Abstract
Environmental factors, such as the duration of daylight, can significantly influence the predation ability of arthropod predators. This study aimed to examine the influence of photoperiods of 8:16 h, 12:12 h, and 16:8 h (L:D) on the predation rate of Phytoseiulus persimilis preying on Tetranychus urticae eggs under constant temperature. The daily predation rate (D(j)) and the total number of prey eggs consumed (P(j)) per predator increased with longer photophases, reaching their peak in the 16L:8D photoperiod. The highest net predation rate (C(0)) was observed under 16L:8D conditions (173.22 prey eggs/predator), while it was 170.28 and 89.77 prey eggs/predator under the 12L:12D and 8L:16D photoperiods, respectively. The finite predation rate (ω) also increased with longer photophases. The transformation rate (Q(p)) was highest under the 16L:8D photoperiod. Significant differences were noted in the stable predation rate (ψ), with the highest value being 5.84 prey eggs/predator under 16L:8D conditions. The number of T. urticae eggs predated by P. persimilis was higher under longer photoperiods, and the 16L:8D photoperiod can thus be recommended as optimal for the biocontrol of spider mites in controlled environments. We suggest that future research explores other effects of the light cycle on plant-herbivore-predator interactions to optimize the lighting conditions for effective spider mite control.