Joseph Lebel Tamesse

Foraging and pollination behaviour of Xylocopa calens Lepeletier (Hymenoptera: Apidae) on Phaseolus coccineus L. (Fabaceae) flowers at Yaounde (Cameroon)

To evaluate impact of carpenter bee, Xylocopa calens, on pod and seed set of Phaseolus coccineus, its foraging and pollinating activities were studied in Yaounde, for two seasons (May–July 2008 and April–June 2009). Observations were made on 40 inflorescences per treatment. The treatments included unlimited floral access by all visitors, bagged flowers to deny all visits, and limited visits by X. calens only. In addition, all flower visitors were recorded. The carpenter bees seasonal rhythm of activity, its foraging behavior on flowers, its pollination efficiency, the fructification rate and the number of seeds per pod were recorded. Individuals from 16 species of insects were recorded visiting flowers of P. coccineus in the 2 years. Xylocopa calens was the most frequent, followed by Chalicodoma cincta cincta and Apis mellifera. Apart from bees, wasps were also recorded as likely predators. Xylocopa calens mainly foraged for nectar resources. The mean foraging speed was 9.62 flowers/min. Flowers visited by X. calens had higher fruiting rate compared with others, while those bagged had the lowest. In addition, seed formation was higher in X. calens‐visited flowers compared with all others. The results show that this crop experiences pollination deficit even under normal circumstances, considering that flowers visited by X. calens had higher yields compared with those under unlimited access by all visitors. The fruiting rate, the number of seeds/pod and the percentage of normal seeds of unprotected inflorescences were significantly higher than those of inflorescences protected from insects. X. calens foraging resulted in a significant increment of the fruiting rate by 25.80%, as well as the number of seeds/pod by 14.97% and the percentage of normal seeds by 27.75% in 2008 and 18.39% in 2009. Conservation of X. calens nests close to P. coccineus fields could be recommended to improve pod and seed production in the region.

Jumping plant‐lice of the family Phacopteronidae (Hemiptera: Psylloidea) from Cameroon

Nine species of the family Phacopteronidae are recorded from Cameroon. All are assigned to the large pan‐tropical genus Pseudophacopteron. Eight species are described as new, and P. electum Capener is redescribed. The species are diagnosed and illustrated, and keys for the identification of adults and fifth instar larvae are provided. Information is given on distribution, host plants, and biology. Eight species are associated with plants of the order Rutales/Sapindales (three Sapindaceae, one Burseraceae, one Burseraceae or Anacardiaceae, one Meliaceae, one Rutaceae, and one Anacardiaceae/Simaroubaceae); host plants of one species remain unknown. Four species, namely P. electum, P. fuscivenosum sp. n., P. lecaniodisci sp. n., and P. morion sp. n., induce nut or pit galls on the leaves.

First record of Blastopsylla occidentalis Taylor, 1985 (Hemiptera: Psyllidae), a Eucalyptus psyllid in Cameroon, Central Africa

In order to investigate the biodiversity of psyllids in Cameroon, we collected a psyllid on Eucalyptus spp. (Myrtaceae) for the first time. Morphometric and morphological studies of this psyllid enable us to identify it as Blastopsylla occidentalis Taylor (Hemiptera: Psylloidea). Blastopsylla occidentalis lives on four Eucalyptus species (Eucalyptus globulus, E. saligna, E. deglupta, E. camaldulensis) in the Western and Central regions of the country. A description and illustration of the different developmental stages of B. occidentalis will allow the identification of this pest of Eucalyptus.

The anti-shigellosis activity of the methanol extract of Picralima nitida on Shigella dysenteriae type I induced diarrhoea in rats

BackgroundPicralima nitida Stapf (Apocynaceae) is a medicinal plant used traditionally in Cameroon to cure various ailments such as gastrointestinal disorders and dysentery. This study reports the in vitro and in vivo anti-shigellosis activity of the methanol extract of this plant on rats.MethodsThe antimicrobial activity of the extract against pathogenic strains was evaluated using the disc diffusion assay and broth microdilution method. After oral administration of a suspension of Shigella dysenteriae type I (sd1), diarrheic rats were divided into 5 groups; the control group received the vehicle of the extract and the four others 125, 250, 500 mg/kg of the plant extract and ciprofloxacin (20 mg/kg) respectively for 7 days. The frequency of faeces emission as well as the weight of normal and diarrheic faeces was recorded. The presence of stools containing mucus or blood and the number of sd1 in faeces were also recorded.ResultsIn vitro, the extract had an antimicrobial effect on 11 out of the 17 pathogenic strains tested. The values of CMI and CMB obtain against Shigella dysenteriae type I were 800 and 6400 μg/ml respectively. In vivo, diarrhoea induction was effective and we notice an increase in faeces frequency and weight (p < 0.05), increase in the percentage of diarrheic stool released as well as the mucus contained in stool (p < 0.05), an increase in bacterial population in stool (p < 0.05). Picralima nitida extract, like ciprofloxacin markedly reduces the frequency faeces released and sd1 density from 100% (diarrheic rats) to 47.22 and 61.69% (500 mg/kg) respectively. It also slowed down the movement of charcoal meal through gastro-intestinal tract with the percentage of intestinal length covered of 60.54 (500 mg/kg).ConclusionThis anti-shigellosis activity in vitro and in vivo attests the usefulness of Picralima nitida in the traditional treatment of gastrointestinal disorders such as dysentery.

Pollination efficiency of Xylocopa olivacea (Hymenoptera: Apidae) on Cajanus cajan (Fabaceae) flowers at Yaoundé, Cameroon

To assess the impact of the carpenter bee, Xylocopa olivacea Fabricius 1787, on the pod and seed yields of Cajanus cajan (L.) Millsp. 1900, in this study, its foraging and pollinating activities were examined in Nkolbisson during two seasons (July 2008-January 2009 and June-December 2009). Observations were made on 180 inflorescences per treatment. The treatments included unlimited floral access to all visitors, bagging of flowers to prevent access to all visitors, and floral access to limited visits by X. olivacea only, fn addition, information on all floral visitors was recorded. The carpenter bee’s seasonal rhythm of activity, its foraging behaviour on flowers, its pollination efficiency, the fruiting rate (Fr) and the number of seeds per pod were recorded. Nineteen species of insects were recorded visiting the flowers of C. cajan. Chalicodoma cincta cincta was the most prominent one, followed by X. olivacea, Apis mellifera adansonii, Megachile bituberculata and Xylocopa albiceps, and the bees were the most frequent floral visitors. Xylocopa olivacea mainly foraged for nectar and pollen and its foraging speed was 11.75 flowers/min. The Fr, the number of seeds/pod and the percentage of normal seeds of unprotected inflorescences were significantly higher than those of inflorescences protected from insects. The foraging activity of X. olivacea resulted in a significant increase in the Fr by 22.26%, as well as the number of seeds/pod by 34.98% and the percentage of normal seeds by 12.09% in the two study years. Placing X. olivacea nests close to C. cajan fields is recommended to increase pod and seed production in Cameroon.

New data on the taxonomy, ecology, and conservation of the rediscovered Louisea edeaensis (Bott, 1969) (Brachyura: Potamoidea: Potamonautidae), an endangered freshwater crab from Cameroon

The rare and endangered Cameroonian potamonautid freshwater crab Louisea edeaensis (Bott, 1969) was recently rediscovered during a biological inventory of the freshwater decapods of southern Cameroon. The previous record dated back more than 100 years. The new specimens allow an updated diagnosis of the species based on comparisons of important taxonomic characters. Photographs of the carapace, gonopods, third maxillipeds, and chelipeds of the largest adult male specimen from Lake Ossa, Cameroon are provided, as are the first photographs of living specimens. The conservation implications of the new data on habitat, population structure, distribution, and threats for this rare and endangered species are discussed.

Morphological and molecular evidence for a new species of freshwater crab of the genus Sudanonautes Bott, 1955 (Brachyura: Potamoidea: Potamonautidae) from Cameroon, with notes on its ecology

A new species of freshwater crab of the genus Sudanonautes Bott, 1955, is described from the tropical rainforests of Edea and Tiko in southern Cameroon, Central Africa. Sudanonautes tiko n. sp. is recognized by a unique combination of characters of the carapace, thoracic sternum, chelipeds, and male first gonopod, and by distinct mtDNA sequences for two loci (COI and 16S rRNA). A diagnosis, illustrations, and a tree of phylogenetic relationships based on mtDNA sequences are provided, along with a comparison to similar species from the region. Brief notes are provided on the ecology of the new species and of three other species of Sudanonautes collected during this study.

Phytolyma tchuentei sp.n. (Hemiptera: Homotomidae), a new species of psyllid associated with Morus mesozygia (Moraceae) from Cameroon

A new Phytolyma species from Cameroon is described. Phytolyma tchuentei sp.n. is similar to P. minuta Hollis but antenna, male and female terminalia are different from the four described African Phytolyma species. P. tchuentei sp.n. develops on Morus mesozygia (Moraceae). Unlike the other Phytolyma species, the new species does not cause galls on leaves and buds of its host.