Interspecific competition among grasshoppers and their effect on plant abundance in experimental field environments

Summary We tested whether grasshoppers in experimental field environments, i.e. cages (40×40 cm) placed on existing old field vegetation, (1) were limited in density by plant abundance and/or nitrogen content, (2) exhibited interspecific competition, and (3) altered the relative abundance of different plant species. We examined interactions among a pair of early season grasshopper species (May–June; Arphia conspersa and Pardalophora apiculata) and a late season pair (July–August; Melanoplus femur-rubrum and Melanoplus bivittatus). Each grasshopper species was placed in cages by itself and with another grasshopper species. Grasshoppers generally survived at higher density in fertilized cages and they reduced plant abundance relative to empty cages, suggesting that grasshoppers may be food limited at these densities. In unfertilized plots, early season grasshoppers preferred grasses (Schizachyrium scoparium and Poa pratensis) and favored the growth of forbs (especially Solidago spp.). However, late in summer, Melanoplus spp. preferred Solidago spp. and favored the growth of grasses.The pattern of grasshopper survivorship and plant reduction within these experimental environments provide preliminary support for some of the predictions of resource competition theory. Grasshoppers exhibited interspecific competition only if they significantly reduced plant biomass. If two species competed, a grasshopper species was eliminated only if the superior competitor, when living by itself, could reduce plant biomass to a significantly lower level than the inferior competitor. Competitors persisted only if they did not differ in their ability to reduce plant biomass or reduced the abundance of different plant species.     

Effects of large herbivore grazing on grasshopper behaviour and abundance in a meadow steppe

1. Adaptive phenotypic plasticity has been a major subject in evolutionary ecology, but how a species' behaviour may respond to certain environmental change is still not clear. In grasslands worldwide, large herbivores are increasingly used as a tool for grazing management, and occur to interact with grasshoppers that dominate grassland insect communities. Previous studies have been well-documented about grazing effects on diversity and abundance of grasshoppers. Yet, how grazing may alter grasshopper behaviour, and potential effects on their abundance remains elusive. 2. We conducted a field experiment by manipulating grazing using sheep, cattle, and their mix to examine the behavioural responses and abundance of the grasshoppers (Euchorthippus unicolor) to grazing in a Leymus chinensis-dominated grassland. 3. Results showed that the grasshoppers spent less time on feeding and resting on grasses, but more time on switching and resting on forbs under cattle grazing and mixed grazing with cattle and sheep. In contrast, the grasshoppers spent more time on feeding but less time on switching and resting on forbs under sheep grazing. The behavioural changes were also potentially linked to grasshopper abundance in the context of grazing management. 4. The responses of grasshopper behaviour and abundance to grazing may be largely triggered by altered vegetation and microclimates. Such behavioural flexibility of grasshoppers must be considered when large herbivores are recognised as a management tool for influencing grasshopper abundance, and grazer species should be paid more attention both individually and jointly for better grassland conservation.     

Grasshoppers efficiently process C4 grass leaf tissues: implications for patterns of host-plant utilization

Leaf‐chewing insects are commonly believed to be unable to crush the nutrient‐rich bundle sheath cells (BSC) of C₄ grasses. This physical constraint on digestion is thought to reduce the nutritional quality of these grasses substantially. However, recent evidence suggests that BSC are digested by grasshoppers. To directly assess the ability of grasshoppers to digest C₄ grass BSC, leaf particles of Bouteloua curtipendula (Poaceae) were examined from the digestive tracts of two grasshopper species: Camnula pellucida (Scudder) (primarily a grass feeder) and Melanoplus sanguinipes (Fabricius) (a forb and grass generalist) (Orthoptera: Acrididae). Transmission electron microscopy was used to make the first observations of BSC crushing by herbivorous insects. Camnula pellucida and M. sanguinipes crushed over 58% and 24%, respectively, of the BSC in ingested leaf tissues. In addition, chloroplast and cell membranes were commonly disrupted in uncrushed BSC, permitting soluble nutrients to be extracted, even when BSC walls remain intact. The greater efficiency with which C. pellucida crushes BSC is consistent with the idea that grass‐feeding species are better adapted for handling grass leaf tissues than are generalist species. By demonstrating the effectiveness with which the BSC of B. curtipendula can be crushed and extracted by both species of grasshoppers, this study suggests one reason why C₄ grasses are not generally avoided by grasshoppers: at least some C₄ grasses can be more easily digested than has been hypothesized.     

Molecular evidence for hybridization between invasive <Emphasis Type="Italic">Solidago canadensis</Emphasis> and native <Emphasis Type="Italic">S</Emphasis>. <Emphasis Type="Italic">virgaurea</Emphasis>

Hybridization between alien and native species is biologically very important and could lead to genetic erosion of native taxa. Solidago × niederederi was discovered over a century ago in Austria and described by Khek as a natural hybrid between the alien (nowadays regarded also as invasive) S. canadensis and native S. virgaurea. Although interspecific hybridization in the genus Solidago is considered to be relatively common, hybrid nature of S. × niederederi has not been independently proven using molecular tools, to date. Because proper identification of the parentage for the hybrid Solidago individuals solely based on morphological features can be misleading, in this paper we report an additive polymorphism pattern expressed in the ITS sequences obtained from individuals representing S. × niederederi, and confirm the previous hypothesis that the parental species of this hybrid are S. canadensis and S. virgaurea. Additionally, based on variability at the cpDNA rpl32-trnL locus, we showed that in natural populations hybridization occurs in both directions.     

Differential herbivory on C3 versus C4 grasses by the grasshopper Ageneotettix deorum (Orthoptera: acrididae)

Summary The hypothesis that graminivorous grasshoppers select C₃ grasses over C₄ grasses was tested with experiments in the field. It was found that the generalist, graminivorous grasshopper Ageneotettix deorum typically chooses C₃ as opposed to C₄ grasses when both types are equally available. This preference is attributed to the differences in leaf anatomies of C₃ and C₄ plants since crude protein, water, lignin, fiber, and silicon content or the size of the individual leaves tested do not explain the observed feeding pattern. However, examination of the actual food plant selection of actual field inhabiting grasshoppers indicates that food plant prefernce may only be a minor component of food selection in natural settings.     

Leaf age dependent changes in within-canopy variation in leaf functional traits: a meta-analysis

Within-canopy variation in leaf structural and photosynthetic characteristics is a major means by which whole canopy photosynthesis is maximized at given total canopy nitrogen. As key acclimatory modifications, leaf nitrogen content (N _A) and photosynthetic capacity (A _A) per unit area increase with increasing light availability in the canopy and these increases are associated with increases in leaf dry mass per unit area (M _A) and/or nitrogen content per dry mass and/or allocation. However, leaf functional characteristics change with increasing leaf age during leaf development and aging, but the importance of these alterations for within-canopy trait gradients is unknown. I conducted a meta-analysis based on 71 canopies that were sampled at different time periods or, in evergreens, included measurements for different-aged leaves to understand how within-canopy variations in leaf traits (trait plasticity) depend on leaf age. The analysis demonstrated that in evergreen woody species, M _A and N _A plasticity decreased with increasing leaf age, but the change in A _A plasticity was less suggesting a certain re-acclimation of A _A to altered light. In deciduous woody species, M _A and N _A gradients in flush-type species increased during leaf development and were almost invariable through the rest of the season, while in continuously leaf-forming species, the trait gradients increased constantly with increasing leaf age. In forbs, N _A plasticity increased, while in grasses, N _A plasticity decreased with increasing leaf age, reflecting life form differences in age-dependent changes in light availability and in nitrogen resorption for growth of generative organs. Although more work is needed to improve the coverage of age-dependent plasticity changes in some plant life forms, I argue that the age-dependent variation in trait plasticity uncovered in this study is large enough to warrant incorporation in simulations of canopy photosynthesis through the growing period.     

Pigmented basidiomycetous yeasts are a promising source of carotenoids and ubiquinone Q<Subscript>10</Subscript>

Strains of basidiomycetous yeasts isolated from different sources were studied in order to determine the content of carotenoid pigments and ubiquinone Q₁₀ for subsequent selection work to obtain producers of these substances. The high specific productivity of carotenoids (600–700 mg/g) was revealed in the representatives of the following species: Cystofilobasidium capitatum, Rhodosporidium diobovatum, R. sphaerocarpum, Rhodotorula glutinis, Rh. minuta, and Sporobolomyces roseus. The ratio of the major pigments (torulene, torularhodine, and β-carotene) in the representatives of different species was studied. Certain specific features of pigment formation in relation to the taxonomic position of the yeasts were determined. Eurybiont species with substantial ecological lability are the most active producers of carotenoids and ubiquinone Q₁₀ among the epiphytes. It is the first time a comparative analysis of the coenzyme Q₁₀ content in different taxa has been performed using several strains of the same species. The maximal coenzyme Q₁₀ production (1.84 mg/g of dry biomass) was found in the yeast species R. sphaerocarpum.     

Patterns of population genetic structure and diversity across bumble bee communities in the Pacific Northwest

Patterns of genetic structure and diversity are largely mediated by a species’ ecological niche and sensitivity to climate variation. Some species with narrow ecological niches have been found to exhibit increased population differentiation, limited gene flow across populations, and reduced population genetic diversity. In this study, we examine patterns of population genetic structure and diversity of four bumble bee species that are broadly sympatric, but do not necessarily inhabit the same ecological niche in the Pacific Northwest of the United States. Testing for the effect of isolation by geographic distance (IBD) with linearized F _st and D _est found that Bombus sylvicola and B. mixtus exhibited significant IBD across populations. In contrast, both B. melanopygus and B. flavifrons, two species that are distributed across a broad elevation gradient, exhibited no IBD, a result further corroborated by Bayesian a priori population assignment tests. Furthermore, we discovered that B. sylvicola populations distributed on the Olympic Peninsula have significantly less average allelic diversity than populations distributed in the Cascade Mountains. Our results suggest that populations distributed in the Olympic Mountains represent a distinct genetic cluster relative to the Cascade Mountains, with B. sylvicola and B. mixtus likely experiencing the greatest degree of population genetic differentiation relative to B. flavifrons and B. melanopygus. While bumble bees are known to co-exist across a diversity of habitats, our results demonstrate that underlying population genetic structure and diversity may not necessarily be similar across species, and are largely governed by their respective niches.     

Invasive goldenrods affect abundance and diversity of grassland ant communities (Hymenoptera: Formicidae)

Goldenrods (Solidago sp.) are currently one of the most invasive plant species in Central Europe. They threaten abandoned semi-natural wet grasslands which are extremely vulnerable to plant succession and invasions. We assessed whether Solidago invasion affects ants, keystone organisms essential to proper ecosystem functioning and to the existence of myrmecophilous Phengaris butterflies. Ten meadows containing 60 plots with and without goldenrods were studied. We found a strong, negative dependence between the presence of goldenrod cover and the number of ant nests (more than 50 % reduction compared to control) as well as the number of species, and changes in species composition. Myrmica ants, essential hosts for Phengaris larvae, were among the most affected species by goldenrod invasion. Immediate action should be undertaken for restoration and maintenance of biodiversity hotspots affected by goldenrod invasion.     

南泥湾片段森林蝗虫群落多样性比较

应用多样性指数、排序和多元逐步回归分析方法比较了南泥湾片断化森林的蝗虫群落结构,并进行了环境因素的解释。结果显示：在南泥湾,树木破坏不严重的片断化森林,随森林面积的减小,林缘草层蝗虫种类、多样性指数和均匀度指数差异不大;林中草层蝗虫密度、多样性指数和均匀度指数减小。在面积小、树木破坏严重、植被结构发生明显改变的片断森林林中草层,相对于树木破坏不严重的片断化森林,蝗虫的密度、多样性指数和均匀度指数明显增大;而林缘草层蝗虫的密度和群落优势度指数上升,多样性指数和均匀度指数下降。以主分量分析方法可明显将林中草层蝗虫群落分为森林破坏严重和不严重两种类型。通过多元逐步回归分析发现,影响片断化森林蝗虫群落结构和多样性的主要因素有片断森林面积、森林植被结构的复杂性、食料植物的多少等几个方面。     

Co-occurring patterns of endophyte infection and genetic structure in the alpine grass, <Emphasis Type="Italic">Festuca eskia</Emphasis>: implications for seed sourcing in ecological restoration

Choosing the provenance of seed used in ecological restoration could entail its success. An alternative approach to examine local adaptation in seed sourcing is the assessment of genetic structure and diversity based on molecular markers. These types of analyses focus on the genetics of the target plant itself and eliminate the genetic influence of associated organisms, such as Epichloë/Neotyphodium endophytes in grasses. By impacting the fitness of their host, such symbionts may influence population genetic structure and diversity. Therefore, seed sourcing for grasses must consider the influence of their endophytes to increase seed translocation success and minimize the risks associated with this practice. To delineate seed zones for restoration of the alpine fescue Festuca eskia Ramond ex. DC. (Poaceae), we assessed population genetic differentiation and diversity patterns in the species including endophyte occurrence along altitudinal and longitudinal gradients in the Pyrenees Mountains. Twenty-three populations were analysed for endophyte status, and three STS and one SSR marker were used to examine genetic differentiation and diversity patterns. Results showed that F. eskia hosts an asexual form of Epichloë and infection frequency within populations decreased from East to West (100 vs. 8–25%). Molecular markers separated F. eskia into two East and West groups, and endophyte infection and genetic patterns were congruent with molecular data. Little evidence for genetic differentiation or difference in endophyte occurrence associated with altitude was detected. Little variation was found in within population diversity, regardless of provenance altitude and site, and/or endophyte infection frequency. The results of this study suggested the establishment of two distinct management units for F. eskia seed sourcing restoration.     

黑河上游天然草地蝗虫空间异质性与分布格局

蝗虫空间分布格局是物种长期适应自然的结果,是蝗虫与环境、蝗虫之间关系的反映,有助于理解蝗虫发生学的环境背景。采用地统计学方法,在黑河上游山区天然草地研究了微生境影响下的蝗虫空间格局与异质性。结果表明:该区域5种优势种蝗虫的半变异函数模型均为非线性模型,表现为聚集分布;不同种类蝗虫样点之间空间依赖的范围为2.29—24.59 m;在蝗虫种群总异质性中随机部分引起的空间异质性占15.77%—88.64%。受食性和栖息地选择的影响,蝗虫种群形成了片状和斑块状的分布格局;尺度依赖性使蝗虫分布格局趋于多元化和繁杂化的特点,不同蝗虫种群之间相互交错嵌插,同种蝗虫高低值呈非均匀扩散,整体上形成了均衡性与互补性的斑块镶嵌结构,这种分布格局反映了蝗虫对生境和气候变化的多元适应性结构。     

Predictions of species interactions from consumer-resource theory: experimental tests with grasshoppers and plants

We tested the ability of consumer-resource theory to predict direct and indirect interactions among species, using an experimental system of insect herbivores and herbaceous plants. Specifically, we examined interactions among three species of grasshoppers (Melanoplus femur-rubrum, Spharagemon collare, andPhoetaliotes nebrascensis; Orthoptera, Acrididae) and herbaceous plants in experimental field cages placed over existing fertilized or unfertilized vegetation in a Minnesota old field. For the conditions inside these cages, we addressed whether (1) grasshopper diet predicted the presence of competition among grasshopper species, and (2) direct effects of grasshoppers on plants produced indirect interactions among plants, grasshoppers and soil nitrogen. Overall,M. femur-rubrum ate a greater proportion of forbs in cages, while the other two species ate primarily grasses. As expected, a pair of grasshopper species competed if they had similar diets. However, there were important exceptions that could be explained from observed indirect effects, although alternative explanations were also possible. First, all three grasshopper species significantly shifted their diets in the presence of other species, and these shifts occurred most often when competition was expected or occurred. Second, the two grassfeeding species reduced the biomass of the dominant grass (Schizachyrium scoparium) and increased available soil nitrogen and biomass of forbs. This effect may explain why the grass-feedingP. nebrascensis had a positive effect on the forb-feedingM. femur-rubrum on unfertilized plots. Overall, we show that direct effects of consumers on resources can predict competition and other important indirect interactions within a community.     

<Emphasis Type="Italic">Genista</Emphasis> dwarf shrubs as key structures for a Mediterranean grasshopper species on alluvial gravel banks

Natural floodplains belong to the most species-rich ecosystems worldwide. However, over the last decades there has been a strong decrease in the extent of natural floodplains. As a consequence, the biodiversity of these ecosystems has experienced a dramatic decline. In this study, we investigated the habitat and food preferences of the grasshopper species Chorthippus binotatus on gravel banks of a nearly natural river system in the Spanish Pyrenees. The studied plots on the alluvial gravel banks in the Spanish Pyrenees were characterised by strong differences in habitat structure. However, C. binotatus only occurred in sparsely-vegetated sub-Mediterranean dry grasslands. The abundance of the grasshopper species was also strongly related to habitat structure and cover of the main food source and dominant plant species of these open grasslands, the dwarf shrub Genista scorpius. Concerning habitat structure, the grasshopper species preferred habitats with sparse and low-growing vegetation with a high cover of bare ground and gravel/stones. C. binotatus occupies a very narrow ecological niche within the studied floodplain. It requires sparsely-vegetated gravel banks that ensure sufficient oviposition sites and a favourable ambient temperature for optimal development. G. scorpius dwarf shrubs have to be considered as multi-functional key elements in the habitats of C. binotatus. They offer high-quality food, shelter against predators and allow thermoregulation in a hot and dry Mediterranean environment. For the conservation of C. binotatus, we recommend maintaining and restoring both natural floodplain dynamics as well as traditional grazing systems.     

Environmental conditions modulate plasticity in the physiological responses of three plant species of the Neotropical savannah

Plasticity in plants could be changed due to abiotic factors, tending to increase fitness across environments. In the Neotropical savannah, a strong water deficit during the dry season is one of the main factors limiting the plasticity in physiological responses of plants. The present study aims to assess the plasticity in physiological responses and vegetative phenology of three plant species of the Neotropical savannah (Cerrado in Brazil) during the dry and the rainy seasons. The three species, Byrsonima verbascifolia, Roupala montana, and Solanum lycocarpum, occur in Serra do Cipó in the state of Minas Gerais, Brazil. The development and vegetative phenology of individuals of these three species were evaluated over the course of 1 year. In February 2012 (rainy season) and August 2012 (dry season), stomatal conductance (g _s), water potential (Ψ), photosynthetic quantum yield, and concentration of leaf photosynthetic pigments were measured. The relative distance among the physiological parameters of all individuals within each season was measured using the relative distance plasticity index. B. verbascifolia has pronounced senescence in July and lost leaves completely by the early September, while R. montana and S. lycocarpum have green leaves throughout the year. The three studied species had greater control of stomatal opening during the dry season. S. lycocarpum and R. montana had negative water potential values in the dry season and in the middle of the day in both seasons. In the dry season, the three species exhibited a decrease in F _v/F _m, with values between 0.7 and 0.75. The relative distance plasticity index varied from 0 to 1. R. montana demonstrated the greatest plasticity and S. lycocarpum had lower plasticity. Then, a seasonal effect on physiological response was observed in all three model-species, with lower values for leaf water potential and stomatal conductance, and increased photoinhibition, in the dry season. Ecophysiological traits, such as stomatal conductance and leaf water potential, exhibited the greatest plasticity. In addition, there was a seasonal effect on the plasticity in physiological responses of the three plants species of the Neotropical savannah. The results are contradicting the idea that water restriction in the dry season would reduce the plasticity in most species of the Neotropical savannah.     

Natural levels of fungal infections in grasshoppers in Northern Benin

The infection of grasshoppers by naturally occurring, entomopathogenic fungi was monitored at two sites in Malanville, northern Benin, Africa. Grasshoppers were collected and recorded from the sites between June and December 1992 and all of them, barring the first instars, were incubated in ventilated cages. At the first site, 1343 individuals of 35 grasshopper species were incubated, and at the second site, 857 individuals of 36 grasshopper species were incubated. Three hyphomycete fungi (Deuteromycotina: Hyphomycetes), Metarhizium flavoviride Gams and Rozsypal, Beauveria bassiana (Bals.) Vuillemin and Sorosporella sp. were found infecting grasshoppers. The average incidence of M. flavoviride infection was 2.9% and 1.8% at the two sites for all host species. M. flavoviride sporulated on most grasshopper cadavers within 10 days of collection. B. bassiana and Sorosporella sp. were only collected from one and five grasshopper individuals respectively. A significant difference was noted in the time to death of small grasshopper species infected with M. flavoviride compared to larger species. At one site, M. flavoviride infection was positively correlated with rainfall during the 10‐day period in which samples were taken.     

Influence of solar energy and tree-crown closure on the species richness of grasses at the south of forest steppe

The perpendicularity of sunlight incidence on the land surface, called slope insolation, is calculated as the nonlinear function of steepness and exposure. This variable better describes the light and thermal regimes of slopes. We demonstrate that grass-cover insolation can be estimated based on the slope insolation and tree-crown closure. It is found for a terrain at the southern boundary of the forest steppe that species richness and green mass of grasses are closely related to topography and grass-cover insolation (R ₂ = 0.77 and R ₂ = 0.83, respectively), and crown closure is closely related to topography and slope insolation from the south (R ₂ = 0.85). A critical level of crown closure (15%) is determined, so that the limiting factor for grasses is soil moisture below and light above this level. It is shown that grass-cover insolation close to its average value (400 W/m₂) differentiates phytocenotic and soil characteristics into areas of increased and diminished values.     

Can perennial dominant grass <Emphasis Type="Italic">Miscanthus sinensis</Emphasis> be nurse plant in recovery of degraded hilly land landscape in South China?

Perennial C₄ grasses, especially Miscanthus sinensis, are widely distributed in the degraded lands in South China. We transplanted native and exotic tree seedlings under the canopy of M. sinensis to assess the interaction (competition or facilitation) between dominant grass M. sinensis and tree seedlings. The results of growth, chlorophyll fluorescence, and ultrastructure showed that negative effects may be stronger in perennial dominant grass M. sinensis. Although M. sinensis buffered the air temperature, improved soil structure, and increased soil phosphorus content, these beneficial effects were outweighed by the detrimental effect, especially overshading. To ensure the establishment of target native species in M. sinensis communities in degraded lands of South China, restoration strategies should include removing aboveground vegetation, planting target species seedlings in openings to reduce the effects of canopy shading, and/or selecting competition-tolerant target species. Also, seedlings of exotic species used in restoration engineering cannot be directly planted under the canopy of M. sinensis.     

Generic reclassification and species boundaries in the rediscovered freshwater mussel ‘<Emphasis Type="Italic">Quadrula’ mitchelli</Emphasis> (Simpson in Dall, 1896)

The Central Texas endemic freshwater mussel, Quadrula mitchelli (Simpson in Dall, 1896), had been presumed extinct until relict populations were recently rediscovered. To help guide ongoing and future conservation efforts focused on Q. mitchelli we set out to resolve several uncertainties regarding its evolutionary history, specifically its unknown generic position and untested species boundaries. We designed a molecular matrix consisting of two loci (cytochrome c oxidase subunit I and internal transcribed spacer I) and 57 terminal taxa to test the generic position of Q. mitchelli using Bayesian inference and maximum likelihood phylogenetic reconstruction. We also employed two Bayesian species validation methods to test five a priori species models (i.e. hypotheses of species delimitation). Our study is the first to test the generic position of Q. mitchelli and we found robust support for its inclusion in the genus Fusconaia. Accordingly, we introduce the binomial, Fusconaia mitchelli comb. nov., to accurately represent the systematic position of the species. We resolved F. mitchelli individuals in two well supported and divergent clades that were generally distinguished as distinct species using Bayesian species validation methods, although alternative hypotheses of species delineation were also supported. Despite strong evidence of genetic isolation within F. mitchelli, we do not advocate for species-level status of the two clades as they are allopatrically distributed and no morphological, behavioral, or ecological characters are known to distinguish them. These results are discussed in the context of the systematics, distribution, and conservation of F. mitchelli.     

Epizootics of the entomopathogenic fungus,Entomophaga grylli (Entomophthorales: Entomophthoraceae), in a grasshopper population in Northwest China

Plagues caused by locusts and grasshoppers have led to severe crop damage and great economic loss in many countries. Nevertheless, populations of these pests are often suppressed by naturally occurring predators and disease. Among such natural control factors, the entomopathogenic fungus, Entomophaga grylli, can markedly disrupt the dynamics of grasshopper populations. However, there are few reports of epizootics of this entomopathogenic fungus occurring in consecutive years. Here we report on a consecutive 2-year field survey of E. grylli epizootics in Xinjiang, Northwest China. E. grylli were observed to infect at least four species of grasshopper, Calliptamus italicus, Gomphocerus sibiricus, Chorthippus sp., and Stauroderus scalaris. This is the first record of infection of the last two species by this pathogen. The highest infection rates at the two study sites (Chonghuer and Jiadengyu, Altay Prefecture) were ≥50%, observed in mid-July 2011, and the lowest rate was >16% in early summer. The density of infected grasshoppers was positively correlated with the density of total grasshoppers collected (r?=?0.981). Therefore, E. grylli is an important natural factor regulating the dynamics of grasshopper populations in regions that are not subjected to artificial treatments.