Long-term effects of cattail pollen on development, population growth potential, and predation capacity of <b> <i>Amblyseius swirskii</i> </b> (Acari: Phytoseiidae)
Alireza Hadadi, Yaghoub Fathipour, Hamidreza Hajiqanbar, Elham Riahi
Abstract
The development and demographic parameters of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) were determined on grains of cattail pollen over 20 consecutive generations (G1-G20). Biological parameters and predation rate of three long-term reread A. swirskii colonies, including those reared on cattail pollen for 10 and 20 generations then switched to Tetranychus urticae (A-G10, A-G20, respectively), and those of A-G10 who fed on T. urticae for three generations (A-G10-3) were evaluated and compared with those fed on T. urticae before long-term rearing (B-G1). According to the results, feeding on pollen for more than 10 generations resulted in a significantly higher intrinsic (r) and finite (λ) rate of increase values than those in the earlier generations. Pre-adult duration of A. swirskii in B-G1 and A-G10 was significantly longer than that in A-G20. Furthermore, r and λ values in B-G1 did not considerably differ from A-G10 and A-G20. The net reproductive rate (R0) of A-G10-3 was higher than that in A-G10, while it did not vary from B-G1. The r and λ were not affected by the time of feeding on natural prey. The net predation rate (C0) of A-G20 was lower than B-G1 and A-G10, while its transformation rate (Qp) was higher than the others. Overall, long-term feeding history did not negatively affect the biological and predation parameters of the predator because after switching from pollen to the prey, the predators’ growth and consumption rates did not change. Consequently, cattail pollen can be considered as a good candidate for A. swirskii mass rearing.