Cameroon Journal of Experimental Biology

Outbreak of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera : Noctuidae) on transplanted sorghum in the Far North Region of Cameroon

Maurice Tindo * — 2026-08-09

Sorghum is the fifth most cultivated cereal crop in the world while in Cameroon, it ranks second after maize. Its production is hampered worldwide by various constraints including insect pests amongst which lepidopteran are predominant. Serious attacks on transplanted sorghum panicles were reported during the year 2023 in the Far North Region of Cameroon and wrongly attributed to Spodoptera frugiperda - although it is initially known to damage sorghum foliage. Field investigations were carried out with the objectives to evaluate the extent of the damages on sorghum panicles, readily identify the insect species responsible of the alarming damages and identify others insects associated with sorghum panicles. Group discussion was made with agriculture extension agents and farmers then, 30-60 sorghum plants randomly selected along two diagonals of a delimited field portion were evaluated for pest incidence and damage severity on panicles. The plague occurred in three Divisions among which Diamare was the highly affected area. This phenomenon was never reported in the past according to farmers. Pest incidence, density and severity varied across visited fields. Damages on panicle included mostly empty or unfilled grains and destroyed grains. Helicoverpa armigera Hübner was identified as the insect responsible of the alarming damages. This is the first report of H. armigera outbreak on sorghum in Cameroon. Implications of this first-time outbreak are discussed and more investigations are needed to clarify this sudden abundance of H. armigera on sorghum panicle. Three others Lepidoptera species and five bugs species emerged from panicles. The impact of sap sucking bugs on the sorghum production deserve more attention in the future.

Compétition intraspécifique chez Callosobruchus maculatus (Coleoptera : Chrysomelidae) pour les sites de ponte sur Vigna subterranea (voandzou)

Marcus Zilbinkaye * — 2026-08-09

The development of Callosobruchus maculatus depends on the availability of bambara groundnut seeds (Vigna subterranea) These seeds are used as oviposition sites and a food source for larvae. The scarcity of this resource induces intraspecific competition that can impact fecundity and population dynamics. This study explores the mechanisms of this competition and its effects on species regulation. Experiments were conducted by varying the seed mass (2 to 20 g in increments of 2 g) for females no more than 24 hours old throughout their lives. The 10 g mass, considered favorable for females, was fed to 2, 3, 4, and 5 females to assess oviposition, larval development, fecundity, and sex ratio. One, five, ten, fifteen, and twenty larvae of all instars (L1, L2, L3, L4) were introduced into tubes containing 10 g of seed in the presence of a 24-hour-old female to evaluate its effect on oviposition. The results show that the average number of eggs laid by a female (71.8 ± 13.37) is dependent on the number of seed. Egg-laying is concentrated at the beginning (39 ± 5.76 eggs in the first few days) before gradually decreasing (6.46 ± 4.6 at the end of the period). With one female per 10 g of seed, fecundity remains high (>80%) and the sex ratio is 0.9. In the presence of more than three females, egg-laying drops significantly (24 eggs for five females) and the sex ratio shifts towards males.Egg laying decreases in the presence of larvae (22.6) for stage 4. These results indicate that the limited availability of seeds leads to competitive exclusion between females, thus contributing to the natural regulation of C. maculatus populations in bambara groundnut stocks.

Résumé

Le développement de Callosobruchus maculatus dépend de la disponibilité des graines de voandzou (Vigna subterranea). utilisées comme site de ponte et source de nourriture pour les larves. La rareté de cette ressource induit une compétition intraspécifique pouvant impacter la fécondité et la dynamique de la population. Cette étude explore les mécanismes de cette compétition et ses effets sur la régulation de l’espèce. Des expériences ont été menées en faisant varier la masse des graines (2 à 20 g par pas de 2) pour une femelle âgée de 24h au plus durant toute sa vie. La masse 10 g favorable pour une femelle a été servie à 2, 3,4, 5 femelles pour évaluer la ponte, le développement larvaire, la fécondité et le sex-ratio. 1, 5, 10, 15, 20 larves de tous les stades (L1, L2, L3, L4) ont été introduites dans les tubes contenant 10g en présence d’une femelle de 24h, pour évaluer son effet sur la ponte. Les résultats montrent que le nombre moyen d’œufs pondus par une femelle (71,8 ±13,37) est dépendant de la masse de graines. La ponte est principalement concentrée au début (39±5,76 œufs aux premiers jours) avant de diminuer progressivement (6,46±4,6 en fin de période). Avec une femelle sur 10 g de graines, la fécondité reste élevée (>80 %) et le sex-ratio est de 0,9. En présence de plus de trois femelles, la ponte chute significativement (24 œufs pour cinq femelles) et le sex-ratio est en faveur de mâles. La ponte diminue en présence des larves (22,6) pour le stade 4. Ces résultats indiquent que la disponibilité limitée des graines entraîne une exclusion compétitive entre femelles, contribuant ainsi à la régulation naturelle des populations de C. maculatus dans les stocks de voandzou

Mother behavioral and offspring’s brain oxidant/antioxidant status changes induced by stress during pregnancy in Wistar rats: The potential benefit of Eucalyptus alba (Myrtaceae)

Mahamat Oumar — 2026-08-09

Exposing a pregnant female to stress is a risk factor for the development of psychiatric disorders in the offsprings. This study aimed at evaluating the aqueous extract of Eucalyptus alba. Reinw.Ex Blume as treatment of depression in gestation and control of prenatal stress-induced neurological changes in offsprings in rat. Thirty female albino gravid rats (150 ± 4 g) were divided equally into different groups (n = 5). From day six of gestation until birth, animals were given the extract (100, 200 and 400 mg/kg). After giving birth, the mothers underwent a behavioural test; a preference test for sucrose was performed, and a test to measure serum corticosterone levels using an ELISA kit was performed. Brain cell viability and oxidant/antioxidant status were examined in offsprings. Administration of aqueous extract during gestation significantly (P<0.05) improved the behavior and reduced corticosterone levels in female rat. Moreover, the extract prevented the loss of brain cell, increased the total antioxidant defense and caused a reduction in total oxidative stress, in litter of rat stressed during pregnancy. The findings demonstrate that E. alba has anti-depressive effect and prevent the neonate from neurological intoxication by free radicals.

Influence de l’activité de butinage du nectar et du pollen de Xylocopa olivacea (Hymenoptera: Apidae) sur la pollinisation et les paramètres de rendement de Calotropis procera (Apocynaceae) à Tongo (Garoua, Cameroun)

Daniel Farda * — 2026-08-09

To investigate the behaviour of Xylocopa olivacea and assess its influence on the fruit and seed development of Calotropis procera (Apocynaceae), observations were conducted on the blooms of this Apocynaceae species in Tongo (Garoua, Cameroon) during 2021 and 2022. For each year of observation, 1920 flowers were labelled and divided into four treatments based on the absence, presence, and presence with opening for a single visit by X. olivacea before reapplying insect protection, or presence with opening and closing without a visit from insects or any other organism. A comparison of fruiting rate, average number of seeds per fruit and percentage of normal seeds across the different treatments enabled the pollination efficiency of this carpenter bee to be determined. Of the eight insect species recorded on the flowers of Calotropis procera, Xylocopa olivacea ranked first with 42.08% of visits. This Apidae foraged on the flowers of C. procera from 6 am to 6 pm, with a peak in activity between 8 am-9 am and 4 pm-5 pm. On the flowers of this plant, X. olivacea foragers collected nectar extensively and pollen sparingly, with an average visit duration per flower of 5.61 seconds for nectar collection and 4.57 seconds for pollen collection. As for the average foraging rate, it was 13 and 10 flowers per minute for nectar and pollen collection respectively. Through its pollination efficiency, Xylocopa olivacea caused a significant increase in the fruiting rate and the percentage of normal seeds, by 35.56% and 36.01% respectively. The establishment of colonies of this Apidae species around C. procera plantations is recommended to increase the agronomic yield of this plant.

Résumé

Calotropis procera est un arbuste de la famille des Apocynaceae, communément appelé pommier de sodome et bambambé en fulfuldé. Cette plante est reconnue en médecine traditionnelle pour ses effets anthelminthiques. Afin d’étudier les activités de Xylocopa olivacea et de déterminer l’impact de celle-ci sur la production fruitière et grainière de C. procera, des observations ont été faites au niveau des fleurs de cette plante du 26 février au 14 mars 2021 et du 20 février au 08 mars 2022 à Tongo (Garoua, Cameroun). Pour chaque année d’observation, 1920 fleurs ont été étiquetées puis réparties en quatre traitements : Traitement 1 : fleurs étiquetées et laissées en libre pollinisation ; Traitement 2 : fleurs étiquetées et protégées des insectes à l’aide des sachets en toile gaze ; Traitement 3 : fleurs étiquetées et protégées, puis destinées à la réouverture, la réception d’une visite de X. olivacea puis à une nouvelle protection ; Traitement 4 : fleurs étiquetées et protégées, puis destinées à la réouverture et à une nouvelle protection sans visite d’insecte ou de tout autre organisme. La comparaison des taux de fructification, des nombres moyens de graines par fruit et les pourcentages de graines normales des différents traitements a permis de déterminer l’efficacité pollinisatrice de cette abeille charpentière. Sur huit espèces d’insectes recensées au niveau des fleurs de C. procera, X. olivacea occupait le premier rang avec 42,08% de visites. Cet Apidae butinait les fleurs de C. procera de 6 h à 18 h, avec un pic d’activité situé entre 8 h - 9 h et 16 h -17 h. Au niveau des fleurs de cette plante, les butineurs de X. olivacea récoltaient fortement le nectar et faiblement le pollen avec une durée moyenne de visite par fleur de 5,61 sec pour le prélèvement du nectar et 4,57 sec pour la récolte du pollen. Quant à la vitesse moyenne de butinage, elle était de 13 et 10 fleurs par minute pour la récolte du nectar et le pollen respectivement. Via son efficacité pollinisatrice, X. olivacea a provoqué un accroissement significatif (P < 0,001) du taux de fructification et du pourcentage de graines normales de 35,56% et 36,01% respectivement. La pose des colonies de cet Apidae autour des plantations de C. procera est conseillée pour augmenter le rendement de cette plante.

Oxidative stress, anemia and inflammation associated with sickle cell disease in Bafoussam (western Cameroon)

Bertille Fotie Mekoguem * — 2026-08-09

Sickle cell anemia Constitutes a public health problem worldwide. It is a heterogeneous disorder, with clinical manifestations including chronic hemolytic anemia, increased susceptibility to infections, and vaso-occlusive complications that often require medical care. The aim of this study was to assess the severity of anemia, oxidative stress, inflammation and certain associations in homozygous sickle cell patients (SS) at the regional hospital in Bafoussam (Cameroon). After obtaining ethical approval, an information sheet was given to participants to obtain their informed consent, and then the questionnaire was administered. 93 patients with sickle cell disease (SS) and 93 healthy individuals (AA) were recruited as controls. Blood samples were taken to assess oxidative stress parameters (catalase and superoxide dismutase (SOD) total antioxidant activity (FRAP), malondialdehyde (MDA) and reduced glutathione (GSH)), hematological analyses (complete blood count (CBC)), and the inflammatory state interleukin 10 (IL-10), tumor necrosis factor (TNF-alpha), C-reactive protein (CRP)). A significant decrease in hemoglobin concentration, red blood cell count and hematocrit percentage in whole blood was observed (p < 0.001). However, a very low catalase activity was recorded (p < 0.001), while a non-significant decrease in SOD was noted. MDA and GSH concentrations and total antioxidant activity increased in sickle cell patients (p < 0.001). In addition, a significant decrease (p < 0.001) in inflammation parameters (IL-10 and TNF-alpha) and a significant increase in CRP (p < 0.001) were noted. The present investigation shows that sickle cell patients at Bafoussam Regional Hospital have severe anemia associated with increased oxidative stress and high levels of inflammation. These factors contribute to a significant deterioration in their health; Moreover, medical care for sickle cell patients should therefore take the aforementioned factors into consideration in order to improve their quality of life.

Acute, sub-chronic and reproductive toxicity of the aqueous leaf extract of Xeroderris stuhlmannii Taub. (Fabaceae) in rats

Joël Tétio Nguémo — 2026-08-09

Xeroderris stuhlmannii is traditionally used to treat various diseases, however, no scientific data exists regarding the safety of this plant. Hence the aim of this study was to evaluate the toxicological profile of the aqueous extract of Xeroderris stuhlmannii (AEXS) leaves. An acute toxicity test was conducted at a limit dose of 2000 mg/kg in female rats (OECD No. 423). Sub-chronic toxicity of AEXS was evaluated in male rat with focus on their reproductive function according to OECD N°421. Forty (40) male rats (6 weeks old) were divided into four groups of 10 rats each treated for 56 days respectively with distilled water (10 ml/kg) and the plant extract at the doses of 50, 100 and 200 mg/kg. Animal behaviour, body weight gain, relative weight of organs, hematological, biochemical, antioxidant, sexual behaviour, fertility and histological parameters were assessed in this study. LD₅₀ of the AEXS was greater than 2000 mg/kg. AEXS caused significant decreases in aspartate aminotransferase (100 mg/kg, p=0.0048), activities (50 mg/kg, p=0.0068), and total bilirubin (all doses, p˂0.05-0.001) and urea levels (50 and 100 mg/kg, p˂0.05-0.001). Significant decrease in sexual motivation parameters such as mount (ML), intromission (IL) and ejaculation (EL) latencies without any significant variation in performance parameters (MF, IF, EF) except the mean interval of copulation (MIC) (200 mg/kg, p=0.0236). A significant increase in epididymal SOD (50 and 200 mg/kg, p=0.0014 and p=0.0075) and testicular CAT (100mg/kg, p=0.0014) activities were observed. No changes in the structure of detoxification and reproductive organs, hematological and fertility parameters were observed in this study. The AEXS is less or not toxic and it prolonged use is not harmful for vital and reproductive organ functions.

Evaluating house fly maggot meal as a sustainable fishmeal alternative for enhanced growth and profitability in Heterotis niloticus production

Aimerance Donhachi Kenfack * — 2026-08-09

This study evaluated the potential of maggot meal as a partial substitute for fishmeal in the diet of Heterotis niloticus to improve aquaculture sustainability in Cameroon, where fishmeal is costly and scarce. Conducted between April and June 2024 at IRAD Nkolbisson, the experiment involved 240 juvenile fish distributed in eight hapas and fed four isoprotein and isoenergetic diets containing 0%, 25%, 50%, and 75% maggot meal. Results showed that survival and growth performance were significantly influenced by diet. The best zootechnical performance, including weight gain, specific growth rates, and feed conversion ratio, was achieved with the 50% maggot meal diet, which also showed high survival. Although the 75% substitution diet had the lowest production cost, the 50% level provided the best balance between growth and profitability. The study concludes that maggot meal can effectively replace up to 50% of fishmeal in H. niloticus diets, enhancing economic efficiency in developing-country aquaculture.

Farmers’ perception of aphid dynamics and management practices on cabbage in Southern Ghana

Ethelyn Echep Forchibe * — 2026-08-09

Cabbage is an important commercial vegetable in Southern Ghana, where its cultivation serves as a major source of income for smallholder farmers. However, insect pests; particularly aphids cause significant damage and transmit viral diseases to cabbage leading to poor yield and quality. To address these challenges, this study evaluated farmers’ knowledge and perceptions of aphids, their seasonal occurrence, infestation levels, and management practices in Southern Ghana. A survey was conducted among 121 commercial cabbage producers across four major production regions: Ashanti (n = 35), Greater Accra (n = 37), Central (n = 20), and Eastern (n = 29). Farmers had a good knowledge on the seasonal fluctuations of aphid populations, their damage, and the various management practices available. Consequently, they recognized aphids as a major threat to cabbage production. Seven varieties of cabbage were cultivated by farmers; mainly Oxylus, Fortune, KK Cross, Super Cross, Santa, Copenhagen market and Leader Cross, but the majority of farmers (> 80%) cultivated Oxylus variety, which they regarded as ‘farmers’ choice’. Farmers employed a wide range of control measures particularly use of pesticides, sometimes rotating synthetic with biological pesticides, and other times, mixing a cocktail of different pesticides. There were significant relations between respondents having formal education and/or agricultural training with knowledge of pest bio-ecology, adoption of integrated pest management (IPM) practices as well as wearing of protective clothing during insecticide application. These findings synthesize farmers’ baseline knowledge and perceptions, which offer key insights for developing adaptive IPM technologies, and demonstrating an urgent need to transition from total chemical dependence toward bio-based IPM interventions and structured extension training for smallholder vegetable growers in Ghana.

Défis actuels de la production du voandzou [Vigna subterranea (L.) Verdc. (Fabaceae)], ressource végétale sous valorisée d’Afrique subsaharienne

Léonard Simon Ngamo Tinkeu * — 2026-08-09

Vigna subterranea (L.) Verdc is a popular, protein rich but neglected seed legumes. Research has promoted the characterization of morphotypes to identify varieties that meet the preferences of producers and consumers. However, the full potential of this plant resource is not being developed nor sufficiently promoted. Future investigations should promote high-performance, short-cycle varieties; improving storage conditions that respect the consumer and do not pollute the environment. The choice and adoption of voandzou, of which many varieties are present and under-exploited despite their high nutritional value and their potential for fighting hunger, justifies the interest in developing some agricultural value chains of this legume.

Résumé

Le voandzou, (Vigna subterranea (L.) Verdc.), est une légumineuse à graines, populaire, riche en protéine mais négligée. Les recherches menées ont promu la caractérisation des morphotypes en vue de l’identification des variétés qui répondent aux préférences des producteurs et des consommateurs. Hélas, tout le potentiel de cette ressource végétale n’est pas valorisé ni suffisamment promu. Les investigations futures devraient cibler la recherche des variétés de haute performance et à cycle court ; l’amélioration des conditions de stockage qui respectent le consommateur et ne polluent pas l’environnement ; le développement de nouveaux produits à base du voandzou de consommation massive contribuant ainsi à l’élimination de la faim sous toutes ses formes. Le choix et l’adoption du voandzou, dont de nombreuses variétés sont présentes et sous exploitées malgré leur forte valeur nutritive et leur potentiel pour la lutte contre la faim, justifie l’intérêt de développer des chaines de valeur agricole de cette légumineuse.

Oviposition and larval development of Ascalaphus festivus Rambur 1842 (Neuroptera: Ascalaphidae) under laboratory conditions

Antoine Bakoidi * — 2026-08-09

In the Afrotropical fauna, the Ascalaphids are still a curiosity despite their constant presence in the fallow during the dry season. The paper presents the first successful rearing of one of the most abundant species. Ascalaphus festivus Rambur, 1842 which is a poorly known Afrotropical ascalaphid whose reproductive biology and immature stages remain insufficiently documented. Adults were captured with butterfly nets from October to January, during the transition from the wet to the dry season, in grassy fallow habitats and reared alive in a vivarium under controlled conditions (23°C, 47% RH). Pregnant females, identified by their enlarged abdomen, were successively placed on oviposition sites for 48-hour periods until death, and eggs were collected from grass stems and leaves. Hatchlings were monitored individually and on fed third-instar larvae of Tribolium castaneum (Coleoptera: Tenebrionidae). Larvae were measured using body length, head capsule length, head width, and mandible length; developmental stages were designated L1, L2, and L3. Females laid eggs in regular rows on grass stems, and the eggs became milky white before hatching. Incubation lasted 13–16 days, with variable hatching success among clutches. Larval development passed through three instars: L1 moulted after 31.1 ± 6.6 days, L2 after 42.8 ± 7.0 days, and L3 survived up to 227 days without pupation. Distinct morphological differences among instars were observed, especially in body size and cephalic structures. These findings provide new baseline data on the oviposition, hatching, and larval development of A. festivus and improve knowledge of Afrotropical Ascalaphidae.