Neoseiulus bicaudus (Wainstein) (Acari: Phytoseiidae) is a native predatory mite species in Xinjiang, China, and a biological control agent for some small pests, such as Tetranychus turkestani (Acari: Tetranychidae) and Thrips tabaci (Thysanoptera: Thripidae) in greenhouse. However, little is known whether N. bicaudus could be an effective natural enemy of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). A series of laboratory and greenhouse experiments were conducted to evaluate the efficiency of N. bicaudus on B. tabaci. The present data showed that each stage of N. bicaudus demonstrated type II functional response when fed on B. tabaci. The adult females showed the highest consumption rate and attack rate, and the shortest handling times were obtained when they preyed on eggs and 1^st instar nymphs. The 1^st instar of B. tabaci was preferred for the feeding of N. bicaudus adult females than eggs, followed by 2^nd instar nymphs of B. tabaci. Under greenhouse conditions, this predator effectively suppressed the population growth of B. tabaci throughout the experimental period. Accordingly, N. bicaudus could be an efficient predator for B. tabaci.

In the polyphagous insect Monolepta signata (M. signata) (Coleoptera: Chrysomelidae), antennae are important for olfactory reception used during feeding, mating, and finding a suitable oviposition site. Based on NextSeq 6000 Illumina sequencing, we assembled the antennal transcriptome of mated M. signata and described the first chemosensory gene repertoire expressed in this species. The relative expression levels of some significant chemosensory genes were conducted by quantitative real-time PCR. We identified 114 olfactory-related genes based on the antennal transcriptome database of M. signata, including 21 odorant binding proteins (OBPs), six chemosensory proteins (CSPs), 46 odorant receptors (ORs), 15 ionotropic receptors (IRs), 23 gustatory receptors (GRs) and three sensory neuron membrane proteins (SNMPs). Blastp best hit and phylogenetic analyses showed that most of the chemosensory genes had a close relationship with orthologs from other Coleoptera species. Overall, this study provides a foundation for elucidating the molecular mechanism of olfactory recognition in M. signata as well as a reference for the study of chemosensory genes in other species of Coleoptera.

The effects of changes in the malondialdehyde (MDA) content on the quality of fish during the low-temperature storage period are unclear. Therefore, the effects of the MDA content on Coregonus peled quality and protein changes were investigated following storage under refrigeration (4 °C) and super chilling (−3 °C) for 15 days (d). The results showed that the MDA content continued to increase during storage and that the highest content was produced at 1.42 mg/kg during refrigeration. The fillet pH, drip loss, texture (hardness and elasticity), and myofibril fragmentation index deteriorated significantly during the storage period. Increased oxidation of the myofibrillar protein (MP) was observed in the 15 d storage period, and the MP carbonyl content was 1.19 times higher under refrigeration than in super chilling, while the protein α-helix structure decreased by 12.48% and 12.20% under refrigeration and super chilling, respectively. Electropherograms also showed that myosin degradation was particularly severe in the refrigeration storage period of 15 d. Overall, the MDA formed at the refrigeration and super chilling storage temperatures could promote structural changes in, and the oxidative degradation of, proteins to different degrees, leading to the deterioration of the fillet quality. This study provides a scientific basis for investigating the relationship between fish quality and changes in the MDA content during low-temperature storage.

Ferritin, as an iron storage protein, regulates iron metabolism and delivers bioactive substances. It has been regarded as a safe, new type of natural iron supplement, with high bioavailability. In this paper, we extracted and purified ferritin from northern pike liver (NPLF). The aggregation stabilities, assemble properties, and structural changes in NPLF were investigated using electrophoresis, dynamic light scattering (DLS), circular dichroism (CD), UV–Visible absorption spectroscopy, fluorescence spectroscopy, and transmission electron microscopy (TEM) under various thermal treatments. The solubility, iron concentration, and monodispersity of NPLF all decreased as the temperature increased, and macromolecular aggregates developed. At 60 °C and 70 °C, the α-helix content of ferritin was greater. The content of α-helix were reduced to 8.10% and 1.90% at 90 °C and 100 °C, respectively, indicating the protein structure became loose and lost its self-assembly ability. Furthermore, when treated below 80 °C, NPLF maintained a complete cage-like shape, according to the microstructure. Partially unfolded structures reassembled into tiny aggregates at 80 °C. These findings suggest that mild thermal treatment (80 °C) might inhibit ferritin aggregation while leaving its self-assembly capacity unaffected. Thus, this study provides a theoretical basis for the processing and use of NPLF.

Neoseiulus bicaudus (Wainstein) is a natural enemy of spider mite and thrip and also a potential biocontrol agent for Tetranychus turkestani (Tetranychidae). Tyrophagus putrescentiae (Schrank) is an important alternative prey of N. bicaudus for mass rearing. We aimed to determine whether previous long-term feeding history, rearing on alternative prey versus target prey affected the performance of N. bicaudus. Therefore, the prey preference and functional response of predatory mites were compared between three strains: N. bicaudus fed on T. turkestani (TTS); N. bicaudus fed on T. putrescentiae (TPS); and N. bicaudus re-adapted from T. putrescentiae to T. turkestani (TPRS). When fed with the target prey, the preference rate and consumption of the TPS strain were significantly lower than the TTS strain. In addition, after 3-day-re-adaptation, the predatory mites (TPRS) increased their preference rate and consumption to target prey. The results suggested that re-adaptation before release could improve the ability of N. bicaudus to control its target prey.

Tetranychus turkestani is a serious pest of cotton, corn, vegetables, fruit trees and forests in Xinjiang. All life stages of T. turkestani were observed using both light and scanning electron microscope. The egg is smooth and spherical. The eupathidial spinnerets of larva and protonymph are different from that of the deutonymph and adult in shape. The spinneret of adult female is obviously thicker and larger than that in male. The palpfemoral seta of adult male is a short, stout, spine-like process. T. turkestani has fourteen pairs of dorsal setae. The number of ventral setae increases regularly in number in each molt. The leg chaetotaxy has a great change from larva to deutonymph.