Diversity, abundance, and trophic interactions of aphid parasitoids in a cereal-based agroecosystem in northeastern Algeria

Abstract This study aims to inventory the diversity and abundance of aphid parasitoids and analyze their trophic interactions in a durum wheat ( Triticum durum Desf.) field located in Guelma province, northeastern Algeria. The methodology involved the collection of mummified aphids, rearing of parasitoids in the laboratory, and their taxonomic identification. A total of 15 parasitoid species were identified, including 8 primary parasitoids and 7 hyperparasitoids. The results revealed a dominance of Aphidius ervi among primary parasitoids (21.74% of the total abundance) and Pachyneuron aphidis among hyperparasitoids (27.17%). Seasonal dynamics showed a peak in primary parasitoid activity during the third sampling session (May 10, 2022), followed by a sharp decline coinciding with the onset of wheat ear hardening. This transition was accompanied by an increase in hyperparasitoid activity, altering the overall effectiveness of natural aphid population regulation. Trophic networks were constructed to visualize species interactions, confirming the central role of Sitobion fragariae as the primary host. The high failure rate of parasitoid emergence (58.18%) raises concerns about the representativeness of the results, potentially requiring further research. These findings highlight the importance of integrating multitrophic dynamics and crop phenological variations to optimize integrated pest management (IPM) strategies in semi-arid cereal agroecosystems.