Plant essential oils are important alternatives in green integrated pest management. This study examined the chemical composition, bioactivity, and control efficacy of four Lamiaceae essential oils (EOs) against Thrips flavus Schrank in laboratory conditions with the goal of exploiting plant-derived insecticides to control Thrips flavus. The four EOs tested were marjoram oil (Origanum majorana L.), clary sage oil (Salvia sclarea L.), perilla leaf oil (Perilla frutescens (L.) Britt.), and spearmint oil (Mentha spicata L.). All these EOs exhibited a certain degree of insecticidal activity against Thrips flavus. The median lethal concentration (LC₅₀) was determined after treatment by the leaf-dipping method in laboratory bioassays, and its values were 0.41 mg/mL for marjoram oil, 0.42 mg/mL for clary sage oil, 0.43 mg/mL for perilla leaf oil, and 0.54 mg/mL for spearmint oil. In the pot experiment, the number of dead insects was recorded at 1, 3, and 7 days post-application, and the control efficacy of EOs against Thrips flavus was calculated. The concentration of 900.00 g a.i.·hm⁻² of spearmint oil was 100% lethal against Thrips flavus after treating potted plants for seven days. The Y-tube olfactometer method was used to test for the attraction or repellent response of EOs against Thrips flavus. The spearmint oil significantly attracted female adults in the olfactory test. Furthermore, gas chromatography–mass spectrometry (GC–MS) was used to examine the chemical composition of the EOs. Linalool (24.52%), isopropyl myristate (28.74%), (+)-limonene (32.44%), and (+)-carvone (70.3%) were their primary ingredients. The findings suggest that all four EOs are highly effective against Thrips flavus and may be a possible alternative in the management of Thrips flavus, especially when considering reducing the use of synthetic pesticides.

Temperature plays a crucial role in influencing insect metabolism. In this study, we measured the body weight, CO₂ emissions, nutrient substances, nutrient metabolic enzymes, and antioxidative enzymes in Riptortus pedestris within the range of 24–44 °C. The results show that CO₂ emissions significantly varied between sexes and temperatures, peaking at 36 °C for females and 44 °C for males. The body weights were the lowest at 40 °C, with notable differences observed between genders. Total carbohydrate and protein contents were the highest at 44 °C, while glycogen and fat contents peaked at 36 °C and 40 °C for females and males, respectively. Enzyme activities varied, with glyceraldehyde-3-phosphate dehydrogenase and glycerol-3-phosphate dehydrogenase activities peaking at 28–32 °C, and citrate synthase activity fluctuated between 24 °C and 40 °C. Lactate dehydrogenase activity reached the highest level at 36 °C in females and at 32 °C in males and then decreased at 44 °C. 3-Hydroxyacyl-CoA dehydrogenase activity peaked at 44 °C in females and at 36 °C in males. Within the range of 24 °C to 44 °C, the ratio of HOAD to GAPDH indicated a shift from carbohydrate to lipid metabolism at higher temperatures, particularly at 44 °C. Superoxide dismutase peaked at 24 °C in females and at 44 °C in males. Catalase reached its maximum concentration between 32 °C and 40 °C. Malondialdehyde peaked between 32 °C and 36 °C. The total antioxidative capacity was the highest at temperatures between 24 °C and 36 °C. Peroxidase activity was the highest at temperatures ranging from 24 °C to 44 °C. Our observations suggest that temperature profoundly impacts the energy metabolism, enzyme activities, and physiological traits of R. pedestris.

The bean bug Riptortus pedestris (Hemiptera: Alydidae) is a major soybean pest in Asia, increasingly threatened by rising temperatures. It is crucial to clarify the high-temperature lethal thresholds of R. pedestris for predicting population dynamics under climate warming. Previous physiological data showed that female adults have significantly higher heat tolerance than males, with HLT₅₀ values of 39.76 °C versus 38.45 °C and HLT₉₀ values of 42.99 °C versus 42.44 °C. This sex-specific difference suggests distinct molecular responses to thermal stress. To test this hypothesis, we performed transcriptome sequencing of adults exposed to 24 °C (control), 40 °C (sublethal), and 44 °C (lethal), with males and females treated separately. A high-quality assembly yielded 270,199 unigenes, with 71 heat shock protein (HSP) genes identified across six subfamilies (sHSP, HSP40, HSP60, HSP70, HSP90, HSFs). HSPs exhibited a dual strategy: constitutive expression for basal proteostasis and strong induction—especially at 44 °C—for stress defense. Notably, responses were sexually dimorphic: females upregulated multiple stress-responsive HSPs (e.g., RpedHsp15.5-3, RpedHsp30.8) to protect reproduction, while males specifically induced RpedHsp83.6, possibly for signaling regulation. Phylogenetic analysis confirmed conservation within Hemiptera. These findings reveal the molecular basis of thermal adaptation in R. pedestris and identify key HSPs as potential targets for RNAi, HSP inhibitors, or precision thermal control.