Grasshoppers are highly diversified in tropical rainforests and considered of both ecological and conservation importance. The population dynamics of central African grasshoppers, however, and the structure of their communities remain poorly studied. We report here on the impact of human activities on the diversity of grasshopper species from three localities in southern Cameroon: Ongot, more anthropized forest; Zamakoe, moderately anthropized forest; and Ngutadjap, less anthropized forest. Data were collected using sweep nets, quadrats, and pitfall traps. We analyzed how pressures from human activities affected the grasshopper species compositions using five statistical methods: (1) two non-parametric estimators for specific richness, (2) abundance, (3) abundance distribution model, (4) α diversity index, and (5) β diversity index. The results showed no significant differences in species richness between the sites (nine species at Zamakoe, seven each at Ongot and Ngutadjap). Among these species, one was specific to Ongot and Zamakoe, while one, two, and three species, respectively, were found only in Ongot, Ngutadjap, and Zamakoe. Abundance and species diversity of grasshoppers increased with anthropogenic pressure on the forests. We noticed a great similarity between the grasshopper communities of the two localities under the greatest anthropogenic pressure (Ongot and Zamakoe) compared to that of the less anthropized locality of Ngutadjap. The most common grasshopper species, Mazea granulosa, was most abundant where deforestation was highest. Species diversity was highest in the more and moderately anthropized forests, and the diversity index showed greater similarity between these two grasshopper communities compared with that of the less anthropized forest. This work enables us to better understand how the parameters of these insect communities reflect the degree of forest degradation in southern Cameroon.

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The increased attention given to health, food security, and biodiversity conservation in recent years should bring together conventional scientists and indigenous people to share their knowledge systems for better results. This work aims to assess how grasshoppers are perceived by the local people in southern Cameroon, particularly in terms of food, health, and landscape conservation. Villagers were interviewed individually using a rapid rural assessment method in the form of a semi-structured survey. Nearly all people (99%) declared that they are able to identify local grasshoppers, generally through the color of the insect (80%). Crop fields were the most often cited landscape (16%) in terms of abundance of grasshoppers, with forest being less mentioned (8%). In general, villagers claimed that grasshopper abundance increased with forest degradation. Grasshoppers were found during all seasons of the year but noted to be more abundant during the long dry seasons. People found grasshoppers both useful and harmful, the most harmful reported being Zonocerus variegatus, an important crop pest. Cassava is the most attacked crop with 75–100% losses. Industrial crops, such as cocoa, coffee, and bananas, were not cited as being damaged by grasshoppers. The most effective conventional method cited for the control of pest grasshoppers is the use of pesticides (53%) with, in most cases (27%), a 75–100% efficiency. The traditional method of spreading ash was also often cited (19%), with an estimated efficiency of 25–75%. Biological methods were neither cited nor used by the villagers. Most of them (87%) declared that they eat grasshoppers; some sold these insects in the market (58%) and some used them to treat diseases (11%).

Eyprepocnemis plorans ibandana is a very common grasshopper species in open environments and agricultural systems of tropical Africa. It is a pest that significantly benefits from forest degradation in southern Cameroon, hence the need to study the bioecology of this subspecies. We studied the reproduction as well as the morphological characteristics and development times of the post-embryonic instars of E. p. ibandana. Sixty-one adult pairs were obtained from sixth instar nymphs caught in grassy vegetation in the Nkolbisson area (Yaoundé) and bred in the laboratory. After hatching, the first instar nymphs were individually placed in cages and fed every two days using fresh leaves of Manihot esculenta. The postembryonic development of E. p. ibandana took six instars in the male and six to seven instars in the female. Mean nymphal development took 79.16 ± 0.51 days in males, 89.93 ± 0.58 days in 6 instar females and 94.96 ± 1.22 days in 7 instar females. The survival rate of the first instar was low (53%). However, from the second instar on the survival rate was very high (> 87%). Sexual dimorphism is distinct in adults, fifth and sixth nymphal instars. Adults of E. p. ibandana took on average 32.57 ± 3.88 days to start mating, and mating lasted 2.12 h on average (1–3 h). Oviposition took place on average 52.03 ± 5 days after first mating; each female deposited one to eleven oothecae with an average of 34.93 ± 2.37 eggs per ootheca. Our study provides important information for the control of this subspecies in southern Cameroon.

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