Acoustic signals in katydids (Orthoptera,Tettigonidae). Communication 2

Three basic trends in the development of acoustic communication in Tettigonioidea are distinguished. The first one is observed in predatory tettigoniids and conocephalids. It is associated with the improvement of the territorial behavior and results in the appearance of territorial, aggressive and protest sounds (only males stridulate) in the acoustic repertoire. The second trend is caused by the development of defensive mechanisms. It is observed in phytophagous katydids belonging to the family Bradyporidae dwelling in deserts and other exposed habitats. As a rule, their acoustic repertoire includes long-lasting calling songs and disturbance (protest) sounds; rather often, these sounds are produced both by males and females. The unmasking effect of signals is compensated for by specific defense adaptations. The third evolutionary tendency is most completely expressed in phytophagous Phaneropteridae and phytophilous Bradyporidae (Ephippigerinae) as a result of the predator press and the improvement of sexual behavior. It leads to appearance of a “slow” system of communication, when the unmasking effect of songs is minimized by the decrease in the acoustic activity of males. Females produce response signals, while males produce complex calling, courtship, and confirming sounds. The temporal pattern of a signal is one of the most reliable criteria for the discrimination of species and subspecies. It is difficult to use physical parameters of sounds as a criterion for the differentiation of taxa at the superspecies rank, since acoustical signalling is obviously a subject of evolution of the acoustic community rather than of the taxon. Parallelisms and convergences are observed in the evolution of acoustic communication systems, but complex analysis allows revealing the initial type of the acoustic system and defining the reasons for adaptive reorganizations.     

Sensory evolution of hearing in tettigoniids with differing communication systems

In Tettigoniidae (Orthoptera: Ensifera), hearing organs are essential in mate detection. Male tettigoniids usually produce calling songs by tegminal stridulation, whereas females approach the males phonotactically. This unidirectional communication system is the most common one among tettigoniids. In several tettigoniid lineages, females have evolved acoustic replies to the male calling song which constitutes a bidirectional communication system. The genus Poecilimon (Tettigoniidae: Phaneropterinae) is of special interest because the ancestral state of bidirectional communication, with calling males and responding females, has been reversed repeatedly to unidirectional communication. Acoustic communication is mediated by hearing organs that are adapted to the conspecific signals. Therefore, we analyse the auditory system in the Tettigoniidae genus Poecilimon for functional adaptations in three characteristics: (i) dimension of sound‐receiving structures (tympanum and acoustic spiracle), (ii) number of auditory sensilla and (iii) hearing sensitivity. Profound differences in the auditory system correlate with uni‐ or bidirectional communication. Among the sound‐receiving structures, the tympana scale with body size, whereas the acoustic spiracle, the major sound input structure, was drastically reduced in unidirectional communicating species. In the unidirectional P. ampliatus group, auditory sensilla are severely reduced in numbers, but not in the unidirectional P. propinquus group. Within the P. ampliatus group, the number of auditory sensilla is further reduced in P. intermedius which lost acoustic signalling due to parthenogenesis. The auditory sensitivity correlated with the size of the acoustic spiracle, as hearing sensitivity was better with larger spiracles, especially in the ultrasonic range. Our results show a significant reduction in auditory structures, shaped by the differing sex roles during mate detection.     

New data on acoustic communication and ecology of grasshoppers of the genera <Emphasis Type="Italic">Eremippus</Emphasis> and <Emphasis Type="Italic">Dociostaurus</Emphasis> (Orthoptera,Acrididae) and notes on the use of bioacoustic data in supraspecific taxonomy of the subfamily Gomphocerinae

The calling songs of Dociostaurus hauensteini, Eremippus simplex, E. miramae, and E. sobolevi are described for the first time. The species composition and ecology of grasshoppers of the genus Eremippus from the Lower Volga basin were studied. Reproductive isolation between Eremippus species in this region was shown to be determined principally by the differences in the acoustic behavior. The calling songs were compared in five Eremippus species, and divided into three groups according to their amplitude-temporal patterns. The importance of bioacoustic data for supraspecific taxonomy of the subfamily Gomphocerinae is discussed.     

Ecology and sound signaling of relict katydid Deracantha onos (Pallas, 1772) (Orthoptera, Tettigoniidae, Bradyporinae)

Life history and acoustic signaling of a Central Asian species Deracantha onos (Pall.) are described. Males and females produce calling signals and protest sounds. For the first time, electronograms of stridulatory files, oscillograms, and frequency spectra of some acoustic signals are given.     

Quality calls: phylogeny and biogeography of a new genus of neotropical katydid (Orthoptera: Tettigoniidae) with ultra pure-tone ultrasonics

This paper describes Artiotonus, a new genus of tropical katydid from Colombia and Ecuador. These acoustic ensiferans are represented by three species with a geographic distribution generally restricted to the rainforest of the Bolivar geosyncline of northwestern South America (Pacific). A phylogenetic analysis based on 28 morphological and six behavioural characters produced a tree (A. artius, (A. tinae, A. captivus)) with a consistency index of 0.9. All species are defined by a few autapomorphic changes. The most reliable character for identification is the temporal pattern of the calling song, suggesting a recent genetic divergence. Biogeographic analysis indicates that such genetic divergence began with geographic isolation produced before the Holocene transgression. Species of this genus are remarkable in that the calling song of males exhibits a narrow spectrum with a high quality factor (37–42), unusual values for such ultrasonic signals. A broad discussion on the evolution of tonal calls and pulse trains is offered.     

The possibility to use bioacoustic characters in the taxonomy of the jumping plant lice with an example of the genus <Emphasis Type="Italic">Craspedolepta</Emphasis> (Homoptera,Psyllinea, Aphalaridae) and description of a new species from Transbaikalia

Oscillograms of calling signals of 14 species of Craspedolepta s. l. are presented. Temporal patterns of the signals in representatives of different species groups are quite similar. Therefore, the use of acoustic characters for distinguishing between genera and subgenera of psyllids appears to be impossible. In certain cases, the structure of signals in different species is almost identical. Nonetheless, in strictly sympatric species occurring in the same territory and living on the host plants of the same species, i.e., involved into acoustic interactions with each other, the signal pattern is always distinctly different. Consequently, the similarity of signals can be considered evidence of the synonymy only in sympatric forms dwelling on the same host plant. On the other hand, distinct differences in the signal patterns indicate conclusively that the forms investigated possess the rank of species. Craspedolepta filifoliae sp. n. collected in the steppe of Transbaikalia on Filifolium sibiricum is described and illustrated. The new species is closely related to the widespread C. malachitica, but differs from it in the pattern of the fore wings and certain details of the genitalia structure. Besides, distinct differences in acoustic characters between these forms provide strong evidence that C. filifoliae sp. n. is a separate (valid) species.     

First song descriptions of some Anatolian species of Tettigoniidae Krauss, 1902 (Orthoptera,Ensifera)

Fourteen endemic and two sub-endemic species belonging to three subfamilies of Tettigoniidae (Tettigoniinae, Bradyporinae and Saginae) were sampled during field trips throughout the different ranges of Anatolia between the years of 2004 and 2013. Acoustic parameters of these 16 species affiliated to 8 genera (Anterastes, Apholidoptera, Gampsocleis, Parapholidoptera, Pezodrymadusa, Psorodonotus, Bradyporus and Saga) have been described for the first time in this study. Acoustical analysis showed that song characters are species-specific in the genera Saga and Psorodonotus. On the other hand, we could not find big differences among species of the genus Pezodrymadusa and Parapholidoptera castaneoviridis species-group.     

Pure Ultrasonic Communication in an Endemic Bornean Frog

Huia cavitympanum, an endemic Bornean frog, is the first amphibian species known to emit exclusively ultrasonic (i.e., >20 kHz) vocal signals. To test the hypothesis that these frogs use purely ultrasonic vocalizations for intraspecific communication, we performed playback experiments with male frogs in their natural calling sites. We found that the frogs respond with increased calling to broadcasts of conspecific calls containing only ultrasound. The field study was complemented by electrophysiological recordings from the auditory midbrain and by laser Doppler vibrometer measurements of the tympanic membrane''s response to acoustic stimulation. These measurements revealed that the frog''s auditory system is broadly tuned over high frequencies, with peak sensitivity occurring within the ultrasonic frequency range. Our results demonstrate that H. cavitympanum is the first non-mammalian vertebrate described to communicate with purely ultrasonic acoustic signals. These data suggest that further examination of the similarities and differences in the high-frequency/ultrasonic communication systems of H. cavitympanum and Odorrana tormota, an unrelated frog species that produces and detects ultrasound but does not emit exclusively ultrasonic calls, will afford new insights into the mechanisms underlying vertebrate high-frequency communication.     

Description of two new species of Diaphanosoma Fischer, 1850 (Crustacea, Branchiopoda, Sididae) from the United States and Canada and species richness of the genus in North America

Investigation of a small number of samples with representatives of the genus Diaphanosoma from the cladoceran collection of the National Museum of Natural History, Smithsonian Institution (Washington, D.C., U.S.A.) has revealed two new species, D. freyi and D. heberti, from Louisiana–Missouri and Newfoundland, respectively. The former looks like one of the most primitive species of the genus. Two other species, D. fluviatile and D. brevireme, are recorded from the southern United States for the first time. Members of the D. brachyurum and D. birgei species groups, which are morphologically variable and need further detailed investigations, were represented in the bulk of the material studied. The species richness of the genus in North America appears to be high and its composition is obviously complex but remains little studied.     

New and little-known orthopteroid insects (Polyneoptera) from fossil resins: Communication 4

New taxa of Ensifera and Caelifera orthopterans (Insecta, Orthoptera), from the families Gryllotalpidae [Marchandiinae, subfam. nov. (Lower Cretaceous)], Haglotettigoniidae [?Haglotettigonia aenigmatosa, sp. nov. (Lower Cretaceous)], Tettigoniidae [Meconematinae: Archixizicus occidentalis, gen. et sp. nov. (Eocene), Eogrigoriora gracilis, gen. et sp. nov. (Eocene), Miophlugis rostratus, gen. et sp. nov. (Miocene)], Stenopelmatidae [Siinae: Electrosia baltica, gen. et sp. nov. (Eocene); Gryllacridinae: Plesiolarnaca prior, gen. et sp. nov. (Eocene)] and Tridactylidae [Mongoloxyinae: Birmitoxya intermedia, gen. et sp. nov. (Upper Cretaceous). The Eocene species Lipotactes martynovi Zeun. and L. bispinatus Weidn. are transferred to the genus Eomortoniellus Zeun. (Tettigoniidae: Tympanophorinae); Prorhaphidophora zeuneri Chop. and P. tachycinoides Chop. are transferred to the genus Protroglophilus Gor. (Rhaphidophoridae: Protroglophilinae). The Eocene species E. handlirschi Zeun., species of the genus Protroglophilus, and a possible member of the genus Succinotettix Piton (Tetrigidae: Tetriginae), as well as a Miocene representative of the genus Archaeoellipes Heads (Tridactylidae: Tridactylinae) are also discussed.     

The Acoustic Properties of Low Intensity Vocalizations Match Hearing Sensitivity in the Webbed-Toed Gecko,Gekko subpalmatus

The design of acoustic signals and hearing sensitivity in socially communicating species would normally be expected to closely match in order to minimize signal degradation and attenuation during signal propagation. Nevertheless, other factors such as sensory biases as well as morphological and physiological constraints may affect strict correspondence between signal features and hearing sensitivity. Thus study of the relationships between sender and receiver characteristics in species utilizing acoustic communication can provide information about how acoustic communication systems evolve. The genus Gekko includes species emitting high-amplitude vocalizations for long-range communication (loud callers) as well as species producing only low-amplitude vocalizations when in close contact with conspecifics (quiet callers) which have rarely been investigated. In order to investigate relationships between auditory physiology and the frequency characteristics of acoustic signals in a quiet caller, Gekko subpalmatus we measured the subjects’ vocal signal characteristics as well as auditory brainstem responses (ABRs) to assess auditory sensitivity. The results show that G. subpalmatus males emit low amplitude calls when encountering females, ranging in dominant frequency from 2.47 to 4.17 kHz with an average at 3.35 kHz. The auditory range with highest sensitivity closely matches the dominant frequency of the vocalizations. This correspondence is consistent with the notion that quiet and loud calling species are under similar selection pressures for matching auditory sensitivity with spectral characteristics of vocalizations.     

Testing concordance in species boundaries using acoustic,morphological, and molecular data in the field cricket genus Itaropsis (Orthoptera: Grylloidea,Gryllidae: Gryllinae)

In most taxa, species boundaries are inferred based on differences in morphology or DNA sequences revealed by taxonomic or phylogenetic analyses. In crickets, acoustic mating signals or calling songs have species‐specific structures and provide a third data set to infer species boundaries. We examined the concordance in species boundaries obtained using acoustic, morphological, and molecular data sets in the field cricket genus Itaropsis. This genus is currently described by only one valid species, Itaropsis tenella, with a broad distribution in western peninsular India and Sri Lanka. Calling songs of males sampled from four sites in peninsular India exhibited significant differences in a number of call features, suggesting the existence of multiple species. Cluster analysis of the acoustic data, molecular phylogenetic analyses, and phylogenetic analyses combining all data sets suggested the existence of three clades. Whatever the differences in calling signals, no full congruence was obtained between all the data sets, even though the resultant lineages were largely concordant with the acoustic clusters. The genus Itaropsis could thus be represented by three morphologically cryptic incipient species in peninsular India; their distributions are congruent with usual patterns of endemism in the Western Ghats, India. Song evolution is analysed through the divergence in syllable period, syllable and call duration, and dominant frequency. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 285–303.     

A new species of Odaginiceps Fiers, 1995 (Copepoda, Harpacticoida, Tetragonicipitidae) from the Mediterranean coast of Turkey

Male and female of Odaginiceps korykosensis sp. n. (Copepoda, Harpacticoida, Tetragonicipitidae), collected in the intertidal zone of Kızkalesi beach along the Mediterranean coast of Turkey (Mersin Province), are described. The new species is the fifth member of the genus and can easily be distinguished from the other species by the presence of four setae/spines on the second endopodal segment of P4 and by the structure of the caudal rami. Previously, representatives of the genus Odaginiceps have been reported from Gulf of Mexico, off Bermuda and Kenya. Odaginiceps korykosensis sp. n. is the first record of the genus in the Mediterranean Sea.     

Song frequency correlates with latitude and individual body size in the cicada <Emphasis Type="Italic">Mogannia formosana</Emphasis> Matsumura (Hemiptera: Cicadidae)

Analyses of acoustic variation between and within populations can help to clarify the evolution and diversification of cicada calling songs. In this study, we analyzed the acoustic variation in the calling song of Mogannia formosana within Taiwan and between Taiwan and Green Island to assess the effects of geographic locations. Furthermore, chorusing males in the Green Island population were recorded and collected from the same habitat site during the same time period to investigate the relationship between individual body size and the acoustic features of calling songs. Among populations of M. formosana, we found that most of the acoustic variation in M. formosana calling songs was associated with frequency parameters, in which six frequency parameters changed significantly with latitude on the island of Taiwan. In contrast, temporal parameters, which were associated with principal components corresponding to less acoustic variation than that of the first principal component, were also found to be significant among populations but did not show consistent trends of difference with latitude. However, the geographically isolated Green Island population exhibited the lowest number of short echemes in segment B, which is the diagnostic structure employed to separate M. formosana from other M. species. This finding suggests that the temporal pattern of segment B in the calling songs of M. formosana might be important for both population differentiation and interspecific recognition. In a chorus of the Green Island population, the sound frequency of the last short echeme was found to be significantly correlated with individual body size. The possible role played by sexual selection in shaping sound frequency as a result of its reliable association with body size was discussed. We suggest that, in comparison with temporal elements, the frequency elements of segment B in calling songs of M. formosana in chorus can serve as a more reliable indicator of body size for female mate choice.     

Inferring species boundaries using acoustic and morphological data in the ground cricket genus Gymnogryllus (Orthoptera: Grylloidea: Gryllinae)

An important function of song production by male crickets is to attract conspecific females. These sound signals can be used to infer species boundaries as they can provide indirect evidence for reproductive isolation. However, many studies of orthopteran diversity in South-east Asia are based mainly on morphology and only occasionally acoustics. As such, there is a lack of information on how acoustic data can be congruent with morphological data when used to delineate species. Crickets of the genus Gymnogryllus (Grylloidea, Gryllidae), are such an example. Gymnogryllus are relatively speciose, but their calling songs have not been studied. We collected specimens and calling songs of five Gymnogryllus species from South-east Asia. The acoustic parameters of the calls, along with male tegminal venation and morphology genitalia, were compared. All data types showed congruency in distinguishing G. sylvestris and G. leucostictus from each other and from the other species. Inferring species boundaries for G. angustus, G. malayanus, and G. unexpectus using acoustics and tegminal morphometry proves to be more challenging. While acoustics, tegminal morphometry, and genital morphology are likely to be useful for inferring species of Gymnogryllus from different species groups, greater coverage of taxa is needed to resolve taxonomy of closely related Gymnogryllus.     

Taxonomic proposal for a deep branching bacterial phylogenetic lineage: transfer of the family Thermodesulfobiaceae to Thermodesulfobiales ord. nov., Thermodesulfobiia classis nov. and Thermodesulfobiota phyl. nov

The family Thermodesulfobiaceae, comprising one genus Thermodesulfobium with two validly published species, is currently assigned to order Thermoanaerobacterales within the class Clostridia of the phylum Bacillota. At the same time, the very first 16S rRNA gene sequence-based phylogenetic studies of representatives of the genus pointed out great differences between Thermodesulfobium and other members of the phylum Bacillota. Subsequent studies of new Thermodesulfobium representatives supported deep phylogenetic branching of this lineage within bacterial tree, implying that it represents a novel phylum. The results of the phylogenomic analysis performed in the frames of the present work confirm previous findings and suggest that Thermodesulfobium represents a distinct phylum-level lineage. Thus, we propose the transfer of the family Thermodesulfobiaceae to the new order Thermodesulfobiales within the new class Thermodesulfobiia and the new phylum Thermodesulfobiota.     

Parasite infection has little effect on sexual signals and reproductive behaviour in strawberry poison frogs

Acoustic and visual signals like mating calls or colour patterns, which are involved in courtship displays, can be affected by the health status of an individual. For example, infection with parasites can result in sexual signals that are less intense or conspicuous than in healthy individuals; thus it is generally assumed that sexual signals indicate the quality of the holder. We use strawberry poison frogs from Costa Rica to find out (1) whether there is variation in the parasite load among individuals, (2) whether the parasite load varies over time, (3) whether the parasite load has an effect on acoustic and visual signals, which are supposed to be important for female mate choice and (4) whether the parasite load influences the reproductive behaviour. We found that 60 % of our focal males were infested with an intestinal nematode of the genus Cosmocerca while the parasite load changed considerably over time. We found slight associations between the intensity of acoustic signals (advertisement calls), visual signals (colour and brightness contrasts) and parasite load. Non-infected males produced significantly lower pulse rates than parasitised males. As pulse rate has been shown to decrease with age, we suggest that males without parasites become older than infected males. Moreover, the visual contrasts of the frogs varied across natural backgrounds. An interaction between parasite infection and the background of the calling place affected the ventral colour contrast. This finding suggests that at least some males without parasites defend calling places that render them more conspicuousness to conspecifics than other potential positions would. There were no differences in several elements of reproductive behaviour between parasitised and healthy males. Further studies are necessary to find out whether parasite infection varies among populations, and whether at higher levels it would have a stronger influence on sexual signals, behaviour and lifetime fitness.     

The release call of Rhaebo guttatus (Anura: Bufonidae)

The bufonid genus Rhaebo contains 13 species, Rhaebo guttatus being one of the two species that occur in Brazil. Here we describe for the first time the release call of R. guttatus from the Brazilian Amazonia. Release calls are highly variable both in the temporal and in the frequency domains. The advertisement and release calls of Rhaebo guttatus are distinguished from each other by their temporal envelope, distribution of sound energy, and calling emission patterns. The acoustic characterization of release calls in Rhaebo could be potentially informative in the taxonomy of this genus, as previously reported for members of the bufonid genus Rhinella.     

Scale effects and constraints for sound production in katydids (Orthoptera: Tettigoniidae): correlated evolution between morphology and signal parameters

Male katydids (Orthoptera: Tettigoniidae) produce mating calls by rubbing the wings together, using specialized structures in their forewings (stridulatory file, scraper and mirror). A large proportion of species (ca. 66%) reported in the literature produces ultrasonic signals as principal output. Relationships among body size, generator structures and the acoustic parameters carrier frequency (f_c) and pulse duration (p_d), were studied in 58 tropical species that use pure‐tone signals. A comparative analysis, based on the only available katydid phylogeny, shows how changes in sound generator form are related to changes in f_c and p_d. Anatomical changes of the sound generator that might have been selected via f_c and p_d are mirror size, file length and number of file teeth. Selection for structures of the stridulatory apparatus that enhance wing mechanics via file‐teeth and scraper morphology was crucial in the evolution of ultrasonic signals in the family Tettigoniidae.