Effects of temperature on the development and reproduction of Macrocheles nataliae.

Macrocheles nataliae (Acari: Macrochelidae) holds promise as a biological control of soil-inhabiting pests. Temperature is a critical abiotic factor influencing the population dynamics and biocontrol efficacy of predatory mites. However, its effects on the development and reproduction of M. nataliae remain poorly understood. In this study, the effects of five constant temperatures (17, 21, 25, 29, and 33 °C) on the growth, survivorship and reproduction of M. nataliae fed on Carpoglyphus lactis was examined using the age-stage, two-sex life table theory and linear degree-day model. Within the 17-29 °C range, the developmental duration and adult longevity of both female and male M. nataliae decreased gradually with increasing temperature. Although immature mites successfully completed development at 33 °C, adult females failed to reproduce, which indicated that high temperature imposes severe inhibitory effects on reproductive function of M. nataliae. The developmental rates of all life stages were adequately described by the linear degree-day model (R² > 0.90), with lower developmental thresholds ranging from 11.11 to 12.61 °C across different stages. Life table analyses identified 25 °C as the optimal temperature for population performance, producing the maximum net reproductive rate (R0 = 14.98), intrinsic rate of increase (r = 0.15 d-¹), finite rate of increase (λ = 1.16 d-¹) and gross reproductive rate (GRR = 28.1). Females exhibited longer lifespans and higher reproductive values than males under suitable temperatures, and individual life expectancy consistently declined with rising temperature. This study firstly defines the suitable thermal range (17-29 °C), optimal temperature (25 °C), and high-temperature (33 °C) reproductive threshold of M. nataliae. These temperature-response parameters provide fundamental data for the mass rearing of this novel biocontrol mite resource under laboratory conditions, and offer a basis for further evaluation of its potential field performance.