Hyperparasitism of Syrphophagus aphidivorus on Aphidius ervi Parasitizing Macrosiphum euphorbiae in Potato

Abstract

Hyperparasitism plays a significant role in regulating biological control efficiency in aphid–parasitoid systems, often influencing the stability and effectiveness of natural enemy complexes in agroecosystems. The present study investigated the hyperparasitism of Syrphophagus aphidivorus on Aphidius ervi parasitizing Macrosiphum euphorbiae in potato crops. Field surveys were conducted in major potato-growing regions to collect aphid mummies and assess parasitoid and hyperparasitoid interactions under natural conditions. Emergence data were recorded to determine rates of primary parasitism and secondary parasitism (hyperparasitism), along with seasonal variation in their occurrence. The results revealed the presence of S. aphidivorus actively attacking mummified aphids containing A. ervi larvae, thereby reducing the overall effectiveness of aphid biological control. Hyperparasitism rates varied across sampling locations and were influenced by aphid density, primary parasitoid abundance, and environmental conditions. Higher levels of hyperparasitism were generally observed during peak aphid infestation periods, indicating density-dependent interactions within the trophic system. The presence of hyperparasitoids resulted in reduced emergence of A. ervi adults, thereby weakening natural suppression of M. euphorbiae populations in potato fields. Seasonal dynamics suggested that temperature and humidity also influenced hyperparasitoid activity and survival. The study highlights the complexity of multitrophic interactions in aphid biological control systems and emphasizes the need to consider hyperparasitism when implementing parasitoid-based pest management strategies. These findings provide important insights into the ecological constraints of biological control and support the development of more robust integrated pest management approaches for sustainable potato production.