Amblyseius swirskii are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. Tetranychus urticae is a global mite that is difficult to manage because of its high population growth rates, necessitating alternative management measures like biological control. Regarding the functional response, the effects of temperature and prey density are some of the essential behaviors of natural enemies. This study investigates the effect of varying temperatures and prey densities on A. swirskii, a biological control agent for T. urticae. The present results demonstrated the change in the functional response estimates when A. swirskii was reared at various temperatures and different prey densities. The results of the estimates regarding the searching efficiency (a′) showed the highest value (a′ = 0.919) at 26 °C and the lowest value (a′ = 0.751) at 14 °C. The handling time per prey item (T_h) for the predatory mites changed with the temperature and prey density, showing the shortest handling time at 26 °C (T_h = 0.005) and the highest value at 14 °C (T_h = 0.015). The functional response curves matched the type II functional response model, demonstrating the inverse dependence of temperatures and prey density with a positive quadratic coefficient. The predation curves for A. swirskii showed a significant difference between the mean numbers of T. urticae consumed at various prey densities and temperatures, illustrating a relationship between A. swirskii and T. urticae. Therefore, the results of this research may be utilized to forecast the behavior of A. swirskii and its usefulness in controlling T. urticae populations.

The functional response of adult females of the predatory mite Euseius scutalis (Athias-Henriot) was assessed at different prey densities of immature Tetranychus urticae Koch and variable plant texture using six plants (Cucumis sativus, Phaseolus vulgaris, Capsicum annuum, Vitis vinifera, Ficus carica and Cucumis melo). The present results demonstrated that the change in predation rate of E. scutalis is caused by the structural and morphological characteristics of the leaf and prey density. The handling time per prey item (T_h) of the functional response for the E. scutalis changed with plant leaf type and numerical density of the prey. The shortest handling time was on P. vulgaris, while the highest handling time was on C. melo. It was evident that the searching efficiency (a') was highest on C. annuum, while lowest on C. melo. On P. vulgaris and C. melo there was significant difference in the mean number of prey killed at the different prey densities. Curves of functional response matched those of the type II response model, implying inverse density-dependence in addition to a positive quadratic coefficient. These findings highlight the significance of host plant traits and prey density on E. scutalis performance and in optimizing natural enemy usage in biological pest management.

Studying the nutritional ecology of Neoseiulus cucumeris (Oudemans) at different temperatures is a fundamental tool for improving mass production for use in biological control of pest mites. The current research studied the impact of both food types and temperatures on the life history and demographic parameters of the predator mite N. cucumeris. Mite cultures in the laboratory were developed using Tetranychus urticae Koch, and N. cucumeris was collected from field plants. The developmental stages of N. cucumeris fed on date palm pollen and the immature stages of T. urticae were investigated in a laboratory setting at different temperatures. Our research revealed that N. cucumeris readily accepted both food types at all the tested temperatures. The developmental stages and adult longevity of N. cucumeris, both female and male, decreased dramatically when the temperature increased from 18 °C to 34 °C. The net reproductive rate (R₀) reached its greatest values of 22.52 and 9.72 offspring/individual at 26 °C, and the intrinsic rate of increase (r_m) reached its maximum values of 0.17 and 0.13 day⁻¹ at 34 °C and minimum of 0.12 and 0.10 day⁻¹ at 18 °C, when fed on date palm pollen and immature stages of T. urticae, respectively. Conversely, the average generation time (T) showed a notable reduction from 22.48 to 16.48 and 20.88 to 16.76 days, accompanied by an upsurge in temperature from 18 °C to 34 °C, when fed on date palm pollen and immature stages of T. urticae, respectively. The finite rate of growth (λ) exhibited distinct variations, reaching its highest value at 34 °C, 26 °C, and 18 °C when fed on date palm pollen and immature stages of T. urticae, respectively. From these results, we can conclude that N. cucumeris was successfully fed date palm pollen as an alternate source of nourishment. In addition, the immature stages of T. urticae are suitable as food sources for N. cucumeris because they shorten the mean generation time. Therefore, the success of mass-rearing the predator mite N. cucumeris on a different, less expensive diet, such as date palm pollen, and determining the most suitable temperature for it has increased its spread as a biocontrol agent.

Tetranychus urticae Koch is a polyphagous mite that infests various agricultural crops, ornamental plants, and fruit orchards worldwide (Maleknia et al. 2016; Elmoghazy et al. 2024). Due to issues ...