Effects of thermal shock on the survival and reproduction of Stratiolaelaps scimitus (Mesostigmata: Laelapidae).

The responses of arthropods to thermal stress are vital in ecological studies in order to understand survival, development, and reproduction. However, this subject is poorly addressed. In the order Mesostigmata, an abundance of species lives in the soil. Among these species, Stratiolaelaps scimitus (Womersley) is a predator used in the control of pest organisms that live in the soil. Mites of this species are commercialized in several countries, including Brazil, presenting efficiency in pest control in several crops. The objective of this study was to evaluate the effect of thermal shock on S. scimitus females, as well as to monitor the temperature variation in the environment. For each temperature, 80 experimental units were assembled for different periods (0.5, 1, 2, and 4 h). Experimental units were maintained at 25 °C, after exposure of the mites. Mortality and oviposition were evaluated. The results showed a 40% reduction in the survival of mites exposed to 37 °C for 4 h, compared to the control treatment (25 °C). Oviposition was less affected at 1 h exposure to temperatures of 19 and 12 °C and thermic fluctuation was observed in the greenhouse, especially inside the slabs. Understanding temperature effects in mites and the thermic fluctuation in the environment is essential to achieve satisfactory results in biological control. It is important to observe the scenario in which predatory mites will be released as these aspects are decisive in predatory activity.

Thermal requirements of Ophyra albuquerquei Lopes, 1985 (Diptera, Muscidae).

This study determines the development rates of the immature stages of the fly Ophyra albuquerquei Lopes, 1985. In this study, with 70% relative humidity and a 12-h photophase, eggs, larvae, and pupae were kept in a biochemical oxygen demand chamber at temperatures of 10, 15, 17, 20, 22, 25, 27, 30, 33, 35, and 40°C. While the rearing temperature increases, the development time for each immature stage of O. albuquerquei decreases and these stages develop at temperatures from 10 to 35°C. For eggs, the average minimum development time was 16h, and the average maximum development time was 81h. The average minimum development time for larvae and pupae was 7 and 6 days, respectively, and the average maximum development time was 22 and 42 days, respectively. To understand the development rate of each immature stage of the fly, a mathematical model is presented.