Effects of cold stress on metabolic regulation in the overwintering larvae of the Chinese white pine beetle, Dendroctonus armandi

Abstract

The Chinese white pine beetle, Dendroctonus armandi Tsai & Li (Coleoptera: Curculionidae, Scolytinae), is considered the most destructive forest pest in the Qinling and Bashan Mountains of China. In recent years, winter temperature has dropped in these regions, and extremely low temperatures are hard to survive for insects. Cold hardiness becomes a crucial strategy because temperature change often leads to fluctuations in insect abundance, and the metabolism rate is a key index of resistance to cold in overwintering insects. Therefore, we investigated the relationship between the change in respiratory rate and the activity of metabolism-related mitochondrial enzymes in D. armandi larvae under cold conditions. We found that the respiratory rate decreased, and it was matched with the activity of glutamate dehydrogenase, aconitase, and lipase during overwintering. Among the various test times under cold conditions, the respiratory rate also decreased with decreasing temperature and increased under very low temperatures. At all cold stress periods, glutamate dehydrogenase and lipase showed increased activity at higher temperatures and decreased activity under lower temperatures, but the activity of NAD-malic enzyme, NADP-malic enzyme, mitochondrial isocitrate dehydrogenase, and aconitase were contrary. Under all low temperatures, the activity of enzymesexcept for NADP-malic enzyme, glutamate dehydrogenase, and lipaseincreased in short-term cold stress and decreased in long-term cold stress at 4, 0, −4, −6, −8, and −10°C. However, at −2°C, the activity of enzymes showed a decreasing trend in short-term treatments and an increasing trend in long-term treatments, except for mitochondrial isocitrate dehydrogenase. The results not only improve our understanding of the metabolic mechanism of cold adaptation in D. armandi, but also provide an important experimental basis for further study and biological pest control.

Roles of Krüppel Homolog 1 and Broad-Complex in the Development of Dendroctonus armandi (Coleoptera: Scolytinae)

“…RNA interference (RNAi) technology has now become a widely used tool to analyze the gene functions of Chinese white pine beetle ( Dendroctonus armandi Tsai and Li). Chen‘s team used RNAi to investigate and analyze the olfactory receptor coreceptor ( DarmOrco ), chemoreceptor ( DarmCSP2 ), aquaporins ( DaAqps ), antifreeze protein genes ( DaAFP ), Capa peptide receptors ( DaCapaRs ), neuropeptide F ( DaNPF ), and 3-hydroxy-3-methylglutaryl coenzyme A reductase genes ( HMGR ) in D. armandi ( Zhang et al, 2016 ; Li et al, 2018 ; Fu et al, 2019 , 2020 , 2021 ; Liu et al, 2021 ; Sun et al, 2021 ). Sun et al (2022) discovered that allatostatin C (PISCF/AST) and juvenile hormone acid O-methyltransferase ( JHAMT ) were major regulators of juvenile hormone synthesis in D. armandi after obtaining dsRNA technology via the L4440 vector construction.…”

The Effect of Ice-Nucleation-Active Bacteria on Metabolic Regulation in Evergestis extimalis (Scopoli) (Lepidoptera: Pyralidae) Overwintering Larvae on the Qinghai-Tibet Plateau

“…Several studies have demonstrated the protective function of trehalose against potential harm that is induced by cold stress in overwintering insects. A marked increase in trehalose concentration was found in Drosophila immigrans after their recovery from cold stress conditions [ 16 ]. Wharton [ 32 ] has indicated that trehalose acts as a cryoprotectant in alpine weta ( Hemideina maori ) and alpine cockroach ( Celatoblatta quinquemaculata ) when they acclimate to rapid cold hardening.…”

“…Low winter temperatures limit the insect populations, activities, and development. The ability to survive annual temperature minima could be a key determinant of insect distribution [ 16 ]. A high level of trehalose in the body plays a key role in protecting them against chilling stresses [ 17 , 18 ].…”

“…A high level of trehalose in the body plays a key role in protecting them against chilling stresses [ 17 , 18 ]. For example, Drosophila immigrans and D. melanogaster that are hardened or acclimated to cold stress are characterized by a stress-triggered accumulation of trehalose [ 16 , 17 , 19 ]. Furthermore, alterations in the level of trehalose could regulate the growth and cold tolerance of Trichogramma dendrolimi [ 16 ].…”

“…For example, Drosophila immigrans and D. melanogaster that are hardened or acclimated to cold stress are characterized by a stress-triggered accumulation of trehalose [ 16 , 17 , 19 ]. Furthermore, alterations in the level of trehalose could regulate the growth and cold tolerance of Trichogramma dendrolimi [ 16 ]. Trehalase (EC 3.2.1.28) hydrolyzes one trehalose molecule into two glucose molecules in insect species, many of which have been identified and cloned, including in Bombyx mori (Lepidoptera: Bombycidae) [ 20 ] and Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) [ 21 ].…”