From July to October 2015 and 2018 at Maroua, Sesamum indicum flowers were observed to determine the reproductive system, specific richness, relative frequency, and impact of the insects on the yields. 7800 and 4560 flower clusters for each studied were labeled and divided into two treatments, differentiated according to the presence or absence of protection against insect’s activities. Observations were made on free-pollinated S. indicum flowers from September to October 2015 and 2018. The sesame is a mixed pollination plant, and the specific richness of the flowering insects was 19 species. The insects foraged the flowers of the sesame from 7:00 am to 4:00 pm, with the peak of the activity of the set of visits of them located between 9:00 am, and 10:00 am (28.59 %). These insects developed and elaborated behavior when they collected the nectar and pollen. Free-pollination produced more yield than pollination restricted with gauze bags. The influence of the insects estimated at 50.84 %, 17.22 %, 58.77 %, and 09.55 % for the fruiting rate, the number of seeds/fruit, the percentage of the average weight of seeds, and the percentage of normal seeds respectively. This study provided some knowledge about the insect’s diversity of this Pedaliaceae, which can be exploited to improve fruit production. In order to improve the yield of S. indicum, pollinators could be protected by rational pest management tactics. Pesticide treatments should be done in the late afternoon to protect the pollinators for high seed yield or spray at a time of day when crop flowers are closed.

To determine the insect species richness, relative frequency, food products, potential pollinators and their impact on the yields, the flowers of Glycine max (Fabaceae) were observed from September 3 rd to 27 th in 2015 (Mayel-Ibbé) and from September 6 th to October 10 th in 2018 (Wourndé). Two hundred plant flower clusters in 2015 and in 2018 they are divided in two treatments, differentiated according to the presence or absence of protection against insect's activities. The diversity of the flowering insects of soybean was 19 and 12 species respectively in Mayel-Ibbé and Wourndé. These insects visited the flowers of the soybean from 6 am to 5 pm with the activity peak situated between 10 am and 11am. These insects developed and elaborated behaviour when they collected the nectar and/or pollen. Thus, they can be grouped into major pollinators, minor pollinators and occasional pollinators. By comparing yield of unprotected plants to yield of protected plants from insect visits, it is appeared that insects have a positive impact on this yield. The influence of the insects on the increasing of soybean yield is estimated at 39.29%, 11.70%, 22.88% and 03.76% for the pod/plant, the number of seeds/pod, the percentage of the mass of seeds and the percentage of normal seeds respectively. In order to improve the yield of G. max, it is advisable to preserve the flower-dwelling insects in the farm by avoiding pesticide treatments during the period of flowering when they are not justified.

Pour déterminer la richesse spécifique, la fréquence relative, les produits alimentaires recherchés, les insectes pollinisateurs et l’impact de ces insectes sur les rendements, deux traitements ont été formés à partir du marquage de 240 boutons floraux en 2015 et 2017 chacun selon la présence ou l’absence de protection contre les insectes. Les observations ont été faites sur les fleurs de Abelmoschus esculentus en libre pollinisation du 11 au 22 septembre 2015 et du 7 au 19 septembre 2017 à Wourndé et Palar respectivement. La diversité spécifique des insectes floricoles de gombo était de 17 et 20 espèces respectivement à Wourndé et à Palar. L’indice de Jacard (J = 0,15) révèle une similarité entre les deux sites, preuve que les conditions environnementales sont similaires dans les deux habitats. Les insectes butinaient les fleurs du gombo de 8 h à 13 h, avec le pic de l’activité de l’ensemble de visites de ceux-ci situé entre 10 h et 11 h. Les insectes développaient un comportement très élaboré lors de la récolte du nectar et/ou du pollen et la consommation du pétale. On peut regrouper ces insectes en pollinisateur majeur (Lipotriches collaris), pollinisateurs mineurs [Sphecodes albilabris, Camponotus flavomarginatus, le Vespidae (1 sp.), Lasioglossum albilabris, Seladonia sp., Lasioglossum albipes, Lipotriches pulchriventris et le Formicidae (1 sp.)] et pollinisateurs occasionnels. La comparaison des rendements des fleurs non protégées à celui des fleurs protégées des insectes ont montré que les insectes ont un impact positif sur ce rendement. L’influence de ces insectes est estimée à 9,57%, 7,18% et 4,34% pour le taux de fructification, le nombre de graines/capsule et le pourcentage de graines normales respectivement. Afin d’améliorer le rendement de A. esculentus, il est conseillé de préserver les insectes floricoles non nuisibles dans les champs de gombo en évitant les traitements aux pesticides pendant la période de floraison lorsqu’ils ne se justifient pas. ABSTRACT To determine the species richness, the relative frequency, desired food products, the pollinating insects and impact of these insects on the yields, two treatments were formed from the marking of 240 flower buds in 2015 and 2017, differentiated according to the presence or absence of protection against insect’s activities. Observations were made on free-pollinated Abelmoschus esculentus flowers from 11 to 22 September 2015 and from 7 to 19 September 2017 in Wourndé and Palar respectively. The specific diversity of the flowering insects of okra was 17 and 20 species respectively in Wourndé and Palar. The Jacard index (J = 0.15) reveals a similarity between the two sites, proof that the environmental conditions are similar in both habitats. The insects foraged the flowers of the okra from 8h to 13h, with the peak of the activity of the set of visits of them located between 10 h and 11 h. The insects developed a much elaborated behaviour during the harvest of the nectar and / or the pollen and the consumption of petal. These insects can be grouped into major pollinators (Lipotriches collaris), minor pollinators [Sphecodes albilabris, Camponotus flavomarginatus, Vespidae (1 sp.), Lasioglossum albilabris, Seladonia sp., Lasioglossum albipes, Lipotriches pulchriventris and Formicidae (1 sp.)).] and occasional pollinators. By comparing the yield of unprotected flowers to that of insect-protected flowers, it appeared that insects have a positive impact on this yield. The influence of these insects is estimated at 9.57 %, 7.18 % and 4.34 % for the fruiting rate, the number of seeds / capsule and the percentage of normal seeds respectively. To improve the yield of A. esculentus, it is advisable to preserve the flower-dwelling insects in okra fields by avoiding pesticide treatments during the flowering period when they are not justified.

The studies were conducted in Maroua-Cameroon to assess the impact of Megachile bituberculata visit on the production of Cajanus cajan. Two treatments were used on each 50 randomly-selected plants. These included Autonomous Self-Pollination (ASP) with flowers from which insects visit, with airborne pollen flow excluded (treatments 1), flowers that received a single bee visit (SBV) of M. bituberculata (treatments 2). This bee mainly foraged for nectar and pollen resources. The mean foraging speed was 11.59 flowers/min (n = 39; s = 1.95) and the duration of visits was 10.65 s (n = 32; s = 4.07) to collect pollen and nectar. Megachile bituberculata is an effective pollinator, it shakes flowers and this movement could facilitate the liberation of pollen by anthers, for the optimal occupation of the stigma and of course their visits increase fruiting rate of 87.18 %, percentage of seeds/pod of 16.4 %, percentage of normal seed of 5.58 % and percentage of weight seed of 19.35 % in Maroua. Conservation of M. bituberculata nests close to pigeonpea farms can be recommended to increase pod and seed production in the region.

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