1
|
Holmes LB, Woodrow C, Sarria-S FA, Celiker E, Montealegre-Z F. Wing mechanics and acoustic communication of a new genus of sylvan katydid (Orthoptera: Tettigoniidae: Pseudophyllinae) from the Central Cordillera cloud forest of Colombia. PeerJ 2024; 12:e17501. [PMID: 38952987 PMCID: PMC11216201 DOI: 10.7717/peerj.17501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/13/2024] [Indexed: 07/03/2024] Open
Abstract
Stridulation is used by male katydids to produce sound via the rubbing together of their specialised forewings, either by sustained or interrupted sweeps of the file producing different tones and call structures. There are many species of Orthoptera that remain undescribed and their acoustic signals are unknown. This study aims to measure and quantify the mechanics of wing vibration, sound production and acoustic properties of the hearing system in a new genus of Pseudophyllinae with taxonomic descriptions of two new species. The calling behaviour and wing mechanics of males were measured using micro-scanning laser Doppler vibrometry, microscopy, and ultrasound sensitive equipment. The resonant properties of the acoustic pinnae of the ears were obtained via μ-CT scanning and 3D printed experimentation, and numerical modelling was used to validate the results. Analysis of sound recordings and wing vibrations revealed that the stridulatory areas of the right tegmen exhibit relatively narrow frequency responses and produce narrowband calls between 12 and 20 kHz. As in most Pseudophyllinae, only the right mirror is activated for sound production. The acoustic pinnae of all species were found to provide a broadband increased acoustic gain from ~40-120 kHz by up to 25 dB, peaking at almost 90 kHz which coincides with the echolocation frequency of sympatric bats. The new genus, named Satizabalus n. gen., is here derived as a new polytypic genus from the existing genus Gnathoclita, based on morphological and acoustic evidence from one described (S. sodalis n. comb.) and two new species (S. jorgevargasi n. sp. and S. hauca n. sp.). Unlike most Tettigoniidae, Satizabalus exhibits a particular form of sexual dimorphism whereby the heads and mandibles of the males are greatly enlarged compared to the females. We suggest that Satizabalus is related to the genus Trichotettix, also found in cloud forests in Colombia, and not to Gnathoclita.
Collapse
Affiliation(s)
- Lewis B. Holmes
- School of Life and Environmental Sciences, University of Lincoln, Lincoln, Lincolnshire, United Kingdom
| | - Charlie Woodrow
- School of Life and Environmental Sciences, University of Lincoln, Lincoln, Lincolnshire, United Kingdom
- Department of Ecology and Genetics, Uppsala Universitet, Uppsala, Norbyvägen, Sweden
| | - Fabio A. Sarria-S
- School of Life and Environmental Sciences, University of Lincoln, Lincoln, Lincolnshire, United Kingdom
| | - Emine Celiker
- School of Engineering, University of Leicester, Leicester, United Kingdom
| | - Fernando Montealegre-Z
- School of Life and Environmental Sciences, University of Lincoln, Lincoln, Lincolnshire, United Kingdom
| |
Collapse
|
2
|
Mason A. Insect acoustics: Listening in on the deep past. Curr Biol 2024; 34:R26-R28. [PMID: 38194924 DOI: 10.1016/j.cub.2023.11.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Insect songs are compelling features of the natural environment, and insects provide diverse model systems merging the worlds of entomologists and engineers. An unusually well-preserved fossil katydid highlights the synergy between these disciplines and offers a compelling glimpse into the deep past.
Collapse
Affiliation(s)
- Andrew Mason
- Integrative Behaviour and Neuroscience Group, Department of Biological Sciences, University of Toronto, Scarborough, Canada.
| |
Collapse
|
3
|
Woodrow C, Celiker E, Montealegre-Z F. An Eocene insect could hear conspecific ultrasounds and bat echolocation. Curr Biol 2023; 33:5304-5315.e3. [PMID: 37963458 DOI: 10.1016/j.cub.2023.10.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 10/08/2023] [Accepted: 10/21/2023] [Indexed: 11/16/2023]
Abstract
Hearing has evolved independently many times in the animal kingdom and is prominent in various insects and vertebrates for conspecific communication and predator detection. Among insects, katydid (Orthoptera: Tettigoniidae) ears are unique, as they have evolved outer, middle, and inner ear components, analogous in their biophysical principles to the mammalian ear. The katydid ear consists of two paired tympana located in each foreleg. These tympana receive sound externally on the tympanum surface (usually via pinnae) or internally via an ear canal (EC). The EC functions to capture conspecific calls and low frequencies, while the pinnae passively amplify higher-frequency ultrasounds including bat echolocation. Together, these outer ear components provide enhanced hearing sensitivity across a dynamic range of over 100 kHz. However, despite a growing understanding of the biophysics and function of the katydid ear, its precise emergence and evolutionary history remains elusive. Here, using microcomputed tomography (μCT) scanning, we recovered geometries of the outer ear components and wings of an exceptionally well-preserved katydid fossilized in Baltic amber (∼44 million years [Ma]). Using numerical and theoretical modeling of the wings, we show that this species was communicating at a peak frequency of 31.62 (± 2.27) kHz, and we demonstrate that the ear was biophysically tuned to this signal and to providing hearing at higher-frequency ultrasounds (>80 kHz), likely for enhanced predator detection. The results indicate that the evolution of the unique ear of the katydid, with its broadband ultrasonic sensitivity and analogous biophysical properties to the ears of mammals, emerged in the Eocene.
Collapse
Affiliation(s)
- Charlie Woodrow
- University of Lincoln, School of Life and Environmental Sciences, Joseph Banks Laboratories, Green Lane, Lincoln LN6 7DL, UK; Uppsala University, Department of Ecology and Genetics, Evolutionary Biology Centre, Norbyvägen 18 D, 752 36, Uppsala, Sweden.
| | - Emine Celiker
- University of Dundee, Division of Mathematics, School of Science and Engineering, Nethergate, Dundee DD1 4HN, UK; University of Leicester, School of Engineering, University Road, Leicester LE1 7RH, UK
| | - Fernando Montealegre-Z
- University of Lincoln, School of Life and Environmental Sciences, Joseph Banks Laboratories, Green Lane, Lincoln LN6 7DL, UK.
| |
Collapse
|
4
|
Woodrow C, Baker E, Jonsson T, Montealegre-Z F. Reviving the sound of a 150-year-old insect: The bioacoustics of Prophalangopsis obscura (Ensifera: Hagloidea). PLoS One 2022; 17:e0270498. [PMID: 35947546 PMCID: PMC9365155 DOI: 10.1371/journal.pone.0270498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 06/10/2022] [Indexed: 11/29/2022] Open
Abstract
Determining the acoustic ecology of extinct or rare species is challenging due to the inability to record their acoustic signals or hearing thresholds. Katydids and their relatives (Orthoptera: Ensifera) offer a model for inferring acoustic ecology of extinct and rare species, due to allometric parameters of their sound production organs. Here, the bioacoustics of the orthopteran Prophalangopsis obscura are investigated. This species is one of only eight remaining members of an ancient family with over 90 extinct species that dominated the acoustic landscape of the Jurassic. The species is known from only a single confirmed specimen–the 150-year-old holotype material housed at the London Natural History Museum. Using Laser-Doppler Vibrometry, 3D surface scanning microscopy, and known scaling relationships, it is shown that P. obscura produces a pure-tone song at a frequency of ~4.7 kHz. This frequency range is distinct but comparable to the calls of Jurassic relatives, suggesting a limitation of early acoustic signals in insects to sonic frequencies (<20 kHz). The acoustic ecology and importance of this species in understanding ensiferan evolution, is discussed.
Collapse
Affiliation(s)
- Charlie Woodrow
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, United Kingdom
| | - Ed Baker
- Natural History Museum, London, United Kingdom
| | - Thorin Jonsson
- Institute of Biology, Karl-Franzens-University Graz, Graz, Austria
| | - Fernando Montealegre-Z
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, United Kingdom
- * E-mail:
| |
Collapse
|
5
|
Rebrina F, Reinhold K, Tvrtković N, Gulin V, Brigić A. Vegetation Height as the Primary Driver of Functional Changes in Orthopteran Assemblages in a Roadside Habitat. INSECTS 2022; 13:insects13070572. [PMID: 35886748 PMCID: PMC9317414 DOI: 10.3390/insects13070572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary This paper reports the results of a field research that investigates functional changes in grasshopper and cricket (Orthoptera) assemblages with distance from a major road (at 10, 25, 50, 100 and 500 m). Expanding on a previous study that adopted a species-based approach to the same subject, in order to gain a different perspective on road-associated dynamics of orthopteran assemblages with potential implications for ecosystem functioning, we aimed for the following: (1) to test how motorway proximity affects functional diversity of orthopteran assemblages and functional traits related to mobility, feeding guild, lifestyle and moisture preference; and (2) to assess the relationships between trait composition and road-influenced environmental factors. We recorded a significant increase in functional diversity and the occurrence of omnivorous and shrub-dwelling orthopterans, and a decrease in larger ground-dwelling orthopterans at sites close to the motorway. Road-induced changes in vegetation height were identified as the primary driver of these changes. Our findings contribute to a more thorough understanding of the links between road-associated changes in vegetation cover and insect community assembly in grassland habitats. Abstract Exhibiting manifold ecological impacts on terrestrial biota, roads have become a major driver of environmental change nowadays. However, many insect groups with high indication potential, such as grasshoppers and crickets (Orthoptera), have been largely neglected in road ecology research from a functional perspective. Using two complementary sampling methods, we have investigated the spatial dynamics of functional diversity and six functional traits in orthopteran assemblages, with respect to motorway proximity and the associated environmental factors, in a grassland habitat in the Lika region, Croatia. This research shows, for the first time, that road proximity can facilitate an increase in the functional diversity of orthopteran assemblages, with shifts in functional traits related to mobility, feeding habits and lifestyle being primarily driven by changes in vegetation height. Our findings also suggest that our ability to detect road-related patterns depends on the choice of a diversity measure and sampling method, since different components of orthopteran assemblages (plant-dwelling vs. ground-dwelling) exhibit different functional responses to road proximity.
Collapse
Affiliation(s)
- Fran Rebrina
- Department of Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia; (V.G.); (A.B.)
- Correspondence:
| | - Klaus Reinhold
- Evolutionary Biology, Faculty of Biology, Bielefeld University, 33615 Bielefeld, Germany;
| | | | - Vesna Gulin
- Department of Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia; (V.G.); (A.B.)
| | - Andreja Brigić
- Department of Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia; (V.G.); (A.B.)
| |
Collapse
|
6
|
Tiwari C, Diwakar S. The katydid country: bioacoustics and ecology of tettigoniid communities from the Indian subcontinent. BIOACOUSTICS 2022. [DOI: 10.1080/09524622.2022.2064330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
7
|
Godthi V, Balakrishnan R, Pratap R. The mechanics of acoustic signal evolution in field crickets. J Exp Biol 2022; 225:274309. [PMID: 35258611 DOI: 10.1242/jeb.243374] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 01/11/2022] [Indexed: 11/20/2022]
Abstract
Field crickets (Family Gryllidae, Subfamily Gryllinae) typically produce tonal calls with carrier frequencies in the range 3-8 kHz. In this study, we explored the use of a finite element model (FEM) of the stridulatory apparatus of a field cricket, Gryllus bimaculatus, based on experimental measurements of resonator geometry and mechanical properties, to predict the measured call carrier frequencies of eight other field cricket species, ranging between 3 and 7 kHz. The model allowed accurate predictions of carrier frequencies for all eight species to within a few hundred hertz from morphological measurements of their resonators. We then used the model to explore the plausible evolutionary design space for field cricket call carrier frequency along the axes of resonator size and thickness, and mapped the locations of the nine experimentally measured species in this design space. Although the nine species spanned the evolutionarily conserved spectrum of carrier frequency and body size in field crickets, they were clustered in a small region of the available design space. We then explored the reasons for this apparent evolutionary constraint on field cricket carrier frequencies at both the lower and higher limit. We found that body size and sound radiation efficiency were the main constraints at the lower limits, whereas the energetics of stridulation using the clockwork mechanism may pose a constraint at higher frequencies.
Collapse
Affiliation(s)
- Vamsy Godthi
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Rohini Balakrishnan
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Rudra Pratap
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| |
Collapse
|
8
|
Hearing sensitivity: An underlying mechanism for niche differentiation in gleaning bats. Proc Natl Acad Sci U S A 2021; 118:2024943118. [PMID: 34426521 DOI: 10.1073/pnas.2024943118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tropical ecosystems are known for high species diversity. Adaptations permitting niche differentiation enable species to coexist. Historically, research focused primarily on morphological and behavioral adaptations for foraging, roosting, and other basic ecological factors. Another important factor, however, is differences in sensory capabilities. So far, studies mainly have focused on the output of behavioral strategies of predators and their prey preference. Understanding the coexistence of different foraging strategies, however, requires understanding underlying cognitive and neural mechanisms. In this study, we investigate hearing in bats and how it shapes bat species coexistence. We present the hearing thresholds and echolocation calls of 12 different gleaning bats from the ecologically diverse Phyllostomid family. We measured their auditory brainstem responses to assess their hearing sensitivity. The audiograms of these species had similar overall shapes but differed substantially for frequencies below 9 kHz and in the frequency range of their echolocation calls. Our results suggest that differences among bats in hearing abilities contribute to the diversity in foraging strategies of gleaning bats. We argue that differences in auditory sensitivity could be important mechanisms shaping diversity in sensory niches and coexistence of species.
Collapse
|
9
|
Jonsson T, Montealegre-Z F, Soulsbury CD, Robert D. Tenors Not Sopranos: Bio-Mechanical Constraints on Calling Song Frequencies in the Mediterranean Field-Cricket. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.647786] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Male crickets and their close relatives bush-crickets (Gryllidae and Tettigoniidae, respectively; Orthoptera and Ensifera) attract distant females by producing loud calling songs. In both families, sound is produced by stridulation, the rubbing together of their forewings, whereby the plectrum of one wing is rapidly passed over a serrated file on the opposite wing. The resulting oscillations are amplified by resonating wing regions. A striking difference between Gryllids and Tettigoniids lies in wing morphology and composition of song frequency: Crickets produce mostly low-frequency (2–8 kHz), pure tone signals with highly bilaterally symmetric wings, while bush-crickets use asymmetric wings for high-frequency (10–150 kHz) calls. The evolutionary reasons for this acoustic divergence are unknown. Here, we study the wings of actively stridulating male field-crickets (Gryllus bimaculatus) and present vibro-acoustic data suggesting a biophysical restriction to low-frequency song. Using laser Doppler vibrometry (LDV) and brain-injections of the neuroactivator eserine to elicit singing, we recorded the topography of wing vibrations during active sound production. In freely vibrating wings, each wing region resonated differently. When wings coupled during stridulation, these differences vanished and all wing regions resonated at an identical frequency, that of the narrow-band song (∼5 kHz). However, imperfections in wing-coupling caused phase shifts between both resonators, introducing destructive interference with increasing phase differences. The effect of destructive interference (amplitude reduction) was observed to be minimal at the typical low frequency calls of crickets, and by maintaining the vibration phase difference below 80°. We show that, with the imperfect coupling observed, cricket song production with two symmetric resonators becomes acoustically inefficient above ∼8 kHz. This evidence reveals a bio-mechanical constraint on the production of high-frequency song whilst using two coupled resonators and provides an explanation as to why crickets, unlike bush-crickets, have not evolved to exploit ultrasonic calling songs.
Collapse
|
10
|
Rebrina F, Petróczki K, Inhofer M, Reinhold K, Schmoll T. Motorway age is linked to larger body size, but not song carrier frequency, in male grasshoppers from roadside populations. Evol Ecol 2020. [DOI: 10.1007/s10682-020-10077-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Rebrina F, Anichini M, Reinhold K, Lehmann GUC. Allometric scaling in two bushcricket species (Orthoptera: Tettigoniidae) suggests sexual selection on song-generating structures. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AbstractIn acoustically communicating bushcrickets (Orthoptera: Tettigoniidae), most signal properties are influenced by the dimensions of the stridulatory apparatus, which in turn reflects body size and condition of the signaller. Females can assess male quality based on acoustic signals, suggesting that male stridulatory structures may be under sexual selection. We investigated scaling relationships between stridulatory structures, body size and body mass in males of the bushcricket Poecilimon veluchianus veluchianus, in comparison to the congeneric Poecilimon ampliatus. Stridulatory structures in P. v. veluchianus exhibited strong left–right correlation and coupling with body size and mass, indicating stabilizing selection for functional integration. In addition, sound-generating (the width of stridulatory teeth) and sound-radiating (mirror area on the right tegmen) structures scaled hyperallometrically to tegmen area, suggesting that both are under sexual selection. Finally, interspecies comparison revealed a steeper slope in tegmen area and stridulatory file length in relation to body size in P. ampliatus than in P. v. veluchianus, implying stronger sexual selection in the former, smaller species. Our study emphasizes the significance of a comparative allometric approach in elucidating evolutionary patterns of sound-generating and -radiating structures.
Collapse
Affiliation(s)
- Fran Rebrina
- University of Zagreb, Faculty of Science, Department of Biology, Zagreb, Croatia
| | - Marianna Anichini
- Humboldt University Berlin, Department of Biology, Evolutionary Ecology, Berlin, Germany
| | - Klaus Reinhold
- Bielefeld University, Faculty of Biology, Evolutionary Biology, Bielefeld, Germany
| | - Gerlind U C Lehmann
- Humboldt University Berlin, Department of Biology, Evolutionary Ecology, Berlin, Germany
| |
Collapse
|
12
|
Tan MK, Ingrisch S, Wahab RBINHA, Japir R, Chung AYC. Ultrasonic bioacoustics and stridulum morphology reveal cryptic species among Lipotactes big-eyed katydids (Orthoptera: Tettigoniidae: Lipotactinae) from Borneo. SYST BIODIVERS 2020. [DOI: 10.1080/14772000.2020.1769223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Ming Kai Tan
- Muséum national d’Histoire naturelle, CNRS, SU, EPHE, UA, Institut de Systématique, Evolution et Biodiversité (ISYEB), 57 rue Cuvier, CP 50, Paris Cedex 05, 75231, France
| | - Sigfrid Ingrisch
- Zoological Research Museum Alexander Koenig, Adenauerallee 160, Bonn, D-53113, Germany
| | - Rodzay BIN Haji Abdul Wahab
- Institute for Biodiversity and Environmental Research, Universiti Brunei Darussalam, Jalan Universiti, BE1410, Brunei Darussalam
| | - Razy Japir
- Sabah Forestry Department, Forest Research Centre (Sepilok), P.O. Box 1407, Sandakan, 90715, Sabah
| | - Arthur Y. C. Chung
- Sabah Forestry Department, Forest Research Centre (Sepilok), P.O. Box 1407, Sandakan, 90715, Sabah
| |
Collapse
|
13
|
Tan MK, Montealegre-Z F, Bin Haji Abdul Wahab R, Lee CY, Belabut D, Japir R, Chung A. Ultrasonic songs and stridulum anatomy of Asiophlugis crystal predatory katydids (Tettigonioidea: Meconematinae: Phlugidini). BIOACOUSTICS 2019. [DOI: 10.1080/09524622.2019.1637783] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Ming Kai Tan
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | | | - Rodzay Bin Haji Abdul Wahab
- Institute for Biodiversity and Environmental Research, Universiti Brunei Darussalam, Jalan Universiti, Darussalam, Brunei
| | - Chow-Yang Lee
- Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Daicus Belabut
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Razy Japir
- Sabah Forestry Department, Forest Research Centre (Sepilok), Sandakan, Malaysia
| | - Arthur Chung
- Sabah Forestry Department, Forest Research Centre (Sepilok), Sandakan, Malaysia
| |
Collapse
|
14
|
Sex differences in immunity in a natural population of bush-cricket (Orthoptera: Phaneropterinae). Biologia (Bratisl) 2019. [DOI: 10.2478/s11756-019-00193-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
15
|
Bailey NW, Pascoal S, Montealegre-Z F. Testing the role of trait reversal in evolutionary diversification using song loss in wild crickets. Proc Natl Acad Sci U S A 2019; 116:8941-8949. [PMID: 30992379 PMCID: PMC6500131 DOI: 10.1073/pnas.1818998116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanisms underlying rapid macroevolution are controversial. One largely untested hypothesis that could inform this debate is that evolutionary reversals might release variation in vestigial traits, which then facilitates subsequent diversification. We evaluated this idea by testing key predictions about vestigial traits arising from sexual trait reversal in wild field crickets. In Hawaiian Teleogryllus oceanicus, the recent genetic loss of sound-producing and -amplifying structures on male wings eliminates their acoustic signals. Silence protects these "flatwing" males from an acoustically orienting parasitoid and appears to have evolved independently more than once. Here, we report that flatwing males show enhanced variation in vestigial resonator morphology under varied genetic backgrounds. Using laser Doppler vibrometry, we found that these vestigial sound-producing wing features resonate at highly variable acoustic frequencies well outside the normal range for this species. These results satisfy two important criteria for a mechanism driving rapid evolutionary diversification: Sexual signal loss was accompanied by a release of vestigial morphological variants, and these could facilitate the rapid evolution of novel signal values. Widespread secondary trait losses have been inferred from fossil and phylogenetic evidence across numerous taxa, and our results suggest that such reversals could play a role in shaping historical patterns of diversification.
Collapse
Affiliation(s)
- Nathan W Bailey
- School of Biology, University of St. Andrews, St. Andrews KY16 9TH, United Kingdom;
| | - Sonia Pascoal
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | | |
Collapse
|
16
|
Baker AA, Jonsson T, Aldridge S, Montealegre-Z F. Complex wing motion during stridulation in the katydid Nastonotus foreli (Orthoptera: Tettigoniidae: Pseudophyllinae). JOURNAL OF INSECT PHYSIOLOGY 2019; 114:100-108. [PMID: 30898560 DOI: 10.1016/j.jinsphys.2019.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/27/2019] [Accepted: 03/17/2019] [Indexed: 06/09/2023]
Abstract
Male Katydids (Orthoptera: Tettigoniidae) rub together their specialised forewings to produce sound, a process known as stridulation. During wing closure, a lobe on the anal margin of the right forewing (a scraper), engages with a tooth-covered file on the left forewing. The movement of the scraper across the file produces vibrations which are amplified by a large wing cell adjacent to the scraper, the mirror. Katydids are known to stridulate with either sustained or interrupted sweeps of the file, generating resonant pure-tone (narrowband frequency) or non-resonant (broadband frequency) calls. However, some species can conserve some purity in their calls despite incorporating discrete pulses and silent intervals. This mechanism is exhibited by many Pseudophyllinae, such as Nastonotus spp., Cocconotus spp., Triencentrus spp. and Eubliastes spp. This study aims to measure and quantify the mechanics of wing stridulation in Nastonotus foreli, a Neotropical katydid that can produce, relatively narrowband calls at ≈20 kHz. It was predicted that this species will use a stridulatory mechanism involving elastic energy whereby the scraper bends and flicks along the file in periodic bursts. The calling behaviour and wing mechanics of seven males were studied using a combination of technologies (e.g. micro-scanning laser Doppler vibrometry, advanced microscopy, ultrasound-sensitive equipment and optical motion detectors) to quantify wing mechanics and structure. Analysis of recordings revealed no clear relationship between wing velocity and carrier frequency, and a pronounced distinction between wing velocity and scraper velocity during wing closure, suggesting that the scraper experiences considerable deformation. This is characteristic of the elastic scraper mechanism of stridulation. Curiously, N. foreli might have evolved to employ elastic energy to double the duration of the call, despite possessing muscles that can reach velocities high enough to produce the same frequency without the help of elastic energy.
Collapse
Affiliation(s)
- Andrew Alexander Baker
- University of Lincoln, School of Life Sciences, Joseph Banks Laboratories, United Kingdom
| | - Thorin Jonsson
- University of Lincoln, School of Life Sciences, Joseph Banks Laboratories, United Kingdom
| | - Sarah Aldridge
- University of Lincoln, School of Life Sciences, Joseph Banks Laboratories, United Kingdom
| | - Fernando Montealegre-Z
- University of Lincoln, School of Life Sciences, Joseph Banks Laboratories, United Kingdom.
| |
Collapse
|