Responses of Episyrphus balteatus DeGeer (Diptera: Syrphidae) in relation to prey density and predator size

• Published in: Journal of Asia-Pacific entomology 2014, 17(3), , pp.207-211
• Main Authors: Amiri-Jami, Ali Reza, Sadeghi-Namaghi, Hussein
• Format: Article
• Language: English
• Subjects: Aphididae; Aphidophagous; Aphids; Aphis fabae; Diptera; Episyrphus balteatus; Fabaceae; Functional response; Homoptera; Hover flies; Numerical response; Population dynamics; Syrphidae; Vicia faba; 농수해양학
• ISSN: 1226-8615; 1876-7990
• DOI: 10.1016/j.aspen.2014.01.007

Laboratory experiments were conducted to determine the functional and numerical responses of the aphidophagous hover fly Episyrphus balteatus DeGeer (Diptera: Syrphidae) to different densities of 4th instar black bean aphids, Aphis fabae Scopoli (Homoptera: Aphididae), on broad bean, Vicia faba L. (Fabaceae). Two different-sized larvae of predators were tested in different densities of similar-sized prey to determine whether functional response parameters depended on the body sizes of predator and prey. In numerical response experiments, gravid E. balteatus females were exposed individually to different densities of 4th instars of A. fabae on cut sections of the broad bean plant, V. faba L. Logistic regression suggested a type II functional response for both larval sizes of E. balteatus. The searching efficiency (a) of the larger larvae was higher than that of the smaller ones. Prey consumption was higher, and handling time (Th) was lower for larger larvae than smaller ones. The theoretical maximum number of A. fabae nymphs eaten by the different-sized larvae was 125 and 269 nymphs per day. Larger E. balteatus larvae are more efficient predators for aphid management strategies. The reproductive numerical response, in terms of the number of eggs laid, increased curvilinearly with increasing prey density, but the proportion of eggs laid (egg number/prey density) decreased as the initial density of prey increased. [Display omitted] •We examined the responses of Episyrphus balteatus when fed on Aphis fabae as prey.•The experiments were in relation to prey density and predator size.•Logistic regression revealed a type II functional response for both larval sizes.•The larger larvae had a shorter handling time and higher searching efficiency.•Reproductive numerical response increased curvilinearly with increasing prey density.