Intermittent food shortages are commonly encountered in the wild. During winter or starvation stress, mammals often choose to hibernate while insects—in the form of eggs, mature larvae, pupae, or adults opt to enter diapause. In response to food shortages, insects may try to find sufficient food to maintain normal growth and metabolism through distribution of populations or even migration. In the face of hunger or starvation, insect responses can include changes in behavior and/or maintenance of a low metabolic rate through physiological adaptations or regulation. For instance, in order to maintain homeostasis of the blood sugar, trehalose under starvation stress, other sugars can be transformed to sustain basic energy metabolism. Furthermore, as the severity of starvation increases, lipids (especially triglycerides) are broken down to improve hunger resistance. Starvation stress simultaneously initiates a series of neural signals and hormone regulation processes in insects. These processes involve neurons or neuropeptides, immunity-related genes, levels of autophagy, heat shock proteins and juvenile hormone levels which maintain lower levels of physiological metabolic activity. This work focuses on hunger stress in insects and reviews its effects on behavior, energy reserve utilization, and physiological regulation. In summary, we highlight the diversity in adaptive strategies of insects to hunger stress and provides potential ideas to improve hunger resistance and cold storage development of natural enemy insects. This gist of literature on insects also broadens our understanding of the factors that dictate phenotypic plasticity in adjusting development and life histories around nutritionally optimal environmental conditions.

Coal burning is a main concern for a range of atmospheric pollutants, including the environmentally sensitive element chromium (Cr). Cr migrates to the environment through stack emissions and can leach out from solid coal-burning byproducts, thereby causing adverse effects on the ecosystem. In this study, atmospheric emissions of Cr from six coal-fired power plants (CFPPs), as well as the distribution of Cr inside these CFPPs in Guizhou Province, Southwest China, were investigated. Among the six CFPPs, one was a circulating fluidized bed boiler and the others were pulverized coal boilers. The results showed that Cr in the feed fuel of these CFPPs ranged from 39.5 to 101.5 mg·kg−1 (average: 68.0 ± 24.8 mg·kg−1) and was approximately four times higher than the national and global average. Cr in the feed fuel correlated significantly with the ash yield, demonstrating that Cr in coal is closely associated with ash-forming minerals. After the coal combustion and the treatment by different air pollution control devices, most Cr (>92%) in the installation was retained in the captured fly ash and bottom ash, with less as gypsum (0.69–7.94%); eventually, only 0.01–0.03% of Cr was emitted into the atmosphere with a concentration of 1.4–2.2 μg·Nm−3. The atmospheric emission factors of Cr for these utility boilers were as low as 14.86 ± 3.62 mg Cr·t−1 coal, 7.72 ± 2.53 μg Cr (kW·h)−1, and 0.70 ± 0.19 g Cr·TJ−1, respectively. About 981 kg·y−1 of Cr was discharged into the atmosphere from Guizhuo’s CFPPs in 2017, much lower than previous reported values. Most of the Cr in the CFPPs ended up in solid combustion products, identifying the need for the careful disposal of high-Cr-containing ashes (up to 500 mg·kg−1) to prevent possible mobilization into the environment.

A new hyphomycete, Rhexoacrodictys broussonetiae is described and illustrated from specimens collected on dead Broussonetia papyrifera stems in Guizhou Province, China. It is characterized by distinct, unbranched conidiophores with monoblastic, percurrently extending conidiogenous cells that produce acrogenous, subspherical to spherical, 17–28 × 19–31 μm, 0–2 transversely septate conidia with several additional oblique longitudinal septa. A dichotomous key to the four Rhexoacrodictys species is provided.

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Mercury (Hg)-laden coal fly ash is an environmental concern when it is exposed to precipitation or surface/groundwater under natural conditions. In this study, fly ash samples collected from fifteen coal-fired power plants in Guizhou province of southwest China were subjected to examine the different Hg binding forms. The results showed that total Hg in fly ash from these CFPPs ranged from 30 to 870 ng/g. The percentage of different Hg binding forms in coal fly ash decreased in the following order: strong complexed form (64%–91%) > acid-soluble form (1%–25%) and sulfide form (3.4%–14.8%) > ion-exchangeable form (0.01%–8.1%), and water-soluble form (0.01%–4.4%). The low proportion of water-soluble and ion-exchangeable forms indicated that Hg was not easily removed under natural conditions. Furthermore, fly ash samples from three out of fifteen CFPPs were carried out the leaching experiments to disclose the leachability of Hg and the transmedia migration potential of this element. The results indicated pH dependence of Hg leachability, with more than 4-times fold higher Hg been leached out under acidic (pH < 5.5) and strong alkaline (pH > 13) conditions than under neutral and weakly alkaline conditions (pH = 7–12). In addition, Hg was leached out more in higher liquid/solid ratio than lower ratios. Nevertheless, Hg concentration in extract (<7 ng/L) of these three CFPPs under all conditions was well below the applicable regulation limits, and less than 0.11% of total Hg was leached out. This study demonstrated that Hg in the CFPP fly ashes was more stable under natural conditions when exposed to surface/groundwaters and had a negligible Hg leachability.