Suchergebnisse

Introduction: In Africa, fruit trees are an important yet a neglected component of people's livelihood that contribute to food security via dietary diversity. Mango trees are attacked by invasive and native fruit flies that are quarantine pests in many parts of the world, including European Union and the United States, threatening export markets. To control fruit flies, farmers usually spray chemicals and harvest the fruits earlier. Conservation biological control is considered as the biological control strategy with great potential for field use in developing world agriculture. Previous studies highlighted the weaver ant, Oecophylla longinoda(Latreille)(Hymenoptera: Formicidae) as a key generalist natural enemy to control this pest, but it is an aggressive predator that disturbs farmers during the harvest. The aim of this study was to improve the biocontrol by finding a sugar source to develop the ant population and to find repellents to protect farmers. Methods: We studied the nectar of cowpea as a sugar source and we tested the repellent effect of 10 products by video tracking. Results/Conclusion: We showed in the laboratory that the extrafloral nectar of cowpea is a sugar source for ants but we found differences in the varieties' attractiveness. Among the repellent tested, the oily ones, coconut oil and paraffin, were the most repellent followed by the powders, talcum, palm ashes and cassava flour, whereas the aqueous repellent, lemongrass extract and lemon juice, did not repel weaver ants. These results are crucial for the development of conservation biological control programs using weaver ants. (Texte integral)

The African weaver ant, Oecophylla longinoda, is used as a biological control agent for the management of pests. The ant has several exocrine glands in the abdomen, including Dufour's, poison, rectal, and sternal glands, which are associated with pheromone secretions for intra-specific communication. Previous studies have analyzed the gland secretions of Dufour's and poison glands. The chemistry of the rectal and sternal glands is unknown. We re-analyzed the secretions from Dufour's and poison glands plus the rectal and sternal glands to compare their chemistries and identify additional components. We used the solid-phase microextraction (SPME) technique to collect gland headspace volatiles and solvent extraction for the secretions. Coupled gas chromatography– mass spectrometry (GC-MS) analysis detected a total of 78 components, of which 62 were being reported for the first time. These additional components included 32 hydrocarbons, 12 carboxylic acids, 5 aldehydes, 3 alcohols, 2 ketones, 4 terpenes, 3 sterols, and 1 benzenoid. The chemistry of Dufour's and poison glands showed a strong overlap and was distinct from that of the rectal and sternal glands. The different gland mixtures may contribute to the different physiological and behavioral functions in this ant species. ; The Deutscher Akademischer Austauschdienst (DAAD), a doctoral scholarship through the icipe ARPPIS-DAAD scholarship programme, the German Academic Exchange Service (DAAD), the University of Pretoria, and the International Centre of Insect Physiology and Ecology (icipe) Capacity Building Program, the Agricultural Research for Development (CIRAD), the UK's Foreign, Commonwealth and Development Office (FCDO), the Swedish International Development Cooperation Agency (SIDA), the Swiss Agency for Development and Cooperation (SDC), the Government of the Federal Democratic Republic of Ethiopia, and the Government of the Republic of Kenya. ; http://www.mdpi.com/journal/molecules ; am2021 ; Zoology and Entomology