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1. Physiological characteristics of single, primary auditory units have been examined in a member of the Orthopteran family Stenopelmatidae. 2. Individual units are tuned more sharply than the whole auditory organ. Units have peaks of sensitivity within the bandwidth described by the summed threshold curve of the auditory organ. 3. Some units display one or two additional peaks of sensitivity at higher frequencies, which may not be harmonically related to the major peak. 4. Units respond to tones with a tonic discharge in which an initial, partial adaptation may occur. Stimulus intensity is coded in terms of spike rate and latency and units display typical, sigmoidal input-output curves. High intensity suppression of the response is sometimes observed. 5. Repetition rates of brief sound pulses that units can follow are limited by mechanical and/or physiological aspects of the sensory process. Minimum latency of response is of the order of 13 ms.

Descriptions of fermoro-abdominal stridulatory structures and frequency spectra of stridulatory sounds are presented for 7 species (Hemideina, Deinacrida) of Stenopelmatidae. In Hemideina, femoral pegs and abdominal file ridges were approximately similar in shape among species, but varied in size. The abdominal component differed in Deinacrida and consisted of either 1 or 2 heavy ridges, or an array of thin, upright, rectangular pegs. The stridulatory structures in some species had elaborate lips, grooves or buttresses. Acoustic spectra of defensive sounds of 3 Hemideina spp. had overlapping peaks between 4 – 14 kHz; a 4th species had a peak at 2 kHz. The spectral intensity dropped sharply above peak frequencies. Spectra for 3 Deinacrida spp. were very broad (1 – 90 kHz) with a shallow roll-off above peaks. The peak frequency band was 10 – 50 kHz. Each species had a different characteristic spectrum. There is no clear, consistent relationship between stridulatory structure size and spectral characteristics of stridulatory sounds.

Specimens of the Acartia subgenus Acartiura which are closely related to A. clausii Giesbrecht, 1889 were examined from European waters, the east and west coasts of the United States, Japan, Australia, and New Zealand. The species A. ensifera Brady, 1899 and A. simplex Sars, 1905 are redescribed, A, hudsonica Pinhey, 1926 is elevated from subspecific to specific status, and five new species (A. jilletti, A. lefevreae, A. omorii, A. teclae, and A. tranteri) are described. A key is given to all known species of Acartiura.

The file teeth of crickets show pronounced interspecific differences. Twenty-four species, representing eight subfamilies, were examined to determine whether such differences reflect differences in acoustic function. We found no relation between particular tooth structures and particular features of the calling song; however, such structures correlated with the major phyletic divisions of crickets.

1. The peripheral tympanal region of the Tettigonioidea (long-horned grasshoppers) has been investigated by means of the scanning electron microscope. 2. The tympana are composed of two membranous parts having different structure. There is an outer, ellipsoid region with a honeycomb structure comparable to that of the surface of the forelimb exoskeleton; around this lies a thin crescent-shaped membrane with a fibrillar texture. The latter part is probably relatively elastic and capable of oscillation. 3. The actual site of the auditory receptors in these grasshoppers, the crista acoustica, takes the form of a row of scolopidia; the sizes of the scolopidia decrease progressively from proximal to distal. The cap cells of the scolopidia are covered by the tectorial membrane; in the middle and distal region of this membrane there are supporting bands running lateral to the cap cells.

Investigation of the physiological and biophysical properties of the auditory system of the New Zealand weta,Hemideina crassidens has revealed the following: 1. The frequency/threshold curve for the massed response of primary auditory fibres in the tympanal nerve has a peak of sensitivity at 2.0–2.5 kHz. Absolute threshold is 20–35 dB SPL in individual preparations and the roll-off is about 15 dB/octave below the optimum and about 27 dB/octave above the optimum frequency (Fig. 1). 2. Occlusion of either the anterior or posterior tympanum causes a small loss of sensitivity (

In continuation of previous work on Eugaster guyoni (Nielsen 1971) stridulation and locomotor activity has been, investigated under various conditions of temperature and illumination. The theory of continuously increasing sensitization was further corroborated, and it is attempted to determine the relative thresholds of release and cessation of stridulation. The subspecies E.g. fernandezi from the Sahara is in its daily stridulation activity adapted to a higher temperature than E.g. berlandi from the Sous valley; however, at the same temperature the number of chirps per minute is the same in the two subspecies. Resume TYPES D'ACTIVITE CHEZ EUGASTER (ORTHOPTERA: ENSIFERA) Les deux sous-especes d'Eugaster guyoni, fernandezi du Sahara et berlandi d'Agadir, different par leur activiTE stridulatoire. La sous-espece du desert semble etre adapTEe a une temperature plus ***elevee de 5° que celle d'Agadir (E. berlandi). Les tres jeunes adultes ont une tres grande activiTE locomotrice pendant que la stridulation se developpe graduellement pendant une periode d'une semaine. II semble y avoir un certain degre d'inhibition reciproque entre les deux activaTEs locomotrice ou stridulatoire. Dans des conditions semi-naturelles l'activiTE du matin et du soir depend de la temperature maximum attcinte durant la periods de repos vers la fin de matinee. En condition d'eclairage permanent, les periodes de stridulation alternent irregulieremeat avec celles de repos. La quantiTE d'activiTE depend de la temperature. Avec une alternance de 12 heures de lumiere et 12 heures d'obscuriTE l'activiTE stridulatoire depend de la temperature comme en condition d'eclairage permanent. Cependant celte activiTE se repartit de faĉon caracTEristique en deux periodes precedant et suivant le changement d'eclairement. Avec 12 heures de pleine lumiere et 12 heures de lumiere atTEnuee il n'y a normalement qu'une seule periode de stridulation qui sc manifeste surtout pendant la phase de lumiere atTEnuee. Pour une temperature donnee l'activiTE est plus grande en lumiere faible qu'en pleine lumiere ou en obscuriTE. Une tentative est faite, dans la discussion, pour etablir les valeurs relatives de la sensibilisation aux differents seuils de declenchement et d'arret de la stridulation.

One of the fundamental problems in auditory research is the origin of the frequency selectivity of auditory receptors. Horridge (1960) demonstrated that the auditory interneuroneS in locusts were tuned to different sound frequencies, thus suggesting that the auditory receptors were frequency selective. Michelsen (1968, 1971) established that the auditory organ of locusts contained four groups of receptors with different characteristic sound frequencies and proposed that the frequency selectivity of the individual groups was dependent on the resonant properties of the tympanum. Investigation using the more sensitive of the two auditory receptors in the moth Prodenia eridania extended this proposal by suggesting that the tuning of this receptor depended on both resonant properties of the auditory organ (scoloparium) and filtering properties of the acoustic system (Adams, 1972), the most important factor in the latter being the tympanal membranes. In crickets and bushcrickets, however, the tympanal membranes vibrate in a simple mode for a wide band of sound frequencies (Paton, Capranica, Dragsten & Webb, 1977; Michelsen & Larsen, 1978), thus making it unlikely that the motion of the tympanum is responsible for the frequency selectivity (Zhantiev & Korsunovskaya, 1978; Esch, Huber & Wohlers, 1980) of the individual auditory receptors. Similarly, Ball & Hill (1978) demonstrated that auditory intemeurones of larval instar crickets are tuned even though they have no tympanal membranes. A recent study of the tonotopic organization of the auditory organ in bushcrickets (Oldfield, 1982) revealed that the auditory receptors remained tuned after the removal of one tympanum. This result, like those obtained from crickets, suggests that the resonant properties of the tympanal membranes are not responsible for the tuning of the individual auditory receptors. Conclusive evidence on this proposal, however, requires the removal of both tympanal membranes, thus eliminating the possibility that the remaining tympanum in the study by Oldfield (1982) determined the tuning of the auditory receptors. Physiological recordings were obtained from 16 auditory receptors in preparations of the bushcricket Mygalopsis marki (Bailey) from which the tympanal membranes

The activity of the cockroach Ectobius lapponicus was found to differ in males and females in the field, the males being active during the afternoon, the females after sunset. The difference was thought to be due to an inhibition by low temperatures in the males, displacing the activity towards an earlier period of the day. This is in accordance with a theory concerning sensitization, and different thresholds of release dependent on light and temperature as established for the stridulation in Orthoptera Ensifera and the locomotion in a domestic cockroach. A relationship between the amount of activity and the relative humidity was found in the nymphs. Laboratory experiments showed that the activity at constant temperature was released by a change from light to darkness. If low temperatures were applied during the dark period, the activity was displaced to the latter half of the light period. The influence of illumination on the activity was investigated, a faint illumination being more favourable than total darkness.

Acoustic signalling during pair formation is more complex in Phaneropterinae than in any other Ensifera. Lone males of most species produce more than one kind of sound, and females of all species studied produce sound during pair formation, a phenomenon with no known parallel in other Ensifera. This report includes (1) an analysis of the singing behaviours and the descriptions of sounds of nine species of Phaneropterinae and (2) the results of numerous experiments with these species to determine the behavioural significance of their sounds. Three kinds of male-female acoustic systems occur in the species studied: (1) the male makes a particular sound, the female answers with a tick and the male goes all the way to the female, (2) the male makes one kind of sound which attracts females from a distance (but not at close-range), the male makes a second sound which the female answers with a tick and the male goes to the female from close-range, and (3) the male makes one kind of sound, the female answers with a tick, the male moves towards the female from a distance (but not all the way), and the male produces a second kind of sound which attracts the female the remaining distance. Some species produce stereotyped sequences of different kinds of sounds; different responses occur to different sounds in the sequences.

Isolated males of the ensiferous Orthoptera stridulate under natural conditions with regular intervals. The main subject of the work described in this paper is an attempt to clarify the interrelationship between internal and external conditions activating this habit. To this end observations were made of several species both in the field and in the laboratory under controlled conditions, in order to establish the relation between the occurrence of stridulation - commencement, duration and intensity - and the prevailing environmental factors. During the work was established the following working hypothesis which covers all the observations: The stridulation is an effect of a continuously produced sensitizing agent which at a certain level releases the activity; the rate of increase of sensitization is correlated with temperature. The threshold of release is higher at high illumination and at high temperature than in darkness and at low temperature. During the activity' the sensitization is reduced to a low level. Reduction in illumination releases also spontaneous motoric activity and, at least in G. domesticus, also feeding. These activities prevail over stridulation, so that the song will first commence after a certain lapse of time, the period of latency. At the beginning of stridulation there is an increase in intensity during an interval of similar duration, the period of increment.

A numerical taxonomic analysis was performed using eight exemplars of the orthopteroids. Two suites of attributes were used in a non-weighted dissimilarities analysis. The same suites of attributes were analyzed for a similarity index with dendrograms based on the shortest connection network of Prim. The Tettigoniidae and Gryllidae are in agreement with current systematic placement within the Ensifera. The Caelifera diverge early from ancestral stem lines and suggest a greater separation from the Ensifera within the Orthoptera than generally accepted for their systematic position. The dendrograms suggest that the Blattaria and Mantodea show a relationship closer than the present subordinal rank permits. In the dendrograms the Grylloblattodea and Dermaptera form a remote complex from the other orthopteroids and each qualifies as a separate order. Modern classification of the orthopteroids considers the Dictyoptera, Dermaptera, Orthoptera, and Phasmida as orders. My analysis elevates the Grylloblattidae to the ordinal level as Grylloblattodea.

The digestive organs of Grylloblatta resemble those of the orthopteran suborder Ensifera but differ strikingly in the cuticle and epithelium lining the proventriculus, in which there are 12 similar longitudinal divisions characterized by rows of flexible, backwardly directed lamellae, in place of the six divisions of the Ensifera armed with columns of complex sclerotized teeth. The proventricular collum is much longer than in any of the Ensifera; the two gastric caeca of the latter are represented by a single bilobed sac; the malpighian vessels are fewer than 30 and are simply arranged; and the salivary glands are very compact, appearing like a single organ.As a main conclusion to this and the previous papers of this series the following views are advanced:(1) The Grylloblattaria, although cursorial, are the nearest relatives of the Ensifera, but differ from the latter group too widely to be included within it.(2) The saltatorial habit has been independently evolved in the Ensifera and Caelifera.A summary is given of the main views on the function of the proventriculus in mandibulate insects, particularly the orthopteroid forms. The proventriculus of Grylloblatta is believed to serve as a regulatory valve and also possibly as a propulsive organ for the movement of food along the digestive tract.

Precrepuscular stridulation of Tettigonia viridissima occurs frequently in the field. In the laboratory it may be produced by a combination of high temperature in the light period and so low temperature during darkness that the activity is inhibited. This is explained by assuming that the sensitizing agent is accumulated and the fast sensitization at high temperature thus is able to reach the high threshold of release in light.

Biophysical measurements exhibit that males of the ground-living gryllid Gryllus bimaculatus DeGeer (Ensifera: Gryllidae) produce vibratory signals while stridulating. Transmitted via the ground, these signals are perceiveable for conspecifics at a distance of a few dm. Experiments on the phonotactic behaviour of females of this species reveal that vibratory signals do influence this phonotactic behaviour pattern when no other directional cue is available. The significance of vibratory signals for the orientation of the gryllid in the biotope is discussed.

The morphology and histology of the tibial auditory system of the New Zealand weta, Hemideina crassidens, are described. The groups of acoustic sensilla conform closely to the subgenual organ, intermediate organ and crista acoustica of the Tettigoniidae. Each prothoracic tibia bears two thick (40-100 micrometers) tympana of approximately equal size divided into two distinct zones. The tracheae of the prothoracic legs are connected across the midline by a transverse commissure and by a chiasma between the ventral longitudinal trunks. No expanded vesicle ("vesicula acoustica") is associated with the spiracle. The anterior and posterior tracheae are divided into three distinct regions within the tibia: (1) a bulbous proximal posterior inflated chamber, (2) the tympanal vesicles to which the tympana attach, and (3) an elongate distal posterior inflated chamber. The pattern of innervation in the tympanal region is similar to that of gryllids as is the central projection of the tympanal nerve. The subgenual organ, which contains ca. 50 sensilla, forms an acute angle with the wall of the leg. The intermediate organ contains ca. 19 sensilla forming an arc against the anterior wall of the leg. The crista acoustica contains ca. 50 sensilla aligned in a gelatinous matrix along the dorsal surface of the anterior tympanal vesicle. Each dendrite projects distally, then is reflected proximally and dorsally to end in a scolopale embedded in an attachment cell. The attachment cells are stellate in the proximal portion of the crista, but distally they occur as parallel lamellae. The weta ear is compared with those of other Orthoptera.

Background Sound localization in small insects can be a challenging task due to physical constraints in deriving sufficiently large interaural intensity differences (IIDs) between both ears. In crickets, sound source localization is achieved by a complex type of pressure difference receiver consisting of four potential sound inputs. Sound acts on the external side of two tympana but additionally reaches the internal tympanal surface via two external sound entrances. Conduction of internal sound is realized by the anatomical arrangement of connecting trachea. A key structure is a trachea coupling both ears which is characterized by an enlarged part in its midline (i.e., the acoustic vesicle) accompanied with a thin membrane (septum). This facilitates directional sensitivity despite an unfavorable relationship between wavelength of sound and body size. Here we studied the morphological differences of the acoustic tracheal system in 40 cricket species (Gryllidae, Mogoplistidae) and species of outgroup taxa (Gryllotalpidae, Rhaphidophoridae, Gryllacrididae) of the suborder Ensifera comprising hearing and non hearing species.

Background The two closely related species of band-winged grasshoppers, Gastrimargus marmoratus and Oedaleus asiaticus, display significant differences in distribution, biological characteristics and habitat preferences. They are so similar to their respective congeneric species that it is difficult to differentiate them from other species within each genus. Hoppers of the two species have quite similar morphologies to that of Locusta migratoria, hence causing confusion in species identification. Thus we determined and compared the mitochondrial genomes of G. marmoratus and O. asiaticus to address these questions. Results The complete mitochondrial genomes of G. marmoratus and O. asiaticus are 15,924 bp and 16,259 bp in size, respectively, with O. asiaticus being the largest among all known mitochondrial genomes in Orthoptera. Both mitochondrial genomes contain a standard set of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and an A+T-rich region in the same order as those of the other analysed caeliferan species, but different from those of the ensiferan species by the rearrangement of trnD and trnK. The putative initiation codon for the cox1 gene in the two species is ATC. The presence of different sized tandem repeats in the A+T-rich region leads to size variation between their mitochondrial genomes. Except for nad2, nad4L, and nad6, most of the caeliferan mtDNA genes exhibit low levels of divergence. In phylogenetic analyses, the species from the suborder Caelifera form a monophyletic group, as is the case for the Ensifera. Furthermore, the two suborders cluster as sister groups, supporting the monophyly of Orthoptera. Conclusion The mitochondrial genomes of both G. marmoratus and O. asiaticus harbor the typical 37 genes and an A+T-rich region, exhibiting similar characters to those of other grasshopper species. Characterization of the two mitochondrial genomes has enriched our knowledge on mitochondrial genomes of Orthoptera.

Data on the genera Anabropsis Rehn, 1901, Glaphyrosoma Brunner-Wattenwyl, 1888, Stenopelmatopterus Gorochov, 1988 and Stenopelmatus Burmeister, 1838, belonging to the families Anostostomatidae and Stenopelmatidae, from Mexico, Guatemala, Honduras, Nicaragua, Costa Rica and Colombia are presented. Sixteen new species are described: A. longipenna sp. nov.; A. weissmani sp. nov.; A. kasparyani sp. nov.; A. proxima sp. nov.; A. johnsi sp. nov.; A. chiapas sp. nov.; A. oaxaca sp. nov.; A. apteroides sp. nov.; G. bulbosum sp. nov.; G. beretka sp. nov.; G. tamaulipas sp. nov.; G. pushenkovi sp. nov.; G. dilutum sp. nov.; G. dentatum sp. nov.; G. karnyi sp. nov.; G. anderi sp. nov. Tribe Brachyporini Gorochov, 2001 is restored from synonymy; lectotypes for G. gracile Brunner-Wattenwyl, 1888 and for G. mexicanum (Saussure, 1859) are designated; and new data on distribution of some other species are given.

Secondary winglessness is a common phenomenon found among neopteran insects. With an estimated age of at least 140 million years, the cave crickets (Rhaphidophoridae) form the oldest exclusively wingless lineage within the long-horned grasshoppers (Ensifera). With respect to their morphology, cave crickets are generally considered to represent a `primitive’ group of Ensifera, for which no apomorphic character has been reported so far. We present the first detailed investigation and description of the thoracic skeletal and muscular anatomy of the East Mediterranean cave cricket Troglophilus neglectus (Ensifera: Rhaphidophoridae). T. neglectus possesses sternopleural muscles that are not yet reported from other neopteran insects. Cave crickets in general exhibit some unique features with respect to their thoracic skeletal anatomy: an externally reduced prospinasternum, a narrow median sclerite situated between the meso- and metathorax, a star-shaped prospina, and a triramous metafurca. The thoracic muscle equipment of T. neglectus compared to that of the bush cricket Conocephalus maculatus (Ensifera: Tettigoniidae) and the house cricket Acheta domesticus (Ensifera: Gryllidae) reveals a number of potentially synapomorphic characters between these lineages. Based on the observed morphology we favor a closer relationship of Rhaphidophoridae to Tettigoniidae rather than to Gryllidae. In addition, the comparison of the thoracic morphology of T. neglectus to that of other wingless Polyneoptera allows reliable conclusions about anatomical adaptations correlated with secondary winglessness. The anatomy in apterous Ensifera, viz. the reduction of discrete direct and indirect flight muscles as well as the strengthening of specific leg muscles, largely resembles the condition found in wingless stick insects (Euphasmatodea), but is strikingly different from that of other related wingless insects, e.g. heel walkers (Mantophasmatodea), ice crawlers (Grylloblattodea), and certain grasshoppers (Caelifera). The composition of direct flight muscles largely follows similar patterns in winged respectively wingless species within major polyneopteran lineages, but it is highly heterogeneous between those lineages.

Background Molecular genetic analyses of parentage provide insights into mating systems. Although there are 22,000 members in Malacostraca, not much has been known about mating systems in Malacostraca. The freshwater shrimp Caridina ensifera blue, is a new species belonging to Malacostraca which was discovered recently in Sulawesi, Indonesia. Due to its small body size and low fecundity, this species is an ideal species to study the occurrence and frequency of multiple paternity and to understand of how the low fecundity species persist and evolve. Methodology/Principal Findings In this study, we developed four polymorphic microsatellites from C. ensifera and applied them to investigate the occurrence and frequency of multiple paternity in 20 C. ensifera broods caught from Lake Matano, Sulawesi. By genotyping the mother and all offspring from each brood we discovered multiple paternity in all 20 broods. In most of the 20 broods, fathers contributed skewed numbers of offspring and there was an apparent inverse correlation between reproductive success of sires and their relatedness to mothers. Conclusions/Significance Our results in combination with recent reports on multiple paternity in crayfish, crab and lobster species suggests that multiple paternity is common in Malacostraca. Skewed contribution of fathers to the numbers of offspring and inverse correlation between reproductive success of sires and their relatedness to mothers suggest that sperm competition occurred and/or pre- and postcopulatory female choice happen, which may be important for avoiding the occurrence of inbreeding and optimize genetic variation in offspring and for persistence and evolution of low fecundity species.

Open habitats in closed forests are formed by various biotic and abiotic factors. These new habitats differ from their former parent stands in light conditions and vegetation structure facilitating their colonisation by heliophilous insects. We studied interseasonal differences (2010 and 2011) in the Orthoptera assemblages on eight clearcuts in beech forests. Using a sweeping method, altogether 20 species were recorded on the clearcuts in the first year, 26 in the second. In the second year, species number and abundance were higher in all orthopterans and also in the suborder of grasshoppers (Caelifera). In the crickets (Ensifera), interseasonal differences in the species number and abundance were not significant. The species composition differed among the plots also within individual years. In the second year, the frequency increased in 22 species (84.6%) while it decreased in four. We suggest that the ground- dwelling Caelifera species are better bioindicators of the deforested plot colonisation than the arbusticolous Ensifera.

The morphology of the complex tibial organs in the forelegs of two bushcricket species belonging to the Phaneropterinae and Decticinae (Tettigoniidae) is described comparatively. In both species the tibial organs are made up of the subgenual organ, the intermediate organ and the crista acustica; the latter are parts of the tympanal organs and serve as auditory receptors. The very thin tympana in the forelegs ofPholidoptera griseoaptera (Decticinae) are protected by tympanal covers whereas inLeptophyes punctatissima (Phaneropterinae) the tympana are thicker and fully exposed. The overall auditory sensitivity ofL. punctatissima is lower and the sensitivity maximum of the hearing threshold lies at higher frequencies compared toP. griseoaptera. The number of scolopidia in the three scolopale organs and the dimensions of parts of the sound conducting system differs in the two species. In the crista acustica ofL. punctatissima a higher number of scolopidia is distributed in a smaller range than inP. griseoaptera; the scolopidia are especially concentrated in the distal part. Morphometrical analyses indicate that the dimensions of the spiracles, the acoustic trachea and the tympana determine the overall auditory sensitivity and that the arrangement of the scolopidia and the dimensions of structures in the crista acustica affect the frequency tuning of the hearing threshold.

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.

BACKGROUND: Secondary winglessness is a common phenomenon found among neopteran insects. With an estimated age of at least 140 million years, the cave crickets (Rhaphidophoridae) form the oldest exclusively wingless lineage within the long-horned grasshoppers (Ensifera). With respect to their morphology, cave crickets are generally considered to represent a `primitive' group of Ensifera, for which no apomorphic character has been reported so far. RESULTS: We present the first detailed investigation and description of the thoracic skeletal and muscular anatomy of the East Mediterranean cave cricket Troglophilus neglectus (Ensifera: Rhaphidophoridae). T. neglectus possesses sternopleural muscles that are not yet reported from other neopteran insects. Cave crickets in general exhibit some unique features with respect to their thoracic skeletal anatomy: an externally reduced prospinasternum, a narrow median sclerite situated between the meso- and metathorax, a star-shaped prospina, and a triramous metafurca. The thoracic muscle equipment of T. neglectus compared to that of the bush cricket Conocephalus maculatus (Ensifera: Tettigoniidae) and the house cricket Acheta domesticus (Ensifera: Gryllidae) reveals a number of potentially synapomorphic characters between these lineages. CONCLUSIONS: Based on the observed morphology we favor a closer relationship of Rhaphidophoridae to Tettigoniidae rather than to Gryllidae. In addition, the comparison of the thoracic morphology of T. neglectus to that of other wingless Polyneoptera allows reliable conclusions about anatomical adaptations correlated with secondary winglessness. The anatomy in apterous Ensifera, viz. the reduction of discrete direct and indirect flight muscles as well as the strengthening of specific leg muscles, largely resembles the condition found in wingless stick insects (Euphasmatodea), but is strikingly different from that of other related wingless insects, e.g. heel walkers (Mantophasmatodea), ice crawlers (Grylloblattodea), and certain grasshoppers (Caelifera). The composition of direct flight muscles largely follows similar patterns in winged respectively wingless species within major polyneopteran lineages, but it is highly heterogeneous between those lineages. Open-Access-Publikationsfonds 2016 peerReviewed

The Acari Laelaps nuttalli Hirst, Hypoaspis sp., Cheyletus cf. malaccensis Oudemans, Radfordia ensifera (Poppe), Listrophoroides cucullatus (Trouessart), Tyrophagus perniciosus Zachvatkin, and Hammerobates trisetosus Balogh and the louse Hoplopleura pacifica Ewing are reported from Rattus exulans (Peale) on the Tokelau Islands. These associations are discussed in relation to other records from the South Pacific region.

Two numerical taxonomic methods, including one that incorporates phylogenetic ideas and one which has a strictly phenetic approach, were applied to the evaluation of the affinities of the orthopteroid orders of insects. These methods were adapted to the special problems which arise when higher taxa are being compared. A total of 92 characters covering most of the internal and external anatomy served as the basis for the calculations, which indicated that similar diagrams of affinities were obtained, whether or not phylogenetic ideas were incorporated into the analysis. The stability of the pattern of affinities was such that repeating the analysis with a random sample of 30 characters instead of the full set of 92 entrained only trivial differences. Although the characters used in this study were qualitative, the extent to which existing multi- variate theory can be used in evaluating the results is stressed. Australian orthopteroids were mainly used for this experiment. A close relationship between the Australian Morabinae and the South American Proscopiidae was found. This group seems to have split off at an early stage from the stem of the Caelifera, which is distinct from the stem bearing the Ensifera. Another fairly close relationship revealed was that between the Phasmatodea and the Dermaptera. Attempts to reveal inconsistencies in the currently accepted taxonomic groupings suggested that the distinction between blattids and mantids within the Dictyoptera is of less than subordinal rank. The essential homogeneity of the orthopteroid orders is shown by the fact that even the most disparate groups share almost half the 92 characters.

Background The phylogeny of the Orthoptera was analyzed based on 6 datasets from 47 orthopteran mitochondrial genomes (mitogenomes). The phylogenetic signals in the mitogenomes were rigorously examined under analytical regimens of maximum likelihood (ML) and Bayesian inference (BI), along with how gene types and different partitioning schemes influenced the phylogenetic reconstruction within the Orthoptera. The monophyly of the Orthoptera and its two suborders (Caelifera and Ensifera) was consistently recovered in the analyses based on most of the datasets we selected, regardless of the optimality criteria. Results When the seven NADH dehydrogenase subunits were concatenated into a single alignment (NADH) and were analyzed; a near-identical topology to the traditional morphological analysis was recovered, especially for BI_NADH. In both the concatenated cytochrome oxidase (COX) subunits and COX + cytochrome b (Cyt b) datasets, the small extent of sequence divergence seemed to be helpful for resolving relationships among major Orthoptera lineages (between suborders or among superfamilies). The conserved and variable domains of ribosomal (r)RNAs performed poorly when respectively analyzed but provided signals at some taxonomic levels. Conclusions Our findings suggest that the best phylogenetic inferences can be made when moderately divergent nucleotide data from mitogenomes are analyzed, and that the NADH dataset was suited for studying orthopteran phylogenetic relationships at different taxonomic levels, which may have been due to the larger amount of DNA sequence data and the larger number of phylogenetically informative sites.