Biodiversity is the diversity of living organisms on Earth, including plants, animals, microorganisms, their genomes, and the ecosystems they inhabit. Halting the biodiversity crisis is one of the major challenges for human society. The importance of biodiversity is recognized worldwide. Some organisms provide food, while others serve as ecosystem health indicators or offer therapeutic benefits (Chandrakar and Dhuria 2019). Furthermore, biodiversity conservation has become a cornerstone, a basic objective, and a collective responsibility for biologists. The goal of bioindicator research is to find species that can reliably detect environmental disturbances and to demonstrate how those disturbances affect other species or biodiversity as a whole (Chowdhury et al. 2023). Human-induced environmental changes cause profound disruptions in natural populations. The rare species, previously undisturbed in their natural habitat, may then be found over large areas where ecological conditions have become favorable to their proliferation. Some species—the most competitive ones—that adapt to newly created habitats continue to thrive there, whereas other less tolerant species move away from transformed and hostile environments toward more suitable areas, thereby shifting their habitat range. Species associated with high plant diversity may decline or even disappear as the plant diversity of the environment decreases (Midgley et al. 2003, Latchininsky et al. 2011, Adu-Acheampong 2017). Endemic species, particularly wingless ones, are generally the most negatively affected by environmental disturbances.

Insects are particularly valuable for assessing the impact of human activities on terrestrial ecosystems. They make up a substantial portion of Earth’s biological diversity and often serve as hosts for numerous other organisms, including parasites, mutualists, and commensals (Larsen et al. 2017, Li and Wiens 2023). Among insects, grasshoppers are a dominant invertebrate group in terrestrial ecosystems in which they are potential bioindicators (Oumarou-Ngoute et al. 2023).

Grasshoppers are a large group within Orthoptera. They belong to the suborder Caelifera, which contains 12 families and over 1,700 genera (Cigliano et al. 2025). Acridomorpha are integral to terrestrial ecosystems and are characterized by elevated degrees of endemism (Yetchom-Fondjo et al. 2020). These insects are an important link in food chains because they are consumed by other organisms, such as birds, reptiles, amphibians, mammals, and other arthropods (Leksono et al. 2020, Oumarou Ngoute et al. 2021). From a nutritional point of view, grasshoppers are among the most important edible insects worldwide and are increasingly being incorporated into Western diets through various derived food products (Paul et al. 2016, Haldar and Malakar 2017, Magara et al. 2025). Moreover, grasshoppers are important ecosystem components, and several taxa are often used for environmental biomonitoring purposes (da Silva et al. 2021).

The ecological importance of these insects as bioindicators for land management and climate change has been highlighted in different parts of the world (Uchida and Ushimaru 2014, Poniatowski et al. 2020, Manna et al. 2020, Sergeev 2021, da Silva et al. 2021, Fartmann et al. 2022, Mariottini et al. 2024). Some authors have found that the richness and abundance of grasshopper species increase with habitat disturbance, except for species with low dispersal ability (Latchininsky 2008, Fartmann et al. 2022). Others have stated that the diversity of these insects decreases in open environments after perturbation (Hao and Wang 2015, Soliman et al. 2017, Mariottini et al. 2024), while others have reported that land use variation does not significantly affect the abundance, species richness, and diversity of grasshoppers (Leksono et al. 2020).

In general, the results of these studies have shown that grasshoppers can be classified into habitat generalists and specialists (Nakajima and Miyashita 2021). The Grinnellian specialist species are organisms whose niches are narrowly defined by specific abiotic conditions (such as climate, altitude, or substrate) rather than by biotic interactions. They show limited adaptability, are often confined to very specific habitats, and are therefore highly vulnerable to environmental change, whereas generalists tolerate a wider range of conditions within an ecosystem (Richmond et al. 2005, Dehling et al. 2021). Comparing the proportions of specialist and generalist species, as well as rare taxa, helps diagnose habitat conditions, assess the impacts of disturbance, and guide conservation strategies by identifying the most vulnerable or ecologically stable areas.

The grasshopper diversity in West-Central Africa and the Congo basin is still understudied. Research on the responses of grasshoppers to environmental disruption is lacking despite the high level of deforestation observed (Oumarou-Ngoute 2024). In Cameroon, few recent studies have been conducted to clarify the effect of land use on grasshopper fauna, and these studies are fragmented, focusing on parts of the highland areas (Kekeunou et al. 2017, Wandji et al. 2019), lowland areas in the coastal region (Yetchom-Fondjo et al. 2020), or in the South Cameroon plateau (Oumarou Ngoute et al. 2020, 2023). In southern Cameroon rainforest areas, forest clearing creates a suitable environment for the proliferation of pest grasshopper species, with the consequences of increased pest activities in crop fields and disruption of the ecosystem’s balance (Oumarou-Ngoute et al. 2023). The status of the highland areas of the country still needs to be clarified. The Bangou area is a transitional zone bridging the low altitude of southern Cameroon and the peaks of the volcanic line. Thus, studying acridids in Bangou is an important step in understanding grasshopper distribution and diversity in Cameroon.

In this study, the following questions were addressed: How does the grasshopper community structure observed at Bangou compare with that of similar habitats elsewhere in Cameroon when such data exist? To what extent does grasshopper community composition vary among the four habitat types? Are there significant differences in the proportion of habitat generalist species across habitats? We hypothesized that Bangou has high and endemic grasshopper biodiversity compared to other similar habitats in Cameroon because it is part of the Cameroon Volcanic Line, which is known for its high levels of biodiversity and endemism, that the grasshopper community differs significantly among the four habitat types with each habitat hosting a distinct assemblage of species, and that the proportion of habitat generalist taxa varies across ecological zones, with more generalists occurring in disturbed areas (such as fallowland and crop fields) than in forests.

Study site.—Grasshoppers were sampled monthly from January to December 2024 across four habitat types (crop fields, fallow lands, forest, and bare soil) at 24 sites in the Bangou district (1500 m a.s.l.; 5°14'12"N, 10°24'21"E), Hauts Plateaux Division, West Cameroon (Fig. 1). The region’s vegetation consists mainly of semi-deciduous forest and savannah, with remnants of evergreen forest in wetlands and mountainous areas (Brénac 1988, Tiokeng et al. 2020). These ecosystems are now heavily disturbed, and original plant species persist only in relics of “sacred forests,” in inaccessible areas, or along waterways (Tiokeng et al. 2020). The original vegetation is almost completely replaced by mixed crop fields (Nkongho et al. 2024). Mixed cropping involves planting multiple crops, such as corns, beans, plantains, groundnuts, legumes, and tubers in the same field to maximize the yield, improve soil health, enhance food security, and manage land scarcity (Jacobsen et al. 2004, Nkongho et al. 2024).

The climate in West Cameroon is of a sub-equatorial type with two seasons: a dry season (from November to March) and a rainy one (from April to October). Annual rainfall ranges from 1,500 mm to 2,000 mm per year with an average temperature of 22 °C (Santoir and Bopda 1995). Soil is reddish and lateritic, with a fertile top layer (Muller 1974). In this work, the studied forests were relics of degraded patches consisting of a few trees (e.g., Ficus sp. and Ceiba pentandra) along with raffia palms (Raphia vinifera) used for construction (raffia bamboo), crafts (fiber products), and beverages (fermented sap–raffia wine). The forest undergrowth was mainly composed of plant species from the Euphorbiaceae, Moraceae, Rubiaceae, Malvaceae, and Sapotaceae families (Tiokeng et al. 2020). Crop fields consisted of mixed plantings of corn, beans, plantains, and groundnuts. Fallowlands were short-term and dominated by herbaceous (grass) species of genera, such as Panicum, Cymbopogon, and Pennisetum, often associated with bushfires and grazing by local communities. Bare soils were reddish and lateritic, with no vegetation cover.

Grasshopper sampling and identification.—Grasshoppers were sampled monthly over a 12-month period (January 2024 to December 2024) in each of the four vegetation types studied. Sampling was conducted in the daytime using sweep netting randomly within each vegetation type for a 120-min period. During the sampling time, researchers walked through habitats and actively flushed grasshoppers using a sweep net consisting of a wooden frame (1.2 m in length, 50 cm in diameter). Grasshopper detection relied on visual observation throughout the sampling period. All collections began from a fixed point and extended across the entire site. Collected grasshoppers were placed in pre-labeled boxes. The collected specimens were photographed in the field and transported to the Zoology Laboratory of the University of Douala for identification at the species level through external morphology and/or genitalia structure. The identification was made using keys from the following: Dirsh (1958, 1965, 1970), Keith and Kevan (1974, 1969), Hollis (1975), Karsch (1891), Ramme (1929), Jago (1984, 1994a, b), Grunshaw (1991), Rowell et al. (2015), Rowell and Hemp (2017, 2018), Mariño-Pérez and Song (2023), Oumarou-Ngoute and Rowell (2024), and Rowell and Oumarou-Ngoute (2025).

Species richness and sampling effort.—We calculated grasshopper species richness (Taxa S) in the different habitat types as the total number of species of the supra-specific taxa (Dajoz 1982). The theoretical values of the species richness were estimated using the Chao 1 estimator, and then individual rarefaction curves (Fig. 2) were generated using PAST software, version 4.17 (Marcon 2018, Hammer 2024). Sampling effort was calculated as the ratio of the observed species richness to the theoretical species richness (Appendix 1: Table A1).

Abundance and abundance distribution model.—The absolute and relative abundances (Marcon 2018) of the grasshopper species were calculated using Excel software, version 2016. The species relative abundance (fx) for each of the studied habitat types was calculated as the ratio of the sum of abundances of a species over the sum of abundances of all the species from the vegetation types, as follows:

f x = ∑ x 1 + x 2 + x 3 … + x 12 N × 100

where ∑x₁+x₂+x₃...+x₁₂ is the sum of the abundances of species x from the first to the twelfth month of sampling in a given habitat, and N is the sum of the abundances of all species across the four habitat types. The species’ relative abundance per habitat was also expressed for each sampling event/month. We categorized the values of the relative abundance (fs) according to Dajoz (1982): fs > 50% = very abundant taxa; 25% ≤ fs ≤ 50% = abundant taxa; 1% ≤ fs < 25% = less abundant taxa; fs < 1% = rare taxa. The mean relative abundance is represented in Fig. 7, with the mean value depicted by a bar and the whisker intervals indicated as a one-sigma range (Hammer 2024). Comparisons of the relative abundances were conducted using the Kruskal-Wallis (H) test and the Mann-Whitney (W) test for pairwise. The abundance distribution model provides data on the use of the available resources in the studied vegetation type by the different grasshopper species (Havyarimana et al. 2013). Using the R 4.4.0. software, we compared the observed grasshopper abundance distribution in the different vegetation types studied to the theoretical distribution models of Fisher (log-series model), Mac-Arthur (broken stick model), Motomura (geometric model), and Preston (log-normal model) (Marcon 2018) using the chi-squared test.

The log-normal model assumes a relatively balanced distribution of available resources within a habitat where species abundances are moderate and evenly distributed; the log-series model indicates a heavily disturbed ecosystem, characterized by intense interspecific competition for resources and dominated by rare species; the broken-stick model reflects minimal interactions between species in a habitat where ecological resources are shared randomly; and the geometric model represents a hierarchical use of resources in a community dominated by pioneer species where each species exploits a constant proportion of the remaining resources (Fattorini et al. 2016, Marcon 2018, Zang et al. 2022).

Frequency of occurrence.—The frequency of occurrence (fo) provides the occupation of the available space by the studied taxa. We express the occurrences in Appendix 1: Table A1, as the ratio of the number of samples in which a species was present over the total number of samples realized. Analysis was performed using the PAST software. We categorized (fo) as Dajoz (1982): fo > 50% = constant taxa; 25% ≤ fo ≤ 50% = accessory taxa; fo < 25% = accidental taxa. Distribution of the grasshopper frequency of occurrence per habitat in Fig. 10, was visualized using box and jitter plots. These plots depict the quartiles as a box with a median as a horizontal line inside the box. Quartile calculations were performed using interpolation methods (Hammer 2024). Data points falling outside the inner fences are displayed as circles in Fig. 10, while those exceeding three times the box height, known as the “outer fences”, are marked with stars. Comparisons of the frequency distributions were made using the Kruskal-Wallis (H) test, while the pairwise comparison was performed using the Mann-Whitney test.

Diversity and similarity.—The diversity indexes expressed the degree of complexity of the grasshopper species assemblages in an ecosystem or habitat. The Shannon (H') index (Carlo et al. 1998) was used in PAST 4.17 to express and compare the grasshopper diversity of the different habitat types. Principal component analysis (PCA) of the species communities was generated using the same software. In the PCA, the first two components were the main axes of variation that best distinguish the habitats and species studied. Component 1 (PC1) captures the largest proportion of variation in the abundance data, whereas component 2 captures the second-largest proportion of variation and is independent of PC1. The software automatically calculated (from abundance data) the Euclidean distances between species and habitat types (Hammer 2024).

Species status.—To assess which taxa are primarily responsible for the observed differences among the four groups of samples/habitats, we applied a SIMPER (Similarity Percentage) analysis in PAST version 5.2 using the Bray–Curtis similarity measure (Clarke 1993, Hammer 2025). As an alternative to SIMPER for identifying specialist, generalist, or rare species of a given habitat (Dufrene and Legendre 1997), we performed an indicator species analysis (IndVal) in which the statistical significance (p-values) of the indicator values was estimated using 9,999 random permutations of species across habitats (Hammer 2025). All the statistics were considered significant for p < 0.05.

Species richness and sampling effort.—A total of 48 grasshopper species were sampled in this study, belonging to three families: Acrididae MacLeay, 1821 (39 species), Pyrgomorphidae Brunner von Wattenwyl, 1874 (eight species), and Thericleidae Burr, 1899 (one species) (Appendix 1: Table A1). These species include 10 species of Acridinae (Fig. 3A–F), eight of Catantopinae Brunner von Wattenwyl, 1893 (Fig. 4A–D), eight of Pyrgomorphinae (Fig. 5A–G), six of Oedipodinae Walker, 1871 (Fig. 6E–H), five of Coptacrinae Brunner von Wattenwyl, 1893 (Fig. 5H), four of Cyrtacanthacridinae Kirby, 1910 (Fig. 6A–D), three of Eyprepocnemidinae Brunner von Wattenwyl, 1893 (Fig. 4E–G), two of Oxyinae Brunner von Wattenwyl, 1893 (Fig. 3G–H), one of Calliptaminae Jacobson, 1905 (Fig. 4H), and one of Thericleinae.

In general, the most species-rich habitat was fallowland (39 species), followed by crop field (33 species), bare soil (21 species), and forest (12 species). Among the vegetation types, sampling was most efficient in bare soil (95%), followed by fallowland (92%), forest (80%), and farmland (75%) (Appendix 1: Table A1). In these vegetation types, the individual rarefaction curve began to flatten toward 600 individuals in fallowland, 450 specimens in crop land, 100 individuals in forest, and 75 specimens in bare soil (Fig. 2). The overall species sampling effort was high, achieving 90% efficiency (Appendix 1: Table A1). We collected 48 of the 53 expected species (48/53): 33/44 (75%) species in crop field, 12/15 (80%) taxa in forest, 39/42 (92%) species in fallowland, and 21/22 (95%) taxa in bare soil (Appendix 1: Table A1). Two species (Catantops melanostictus Schaum, 1853 and Gymnobothrus cruciatus (Schaum, 1853)) were collected in all the four studied vegetation types. Abisares viridipennis (Burmeister, 1838) and Occidentosphena uvarovi (Rehn, 1942) were found only in crop field. Parapetasia rammei Sjöstedt, 1923, Parapterotiltus minimoides Oumarou Ngoute & Rowell, 2024, Parepistaurus sp., and Thericles sp., were found only in the forest; Cannula gracilis (Burmeister, 1838), Criotocatantops pulchripes (Karny, 1917), Eucoptacra exigua Bolívar, 1912, Eucoptacra gowdeyi Uvarov, 1923, Exopropacris rehni (Sjöstedt, 1923), Machaeridia bilineata Stål, 1873, Ornithacris cyanea (Stoll, 1813), and Acorypha sp. were collected only in fallowland. No taxa were specific to bare soil habitat (Appendix 1: Table A1).

Abundance and abundance distribution model.—Among the 1191 grasshopper specimens sampled, 561 (47.10%) were collected from fallowland, 449 (37.70%) from crop field, 126 (10.58%) from bare soil, and 55 (4.62%) from forest (Appendix 1: Table A1). We observed statistical differences in the mean of relative abundances (H = 32.50, p < 0.0001) between the vegetation types; the values were higher in fallowland, followed by crop field, bare soil, and lower in forest (Fig. 7). The studied grasshopper species were categorized as either ‘abundant’ (one species), ‘less abundant’ (22 species), or ‘rare’ (25 species) (Appendix 1: Table A1). Coryphosima stenoptera (Schaum, 1853) was the only abundant species (29.7%). Among the less abundant taxa, Orthochtha nigricornis (Karsch, 1893) (7.64%) and Roduniella insipida (Karsch, 1896) (7.64%) had more individuals: about twice as many as C. melanostictus (4.70%), Heteropternis thoracica (Walker, 1870) (4.61%), Chrotogonus homalodemus (Blanchard, 1836) (4.03%), and Heteropternis couloniana (de Saussure, 1884) (3.27%) and four times more than Trilophidia conturbata (Walker, 1870) (2.68%), Hadrolecocatantops glauningi (Ramme, 1929) (2.60%), Eyprepocnemis plorans (von Charpentier, 1825) (2.09%), G. cruciatus (2.01%), Epistaurus bolivari Karny, 1907 (2.01%), M. bilineata (1.93%), Eucoptacra anguliflava (Karsch, 1893) (1.59%), and Pyrgomorpha vignaudii (Guérin-Méneville, 1847) (1.59%). The other remaining species represented less than 1.50% of the collected specimens. Acrididae (90.68%) were very abundant, Pyrgomorphidae (8.90%) less abundant, and Thericleidae (0.41%) were rare. Acridinae was very abundant (54.66%), while Oedipodinae (12.76%), Catantopinae (9.32%), and Pyrgomorphinae (8.90%) were less abundant. Oxyinae (1.18%) dominated in forest habitat, whereas Pyrgomorphinae (4.11%) were most abundant in bare soil (Appendix 1: Table A1). In general, grasshopper species were more abundant in the rainy season (64.73%) than in the dry season (35.26%) (Appendix 1: Table A1) with March, May, August, and October being the richest months (Fig. 8). However, it was during the dry season that pest grasshopper species such as E. plorans and C. melanostictus were most active in cultivated fields (Fig. 8). The studied species were distributed into 22 ranks of abundance in bare soil, 22 ranks in fallowland, 13 ranks in forest, and six octaves in crop field (Fig. 9). The distribution models of species abundance were close to (all the p-values < 0.001) Motomora’s geometric model in bare soil (Fig. 9A) as in fallowland (Fig. 9D), to the MacArthur’s broken stick model in forest (Fig. 9B), and Preston’s log-normal model in crop field (Fig. 9C).

Frequency of occurrence.—Our study revealed a statistical difference (H = 33.31, p < 0.0001) in the grasshopper distributions of frequency of occurrence between the studied habitats; the medians were higher in fallowland, followed by crop field, bare soil, and lower in forest (Fig. 10). Coryphosima stenoptera (60.41%) was the only constant species in our samples. Eight other accessory species were collected. Among these, the most common species was R. insipida (43.75%), followed by C. melanostictus (41.66%), H. thoracica (33.33%), T. conturbata (33.33%), E. plorans (27.08%), C. homalodemus (27.08%), and E. bolivari (27.08%). All other taxa occurred only accidentally in our samples (Appendix 1: Table A1).

Diversity and similarity.—The Shannon index revealed higher grasshopper diversity in fallowland (H' = 2.42), followed by crop field (H' = 2.23), bare soil (H' = 2.14), and forest (H' = 2.11) (Fig. 2B). Furthermore, the PCA showed that the two grasshopper communities in crop field and fallowland were close to each other and the communities from forest and bare soil were similar. The vectors in the PCA showed strong correlations with the most disturbed landscapes (Fig. 11).

Species status.—Coryphosima stenoptera (Av. dissim. = 21.07, Contrib. = 23.49%) was the species that contributed most to explaining the observed differences among the four studied habitats (Appendix 1: Table A2). Chrotogonus homalodemus (Av. dissim. = 5.89), O. nigricornis (Av. dissim. = 5.67), R. insipida (Av. dissim. = 5.50), H. thoracica (Av. dissim. = 4.08), C. melanostictus (Av. dissim. = 4.03), and H. couloniana (Av. dissim. = 2.99) each contributed less than 7% (Appendix 1: Table A2). Each of the other taxa had a Contrib. < 3.00%. Four species—Thericles sp. (IndVal = 33.33%, p = 0.002), P. minimoides (IndVal = 25%, p = 0.01), Parepistaurus sp. (IndVal = 75%, p < 0.001), and Pterotiltus coeruleocephalus (IndVal = 37.04%, p = 0.001)—were identified as bioindicators or specialists of forest habitat. One taxon, C. homalodemus (IndVal = 51.39%, p < 0.001), was identified as a specialist of bare soil (Table 1). Six species were categorized as non-specialists: Acrida bicolor (IndVal = 22.73, p = 0.02), Atractomorpha accutipennis (IndVal = 15.63, p = 0.04), and Dictyophorus griseus (IndVal = 23.33, p = 0.01) in Fallowland; A. viridipennis (IndVal = 16.67, p = 0.05), Cyrtacanthacris aeruginosa (IndVal = 18.75, p = 0.04), and Morphacris fasciata (IndVal = 16.67, p = 0.04) in crop field; and Odontomelus kamerunensis (IndVal = 20.83, p = 0.03) in forest. The 14 remaining taxa were categorized as either generalists or rare species in the four studied landscapes. In general, the number and proportion of generalist species increased with land use or vegetation degradation: the IndVal proportions and p-values revealed one species (8%) in forest, four (19%) in bare soil, five (15%) in crop field, and 11 (28%) taxa in fallowland (Table 1). Rare species decreased with land use, accounting for 50% (6/12) in forest, 61% (13/21) in bare soil, 30% (10/33) in crop field, and 23% (9/39) in fallow land (Table 1).

Species richness.—Our study confirms our first hypothesis, demonstrating that Bangou has high and endemic grasshopper diversity compared with other similar habitats in Cameroon. We found 48 short-horned grasshoppers in the studied vegetation types. Yetchom-Fondjo et al. (2020) identified 38 grasshopper species in the coastal area of the Littoral region of Cameroon, while Oumarou Ngoute et al. (2023) collected 43 species in the south Cameroon plateau. Previously, Kekeunou et al. (2017) reported 27 species in the Kouoptamo district in West Cameroon, and Seino et al. (2013) documented 28 species in the Menoua division, West Region. Such observations might stem from the varying climatic characteristics, altitude variations, and vegetation types across the above-cited regions of Cameroon. Indeed, the south Cameroon plateau (about 650 m above sea level) is under a Guinean climate type with four seasons, two rainy seasons and two dry seasons, and annual rainfall between 1,500 mm to 2,000 mm (Njopkou, 2014); the Littoral region (in the coastal area) is under a Cameroonian climate type, humid and hot, with two seasons and unimodal distribution of rainfall (4,000 mm per year) (Letouzey 1985); while the West region (in the highland area) has a Cameroonian-type climate, dry and cool, with two seasons (Santoir and Bobda 1995). Furthermore, the high species richness in our work can be justified by the fact that Bangou is in the Cameroon Volcanic Line. This volcanic line is recognized worldwide as a hotspot of biodiversity in the Congo Basin, with a high rate of endemism (Rejou-Mechain et al. 2021, Zwets et al. 2024). The same observation has been made in other volcanic zones in Africa (Rowell and Hemp 2017, Rowell and Hemp 2018, Rowell et al. 2015). A decade earlier, Hemp (2009) reported a list of 139 OrthopteraCaelifera (Tetrigoidea, Eumastacoidea, and Acridoidea) in Mt Kilimanjaro in East Africa, and Roy (2003) collected 110 species of Acridomorpha (Eumastacoidea and Acridoidea) from the Nimba mountain and its surroundings in West Africa.

Our study shows that grasshopper species richness was higher in herbaceous vegetation (fallowland: 39 species, crop field: 33 species), whereas habitats with limited herbaceous cover (bare ground: 21 species, forest: 12 species) had the lowest species richness. Theron et al. (2022) in the KwaZulu-Natal Midlands in South Africa and Yetchom-Fondjo et al. (2020) in the Littoral region in Cameroon also showed a positive correlation between grasshopper species richness and the presence of a herbaceous layer in the environment. In the latter study, a total of 32 species were recorded in crop field, 29 in fallowland, and 7 additional species in forest (Yetchom-Fondjo et al. 2020).

Abundance, occurrence, and distribution model.—Our results also support our second hypothesis, showing that the grasshopper community varies markedly across the four habitat types, each of which supports a distinct species assemblage. Indeed, the present study revealed high grasshopper species abundance and occurrence in herbaceous vegetation (crop field: 37.70%, fallowland: 47.10%), whereas in forest (4.62%) and bare soil (10.58%), we observed low species diversity, indicating an increase in the Shannon (H') index diversity with land-use intensification.

Plant and herbivorous insect communities are likely to differ among habitat types (Nakajima and Miyashita 2021). Grasshoppers are known to be diversified in grassland ecosystems in which they feed on gramineous plants (Masaki et al. 2011). However, in the Pampas region of Argentina (2.51% of individuals in crop, 51.87% in grassland), as well as in the Al-Tebbin region (South Cairo) of Egypt (402.6 ± 27 of specimens in highly polluted station, 594.6 ± 23.3 in moderately polluted station), grasshopper species diversity decreased after environmental perturbation (Soliman et al. 2017, Mariottini et al. 2024). The effect of land use on grasshopper biodiversity likely depends on eco-climatic areas and climates, which are a function of the relief and vegetation types. Land use fragments grasshopper communities into different assemblages leading to a proliferation or a decrease in species’ population size depending on the available habitats (Nakajima and Miyashita 2021, Mariottini et al. 2024, Oumarou Ngoute 2025). Three distinct species abundance distribution models emerged in our study: the geometric model in bare soil and fallowland, the broken stick model in forest habitat, and the log-normal model in crop field. The observed models corresponded closely to the variations in vegetation structure and disturbance intensity across the studied habitats. The broken-stick distribution in forest confirmed the less disturbed habitat described in our study. The studied forests have high plant species diversity, including trees, shrubs, and herbaceous; this environment leads to minimal interactions between the studied grasshopper species because of the available resources (Fattorini et al. 2016, Zang et al. 2022). The limited and often monospecific plant diversity in the studied fallowland (herbaceous) and bare soil (no vegetation) corroborated the geometric model, which revealed a heavily disturbed ecosystem marked by strong interspecific competition (Fattorini et al. 2016). However, the log-normal model in crop field with moderate species interactions and abundances (Zang et al. 2022) is somewhat unusual. This result can be explained by the polyculture, or mixed cropping, observed and described in the Bangou district. Polyculture creates a diversity of plant resources that provides multiple ecological niches, allowing most species to maintain moderate abundances, while only a few remain very rare or highly dominant, producing a characteristic of the log-normal distribution. Fried et al. (2010) showed that monocultures contain significantly more specialist species than crop rotations, indicating that rotations mainly promote generalist species rather than specialists tied to each crop type. In general, human-driven forest clearing provides favorable conditions for grasshopper species associated with herbaceous or grassland vegetation but threatens other vulnerable taxa (Oumarou Ngoute et al. 2023). Indeed, in the Bangou district, environmental degradation has promoted an increase in the density of pest taxa such as E. plorans or C. melanostictus, along with their activities in croplands, whereas other taxa, such as P. minimoides or P. rammei, have been threatened by human disturbance and are now restricted to the remaining small forest patches.

Similarity and species status.—Our results also confirm the third hypothesis, showing that the proportion of habitat generalist species varies across ecological zones, with a higher occurrence of generalists in more disturbed areas.

The PCA revealed correlations between the most disturbed habitats, showing that the proportion of generalist species increased with habitat disturbance (forest 8%, crop field 15%, bare soil 19%, fallowland 28%), while rare taxa declined. In investigating the invasion impacts of the grass species Eragrostis curvula on 12 native grasshopper species on the gravelly floodplains of the Kinu River, Yoshioka et al. (2010) supported the hypothesis that grasshopper species with specific habitat preferences are more affected by the invasion of weeping lovegrass than habitat generalists. In the Cape Floristic Region of South Africa, highly mobile, generalist-feeding grasshopper species occupy a greater number of habitat patches across the landscape, whereas low-mobility specialist feeders and rare taxa are restricted to high-quality natural patches that remain continuously available (Adu-Acheampong and Samways 2019). When studying the feeding behavior of the generalist grasshopper Chorthippus parallelus, Franzke et al. (2010) concluded that generalist herbivores can compensate for the potential nutritional deficiencies of single food plants through selective dietary mixing. Empirically, studies have shown that, unlike species with specialized resource requirements, generalist species may actually benefit from habitat destruction (Ramiadantsoa et al. 2018). However, according to Unsicker et al. (2010), decreasing biodiversity threatens the persistence of both specialist and generalist insect herbivores through multiple mechanisms, including the reduced diversity of food plants available to generalists.

Ecological niches remain a key framework for explaining variations in community structure. The balance depends on the types of resources exploited, the biotopes, and the niche space occupied. These factors vary across regions and generate taxonomic biases favoring either generalists or specialists (Dennis et al. 2011). In the context of our study, most specialist species were particularly vulnerable to extinction. In the complex, dynamic metapopulation landscape of local adaptation and migration, generalist strategies can enhance persistence (Dennis et al. 2011, Ramiadantsoa et al. 2018). By differing in their resource use, they are also more likely to coexist, even under highly variable environmental conditions.

The study demonstrates that grasshopper communities in the Bangou district are closely associated with habitat structure. Compared with other regions, our results highlight the influence of vegetation cover, climate, and land use on grasshopper biodiversity. Herbaceous habitats such as fallowland and crop field supported the highest species richness and abundance, while forest and bare soil ecosystems hosted fewer but more specialized taxa. Indeed, Chrotogonus homalodemus was identified as a specialist in bare soil, and Parapterotiltus minimoides, Pterotiltus coeruleocephalus, Parepistaurus sp., and Thericles sp. were classified as bioindicators of forest habitat. The generalist species increased in both number and relative proportion along the gradient of land use or vegetation degradation, whereas the proportion of rare species was lower in the most disturbed lands. Polyculture increases plant-resource diversity and thus multiplies ecological niches, enabling most species to persist at moderate abundances while only a few taxa become very rare or highly dominant, ultimately favoring generalist species. The abundance distribution of Coryphosima stenoptera effectively accounted for the observed dissimilarities among the studied lands. Overall, the landscape of the Bangou district, located on the Cameroon Volcanic Line, represents an important hotspot of grasshopper diversity, harboring both endemic taxa and numerous habitat specialist species. This emphasizes the need for sustainable land management practices that maintain herbaceous cover while conserving the remaining forest patches. Protecting habitat heterogeneity is essential to preserve the observed grasshopper diversity, ecological functions, and the long-term stability of natural ecosystems.