L'homme et l'animal dans le bassin du lac Tchad

Le glossaire (encore incomplet) du vocabulaire des Mofu de Douvangar recense près de 140 mots désignant des insectes et autres anthropodes. Ce vocabulaire est analysé d'un point de vue exclusivement entomologique. Certains mots peuvent être rapprochés des taxons de la classification zoologique (au niveau des groupes espèce, sous-famille, famine ou ordre). Mais serait-il pertinent de confondre des concepts issus d'approches aussi différentes de la nature ? Il ne suffit pas qu'un terme vernaculaire désigne un animal ou un groupe d'animaux précis pour être assimilable à un taxon ! Un taxon est un concept qui n'existe que dans le cadre d'une théorie scientifique. Les Mofu ne nomment pas tous les insectes qu'ils côtoient : certains les intéressent beaucoup et d'autres pas du tout. Leur grille d'analyse, logique, cohérente et non dépourvue d'efficacité pratique, s'inscrit dans une conception du monde très différente de la nôtre, fondée sur le paradigme scientifique contemporain (le monde "désenchanté"). L'entomologiste à l'écoute du discours des Mofu sur les insectes est ballotté entre ce qu'il perçoit d'une part comme des observations souvent fines de la réalité objective, et d'autre part comme relevant d'une riche mythologie qui lui est étrangère. Il ne peut s'empêcher de s'interroger : "Et si notre paradigme scientifique était lui aussi une mythologie" ? Mais ceci est une autre histoire. (Résumé d'auteur

Functionnal biodiversity in mango orchards on Reunion. Ecosystemic and landscape effects on epigeous predatory arthropods.

The knowledge of factors implicated in agroecosystem diversity is necessary to better evaluate their role. The study aims to link within-field plant diversity, cultural practices, and landscape context with terrestrial predatory arthropods in mango orchards on Reunion. Twenty-four plots distributed within the mango production area have been studied. Arthropods were sampled with pitfall traps. The land plots were grouped into three groups of agricultural practice intensity. The landscape was mapped within a circle of 400 meters around the orchards, which permitted to distinguish three different landscape contexts. Based on 83181 arthropods collected, 65124 were determined as predators, their communities were mainly composed of ants (Hymenoptera: Formicinae) and spiders (Araneae). The species richness and their equitability were influenced by factors at three different scales: (1) the within-field plant diversity improved evenness of predatory arthropods communities; (2) the moderate farming practices, as organic farming practices, had higher species richness than those obtained with “conventionnal” practices; (3) a landscape context with relevant heterogeneity and fragmentation increased the species richness of epigeal predatory arthropods in mango orchards

Inventaire des plantes-hôtes d'Aphis gossypii Glover (Hemiptera, Aphididae) en Afrique

L'inventaire des plantes-hôtes d'#Aphis gossypii$ sur le continent africain est établi à partir de données bibliographiques en tenant compte des dernières modifications et synonymies de la classification botanique. 658 espèces appartenant à 103 familles et 420 genres sont recensées. (Résumé d'auteur

Fruit flies (Diptera: Tephritidae) on vegetable crops in Reunion Island (Indian Ocean): state of knowledge, control methods and prospects for management

Significance of fruit flies in vegetable crops. Vegetable crops hold a key position in agricultural production in Reunion (Indian Ocean); however, many pests and diseases threaten the profitability of this agricultural sector. Fruit flies (Diptera: Tephritidae) figure among the main pests for solanaceous crops and cucurbits (cucumber, zucchini, melon, etc.). Losses of as much as 80% of tomato and 100% of cucurbit crop harvests have been frequently observed. Inventory and distribution. Four fruit fly species belonging to the Tephritidae family cause major damage to vegetable crops in Reunion: Bactrocera cucurbitae (Coquillet), Dacus ciliatus Loew and D. demmerezi (Bezzi) on Cucurbitaceae, and Neoceratitis cyanescens (Bezzi) on Solanaceae (primarily the tomato). Distribution of each of them is presented. Biology and behavior. A few studies on the biology and behavior of the four fruit flies were conducted in Reunion in the late 1990s. Their main biological characteristics are summarized. Population control methods used in Reunion. Various methods such as chemical control, preventive measures (sanitation), physical control, biotechnical control [colored traps, the Male Annihilation Technique (MAT) and the Bait Application Technique (BAT)], and biological control currently used in Reunion against fruit flies are reported. Other control methods such as Integrated Pest Management and the Sterile Insect Technique are not used in Reunion. Prospects for implementing agro-ecological management of vegetable fruit flies in Reunion. This part presents research actions implemented in fly bio-ecology, research actions into the genetic structure of populations and design of an agro-ecological management scheme for vegetable fruit flies. Conclusions. The control methods used independently have not been successful to effectively control tephritid populations. A more integrated approach is required, also taking into account the landscapescale and its mosaic of habitats, especially wild plants, whose role must be considered within a framework of agro-ecological management of these pest populations