The history of the study of orthopteran chromosomes is coincident with the formulation of the chromosome theory of heredity and the rediscovery of Mendel's laws, thus with the birth of cytogenetics. We review the early contributions of grasshopper chromosomes to the chromosome theory the understanding of sex chromosomes, the phenomena of mitosis, meiosis, linkage, crossing over and recombination, the problems of chiasma localization and terminalization, reproduction and parthenogenesis, the nature and behavior of B chromosomes and supernumerary segments, and the role of chromosomal rearrangements in microevolution and speciation. We also discuss the influence of early works on later research, and emphasize the fundamental contributions of Michael J. D.White to modern cytogenetics and evolutionary biology in general.

We analyse here three components of reproductive success (egg fertility, egg clutch size and embryo clutch size) in several temporal samples from different Spanish and Moroccan populations of the grasshopper Eyprepocnemis plorans. The analysis of spatial and temporal variation suggests that egg clutch size, but neither embryo clutch size nor egg fertility depends significantly on both year of sampling and population of origin. While the former effect could mainly be due to year-to-year variation in food availability (essential to egg production but not to hatching success), the spatial variation may also include population-dependent genetic factors. We also tested the effect of the presence of supernumerary (B) chromosomes carried by many individuals in most natural populations of this species. We found a slight but significant decrease in egg fertility associated with the presence of B chromosomes. We discuss possible causes of the observed variation for these three reproductive traits at both spatial and temporal levels, as well as the effect of B-chromosome presence as a parasitic element disturbing reproduction of carrier females.

Chorthippus parallelus parallelus (Cpp) and Chorthippus parallelus erythropus (Cpe) are two grasshopper subspecies whose distributions overlap in the Pyrenees, where they form a hybrid zone at those points where the topography and their ecological requirements allow. This hybrid zone is a consequence of secondary contact between endemic Iberian (Cpe) and continental European populations (Cpp) that expanded after the most recent glaciations from the refugia in which they had diverged genetically in allopatry.

The morphological, physiological, genetic and behavioral differences between these subspecies (and their natural and laboratory-reared hybrids) have been intensively studied in recent years, for which reason this hybrid zone is considered a singular model in evolutionary biology. These studies reveal a complex pattern of factors involved in the origin, structure and maintenance of the hybrid zone. They offer an excellent panorama of evolution “in action”.

Wolbachia is a genus of obligate endosymbiont bacteria that induce changes in the reproduction of arthropods and nematodes. In previous studies we have reported the existence of these bacteria in individuals and populations of Chorthippus parallelus. Now we show that they produce a significant reproductive barrier in this hybrid zone, implying, as proposed elsewhere, that Wolbachia may be involved in speciation phenomena.

We review historical and pioneering work as well as recently published papers about orthopteran sex chromosomes and neo-sex mechanisms, highlighting Michael White's significant contributions. Meiotic research in Orthoptera in the early twentieth century was central to confirming that sex determination had a chromosomal basis: the study of sex chromosomes produced fundamental support to the chromosome theory of heredity. We also explore recent theoretical models of sex-chromosome evolution and consider the possible causes of crossing over restriction in proto-sex chromosomes, as well as the progressive differentiation (erosion and degeneration) of the Y chromosome in neo-chromosome systems in different taxa. We discuss neo-XY and neo-X₁X₂Y chromosome systems of South American Melanoplinae (Acrididae) as potential experimental models to study steps in sex-chromosome evolution because these systems fall within a continuum of evolutionary stages, some of them recently established. We also provide an explanation for the disproportionate frequency of neo-sex systems and Robertsonian-derived karyotypes in Neotropical Melanoplinae, based on the centromeric drive theory, and propose that Neotropical melanoplines' high karyotypic diversity supports an ancient South American origin of the subfamily. We discuss the hypothesis that neo-sex chromosome systems produce favorable new linkage relationships between genes in the X and the involved autosome, some of which could be sex determination related, creating a new balance between sex chromosomes and autosomes. We also review Mesa's hypothesis that, based on the observed fact that no major taxon of orthopterans shows neo-sex chromosomal mechanisms in all their species, the acquisition of a neo-sex chromosome system could condemn species of grasshoppers to a short evolutionary career. Little is yet known about the role of neo-Y chromosomes in Orthoptera, thus mostly speculative explanations about neo-sex chromosome function can be made at present. New studies with modern molecular techniques are needed to understand chromosomal sex determination in Orthoptera, which could in turn help explain the role of new chromosomal sex systems in grasshopper species.

All four species of the genus Dichromatos now cytologically analyzed, including D. montanus and D. corupa (Cigliano 2007), studied in the present paper, are 2n = 21(♂)/22(—) (FN = 23/24) with a X₁X₂Y ♂ / X₁X₁X₂X₂ ♀ sex-determination mechanism. The possibility that this mechanism arose from a single ancestral species from which a rapid process of speciation and dispersion took place is discussed.

Scaphura nigra has a unique chromosome complement among approximately 100 species studied so far belonging to the subfamily Phaneropterinae. It is formed by 2n (♂) = 26 and a FN = 29 and derived from the ancestral karyotype of the group 2n (♂) = 31, FN = 31, by means of two centric fusions and one tandem fusion. The first between the X chromosome and a medium-sized autosome giving rise to a neo-XY sex chromosome mechanism of recent origin, and the second between two acrocentric ones, the bigger and a medium size, that gave rise to a large submetacentric element whose length is very uncommon in the subfamily This process has created a bimodal karyotype that contrasts with the majority in this group, whose chromosomes usually can be arranged in a decreasing order of size. A third rearrangement incorporating the chromatin of a medium-sized autosome to the bigger one, explains the reduction observed in the number of chromosomes and the enlarged size of the submetacentric elements. These features demonstrate the effectiveness of chromosome number, their morphology and the change of the sex mechanism as useful tools for taxonomy.

This contribution briefly reviews the importance of grasshopper chromosomes in evolutionary studies and in achieving a comprehensive view of cytogenetics, emphasizing that meiotic chromosomes have been the traditional means for analyzing the nature of such problems. Structural changes occurring in the sperm, as a direct consequence of some chromosomal changes, have received less attention. We propose that grasshopper sperm could be a good model for the study of: 1) aspects of genome territoriality, and 2) consequences in the sperm DNA molecule, derived from a compromised meiotic process, linked with naturally forced genome hybridization. The results presented here, by using appropriate DNA probes for genome regionalization, allow the proposal of a grasshopper sperm chromosome organization. Centromere regions are distributed and concentrated at the proximal end of the sperm head where the flagellum is inserted. Also, chromosome arms are longitudinally organized from the proximal to the distal end, where the telomere of the longest autosome is the most distant genome region from the flagellum insertion. Subsequently, and because the length of the chromosome arms is different among nonhomologous chromosomes, the telomeres are distributed along the length of the sperm head. Sperm DNA quality was analyzed using the sperm chromatin-dispersion test, demonstrating that in sperm nuclei of early spermatids containing fragmented DNA, there exist large haloes of dispersed chromatin, while those nuclei remaining compact, contain an intact DNA molecule. Interestingly, and as a main difference with respect to other analyzed species, the DNA loops remain attached to a central proteic core. The aforementioned observation is clearly visible in partially elongated spermatozoa and the DNA loops forming the halo expand from this central region. This aspect of sperm chromatin organization found in grasshoppers is a new contribution to orthopterology. Further, it provides a unique insight and allows questioning the possible existence of this kind of chromatin organization in other noninsect species, where reproduction is based on gamete production.

In the past few years large-scale genome sequencing has demonstrated that inversion rearrangements are more frequent than initially hypothesized. Many examples suggest they may have played an important function in delineating the evolution of biodiversity. In particular, clinal patterns of variation for this type of rearrangement point out its significance in relation to the evolution and adaptation of organisms to changing environments. Within grasshoppers, Trimerotropis and Circotettix show high incidence of inversion rearrangements, either in fixed or polymorphic state, according to which several hypotheses about phylogenetic relationships have been proposed. Herewith we review the evolutionary significance of inversions in Trimerotropis pallidipennis, whose South American populations show clinal variation for pericentric inversions along environmental gradients. We report a new phylogeographic analysis that includes populations of this species from North and South America, and also other species of Trimerotropis and Circotettix. This study was performed in order to gain further insights into the phylogenetic relationships of this group of species, the dispersion routes followed by T. pallidipennis in South America and the evolutionary significance of inversion clines.

Dichroplus elongatus is a South American grasshopper that shows simultaneous polymorphisms for B chromosomes and several supernumerary segments located in chromosome pairs S10, S9, and M6 (SS10, SS9 and SS6 respectively), in natural populations from Argentina. Heterochromatin characterization with DAPI-CMA₃ banding reveals that B chromosomes show an interstitial GC-rich band. The distal SS10 segment seems to also be GC-rich, whereas the proximal supernumerary segments (SS6 and SS9) show two different heterochromatin regions: one GC-rich region (CMA₃ /DAPI-) and the other that has no specificity to AT or CG base pairs (CMA₃/DAPI dull). The results obtained permit us to distinguish two types of constitutive heterochromatin in the supernumerary segments of D. elongatus. The variation in the frequency of these chromosome polymorphisms was analysed with respect to some climatic and geographic variables. There is considerable B chromosome variation between populations, and this variation correlates negatively with latitude and positively with altitude and mean annual temperature. The incidence of the proximal SS9 segment is positively correlated with altitude. The pattern of chromosome variation is discussed in relation to the population's ability to maintain supernumerary DNA in more climatically favorable geographic regions.

The present study is a sincere tribute from some of the cytogenetic laboratories of Madrid involved in the study of grasshopper meiosis, for the inestimable contribution of Professor Michael J.D. White to orthopteran cytogenetics, on the 100th anniversary of his birth. Here we review the knowledge accumulated over almost 90 y on the meiosis of the grasshopper Stethophyma grossum, especially on the male side, because of the very unusual meiotic characteristics shown by the spermatocytes, namely: whereas the three shortest bivalents achieve full synapsis and do not show chiasma localization and the single X chromosome remains asynapsed, the remaining eight bivalents show restricted synapsis and proximal chiasma localization. In addition, supernumerary segments and accessory chromosomes are present in some natural populations. Special attention is paid to the relationships among cohesin axis morphogenesis, initiation of recombination events and synapsis achievement.

Huastecacris alexandri n. sp., is described from the El Cielo Biosphere Reserve in southern Tamaulipas, northeastern México. Geographic distribution is limited to the highlands of the reserve where it occurs from 1300 to 1700 m in open areas on natural, low vegetation. This species is most related to Huastecacris zenoni Fontana & Buzzetti 2007, which is found in the lowlands of the reserve, extending the distribution of the genus along the Eastern Sierra Madre up to Cd. Victoria's mountain range. The species are distinguished by details of the male cerci, supra-anal plate, genitalia and color pattern.

Melanoplus packardii Scudder was described in 1897. Three additional closely-related species were later described and their status as species has been questioned on numerous occasions. We examined morphology from specimens collected in Nebraska which fit descriptions of three of the four forms and specimens that appeared to be hybrids. We found distinct morphological characters suggesting species status for M. foedus and M. packardii, but not for M. foedus fluviatilis. Examination of aedeagi of these three forms suggests that M. foedus and M. packardii are each distinct, but that the aedeagi of M. f. fluviatilis and M. f. foedus cannot be distinguished. Molecular analyses of the three groups did not produce clear separations and suggest gene exchange between these three forms may be ongoing. Together, these data suggest that M. foedus and M. packardii should be recognized as sibling species, but M. foedus fluviatilis is best considered a form of M. foedus, typically found in low lying areas.

Pterodichopetala cieloi cieloil n. gen. n. sp. from Mexico is here described. The song of the male is outlined and affinities with the genera Dichopetala Brunner v. W., 1878 and Marenestha Brunner v. W., 1878 discussed.

The relationship between species-richness of Orthoptera and remotely sensed land cover was investigated at a grain size of 100 km² within an area of 9,900 km² in central southern England, using species data extracted from county and national atlases. Gradients in landscape composition, identified using multivariate ordination, reflected agricultural intensification (associated with increasing acreage of arable crops) and urbanisation. The number of species declined as the area under arable crops increased, yet even in the most agriculturally intensive grid-squares there appeared to be sufficient nonarable land to support all species. A range of factors such as fragmentation and degradation of nonarable habitats may become more important as the area of cropped land increases. Investigation at greater spatial resolution is needed to confirm this hypothesis. No relationship was found between species richness and urbanisation, but it was concluded that the extent of urban development was too limited to enable detailed investigation of this phenomena. The study demonstrates that coarse-grained species data within county and national atlases, combined with remotely-sensed land cover data, can be useful in detecting and interpreting spatial variation in orthopteran species diversity at the regional scale. The relationship between species richness and land cover quantifies past human impacts and suggests the approach may be useful for monitoring and interpreting future changes.

The Mormon cricket (Anabrus simplex Haldeman) (Orthoptera: Tettigoniidae) is a historic pest on millions of acres in the western US. During outbreak years, annual losses attributed to it have amounted to millions of dollars. Nonchemical controls are needed for environmentally sensitive areas — an increasing concern. Myco-insecticides are available but show an unpredictable and unexplainable lack of effect on Mormon crickets. This research sought to understand performance of Beauveria bassiana and Metarhizium brunneum under field conditions, compared to studies showing excellent performance under laboratory conditions. Our objectives were: (1) to evaluate B. bassiana GHA and M. brunneum F52 for potential use against Mormon crickets; (2) to compare spray and bait formulations of each fungus against immature and adult Mormon crickets; and (3) to understand the effect of Mormon-cricket body temperatures on the speed of efficacy by the two fungi. No mortality of 3^rd-instar Mormon crickets was detected in the field 14 d after treatment with fungal baits or sprays of either B. bassiana Strain GHA or M. brunneum Strain F52. Unexpected bait aversion may have adversely affected the success of the bait treatments. Lack of spray efficacy was also unexpected, given the laboratory infectivity of both fungi for the Mormon cricket. Possible body temperatures were estimated by thermal surrogates located on the ground and in the plant canopy within field cages. Surrogate temperatures below 18°C, as well as above 30°C, were common during the study. When cumulative amount of time at temperatures optimal for fungal growth (18 to 30°C) was calculated for the duration of the post-treatment observation period, there was an insufficient number of fungal growth hours to produce mortality within the 14-d post-treatment period. Our data suggest that at least 32 to 43 d (M. brunneum) or 58 to 75 d (B. bassiana) should have been required for insect mortality to occur under the conditions of the test. In a second test, targeting seventh-instar nymphs and adults, the in-field mortality was not followed, but treated individuals were incubated both indoors and in outdoor cages. Infections by B. bassiana and M. brunneum in the indoor-incubated insects caused 69 and 100% mortality (corrected for untreated controls) respectively, with 71 and 80% mycosis in cadavers. Mormon crickets in outdoor cages succumbed to unexpected high temperatures. Our data illustrate the importance of Mormon cricket body temperatures and their effects on fungal infection. Because physical location and thermoregulation may alter the environ inside the insect, at least a month may be required after treatment for infections by B. bassiana GHA and M. brunneum F52 to cause mortality. Future studies should take this longer observational time into account. There is some potential for faster fungal growth in Mormon crickets under natural conditions, as opposed to our experimental cages, particularly in the immature stages. Mormon crickets aggregate in sheltered locations under inclement weather and at night. This behavior may conserve and actually promote body temperatures more favorable to fungal development. The potential value of this aspect of Mormon cricket behavior will require additional study.

Insects of mesic and hydric habitats may be affected by increased frequency of summer droughts brought about by climate change, in addition to habitat degradation caused by scrub encroachment. The common green grasshopper Omocestus viridulus prefers moist grassland and is relatively rare in the County of Essex, perhaps being limited by low precipitation in southeastern England. The abundance and distribution of O. viridulus populations were compared for high- (Epping Forest) and low-precipitation areas using Geographic Information Systems (GIS) software. Populations were aggregated in Epping Forest (population isolation: 1 km), a high precipitation area (ca 69 cm precipitation/yr), and present on both well and poorly drained soils where acid grassland/wet heathland occurred. Outside of the Forest, where precipitation was generally lower (ca 58 cm/yr), populations of this grasshopper were highly isolated (isolation: 4 km) and more often present on clay soils with high water retention in winter/early summer than on well-drained soils. However, there was no significant difference in the abundance of this grasshopper within Epping Forest or outside it, and there has likely been an overall decline of 50% since 1997 for this insect in Essex Co.

The decline has partly occurred due to unmanaged scrub encroachment and loss of favorable open grassland/wet heathland habitat. Intensive grazing (particularly by large numbers of rabbits Oryctoloagus cuniculus), regular mowing, and trampling by walkers, led to the creation of short swards (< 10 cm in height) in midsummer, effectively extirpating this tall-grassland grasshopper from many of its former sites not threatened by natural succession to woodland.

Unfortunately, the predicted decline in summer rainfall may lead to this grasshopper becoming scarce in southeastern England, outside of relatively high precipitation areas such as Epping Forest. Given concern about this grasshopper it may be important to prevent further drainage of ecologically valuable wetlands and to promote appropriate conservation management of the remaining sites (such as cattle grazing in Epping Forest). Large-scale wetland creation should allow populations of this declining grasshopper to exist in a changing climate.

Azadirachtin prolonged the incubation period and reduced hatchability of desert locust eggs. Many embryos suffered morphological deformation of the compound eyes and legs and incomplete development of abdominal segments. Histologically the brain was poorly developed, this being reflected in the compound eyes, neurosecretory cells and entire ventral nerve cord. The embryonic cuticle was insufficiently deposited. The electrophoretic mobilities of the egg proteins after the addition of 200 ppm of azadirachtin were characterized by SDS-PAGE analysis and revealed the appearance of new protein bands and the disappearance of others. We conclude that after suitable field trials, the use of azadirachtin may be a viable alternative to chemical insecticides for control of grasshoppers in Egypt.

We reared Baeacris punctulatus (Orthoptera: Acrididae) in cages under seminatural conditions in Cuiabá, Mato Grosso, Brazil. Five nymphal instars were recorded. One generation required ∼ 82 d (24 d egg stage 43 d nymphal development 15 d preoviposition period). Colony females laid ∼ 4.4 egg pods during their ∼ 30-d adult life. Pods contained ∼ 13 eggs, and most eggs hatched, giving ∼ 56 offspring per female. Survival during the nymphal stage was 38.9%, with highest mortality in 4^th–5^th instars. Average and maximum lifespans from hatch to adult death were 73 and 80 d, respectively. Field sampling in Campo Novo do Parecis and Parecis Plateau regions of Brazil showed that adults and older nymphs were present in all months of the year, but that oviposition and young nymphs were scarce during the dry-cool months of May to mid-August. Overall, our study suggests that in the State of Mato Grosso, there are 3.9 to 5.1 generations per year. The various instars could be differentiated by the number of antennal segments, body size, and shape and size of wing pads. Annual and regional variation in temperature and moisture may influence the life history and population dynamics of B. punctulatus.

Melanoplus ingrami n. sp. is described from the cedar glades of central Tennessee.

This article describes the acoustic characters of Copiphora gorgonensis, a new species endemic to Gorgona Island National Park, Colombia. It is closely related to C. brevicauda, a congener distributed in the Pacific rainforest of Ecuador and Colombia, and also reported in Central America and other countries of northern South America. Here we provide diagnostic characters for identification; we study the mechanics of stridulation using laser vibrometry and optical motion detectors. Distinguishing features include: the highly tonal song of males with a carrier frequency peaking at 23 kHz; pulses repeated with a high rate of nearly 50/s and wing motion exhibiting a typical subsinusoidal pattern, as has been described for other Copiphorini. The natural frequency of the right forewing is close to that of the calling song and the wing-motion patterns indicate that sound vibrations are the result of sustained tooth impacts, corresponding to the natural frequency of wing vibration, i.e., the tonal characteristic of the calling song in this species is the result of resonant stridulation. This resonance, and the amplitude component of the song, are attributed to the mirror frame and its surrounding cells and veins. These results are contrasted and discussed in regard to published literature on tettigoniid stridulation.

We present a first preliminary molecular analysis of relationships among a sample of living members of the Gryllotalpidae, based on partial nucleotide sequence data of the 16S mitochondrial gene. Our analysis defines five groups that diverged from each other approximately 196 to 284 Mya in the Mesozoic era. This study supports the monophyly of the genus Scapteriscus and its placement in the subfamily Scapteriscinae, as well as the inclusion of the genus Triamescaptor in the subfamily Gryllotalpinae. The monophyly of the large genus Gryllotalpa is not supported, suggesting a revision of the genus is needed.

Recent palaeo-oceanographic work (Ali & Huber 1910) shows that strong surface currents existed from the East Africa coast to Madagascar and beyond in the Palaeogene, making the rafting of masses of African vegetation possible during this period. Source Euschmidtiinae are common on the East African coast. The only African relative of the Miraculinae is the chorotypid genus Hemierianthus of West and Central Africa. This leads to the hypothesis that the Miraculinae are closer to the Chorotypidae than to the Episactidae, as suggested by Descamps (1973), which is testable by molecular systematic methods.

The effect of DIMILIN 25 WP, the common name of diflubenzuron, was first examined on the weight of ovaries and on the weight of eggs laid by females of Schistocerca gregaria. Treatment was made 24h earlier by ingestion at 30 mg/ml. DFB reduces the weight of ovaries at 8, 12 and 16 days, compared to control series of the same age. Moreover, the insecticidal treatment causes a significant reduction in the weight of eggs laid.

DFB action on ecdysteroid levels in ovaries and in eggs in females was also evaluated. The compound reduced ovarian ecdysteroid titres of the first ovarian cycle.

In laid eggs of S. gregaria females, we measured ecdysteroid content before and after enzymatic hydrolysis, to compare free and conjugated ecdysteroids in both control eggs and after DFB treatment during embryonic development. DFB significantly reduced the levels of both free and conjugated ecdysteroids compared to the control.

Oecanthus alexanderi n. sp. Walker occurs in the lower Rio Grande valley of Texas and in Mexico as far south and west as Michoacan. Its song and morphology establish it as a member of the Oecanthus rileyi species group. Other members of this group of New World species include O. rileyi Baker, O. allardi Walker & Gurney, and O. fultoni Walker. Calling songs of the rileyi group consist of chirps or brief trills in which trios of pulses are produced in such rapid succession as to be indistinguishable to the human ear. The chirps/trills are easily countable and have a highly regular rate that varies linearly with temperature. Extrapolated regression lines tend to converge at 4°C and an expected chirp rate of O. Because of these relations, simple formulas can convert counts of chirps vs time into surprisingly close approximations of ambient temperature—justifying the group's designation as “thermometer crickets”.

Grasshoppers are thought to be herbivores that primarily feed on plant leaves. But, many grasshopper species actually are omnivorous and will consume a wide range of living and dead organic matter. We documented the feeding behavior of the Western Lubber grasshopper, Taeniopoda eques, on a coyote, Canis latrans, carcass in Arizona, USA. The number of adult T. eques on the carcass ranged from 1 to 8 during each of six visits to the site and were predominantly female. Nymphs were not observed on or immediately adjacent to the carcass, although they were present in low numbers in the surrounding population. We observed females attempt to consume hair, dried hide, and especially dried tissue adhering to the bones. Our observation that most of the individuals feeding on the carcass were female, suggests that egg production requires nutrients that may make vertebrate carrion a complement to a herbivorous diet. T. eques lives in a desert habitat with a short and highly variable growing season, so carnivory/necrophagy may be adaptive by providing essential nutrients, thereby speeding oocyte maturation and increasing the likelihood that females will be able to develop and lay eggs before the onset of winter.

The identity of the subspecies Megacrinia batesi speiseri Carl, 1915 (Carl spelled batesii as batesi in error) from Malo, New Hebrides is clarified. Carl's subspecies is elevated to the species Megacrania speiseri Carl, 1915 and morphological characters are redescribed with measurements. A key of the genus Megacrania is provided.