Abundância de espécies da mosca da fruta associadas ao Canhú (Sclerocarya birrea L.) com ênfase a Bactrocera dorsalis, num contexto de substituição competitiva

Abstract

Fruit flies (Diptera: Tephritidae) are important pests in the fruit growing sector due to the enormous direct losses they cause, resulting in reduced production and marketing of both non-native and native fruits. The species Bactrocera dorsalis is a type of invasive fruit fly that has been present in the country since 2007, triggering speculation that it is competing with and replacing native fruit fly species of the genera Ceratitis and Dacus, affecting the abundance of fruit flies. To verify the occurrence of competitive replacement, the present study was conducted, which consisted of collecting samples of canhú (Sclerocarya birrea L.) in Maputo Province and City. The samples were incubated in the laboratory until the emergence of adult fruit flies, which were identified and counted. Absolute and relative abundance of fruit fly species, percentage of emergence, male-female ratio, as well as infestation rates by pupae and adults were recorded. A total of 1477 adult fruit flies emerged from the fruits, belonging to three (3) species: Ceratitis cosyra (1220), Bactrocera dorsalis (237), Ceratitis capitata (20) with the highest relative abundance of C. cosyra. Regarding the male-female ratio, it was observed that all species had a higher proportion of males. Boane showed higher levels of infestation by pupae as well as by adults, with 1.40 pupae/fruit and 0.82 adults/fruit. The infestation of C. cosyra per fruit and by weight (Kg) was higher compared to the other species. Results suggest that the invasive fly B. dorsalis has not yet replaced the native C. cosyra in the host under study. (tradução nossa)