Livestock grazing is a key factor in many grassland ecosystems and can substantially influence the conservation of grassland species. The Crau steppe in southern France is a protected area that is traditionally grazed by sheep. The Critically Endangered Crau plain grasshopper Prionotropis rhodanica is endemic to the area and a flagship for the conservation of this unique ecosystem. Its population has declined significantly during the last 2 decades, but the reasons remain poorly understood. One potential factor is an altered habitat structure caused by changes in the grazing regime. We examined the microhabitat preferences of the species and compared the habitat structure of populated sites with those where the species is now extinct (former habitat). We found that populated sites had denser and higher vegetation, whereas former habitat had higher cover of stones and bare ground. Vegetation structure in the habitat of the smallest subpopulation was similar to areas of former habitat, suggesting a marginal habitat quality. Our results show that P. rhodanica requires 50–70% vegetation cover and suggest that grazing has contributed considerably to the population decline, but it remains unclear whether this is a direct effect of habitat degradation or an indirect effect by attracting predators associated with grazing activities. We recommend careful management of grazing to improve habitat quality, which would also benefit other invertebrates and insectivores. Continued monitoring is required to conserve habitat specialists in protected areas.

The bamboo grasshopper Ceracris fasciata is regarded as a major pest species because of the damage it causes to bamboo, and its classification within the families and subfamilies of the suborder Caelifera remains unclear. Thus, we attempted to resolve these questions using molecular biology methods and analyses. Our results are as follows: (1) the complete mitochondrial genome of C. fasciata is 15,569 bp in length. The mitochondrial genome contains 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. The putative start codon for the COX1 gene in C. fasciata is ACC, although it is not defined in other genes. The presence of tandem repeats of different sizes in the A + T-rich region may lead to size differences in other mitochondrial genomes. The mitochondrial genome of C. fasciata harbours the typical 37 genes and an A + T-rich region, and it shows similar characteristics to those of other grasshopper species. Characterization of the mitochondrial genome has enriched our knowledge of the mitochondrial genomes of Orthoptera around the world. Therefore, the phylogenetic relationships in Orthoptera can be re-examined. (2) In phylogenetic analyses, the monophyly of Orthoptera and its two suborders (Caelifera and Ensifera) has been consistently recovered based on most of the datasets selected, regardless of the optimal criteria. Our results do not support the monophyly of the subfamily Oedipodinae of Caelifera. We found that Phlaeoba albonema of the Acridinae is sorted into a clade with Ceracris in all our phylogenetic trees, and field experiments show that Phlaeoba always lives with Ceracris in the same ecotopes. Therefore, we suggest that Phlaeoba should be classified as a member of the Oedipodinae. We found that C. fasciata always clustered with Ceracris kiangsu, and both were sisters to Ceracris versicolor. Therefore, the genetic relationship between C. fasciata and C. kiangsu is closer than that between C. fasciata and C. versicolor. (3) The oldest estimated time of divergence of Ensifera in this context was determined to be 146.16 million years ago (Mya), or around the late Jurassic or early Cretaceous. We estimated that katydids (Grylloidea) likely diverged from other groups in the early Cretaceous. According to our divergence time analyses, we concluded that the ancestral Acrididae probably originated in the early Paleogene, and it is likely that the major diversification events happened at the middle Paleogene, well into the next geologic time. We estimated that crickets (Tettigoniidae) likely diverged from other groups in the early Cretaceous. Acrididae and Romaleinae group, Pyrgacrididae and Ommexechidae group, the youngest two clades we observed, were estimated to have diverged 58.79 Mya, between the middle and early Paleogene. C. versicolor is a sister to the group containing C. kiangsu and C. fasciata. First, C. versicolor diverged from the sister group (C. kiangsu + C. fasciata) around 44.81 Mya, and then the C. kiangsu and C. fasciata group separated at 43.04 Mya.

Chorthippus vagans is a common species of Gomphocerinae (Orthoptera) on the Iberian Peninsula. It is endangered in Central Europe where information about its ecological requirements is available; however, aspects of its biology are almost unknown in Mediterranean ecosystems, where it is widespread and common. The focus of this study was to determine how C. vagans adjusts its biology to environmental features of this ecosystem and to interpret how it may be affected by the ecological changes related to the re-vegetation programme linked to the construction of the Breña dam (SW Spain). The research parameters included the autoecology, feeding response and some aspects of reproduction of this species in the Southern Iberian Peninsula. To determine the local distribution and phenology of C. vagans, monthly samplings were conducted (2007–2010) in 12 sampling plots. For the food selection tests, ten nymphs and ten adults were placed individually in insectaries under controlled conditions. Grasses (Lolium sp.) and shrubs (Cistus sp.) were supplied ad libitum in two types of tests, monospecific and mixed diet. The reproductive biology was analysed by both observations of anatomical structures (integument, bristles, tibial spines, tarsal claws and mandibles) and ovarian dissections of 29 females and in laboratory rearing experiments with 15 pairs of adults. The results indicate that C. vagans shows an extended activity period which peaks at the end of summer. It is a polyphagous grasshopper, although adults show a slight preference for grasses. In addition, it is a univoltine species with spring–summer breeding activity.

Oxyspirura petrowi is a heteroxenous parasitic nematode that has been reported in high prevalences from birds in the Order Galliformes experiencing population declines in the USA. There is a paucity of information regarding the natural history O. petrowi, including the life cycle and effects of infection on wild bird populations. In order to study the life cycle of this parasite, we collected plains lubber grasshoppers (Brachystola magna) from a field location in Mitchell County, Texas. We found third-stage larvae (L3) in 37.9% (66/174) B. magna. We determined that they were O. petrowi through morphological comparison of L3 from experimentally infected Acheta domesticus and by sequence analysis. Then, we showed that B. magna are a potential intermediate hosts for O. petrowi infections in northern bobwhites (Colinus virginianus) in a laboratory setting by experimental infection. We first detected shedding of eggs in feces using a fecal float technique 52 days post infection. In addition, we recovered 87 O. petrowi from experimentally infected northern bobwhites. Although we detected shedding in feces, recovery of eggs was low (>5 eggs/g). Future work is needed to understand shedding routes and shedding patterns of northern bobwhites infected with O. petrowi.

Mangroves generally grow in nutrient-poor environments and maintain high levels of productivity through unique adaptations for nutrient conservation (Reef et al. 2010). One such adaptation in mangroves is highly efficient resorption of limiting nutrients from senescing leaves prior to abscission (Feller et al. 2003). Thus processes that lead to loss of foliage prior to senescence and nutrient resorption (e.g. storms and herbivory) can be detrimental to tree growth and productivity (Bryant et al. 1983, May & Killingbeck 1992). Furthermore, decomposition of fallen leaves by soil microbial communities (Alongi 1994, Holguin et al. 2001) and crabs (Nagelkerken et al. 2008) is another important process contributing to the recycling of nutrients that are in short supply. Therefore, processes that lead to a substantial reduction in litterfall can have a strong negative effect on nutrient cycling and forest productivity. Mangroves have long been recognized as an important source of organic carbon (both particulate and dissolved) for the surrounding tropical coastal ecosystems (Bouillon et al. 2008, Kristensen et al. 2008). Thus, processes affecting litterfall in mangroves can affect the surrounding marine food webs.

Grasshoppers host a number of parasitoids, but little is known about their impact on grasshopper life history attributes or how those impacts may vary with land use. Here, we report on a three-year survey of nine grasshopper species in a tallgrass prairie managed with fire and bison grazing treatments. We measured parasitoid prevalence and the impact of parasitoid infection on grasshopper fecundity to determine if grasshopper-parasitoid interactions varied with management treatment. Adult female grasshoppers were collected every three weeks from eight watersheds managed with different prescribed burning and grazing treatments. Grasshopper fecundity with and without parasitoids was estimated through dissections of reproductive tracts. Dipteran parasitoids from two families (Nemestrinidae and Tachinidae) were observed infecting grasshoppers. We found significant effects of grazing treatment, but not burn interval, on grasshopper-parasitoid interactions. Parasitoids were three times more abundant in watersheds with bison grazing than in ungrazed watersheds, and the relative abundance of nemestrinid and tachinid flies varied with grazing treatment. Parasitoid prevalence varied among grasshopper species from <0.01% infected (Mermiria bivittata) to 17% infected (Hypochlora alba). Parasitoid infection reduced individual grasshopper fecundity, with stronger effects on current reproduction than on past reproduction. Furthermore, current fecundity in parasitized grasshoppers was lower in grazed watersheds compared to ungrazed watersheds. Nemestrinid parasitoids generally had stronger impacts on grasshopper fecundity than tachinid parasitoids, the effects of which were more variable.

We investigate the degree of between-population genetic differentiation in the Mediterranean field cricket Gryllus bimaculatus, as well as the possible causes of such differentiation. Using cytochrome b mtDNA sequences, we estimate genetic variation in G. bimaculatus from seven South African and two Mediterranean populations. Within-population genetic variation in Europe (two haplotypes, one unique to a single individual) suggest low effective population size and strong bottlenecks with associated founder effects, probably due to cold winter environments in Europe that limit reproduction to a short part of the summer. The likely cause for this is the daily maxima in winter temperatures that fall below the critical level of 16°C (enabling normal calling and courtship behaviour) in Mediterranean Europe, whereas the equivalent temperatures in southern Africa are above this limit and enable reproduction over a large part of the year. European genetic variants were either shared with Africa or closely related to African haplotypes. For survival, European populations are probably dependent on immigration from other areas, including Africa. South African populations have low but measurable gene flow with Europe and show significant between-population genetic differentiation (30 haplotypes). Isolation-by-distance is not sufficient to explain the degree of between-population genetic differences observed, and a large degree of dispersal is also required in order to account for the observed patterns. Differences in morphology and calling behaviour among these populations are underlied by these genetic differences.

The present study provides comparative data on the types and microhabitats of animal prey captured by associating saddleback Saguinus fuscicollis and moustached Saguinus mystax tamarins. The main prey items were katydids (Tettigoniidae, Orthoptera), stick grasshoppers (Proscopiidae, Orthoptera) and spiders (Araneida), although lizards (Squamata) and frogs (Anura) were also taken. The tamarins foraged for, and captured prey from, significantly different substrates. This resulted in a significant partitioning of the prey spectrum between the two species. Sylvan katydids (Pseudophyllinae) accounted for most of the prey of both species, but the moustached tamarins captured more bush katydids (Phaneropterinae) than the saddlebacks. The degree of dietary overlap was less for animal prey than the plant-based portion of the tamarins' diet.

The historical account of the rise and fall of Nosema locustae as a biological control agent of grasshoppers has substantial implications for the successful development and implementation of biological control of migratory locusts in Africa. The potential of N. locustae was ultimately not sufficient to overcome a set of impediments, including: efficacy (the rate and extent of mortality were relatively low), target specificity (not all pest species were susceptible), formulation (wheat bran bait excluded feeding by some pests), cost (the price of the formulated product was excessive), storage (the organism lacked long-term stability), complex application (the pathogen and its carrier had to be applied during a narrow set of environmental and logistical parameters) and production (the use of an in vivo production system made high-volume production difficult). Some of the most significant limitations that led to the failure of N. locustae have been overcome by work on other pathogens, including the problems of formulation, storage, efficacy and production. However, at least four relevant lessons can be derived from the N. locustae story and applied to ongoing work with biological control of migratory locusts. First, the erratic population dynamics of acridids necessitates that the production, storage and distribution of an augmentative biological control agent will be driven by a boom-and-bust cycle. Second, the immense spatial scale and low unit value of the resources (rangelands) being protected create a unique set of logistical challenges. Third, the control of acridids involves the management of a native insect pest embedded within complex, native ecosystems, which suggests that our interventions should be undertaken with a great deal of caution, monitoring and, ultimately, humility. Fourth, although pathogens can be used as ‘bio-insecticides’, biological control requires education of end-users regarding a more sophisticated approach to pest management.

The development of a single cohort of the armoured ground cricket, Acanthoplus speiseri Brancsik was followed in the environs of the University of Zambia campus, Lusaka and a preliminary life table of the grain pest constructed. The pest's total generation mortality was influenced by: failed egg eclosion, failed ecdysis, cannibalism/predation and parasitism. The egg stage had the highest percent real mortality (98.57%) and sub-mortality k-value, indicating that this was the main contributor to the total generation mortality. The rest of the developmental stages suffered lower mortalities, although that of the 6th instar was comparatively higher. A mermithid nematode, Mermis sp., and another unidentified nematode species caused 2.61% sub-mortality in the 6th nymphal instar. The constructed preliminary life table of A. speiseri is analysed and the possible causes of the observed high mortalities in the egg and 6th instar stages are discussed.

The relationships between body size and host specificity were studied in leaf-chewing and sap-sucking insect communities, including 792 species, feeding locally on 15 species of Ficus in a lowland rain forest in Papua New Guinea. A negative correlation between body size and host specificity, i.e., the tendency for large species to feed on numerous Ficus hosts and those smaller to have a more restricted host range, was found within both the sap-sucking and the leaf-chewing community. A more detailed analysis, which divided herbivorous species into three sap-sucking and four leaf-chewing guilds, revealed that the correlation between body size and host specificity was caused by differences in these traits between the guilds, while no such correlation was detected within any of the guilds. As the changes in feeding mode, defining various guilds, were unique evolutionary events, it is uncertain whether there is a functional relationship between feeding mode, body size and host specificity, or whether their correlation is only coincidental. It is suggested that, in the sap-sucking community at least, the positive body size versus host specificity correlation is a coincidental by-product of the causal relationship between the feeding mode and both the body size and host specificity. The causes of analogous patterns in a leaf-chewing community require further investigation. Methodological problems in the analysis of tropical insect communities, dominated by rare species, are discussed.

The dispersal characteristics of a population of 124 marked adult individuals (62 males and 62 females) of the armoured ground cricket (AGC), Acantliophis speiseri Brancsik (Orthoptera: Tettigoniidae, Hetrodinae), released at the centre of a circular study site, were investigated using the capture-mark-release-recapture method for five successive days. The 110 m-diameter study site comprised five grass-trap annuii (each 1 m wide) spaced at 10-m intervals from the centre.

The frequency curve of numbers derived from recapture data for day 1 departed from normal (Kurtosis = 2.7), indicating that the released AGC population was heterogeneous in its dispersing behaviour. A comparison of mean numbers of recaptures from grass-traps per quarter portion of the study site revealed no drift in the dispersal of the population (P > 0.05), though differences in the variances of the recapture frequencies indicated a tendency towards non-random movement in the AGC population.

The population covered a mean distance of 24.47 m in the first 24 h following release and the rate of dispersal changed daily in the five-day study. The implications of the dispersal characteristics observed in this study to future design of control strategies for the pest in Zambia are discussed.

Acanthoplus speiseri Brancsik, a pest of grain crops in Zambia, was reared in the laboratory at different temperatures. Mean development times of the eggs, nymphs and adults were determined at the different temperatures and used to develop a thermal unit model for use by farmers to predict the appearance dates of the different nymphal instars and the adults in the field in a given season. The predictions generated by the developed model for the 1990/1991 season, were compared to the actual dates on which the first specimen of each developmental stage was collected in the field during the season. The predicted dates of appearance all fell within 1 week of the observed dates of collection. Reasons for the slight deviations between the predicted and observed dates and the significance of the developed thermal unit model to the future control of A. speiseri in Zambia, are discussed.

Food plant preferences and spatial dispersion patterns of the armoured ground cricket, A canthoplus speiseri Brancsik were investigated. The average numbers of the ground cricket found feeding on each food plant per transect in each of the three study areas were tested for differences at the 0.05 level of probability by Duncan's multiple range test. The variance/mean ratio was used to analyse spatial dispersion patterns. A. speiseri fed on 12 plant species from the Compositeae, Gramineae and Solanaceae families. Hyparrhenia nyassae (Rendle) Stapf., (Gramineae) and Rottboelia exaltata Linn, f., (Gramineae), were the most preferred food plants. The armoured ground cricket densities on the two food plants were insignificantly different from each other. The cultivated plants, Zea mays L., and Sorghum vulgare Pers., were fed upon opportunistically by the ground crickets. The variance/mean ratio identified aggregation in the armoured ground cricket populations in all three study areas . The significance of the findings on food plant preferences and dispersion patterns are discussed in relation to future sampling and control of A. speiseri.

Spatial dispersion patterns of Acanthoplus speiseri were inestigated. Four indices of dispersion derived from either Iwao's measure or Taylor's Power Law were used to study spatial dispersion patterns. All indices were in agreement in identifying aggregated dispersion patterns in the cricket populations sampled. Iwao's index of basic contagion revealed that individual crickets formed the basic components in the aggregated dispersion of the populations.

Consumption indices and apparent digestibility are measured for seven species of grasshoppers from Lamto (Ivory Coast), representative of different trophic specialization steps (Le Gall and Gillon, 1989), The consumption indices vary from 0.11 to 0.34 and the apparent digestibility from 30 to 65%. Specialists are not more efficient on their host plant than are generalists on convenient host plants, but some specialists fed on plants which are not convenient for generalists. Anthermus granosus and Eucoptacra spathulacauda feeding on Lippia multiflora is not convenient for a generalist like Eucoptera anguliflava. If feeding efficiency does not seem to be a real selective pressure, it can be an important step in specialization processes, when there is an adaptation to an unusable host plant for polyphagous species.

Differences in the constitution of plant parts eaten by the grasshopper play an important role in the digestibility. The differences in the efficiency observed between the two specialists of Lippia are from their differences in feeding behaviour.

DNA replication in the spermatogonial cells of Schistocerca gregaria and Gryllotalpa fossor has been analysed. This study has demonstrated the presence of at least two discrete populations of spermatogonial cells in both the insects with different intermitotic timings. The replication pattern of the sex chromosome in Schistocerca seems to be dependent on the pycnosity status, whereas, in Gryllotalpa, it is independent of the condensation pattern.