Three Heat Shock Protein Genes and Antioxidant Enzymes Protect Pardosa pseudoannulata (Araneae: Lycosidae) from High Temperature Stress.

Pardosa pseudoannulata (P. pseudoannulata) is an essential natural predatory enemy in rice ecosystems. The fluctuating climate may cause them to experience heat stress, whereas heat shock proteins (HSPs) and antioxidant enzymes help resist heat damage. Herein, we cloned and characterized the full-length genes PpHSP27, PpHSP60, and PpHSC70 from P. pseudoannulata. Changes in gene expression levels and superoxide dismutase (SOD), catalase (CAT), and glutathione transferase (GST) activities in adult male and female P. pseudoannulata were measured at different stress exposure times and temperatures. We found that the abovementioned HSP genes belong to the sHSP, HSP60, and HSP70 families. The expression of the three HSP genes and the activities of SOD, CAT, and GST were significantly upregulated with the increasing stress temperature and time. The knockdown of the three HSP genes via RNA interference significantly decreased the survival rate of male and female P. pseudoannulata during high temperature stress. Thus, PpHSP27, PpHSP60, and PpHSC70 play an important role in the heat tolerance of P. pseudoannulata, and SOD, CAT, and GST enable recovery heat stress-induced oxidative damage. Their changes and regulation during high temperature stress can improve spiders' adaptability in the field and enhance the biological control of environmental pests.

Fitness implications of low-temperature storage for Eocanthecona furcellata (Hemiptera: Pentatomidae).

Exploring the impact of low-temperature storage on the fitness of natural enemy insects is crucial for practical field applications because this parameter directly influences their potential for population growth and effective pest control. Eocanthecona furcellata (Wolff) (Hemiptera: Pentatomidae) is widely used in biological pest control. This study aimed to identify optimal storage stages, temperatures, and durations for E. furcellata to produce high-quality individuals for practical use. The quality of E. furcellata after storage was evaluated by assessing parameters such as predatory capacity and fecundity, along with age-stage, two-sex life table. The findings revealed that the adult stage was the optimal storage form for E. furcellata, and the most favorable temperature for storage was 12 °C. Adult females had the highest predatory ability after 15 days of storage at 12 °C. Although survival rates declined with prolonged storage, they remained above 50% after 30 days, and longevity, fecundity, and predatory capacity of surviving individuals remained comparable to those of individuals in the control group (rearing at a constant temperature of 26 °C without low-temperature storage). The effects of low-temperature storage extended to the F1 generation of E. furcellata, which exhibited maximum mean longevity, fecundity, net reproductive rate, and mean generation time as well as fastest population growth after 30 days of storage at 12 °C. These results can be used to achieve optimal low-temperature storage conditions for E. furcellata production, particularly for extending its shelf life.

Assessment of Suitable Reference Genes for qRT-PCR Normalization in Eocanthecona furcellata (Wolff).

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is a widely used tool for measuring gene expression; however, its accuracy relies on normalizing the data to one or more stable reference genes. Eocanthecona furcellata (Wolff) is a polyphagous predatory natural enemy insect that preferentially feeds on more than 40 types of agricultural and forestry pests, such as those belonging to the orders Lepidoptera, Coleoptera, and Hymenoptera. However, to our knowledge, the selection of stable reference genes has not been reported in detail thus far. In this study, nine E. furcellata candidate reference genes (ß-1-TUB, RPL4, RPL32, RPS17, RPS25, SDHA, GAPDH2, EF2, and UBQ) were selected based on transcriptome sequencing results. The expression of these genes in various samples was examined at different developmental stages, in the tissues of male and female adults, and after temperature and starvation treatments. Five algorithms were used, including ΔCt, geNorm, NormFinder, BestKeeper, and RefFinder, to evaluate reference gene expression stability. The results revealed that the most stable reference genes were RPL32 and RPS25 at different developmental stages; RPS17, RPL4, and EF2 for female adult tissue samples; RPS17 and RPL32 for male adult tissue samples; RPS17 and RPL32 for various temperature treatments of nymphs; RPS17 and RPS25 for nymph samples under starvation stress; and RPS17 and RPL32 for all samples. Overall, we obtained a stable expression of reference genes under different conditions in E. furcellata, which provides a basis for future molecular studies on this organism.