco Guarato
- Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
| | - James F C Windmill
- Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
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11
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Kadlec T, Pikner M, Piknerova G. Sex-biased response in activity to light sources with different spectral composition in geometrid moths with flightless females (Lepidoptera: Geometridae). BULLETIN OF ENTOMOLOGICAL RESEARCH 2016; 106:581-590. [PMID: 27121274 DOI: 10.1017/s0007485316000298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Geometrid moths occurring in late autumn and early spring in temperate forest habitats are often harmful defoliators of deciduous stands. Their populations can cause locally cyclic outbreaks and thus preventive monitoring actions have been developed, mainly based on pheromone attraction of males. Females are mostly flightless with reduced or lost wings and reduced senses associated with flying. Males are standard flyers with well-developed eyes and must be able to deal with rapidly changing light conditions during their activity. Although such differences indicate sex-biased differences in reactions to light, this has been insufficiently tested. In conditions of an experimental arena and using light-emitting diodes, we tested the different reactions of the sexes for nine species to precisely defined short segments of the electromagnetic spectrum in the range 360-660 nm. Across all species, males preferred shorter wavelengths up to 500 nm, while females were nonselective and generally less active. The sexes differed by eye size and body mass, with males having significantly larger eyes and lower body mass. Between brachypterous and apterous females, the former had larger eye size, while body mass differences were statistically insignificant. There were differences between the sexes in move-to-light reactions and changes in eye size and body mass in line with wing reduction. While males preferred a relatively distinct range of shorter wavelengths, a method of attraction to lights with distinct narrow spectra could be used markedly to enhance the established methods of forest pest monitoring, either alone or in combination with chemical male attraction.
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Affiliation(s)
- T Kadlec
- Faculty of Environmental Sciences,Czech University of Life Sciences,Kamycka 129,CZ-165 21 Prague,Czech Republic
| | - M Pikner
- Faculty of Environmental Sciences,Czech University of Life Sciences,Kamycka 129,CZ-165 21 Prague,Czech Republic
| | - G Piknerova
- Faculty of Forestry and Wood Sciences,Czech University of Life Sciences,Kamycka 129,CZ-165 21 Prague,Czech Republic
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Wakefield A, Stone EL, Jones G, Harris S. Light-emitting diode street lights reduce last-ditch evasive manoeuvres by moths to bat echolocation calls. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150291. [PMID: 26361558 PMCID: PMC4555863 DOI: 10.1098/rsos.150291] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 07/09/2015] [Indexed: 05/28/2023]
Abstract
The light-emitting diode (LED) street light market is expanding globally, and it is important to understand how LED lights affect wildlife populations. We compared evasive flight responses of moths to bat echolocation calls experimentally under LED-lit and -unlit conditions. Significantly, fewer moths performed 'powerdive' flight manoeuvres in response to bat calls (feeding buzz sequences from Nyctalus spp.) under an LED street light than in the dark. LED street lights reduce the anti-predator behaviour of moths, shifting the balance in favour of their predators, aerial hawking bats.
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Nakano R, Takanashi T, Surlykke A. Moth hearing and sound communication. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 201:111-21. [DOI: 10.1007/s00359-014-0945-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/13/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022]
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Next generation sequencing of fecal DNA reveals the dietary diversity of the widespread insectivorous predator Daubenton's Bat (Myotis daubentonii) in Southwestern Finland. PLoS One 2013; 8:e82168. [PMID: 24312405 PMCID: PMC3842304 DOI: 10.1371/journal.pone.0082168] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/31/2013] [Indexed: 12/22/2022] Open
Abstract
Understanding predator-prey dynamics is a fundamental task in the evaluation of the adaptive capacities of species. However, direct observations or morphological identification of fecal remains do not offer an effective way to study the dietary ecology of elusive species, such as nocturnal insectivorous bats. However, recent advances in molecular techniques have opened a new method for identifying prey species from fecal samples. In this study, we amplified species-specific mitochondrial COI fragments from fecal DNA extractions from 34 individual Daubenton’s bats (Myotis daubentonii) collected between 2008 and 2010 from southwestern Finland. Altogether, 128 different species of prey were identified based on a comprehensive local DNA reference library. In our study area, Daubenton’s bats feed most frequently on insects of the orders Diptera (found in the diet of 94% individuals), Trichoptera (69%) and Lepidoptera (63%). The most frequent dipteran family in the diet was Chironomidae, which was found in 31 of 34 individuals. Most common prey species were chironomids Microtendipes pedellus (found in 50% of bats), Glyptotendipes cauliginellus (44%), and Procladius ferrugineus (41%). For the first time, an accurate species level list of the diet of the insectivorous Daubenton’s bat (Myotis daubentonii) in Finland is presented. We report a generally applicable method for describing the arthropod diet of vertebrate predators. We compare public databases to a national database to highlight the importance of a local reference database.
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Aihara I, Fujioka E, Hiryu S. Qualitative and quantitative analyses of the echolocation strategies of bats on the basis of mathematical modelling and laboratory experiments. PLoS One 2013; 8:e68635. [PMID: 23861930 PMCID: PMC3702606 DOI: 10.1371/journal.pone.0068635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/06/2013] [Indexed: 12/04/2022] Open
Abstract
Prey pursuit by an echolocating bat was studied theoretically and experimentally. First, a mathematical model was proposed to describe the flight dynamics of a bat and a single prey. In this model, the flight angle of the bat was affected by angles related to the flight path of the single moving prey, that is, the angle from the bat to the prey and the flight angle of the prey. Numerical simulation showed that the success rate of prey capture was high, when the bat mainly used the angle to the prey to minimize the distance to the prey, and also used the flight angle of the prey to minimize the difference in flight directions of itself and the prey. Second, parameters in the model were estimated according to experimental data obtained from video recordings taken while a Japanese horseshoe bat (Rhinolphus derrumequinum nippon) pursued a moving moth (Goniocraspidum pryeri) in a flight chamber. One of the estimated parameter values, which represents the ratio in the use of the angles, was consistent with the optimal value of the numerical simulation. This agreement between the numerical simulation and parameter estimation suggests that a bat chooses an effective flight path for successful prey capture by using the angles. Finally, the mathematical model was extended to include a bat and prey. Parameter estimation of the extended model based on laboratory experiments revealed the existence of bat’s dynamical attention towards prey, that is, simultaneous pursuit of prey and selective pursuit of respective prey. Thus, our mathematical model contributes not only to quantitative analysis of effective foraging, but also to qualitative evaluation of a bat’s dynamical flight strategy during multiple prey pursuit.
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Affiliation(s)
- Ikkyu Aihara
- Brain Science Institute, RIKEN, Wako, Saitama, Japan.
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17
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Jackson ME, Asi NS, Fullard JH. Auditory sensitivity and ecological relevance: the functional audiogram as modelled by the bat detecting moth ear. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2010; 196:453-62. [PMID: 20449595 DOI: 10.1007/s00359-010-0529-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
Abstract
Auditory sensitivity has often been measured by identifying neural threshold in real-time (online) which can introduce bias in the audiograms that are produced. We tested this by recording auditory nerve activity of the notodontid moth Nadata gibbosa elicited by bat-like ultrasound and analysing the response offline. We compared this audiogram with a published online audiogram showing that the bias introduced can result in a difference in the audiogram shape. In the second part of our study we compared offline audiograms using spike number as threshold with others that used spike period and stimulus/spike latency, variables that have been suggested as providing behaviourally functional criteria. These comparisons reveal that functional audiograms are more flatly tuned than simple spike audiograms. The shapes of behavioural audiograms are discussed in the context of the selection pressure that maintains their shape, bat predation. Finally, we make predictions on the distance from bats at which notodontid moths use negative phonotaxis or the acoustic startle response.
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Affiliation(s)
- Matthew E Jackson
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Rd., Mississauga, ON, L5L 1C6, Canada.
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18
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Ellard CG, Eller MC. Spatial cognition in the gerbil: computing optimal escape routes from visual threats. Anim Cogn 2008; 12:333-45. [PMID: 18956215 DOI: 10.1007/s10071-008-0193-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 08/29/2008] [Accepted: 09/25/2008] [Indexed: 11/29/2022]
Abstract
Previous studies in our laboratory have shown that when presented with a sudden stimulus simulating an oncoming predator, Mongolian gerbils can compute the optimal trajectory to a safe refuge, taking into account the position of the threat, the location of a clearly visible refuge, and several other contextual variables as well. In the present studies, the main goal was to explore the abilities of gerbils to use mental representations of spaces that were visually occluded by opaque barriers to compute efficient escape trajectories. In all studies, gerbils were placed into a round open field containing a single refuge. On each trial, an overhead visual stimulus was caused to 'fly' overhead, eliciting robust escape movements from the gerbils. By manipulating the shape and position of a series of opaque barriers that were interposed between the gerbils and the refuge, we were able to show that gerbils can compute the shortest route to an invisible target, even when the available routes to the target are made complex by using elaborate barrier shapes. These findings suggest that gerbils can maintain representations of their locations with respect to salient environmental landmarks and refuges, even when such locations are not continuously visible.
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Affiliation(s)
- Colin G Ellard
- Department of Psychology, University of Waterloo, Waterloo, ON N2L3G1, Canada.
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19
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Sueur J, Windmill JFC, Robert D. Sexual dimorphism in auditory mechanics: tympanal vibrations of Cicada orni. J Exp Biol 2008; 211:2379-87. [DOI: 10.1242/jeb.018804] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
In cicadas, the tympanum is anatomically intricate and employs complex vibrations as a mechanism for auditory frequency analysis. Using microscanning laser Doppler vibrometry, the tympanal mechanics of Cicada orni can be characterized in controlled acoustical conditions. The tympanum of C. orni moves following a simple drum-like motion, rather than the travelling wave found in a previous study of Cicadatra atra. There is a clear sexual dimorphism in the tympanal mechanics. The large male tympanum is unexpectedly insensitive to the dominant frequency of its own calling song,possibly a reflection of its dual purpose as a sound emitter and receiver. The small female tympanum appears to be mechanically sensitive to the dominant frequency of the male calling song and to high-frequency sound, a capacity never suspected before in these insects. This sexual dimorphism probably results from a set of selective pressures acting in divergent directions,which are linked to the different role of the sexes in sound reception and production. These discoveries serve to indicate that there is far more to be learnt about the development of the cicada ear, its biomechanics and evolution, and the cicada's acoustic behaviour.
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Affiliation(s)
- Jérôme Sueur
- Muséum National d'Histoire naturelle, Département Systématique et Evolution, UMR 5202 CNRS & USM 601 MNHN, 75005 Paris, France
| | - James F. C. Windmill
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
| | - Daniel Robert
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
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Triblehorn JD, Ghose K, Bohn K, Moss CF, Yager DD. Free-flight encounters between praying mantids (Parasphendale agrionina) and bats (Eptesicus fuscus). J Exp Biol 2008; 211:555-62. [DOI: 10.1242/jeb.005736] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
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) `last-ditch' maneuvers triggered by bat-generated 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–1; escape rates>60% for transition slopes <16 p.p.s. 10 ms–1). This suggests that echolocation attack sequences containing very rapid transitions(>16 p.p.s. 10 ms–1) 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, cercal-mediated 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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Affiliation(s)
- J. D. Triblehorn
- Department of Psychology, University of Maryland, College Park, MD 20742,USA
| | - K. Ghose
- Department of Psychology, University of Maryland, College Park, MD 20742,USA
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA
| | - K. Bohn
- Department of Psychology, University of Maryland, College Park, MD 20742,USA
| | - C. F. Moss
- Department of Psychology, University of Maryland, College Park, MD 20742,USA
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA
- Institute for Systems Research, University of Maryland, College Park, MD 20742, USA
| | - D. D. Yager
- Department of Psychology, University of Maryland, College Park, MD 20742,USA
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA
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Yamamoto S, Sota T. Phylogeny of the Geometridae and the evolution of winter moths inferred from a simultaneous analysis of mitochondrial and nuclear genes. Mol Phylogenet Evol 2007; 44:711-23. [PMID: 17363285 DOI: 10.1016/j.ympev.2006.12.027] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2006] [Revised: 11/06/2006] [Accepted: 12/28/2006] [Indexed: 10/23/2022]
Abstract
Geometridae is one of the most diverse families within the Lepidoptera, comprising nine subfamilies. Winter moths, which have a unique life history, are found in three subfamilies. To examine the phylogeny of the Geometridae at the subfamily level and determine the evolutionary history of winter moths, we constructed phylogenetic trees for all nine geometrid subfamilies using two mitochondrial and two nuclear gene sequences. Specimens of all subfamilies were sampled from Japan. Simultaneous analyses of the combined data from all genes revealed that the Geometridae comprised two major clades: one with subfamilies Larentiinae and Sterrhinae, and the other with the remaining seven subfamilies. The second clade included the largest subfamily, Ennominae, and the subfamily Archiearinae, which is traditionally considered to be an ancestral lineage of the Geometridae. The Larentiinae+Sterrhinae clade contained one winter moth lineage, and the second major clade consisted of three winter moth lineages, including Alsophilinae, which contains winter moths exclusively. Using a Bayesian inference of divergence times, we estimated that geometrids began to diverge 54 Mya (62-48 Mya), whereas winter moth lineages differentiated from non-winter moth lineages 34-12 Mya, during the global cooling events in the Oligocene and the early Miocene. The adaptation to cool climates may have been a preadaptation that facilitated the winter moth life cycle.
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Affiliation(s)
- Satoshi Yamamoto
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
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St. Juliana JR, Fenton BM, Korine C, Pinshow B, Wojciechowski M, Kravchenko V. Note: A Field Assessment of the Defensive Responses of Moths to an Auditory Stimulus. Isr J Ecol Evol 2007. [DOI: 10.1560/ijee.53.2.173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We examined the responses of moths to an auditory stimulus in the field with respect to moth size, moth activity state (at rest or flying), whether it responded, and response type. Moths most commonly responded by changing flight direction. Flying moths responded significantly more often to the auditory stimulus than did resting moths; small- and medium-sized moths responded significantly more often than larger ones. We found no differences in use of response types between size classes. We suggest that these behavioral responses to the auditory stimulus are likely due to evolved induced responses to detection of predatory bats.
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Affiliation(s)
- Justin R. St. Juliana
- Mitrani Department of Desert Ecology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev
- Department of Ecology and Organismal Biology, Indiana State University
| | - Brock M. Fenton
- Department of Biology, The University of Western Ontario, London
| | - Carmi Korine
- Mitrani Department of Desert Ecology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev
| | - Berry Pinshow
- Mitrani Department of Desert Ecology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev
| | - Michal Wojciechowski
- Mitrani Department of Desert Ecology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev
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Svenssona GP, Löfstedt C, Skals N. Listening in pheromone plumes: disruption of olfactory-guided mate attraction in a moth by a bat-like ultrasound. JOURNAL OF INSECT SCIENCE (ONLINE) 2007; 7:59. [PMID: 20331396 PMCID: PMC2999453 DOI: 10.1673/031.007.5901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Accepted: 03/28/2007] [Indexed: 05/29/2023]
Abstract
Nocturnal moths often use sex pheromones to find mates and ultrasonic hearing to evade echolocating bat predators. Male moths, when confronted with both pheromones and sound, thus have to trade off reproduction and predator avoidance depending on the relative strengths of the perceived conflicting stimuli. The ultrasonic hearing of Plodia interpunctella was investigated. A threshold curve for evasive reaction to ultrasound of tethered moths was established, and the frequency of best hearing was found to be between 40 and 70 kHz. Flight tunnel experiments were performed where males orienting in a sex pheromone plume were stimulated with 50 kHz pulses of different intensities. Pheromone-stimulated males showed increased defensive response with increased intensity of the sound stimulus, and the acoustic cue had long-lasting effects on their pheromone-mediated flight, revealing a cost associated with vital evasive behaviours.
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Affiliation(s)
| | | | - Niels Skals
- Department of Ecology, Lund University, SE-223 62 Lund, Sweden. Center for Sound Communication, Institute of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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Fullard JH, Ratcliffe JM, Soutar AR. Extinction of the acoustic startle response in moths endemic to a bat-free habitat. J Evol Biol 2004; 17:856-61. [PMID: 15271085 DOI: 10.1111/j.1420-9101.2004.00722.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Most moths use ears solely to detect the echolocation calls of hunting, insectivorous bats and evoke evasive flight manoeuvres. This singularity of purpose predicts that this sensoribehavioural network will regress if the selective force that originally maintained it is removed. We tested this with noctuid moths from the islands of Tahiti and Moorea, sites where bats have never existed and where an earlier study demonstrated that the ears of endemic species resemble those of adventives although partially reduced in sensitivity. To determine if these moths still express the anti-bat defensive behaviour of acoustic startle response (ASR) we compared the nocturnal flight times of six endemic to six adventive species in the presence and absence of artificial bat echolocation sounds. Whereas all of the adventive species reduced their flight times when exposed to ultrasound, only one of the six endemic species did so. These differences were significant when tested using a phylogenetically based pairwise comparison and when comparing effect sizes. We conclude that the absence of bats in this habitat has caused the neural circuitry that normally controls the ASR behaviour in bat-exposed moths to become decoupled from the functionally vestigial ears of endemic Tahitian moths.
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Affiliation(s)
- J H Fullard
- Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada.
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26
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Svensson GP, Löfstedt C, Skals N. The odour makes the difference: male moths attracted by sex pheromones ignore the threat by predatory bats. OIKOS 2004. [DOI: 10.1111/j.0030-1299.2004.12517.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Greenfield MD, Baker M. Bat Avoidance in Non-Aerial Insects: The Silence Response of Signaling Males in an Acoustic Moth. Ethology 2003. [DOI: 10.1046/j.1439-0310.2003.00886.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Svensson AM, Eklöf J, Skals N, Rydell J. Light dependent shift in the anti-predator response of a pyralid moth. OIKOS 2003. [DOI: 10.1034/j.1600-0706.2003.12156.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Using near-infrared videotaping we measured the nocturnal flight times of six species of eared moths (Amphipyra pyramidoides Guenée, Caenurgina erechtea (Cramer), Feltia jaculifera (Guenée), Phlogophora periculosa Guenée, Lymantria dispar (Linné), and Ennomos magnaria Guenée) in cages in which they flew, under randomized conditions, for 3 h in the absence and 3 h in the presence of simulated bat-attack sounds. When exposed to the ultrasound, four of the six species exhibited significant reductions in total flight time ranging from 38 to 98%. We suggest that this quantified measurement of flight time will be useful for fundamental studies on the evolution and ecology of moth hearing as well as applied studies on acoustic methods of controlling moth pests.
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Rydell J, Kaerma S, Hedelin H, Skals N. Evasive response to ultrasound by the crepuscular butterfly Manataria maculata. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2003; 90:80-3. [PMID: 12590303 DOI: 10.1007/s00114-002-0391-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2002] [Accepted: 11/26/2002] [Indexed: 10/25/2022]
Abstract
The crepuscular nymphalid butterfly Manataria maculata was studied in Monteverde cloud forest, Costa Rica, during the dry season reproductive diapause. M. maculata has ears in the form of Vogel's organs located near the base of the forewings. Its behaviour in response to bursts of ultrasonic pulses (26 kHz, 110 dB SPL at 1 m) was condition-dependent. At dusk and dawn the sound consistently elicited evasive responses, similar to those of moths, in flying individuals. In contrast day-roosting individuals always remained motionless although they were alert to other stimuli. The daily movements between day- and night-roosts coincided in time and light intensity with the activity of insectivorous bats. This is the first reported case of ultrasonic hearing connected to evasive flights in a true butterfly (Papilionoidea). It strongly supports the idea that echolocating bats were involved in the evolution of hearing in butterflies.
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Affiliation(s)
- Jens Rydell
- Zoology Department, Göteborg University, Box 463, 405 30, Göteborg, Sweden.
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31
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MILLER LEEA, SURLYKKE ANNEMARIE. How Some Insects Detect and Avoid Being Eaten by Bats: Tactics and Countertactics of Prey and Predator. Bioscience 2001. [DOI: 10.1641/0006-3568(2001)051[0570:hsidaa]2.0.co;2] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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32
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Fullard JH. Day-flying butterflies remain day-flying in a Polynesian, bat-free habitat. Proc Biol Sci 2000; 267:2295-300. [PMID: 11413646 PMCID: PMC1690820 DOI: 10.1098/rspb.2000.1282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To test the theory that insectivorous bats have selected for diurnality in earless butterflies I compared the nocturnal flight patterns of three species of nymphalid butterflies on the bat-free Pacific island of Moorea with those of three nymphalids in the bat-inhabited habitat of Queensland, Australia. Nocturnal flight, measured as the ratio of deep night (1 h following sunset to 1 h preceding sunrise) to twilight night (1 h before sunset to 30 min after sunrise) activity did not differ significantly between the two locations, nor did the percentage of individuals active and I conclude that living in a bat-released habitat has not produced nocturnal flight in these insects. This result is surprising considering the potential advantages of escaping diurnally active predators and suggests that physiological adaptations (e.g. thermoregulation and/or vision) currently constrain these insects to diurnal flight. Since taxonomic records suggest that gene flow does not exist with bat-exposed conspecifics, I suggest that insufficient time has elapsed since these species migrated to Moorea to have resulted in major phenotypic changes such as diel flight preferences.
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Affiliation(s)
- J H Fullard
- Department of Zoology, Erindale College (University of Toronto), 3359 Mississauga, Road, Mississauga, Ontario, Canada L5L 1C6.
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33
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Greenfield M, Weber T. Evolution of ultrasonic signalling in wax moths: discrimination of ultrasonic mating calls from bat echolocation signals and the exploitation of an antipredator receiver bias by sexual advertisement. ETHOL ECOL EVOL 2000. [DOI: 10.1080/08927014.2000.9522800] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Rydell J, Roininen H, Philip KW. Persistence of bat defence reactions in high Arctic moths (Lepidoptera). Proc Biol Sci 2000; 267:553-7. [PMID: 10787157 PMCID: PMC1690572 DOI: 10.1098/rspb.2000.1036] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We investigated the bat defence reactions of three species of moths (Gynaephora groenlandica, Gynaephora rossi (Lymantriidae) and Psychophora sabini (Geometridae)) in the Canadian Arctic archipelago. Since these moths inhabit the Arctic tundra and, therefore, are most probably spatially isolated from bats, their hearing and associated defensive reactions are probably useless and would therefore be expected to disappear with ongoing adaptation to Arctic conditions. When exposed to bat-like ultrasound (26 kHz and 110 dB sound pressure level root mean square at 1 m) flying male Gynaephora spp. always reacted defensively by rapidly reversing their flight course. They could hear the sound and reacted at least 15-25 m away. Psychophora sabini walking on a surface froze at distances of at least 5-7 m from the sound source. However, two out of three individuals of this species (all males) did not respond in any way to the sound while in flight. Hence, we found evidence of degeneration of bat defence reactions, i.e. adaptation to the bat-free environment, in P. sabini but not in Gynaephora spp. Some Arctic moths (Gynaephora spp.) still possess defensive reactions against bats, possibly because the selection pressure for the loss of the trait is such that it declines only very slowly (perhaps by genetic drift; and there may not have been enough time for the trait to disappear. One possible reason may be that Arctic moths have long generation times.
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Affiliation(s)
- J Rydell
- Department of Zoology, Göteborg University, Sweden.
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35
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Skals N, Surlykke A. Sound production by abdominal tymbal organs in two moth species: the green silver-line and the scarce silver-line (Noctuoidea: Nolidae: Chloephorinae). J Exp Biol 1999; 202:2937-2949. [PMID: 10518475 DOI: 10.1242/jeb.202.21.2937] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Male moths of the chloephorine species Pseudoips prasinana and Bena bicolorana produce clicks (approximately 100 dB peSPL at 10 cm) using ventral tymbal organs located in a cleft in the second abdominal sternite. Large muscles insert on the dorsal part of the tymbal frame and rhythmically flex a thin sheet of cuticle. Normally, each sound-production cycle contains four clicks, the left and right tymbals producing clicks both on active buckling caused by muscle contraction and on the passive elastic return from buckling. Histochemical staining indicated the presence of elastic resilin-like proteins in the tymbals. Obvious differences between the click patterns of the two species reflect differences in their tymbal morphology. P. prasinana has smooth tymbals and produces a single click (300?s, 40 kHz) for each tymbal buckling. In contrast, B. bicolorana has striae on the medial part of the tymbals. Accordingly, it produces many clicks per buckling. The click pattern is a heterogeneous mixture of large clicks at 52 kHz, resembling those of P. prasinana, interspersed with series of broad-band clicks (20–100 kHz) of lower intensity (15–20 dB). Thus, in chloephorine moths, there is a correlation between the structure and function of the smooth and striated tymbals that is strikingly similar to that in arctiid moths, although the two types of tymbals have evolved independently. The hearing of P. prasinana is tuned to its own sounds with lowest threshold (38 dB SPL) at 40–60 kHz. We suggest that sound production in male chloephorines plays a part in sexual acoustic communication.
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Affiliation(s)
- N Skals
- Centre for Sound Communication, Institute of Biology, Odense University, Campusvej 55, DK-5230 Odense M, Denmark.
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Abstract
Tympanal sound receptors in moths evolved in response to selective pressures provided by echolocating insectivorous bats. The presence of these ultrasound detectors also set the stage for the later evolution of ultrasonic courtship signals in the tympanate moth families. Male moths have repeatedly exploited the bat-detection mechanisms in females for the purpose of finding, identifying and obtaining mates. Ultrasonic courtship has been described in several members of the moth families Arctiidae, Noctuidae and Pyralidae, and ultrasound is predicted to play a significant role in the courtship of other tympanate moths including the Sphingidae, Lymantriidae, Notodontidae and Geometridae. Ultrasonic signals are involved in species recognition, in male-male competition for mates and in female mate-choice systems. Pre-existing motor systems, including those involved in bat defence, have also been exploited for the purpose of generating high-frequency courtship signals. Sound production mechanisms in moths include thoracic tymbals, tegular tymbals, alar castanets and genital stridulatory organs. Thus, in both their sensory and motor aspects, the weapons of bat/moth warfare have frequently evolved into components of courtship systems.
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Affiliation(s)
- WE Conner
- Department of Biology, Wake Forest University, PO Box 7325, Winston-Salem, NC 27109, USA.
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Rydell J. Bat defence in lekking ghost swifts (Hepialus humuli), a moth without ultrasonic hearing. Proc Biol Sci 1998; 265:1373-6. [PMID: 9721686 PMCID: PMC1689220 DOI: 10.1098/rspb.1998.0444] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Hepialidae represents an early branch of the Lepidoptera, whose members lack the ultrasonic hearing and other obvious predator defence systems present in other extant moths. I observed lekking male ghost swifts, Hepialus humuli, being exploited by northern bats, Eptesicus nilssonii, over a hayfield in southern Sweden. Because the moth's display flight was restricted to a brief (30 min) period at dusk, they avoided most predators temporally but were exposed to early emerging aerial-hawking bats. Against these, they apparently employed 'acoustic crypsis', achieved by flying close (< 0.5 m) to the vegetation, thereby hiding from the bats among clutter (echoes returning from the background). Nevertheless, the predation risk for the displaying moth males was very high (20% per night), mainly because they sometimes left the safety of the vegetation. The lack of 'advanced' predator defence mechanisms in H. humuli requires alternative defence strategies, which, however, restrict the behavioural repertoire and still carry a high predation risk.
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Affiliation(s)
- J Rydell
- Zoology Department, Göteborg University, Sweden.
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Svensson AM, Rydell J. Mercury vapour lamps interfere with the bat defence of tympanate moths (Operophtera spp.; Geometridae). Anim Behav 1998; 55:223-6. [PMID: 9480689 DOI: 10.1006/anbe.1997.0590] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bats often forage near streetlamps, where they catch moths in particular. At least two hypotheses may explain the apparent increase in the availability of moths to bats feeding around streetlamps: (1) the moths become concentrated near the light and therefore more profitable to exploit; and (2) the light interferes with the moths' evasive flight behaviour. We tested the second of these hypotheses by exposing flying male winter moths, Operophtera spp., to bursts of ultrasound (26 kHz, 110 dB sound pressure level) from an electronic source. The light from a 125 W mercury vapour lamp had a quantitative effect on the moths' evasive flight response at close range (within ca 4 m), inhibiting it totally in nearly half (43%, N=125) of the cases. By contrast, moths flying in the surrounding woodland and without interference from the lamp always responded to the sound. Streetlamps of the mercury vapour type (white lamps) thus interfere with the defensive behaviour of moths and presumably increase their vulnerability to echolocating bats. This may have implications for the conservation of both moths and bats. Copyright 1998 The Association for the Study of Animal Behaviour.
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Affiliation(s)
- AM Svensson
- Department of Zoology, University of Goteborg
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