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Intraguild predation between Harmonia axyridis and Aphidius gifuensis: effects of starvation period, plant dimension and extraguild prey density

Yu, Xing-Lin, Feng, Yi, Fu, Wen-Yan, Sun, Yuan-Xing, Liu, Tong-Xian
BioControl 2019 v.64 no.1 pp. 55-64
Aphidius, Braconidae, Harmonia axyridis, Myzus persicae, adults, biological control, instars, laboratory experimentation, natural enemies, parasitoids, predation, predators, starvation
The effects of various factors on intraguild predation (IGP) between predators have been widely investigated. However, little is known about the influence of these factors on IGP between predators and parasitoids. Under laboratory conditions, we studied the effects of starvation period of predator, plant dimension, and extraguild prey density on IGP between Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) and Aphidius gifuensis Ashmead (Hymenoptera: Braconidae), two natural enemies of Myzus persicae (Sulzer) (Hemiptera: Aphididae). Both H. axyridis fourth instar and adults consumed A. gifuensis mummies. H. axyridis fourth instar and adults starved for 24 and 48 h had a higher frequency of IGP than those that were not starved. However, the number of aphids and mummies consumed by H. axyridis did not differ between the 24 and 48 h starvation treatments. Although IGP still occurred, mummy consumption decreased with increasing aphid density and plant dimension. In addition, H. axyridis consistently preferred aphids to mummies. Our results indicate that prey preference of H. axyridis, a shorter starvation period of predator (< 48 h), larger plant dimension, and higher extraguild prey density could reduce the frequency of IGP by H. axyridis on A. gifuensis, and thus decrease the negative impact of IGP on aphid control.