Functional response and mutual interference of Episyrphus balteatus and Scaeva albomaculata (Dip.: Syrphidae) fed on Myzus persicae (Hom.: Aphididae)

Functional response and mutual interference of two aphidophagous syrphid flies Episyrphus balteatus and Scaeva albomaculata fed on Myzus persicae were determined in laboratory conditions at 25 ± 2ºC, 55 ± 10 relative humidity and a photoperiod of 16L:8D h. Using logistic regression, a type II functional response was determined for both predators. The Rogers model was used for estimating searching efficiency (a) and handling time (Th). For the first, second and third instars of E. balteatus, the estimated values of searching efficiency were 0.0359, 0.0420, and 0.0677 and the values of handling time were 2.257, 0.506 and 0.316, respectively. For the second and third instars of S. albomaculata, the estimated values of searching efficiency were 0.0590, and 0.0655 and the values of handling time were 0.575 and 0.252, respectively. According to the obtained results, no significant relationship was observed between log searching efficiency (a) and log third instars density (P) of E. balteatus, but this relationship was significant in S. albomaculata and the value of interference coefficient for third instars of this predator fed on 100 density of M. persicae was -0.274.