Effect of photoperiod on development and demographic parameters of Neoseiulus barkeri (Acari: Phytoseiidae) fed on Tyrophagus putrescentiae (Acari: Acaridae).

Abstract

Effects of five photoperiods (Light:Dark=4:20, 8:16; 12:12, 16:8, 20:4) on the development, survival and reproduction of Neoseiulus barkeri Hughes fed on storage mite Tyrophagus putrescentiae (Schrank) were examined under laboratory conditions at 85% relative humidity and 24°C. Development time of almost all immature stages in N. barkeri was the shortest (5.43±0.12days) under 12h of daylight. Total duration of immature stages was as high as 8.55±0.16days during the longest photoperiod. Photoperiod had no effect on hatching rate, but did affect survival of larvae, protonymphs and deutonymphs. Total survivorship ranged from 20 (4:20) to 60% (12:12). Under 12h daylight, female adults had the shortest pre- and post-oviposition period, longest oviposition period and longevity, largest total number of eggs (15.95) and and highest daily egg production (1.43) per female. Under 12h light, N. barkeri experienced its highest net reproductive rate (R 0 =11.791), intrinsic rate of increase (r m =0.180), and finite rate of increase (λ=1.197), and lowest mean generation time (t=13.71days) and population doubling time (DT=3.86days). All demographic parameters displayed a parabolic relationship with photoperiod. The results of the present study indicated that the photoperiod of 12:12 is optimal for the development and reproduction of N. barkeri fed on T. putrescentiae, and that N. barkeri may serve most efficiently as a biological control agent under this regime.