放牧干扰下的蝗虫－植物相互作用关系

本文研究了内蒙古典型草原植物和蝗虫群落在不同放牧强度影响下的多样性、均匀性和丰盛度变化。比较了蝗虫群落与植物群落在放牧梯度上的相互作用关系。研究发现,放牧干扰活动会明显地影响植物和蝗虫群落结构,但蝗虫群落结构的变化趋势并非与植物完全同步。蝗虫与植物间的联系更多地表现在植物起着蝗虫栖息地条件的作用,而并不完全是食料植物的作用。文中对放牧实践与多样性保护的关系进行了讨论。     

Effects of grazing regime on the relative body mass of the endangered pygmy bluetongue lizard (Tiliqua adelaidensis)

Many animals rely on fat reserves, to keep them alive through extended periods of food shortage, such as the winter, and to provide additional energy for reproduction. Fat reserves, measured relative to an animal's size, are often referred to as the animal's body condition. The present study investigated how different levels of grazing by domestic stock in native grassland habitat affect the body condition of the pygmy bluetongue lizard (Tiliqua adelaidensis), and if these effects are related to changes in the abundance and size of grasshoppers which are the lizards primary source of food. The initial hypothesis was that lizards would have the highest body condition in moderately grazed paddocks, because those paddocks would have more grasshoppers than heavily grazed paddocks, and better visual conditions for lizards to catch those grasshoppers than in ungrazed paddocks. The results, however, showed that both lizard body condition and the abundance of grasshoppers increased with decreasing grazing intensity. The connection between lizard body condition and abundance of grasshoppers was complex. Within an activity season, lizard body condition generally declined from spring to summer, while the number of grasshoppers grew. The mean size of grasshoppers seemed to be more important, as lizard body condition was higher in spring, the time of year with the largest grasshoppers. These results show that the intensity of grazing by domestic stock influences the body condition of pygmy bluetongue lizards, but that this effect is not entirely due to the reduction in the number of grasshoppers resulting from grazing.     

Mitochondrial DNA variation in North American Oedipodinae

Restriction fragment analysis of mitochondrial DNA (mtDNA) was used to examine genetic variation and population structure in 13 species of banded-winged grasshoppers (subfamily Oedipodinae). Total DNA of 246 individuals was digested with 11 restriction enzymes and probed with three clonedEcoRI fragments representing the entire mitochondrial genome ofMelanoplus sanguinipes. On average, members of this subfamily were five times more variable than those in another subfamily, Melanoplinae, previously examined. This would appear to lend support to Vickery's claim that the time of origin of Nearctic oedipodines is more ancient than that of melanoplines. With respect to population structure, a few different patterns were exhibited. Species such asCamnula pellucida had populations containing a mixture of haplotypes, some widespread and some geographically restricted. In contrast,Chortophaga viridifasciata populations were characterized by unique assemblages of diverse haplotypes. Phylogeographic hypotheses are advanced to account for these observations.     

NESTLING DIETS OF PRAIRIE PASSERINE BIRDS AT MATADOR, SASKATCHEWAN, CANADA

The nestling diets of seven species of grassland passerines were studied from gullet samples collected in 1969–1971 at Matador, Saskatchewan, Canada. Relative population densities on census plots on grazed and ungrazed prairie showed that Horned Lark Eremophila alpestris, McCown's Longspur Calcarius mccownii and Chestnut-collared Longspur C. ornatus preferred grazed areas and Sprague's Pipit Anthus spragueii, Western Meadowlark, Sturnella neglecta, Savannah Sparrow Passerculus sandwichensis and Baird's Sparrow Ammodramus bairdii preferred ungrazed prairie. Fifteen invertebrate ordinal taxa, and seeds were represented to an important extent in combined gullet contents; but two taxa, Lepidoptera (77% larvae) and grasshoppers (all Acrididae), comprised the bulk of nestling diets. Four grasshopper species contributed 70–100% of grasshoppers eaten in June-August. Overlap at the family level was also high in several other important prey. Comparison with invertebrate populations of ungrazed prairie showed that the birds ignored some abundant taxa of very small invertebrates, and apparently preferred the two least abundant groups which offered large individual prey items. Average nestling food overlap indices for the season among all species except Savannah Sparrow and Baird's Sparrow, based on taxonomic composition, was 0.85. Overlap was moderate in May and June and became very high in July and August. The number of nestlings reached a peak in June and early July when nestling food overlap was much lower than later in the season. Horned Larks avoid competition by nesting earlier than do the other species, while McCown's Longspur, which depends on grasshoppers for nestling food more than do the other species, tends to breed later in the season than the other species. Finally, data suggest that nestling food may be superabundant.     

Discriminating tastes: self‐selection of macronutrients in two populations of grasshoppers

Abstract The capacity to self‐select an optimal balance of macronutrients (protein and carbohydrate) is studied in two populations of Melanoplus sanguinipes F. (Orthoptera: Acrididae). One population derives from the subarctic (interior of Alaska) and the other from the temperate zone (Idaho, U.S.A.). Over the duration of the fourth and fifth stadia, Alaskan grasshoppers consistently self‐select a diet centred on a 0.90 ratio of protein : carbohydrate, whereas protein and carbohydrate intake by the Idaho grasshoppers is contingent on the particular food choices presented to them. When restricted to imbalanced diets, the Alaskan grasshoppers develop more rapidly than the Idaho grasshoppers, regardless of diet composition. The Idaho grasshoppers also have a greater amount of lipid than the Alaskan grasshoppers across all diets. Performance measures (body mass, survival, developmental times) are more sensitive to dietary imbalances in the Alaskan grasshoppers than in the Idaho grasshoppers. When fed diets with low, but balanced, proportions of protein and carbohydrate, grasshoppers of both populations are able to increase consumption to compensate for the low concentration of nutrients. The results suggest that demographic responses of insects to changes in host plant quality, such as may result from climate change, may differ among populations within a species.     

Herbivore phenology can predict response to changes in plant quality by livestock grazing

Livestock grazing can have a strong impact on herbivore abundance, distribution and community. However, not all species of herbivores respond the same way to livestock grazing, and we still have a poor understanding of the underlying mechanisms driving these differential responses. Here, we investigate the effect of light intensity cattle grazing on the abundance of two grasshoppers (Euchorthippus cheui and E. unicolor) that co-occur in the same grasslands and feed on the same food plant (the dominant grass Leymus chinensis). The two grasshopper species differ in phenology so that their peak abundances are separated into early- and late-growing seasons. We used an exclosure experiment to monitor grasshopper abundance and food quality in the field under grazed and ungrazed conditions, and performed feeding trials to examine grasshopper preference for grazed or ungrazed food plants in the laboratory. We found that the nitrogen content of L. chinensis leaves continuously declined in the ungrazed areas, but was significantly enhanced by cattle grazing over the growing season. Cattle grazing facilitated the early-season grasshopper E. cheui, whereas it suppressed the late-season grasshopper E. unicolor. Moreover, feeding trials showed that E. cheui preferred L. chinensis from grazed plots, while E. unicolor preferred the leaves from ungrazed plots. We conclude that livestock grazing has opposite effects on the two grasshopper species, and that these effects may be driven by grazing-induced changes in plant nutrient content and the unique nutritional niches of the grasshoppers. These results suggest that insects that belong to the same guild can have opposite nutrient requirements, related to their distinct phenologies, and that this can ultimately affect their response to cattle grazing. Our results show that phenology may link insect physiological needs to local resource availabilities, and should be given more attention in future work on interactions between large herbivores and insects.     

Cooperation and Prey Capture Efficiency in a Social Spider,Anelosimus eximius (Araneae,Theridiidae)

We studied the efficiency of the hunt and the characteristics of cooperation during the prey capture in a social spider Anelosimus eximius. Two natural types of prey of roughly the same length (20 mm) were used: grasshoppers (Orthoptera) and moths (Lepidoptera); 128 tests were made on 14 colonies, the smallest with 20 and the largest with 1,700 individuals. Test times were 12.00 h, defined as an inactive period for the spiders and 18.00 h, defined as an active period. Overall capture rate of intercepted prey was 66%: it was higher in large colonies or at 18.00 h, when more spider alerts were triggered by the struggling prey. Characteristics of cooperation during capture did not vary with colony size. Capture rate was higher for grasshoppers than moths (73%-58%) in spite of similar number of alerts (76%-87%); so moths must have been more difficult to capture. For both prey types, large colonies capture more rapidly and so had advantages in terms of time gain. We showed that cooperation depended on prey type: more spiders mobilised to attack moths and attack was faster than on grasshoppers. This may be interpreted as an adaptive response of the group to the prey type.     

Prey Luring Coloration of A Nocturnal Semi‐Aquatic Predator

Body coloration serves a variety of purposes in animals. Diurnal and nocturnal predators such as spiders may use their body coloration to lure prey. We predicted here that the white patches on the forelegs on females of the nocturnal semi‐aquatic spider Dolomedes raptor lure prey, explaining why they are primarily displayed when the spider forages along the water edge. To test our prediction, we developed a color vision model assessing whether the patches are visible to pygmy grasshoppers, the spider's primary prey. We conducted a field experiment using cardboard dummies that resemble D. raptor in size, shape, and color, but with half of them lacking leg patches, and we staged interactions between pygmy grasshoppers and D. raptor with and without leg patches in a greenhouse. We found the white patches to be visible to grasshoppers. The dummies with white patches attracted more grasshopper prey than the dummies without the patches. Moreover, grasshoppers were more attracted to spiders when their white patches were present. Our results supported the hypothesis that the white patches of D. raptor lure prey. Our findings, nevertheless, could not be explained as the spider's body coloration acting as a sensory trap but it should not be ruled out. More studies on a wider range of predators and prey will give more meaningful insights into the co‐evolution of predatory lures and prey sensory modalities.     

Phylogeny of bird-grasshopper subfamily Cyrtacanthacridinae (Orthoptera: Acrididae) and the evolution of locust phase polyphenism

Locust phase polyphenism is an extreme form of density-dependent phenotypic plasticity in which solitary and cryptic grasshoppers can transform into gregarious and conspicuous locusts in response to an increase in local population density. We investigated the evolution of this complex phenotypic plasticity in a phylogenetic framework using a morphological phylogeny of Cyrtacanthacridinae, which contains some of the most important locust species, and a comprehensive literature review on the biology and ecology of all known members of the subfamily. A phylogenetic analysis based on 71 morphological characters yielded a well-resolved tree and found that locust phase polyphenism evolved multiple times within the subfamily. The literature review demonstrated that many cyrtacanthacridine species, both locust and sedentary, are capable of expressing density-dependent color plasticity. When this color plasticity was divided into two smaller components, background coloration and development of black pigmentation, and when these plastic traits were optimized on to the phylogeny, we found that the physiological mechanisms underlying this plasticity were plesiomorphic for the subfamily. We also found that different locust species in Cyrtacanthacridinae express both similarities and differences in their locust phase polyphenism. Because locust phase polyphenism is a complex syndrome consisting of numerous plastic traits, we treat it as a composite character and dissected it into smaller components. The similarities among locust species could be attributed to shared ancestry and the differences could be attributed to the certain components of locust phase polyphenism evolving at different rates.
© The Willi Hennig Society 2007.     

Grasshopper feeding rates, preferences, and growth on safflower

Laboratory experiments were conducted to measure the feeding rates, preferences, survival rates, maturation times, and weight gain of four common species of grasshoppers (Orthoptera: Acrididae) on four lines of safflower (Carthamus tinctorius). When safflower lines were presented individually, all were readily consumed although consumption differed significantly according to grasshopper species, age and sex, and to safflower line. Consumption was greatest on a safflower line devoid of spines. However, grasshoppers also fed readily on spiny lines, and results of experiments in which all safflower lines were presented together indicated preferences that did not necessarily correspond to the results of the single-line feeding trials. Camnula pellucida, a graminivorous species, did feed on safflower, but restricted feeding almost exclusively to stem cambium, whereas Melanoplus bivittatus, M. packardii and M. sanguinipes fed mainly on the heads, flowers and leaves. Highly significant differences in grasshopper maturation time and weight gain were apparent among grasshopper species, and among safflower lines. Seedtec-5, the line which was least digestible, least consumed and least preferred nevertheless yielded rapid development and the greatest body weights of grasshoppers. All species of Melanoplus developed more quickly and gained more weight on safflower than on wheat. One species, M. packardii, was more able to utilise safflower than its congeners, and may gain competitive advantage if safflower becomes widely grown.     

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.     

Variable effects of dipteran parasitoids and management treatment on grasshopper fecundity in a tallgrass prairie

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.     

Herbivore-induced changes in plant carbon allocation: assessment of below-ground C fluxes using carbon-14

Effects of above-ground herbivory on short-term plant carbon allocation were studied using maize (Zea mays) and a generalist lubber grasshopper (Romalea guttata). We hypothesized that above-ground herbivory stimulates current net carbon assimilate allocation to below-ground components, such as roots, root exudation and root and soil respiration. Maize plants 24 days old were grazed (c. 25–50% leaf area removed) by caging grasshoppers around individual plants and 18 h later pulse-labelled with¹⁴CO₂. During the next 8 h,¹⁴C assimilates were traced to shoots, roots, root plus soil respiration, root exudates, rhizosphere soil, and bulk soil using carbon-14 techniques. Significant positive relationships were observed between herbivory and carbon allocated to roots, root exudates, and root and soil respiration, and a significant negative relationship between herbivory and carbon allocated to shoots. No relationship was observed between herbivory and¹⁴C recovered from soil. While herbivory increased root and soil respiration, the peak time for¹⁴CO₂ evolved as respiration was not altered, thereby suggesting that herbivory only increases the magnitude of respiration, not patterns of translocation through time. Although there was a trend for lower photosynthetic rates of grazed plants than photosynthetic rates of ungrazed plants, no significant differences were observed among grazed and ungrazed plants. We conclude that above-ground herbivory can increase plant carbon fluxes below ground (roots, root exudates, and rhizosphere respiration), thus increasing resources (e.g., root exudates) available to soil organisms, especially microbial populations.     

Loxocaudinae: A new subfamily in the ostracod family loxoconchidae

A new Ostracoda subfamily, Loxocaudinae subfam. nov., separated from the subfamily Loxoconchinae of the family Loxoconchidae with five genera (Loxocauda Schornikov, 1969, Glacioloxoconcha Hartmann, 1990, Phlyctocythere Keij, 1958, Pseudoloxoconcha Müller, 1894 and Sarmatina Stancheva, 1984) is described in the paper. The new subfamily differs from Loxoconchinae Sars, 1926 s. str. by the presence of a compact eye, the absence of an eye tubercle, an originally adont hinge with a tendency to formation of an anterior tooth on the left valve and a posterior one on the right valve, a pronounced caudal process and reduction of fossa-mural sculpture. The volume of the genera that are included in the subfamily is determined. A review of 55 various species and forms mentioned in the literature in open nomenclature, whose taxonomic position has not been determined yet is presented. A total of 45 species close to Loxocauda are attributed to the new subfamily, but proper morphological investigations are necessary for their classification. Ten species that were referred earlier to the genera included in Loxocaudinae are excluded from this subfamily. Issues of functional morphology of Loxocaudinae shells and morphological evolution of their sculpture are considered.     

Survival and fecundity of Dichroplus maculipennis and Ronderosia bergi (Orthoptera: Acrididae: Melanoplinae) following infection by Beauveria bassiana (Ascomycota: Hypocreales) under laboratory conditions

This study examined the effects of strain Beauveria bassiana (LPSC 1067) on nymphal development time, fecundity and adult survival in Dichroplus maculipennis and Ronderosia bergi under laboratory conditions. It was observed that infection with 1×10³ conidia/ml altered nymphal development time, fecundity and adult survival in both species. Mortality of D. maculipennis during third through the last instar (sixth) was significantly higher among treated nymphs (66±3.8%) than in controls (15±1.7%). Similarly, mortality in R. bergi during third through the last instar (fifth) was higher in treated nymphs (71±2.8%) than in controls (19±1.5%). Nymphal development times of both infected D. maculipennis and R. bergi were longer than controls. On the other hand, among survivors of both the species, control adults lived longer than infected adults. Finally, control grasshoppers of both species were much more successful reproductively than infected grasshoppers.     

Impact of predation by the robber fly Proctacanthus milbertii (Diptera: Asilidae) on grasshopper (Orthoptera: Acrididae) populations

The impact of predation by the robber fly Proctacanthus milbertii Macquart on populations of adult grasshoppers from grasslands of the Nebraska sandhills was estimated. Densities of P. milbertii were estimated at 437 individuals per hectare (2 se=122). Overall densities of 23 species of grasshoppers were estimated to be 64,000 individuals per hectare with the most abundant species (Ageneotettix deorum) having a population size of approximately 15,000 individuals per hectare. Based on three estimates of predation level (ranging from 0.5 to 2 prey per day per robber fly), P. milbertii may take from 0.5% to 2% of the adult grasshoppers per day. Species of grasshoppers were taken by P. milbertii in about the same proportion in which they occurred at the study site and no size-selective component of predation was detectable.     

Consumption rates and the evolution of diet-induced plasticity in the head morphology of Melanoplus femurrubrum (Orthoptera: Acrididae)

Summary Phenotypic plasticity may be an ecologically important evolutionary response to natural selection in multiple environments. I have determined the effect of diet-induced developmental plasticity in the head size of grasshoppers (Melanoplus femurrubrum) onfeeding performance on two types of plants. Full-sib families were divided and raised on either red clover, Trifolium repens, or rye grass, Lolium perenne. In three different stages of ontogeny, grasshoppers raised on rye grass had significantly larger heads, relative to body size, than full-sibs raised on clover. A principal components analysis indicated that two to five relative head size characters covaried as a block in their plastic response to the feeding environment. Regressions of adjusted consumption rates (mg/sec) against relative head size revealed that larger head sizes, induced by the rye grass diet, enhanced consumption rates of rye grass, but not clover. Unexpectedly, a similar positive association was observed between head size and consumption rate for grasshoppers raised on clover when they were feeding on clover. These results support the inference that grasshoppers exhibit adaptive phenotypic plasticity. However, the unexpected influence of head size on consumption rates of clover indicates that the functional relationship between head morphology and feeding performance is complex and that variation in this relationship among plant environments is not sufficient to explain the evolution of diet-induced phenotypic plasticity.     

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.     

Effects of traditional pastoralism on grasshopper (Caelifera) assemblages in East Africa

In East Africa, traditional pastoralists increase landscape heterogeneity by creating traditional livestock corrals (bomas). When these bomas are abandoned, they serve as long‐term hot spots of increased nutrients and unique vegetation. However, the effect of bomas on insect populations is unclear. Grasshopper (Suborder Caelifera) assemblages are thought to reflect vegetation, and within Caelifera, the subfamily Oedipodinae is known to be associated with degraded areas. We sampled vegetation and collected grasshoppers inside of abandoned bomas, 50 m from abandoned bomas and 250 m from abandoned bomas. Bomas had significantly lower grass abundance than background vegetation. Total grasshopper abundance was positively correlated with grass and forb abundance, while the proportion of grasshoppers in the subfamily Oedipodinae was negatively correlated with grass abundance. Grasshopper abundance was significantly lower inside of bomas than outside of them, but the proportion of grasshoppers in the subfamily Oedipodinae was significantly higher inside of bomas than outside of them. This suggests that the decreased vegetation in abandoned bomas supports fewer grasshoppers, but a higher fraction of the grasshopper assemblage in abandoned bomas is composed of Oedipodinae. Thus, traditional pastoralists can have long‐term effects on the size and composition of grasshopper assemblages through the use of bomas.     

Yaks and sheep trigger different changes in the grasshopper assemblages of the Qilian Mountains via differentially altering plant assemblages

1. The Qilian Mountains represent one of the key livestock‐raising grasslands in China. The two main herbivore species raised in this area – yaks and sheep – are of critical economical value. Grasshoppers compete with these animals for available nutrients, creating multifaceted relationships between livestock, grasshoppers and plants. A clear understanding of such relationships is lacking and is urgently needed to guide conservation efforts. 2. This study aims to document the effects of yak and sheep grazing on grasshopper assemblages and to elucidate the underlying mechanisms of such effects. 3. It is shown here that yaks and sheep impact grasshopper assemblages differently. Grasshopper assemblages exhibited lower density, biodiversity, richness, and evenness of distribution in yak‐grazed pastures than in grazing‐free grasslands. Sheep‐grazed pastures exhibited a dramatically divergent picture, with elevated density, biodiversity and richness, and a slightly decreased evenness of distribution. Grasshoppers were generally larger in grazed pastures than in grazing‐free grasslands, especially in yak‐grazed plots. 4. The present study suggests that differences between yak and sheep pastures in plant assemblage structure and plant traits are probably the underlying forces driving the differences in grasshopper assemblage structure and grasshopper traits, respectively. 5. The study shows that the grasshopper habitat indicator species differ between yak and sheep pastures, raising the possibility that such indicators can be used to monitor grassland usage and degradation in the Qilian Mountains. 6. These results provide novel insights into the dynamic interactions of common domesticated herbivore species, grasshoppers and plants in Qilian Mountains, which augment current knowledge and may ultimately lead to better conservation practices.