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Insects Apr 2024Adults of the pine sawyer are the primary vector of , the causative agent of pine wilt disease. A sawyer subspecies in Taiwan (abbreviated 'T') has two generations a...
Adults of the pine sawyer are the primary vector of , the causative agent of pine wilt disease. A sawyer subspecies in Taiwan (abbreviated 'T') has two generations a year (bivoltinism) due to facultative diapause, whereas another subspecies in Japan (abbreviated 'J') has a one- or two-year life cycle due to obligate diapause. T, with two infection periods a year, will cause more severe disease epidemics than J if it is introduced into Japan. Inter-subspecies hybridization may inhibit the expression of bivoltinism because many F1 hybrids induce diapause. To predict the effects of introducing T into Japan, the present study investigated copulation duration and late-male sperm precedence to fertilize eggs. The results indicated that a single copulation for more than 65 s supplied sufficient sperm to fertilize a lifetime production of eggs. The incidence of larval diapause was 0.15 for the offspring of T females that mated with a T male and increased to 0.292-0.333 after remating with a J male, while the incidence of larval diapause was 0.900-1.000 for hybrids from T females mated with a J male. Consequently, the estimated proportion of second-male sperm used by T females was 0.185-0.217. The effects of introducing T populations into Japan on the severity of disease epidemics were also discussed.
PubMed: 38667385
DOI: 10.3390/insects15040255 -
Current Issues in Molecular Biology Apr 2024is a widely distributed small aquatic crustacean, renowned for its ability to enter a state of embryonic diapause. The embryonic diapause termination (EDT) is closely...
is a widely distributed small aquatic crustacean, renowned for its ability to enter a state of embryonic diapause. The embryonic diapause termination (EDT) is closely linked to environmental cues, but the precise underlying mechanisms remain elusive. In this study, ATAC-seq and RNA-seq sequencing techniques were employed to explore the gene expression profiles in cysts 30 min after EDT. These profiles were compared with those during diapause and 5 h after EDT. The regulatory mechanisms governing the EDT process were analyzed through Gene Ontology (GO) enrichment analysis of differentially expressed genes. Furthermore, the active G-protein-coupled receptors (GPCRs) were identified through structural analysis. The results unveiled that the signaling transduction during EDT primarily hinges on GPCRs and the cell surface receptor signaling pathway, but distinct genes are involved across different stages. Hormone-mediated signaling pathways and the tachykinin receptor signaling pathway exhibited heightened activity in the '0-30 min' group, whereas the Wnt signaling pathway manifested its function solely in the '30 min-5 h' group. These results imply a complete divergence in the mechanisms of signal regulation during these two stages. Moreover, through structural analysis, five GPCRs operating at different stages of EDT were identified. These findings provide valuable insights into the signal regulation mechanisms governing diapause.
PubMed: 38666959
DOI: 10.3390/cimb46040229 -
Integrative and Comparative Biology Apr 2024In temperate environments most species of insects enter an arrested state of development, known as diapause, that enables them to survive the adverse environmental...
In temperate environments most species of insects enter an arrested state of development, known as diapause, that enables them to survive the adverse environmental conditions associated with winter. Although diapause is restricted to a single life stage within species of insects, there are examples of insects that overwinter in the egg, larval, pupal and adult stages. Here we offer a targeted, non-systematic literature review examining how overwintering impacts subsequent reproduction in female insects. Several factors, including the lifestage at which insects overwinter, the type of energy investment strategy females use for breeding, elements of the winter environment, and contributions from male insects can influence trade-offs that female insects face between overwintering survival and post-diapause reproduction. Additionally, climate change and elements of the urban environment, including light pollution and higher temperatures in cities, can exacerbate or ameliorate trade-offs faced by reproducing female insects. Better understanding trade-offs between overwintering survival and reproduction in insects not only enhances our understanding of the underlying physiological mechanisms and ecological processes governing diapause and reproduction, but also provide opportunities to better manage insect pests and/or support beneficial insects.
PubMed: 38664063
DOI: 10.1093/icb/icae027 -
Experimental & Applied Acarology May 2024The European red mite Panonychus ulmi (Koch) is widely distributed and it can severely affect pome fruit crops, particularly apple. Pest outbreaks are related to an...
Influence of abiotic factors on diapause termination and temperature requirements for postdiapause development in the European red mite, Panonychus ulmi (Acari: Tetranychidae).
The European red mite Panonychus ulmi (Koch) is widely distributed and it can severely affect pome fruit crops, particularly apple. Pest outbreaks are related to an overuse of non-selective pesticide treatments that lead to the development of resistance and the absence of natural enemies in the orchard. A key aspect to optimize the use of pesticide treatments in the context of IPM is to increase the knowledge on the biology and ecology of the pest to better predict population dynamics and outbreaks. For the European red mite, knowledge on the conditions that lead to diapause breaking by winter eggs is essential to model population dynamics. To increase this knowledge, winter eggs were collected during field surveys in northen Spain during three years and egg hatching was monitored under controlled temperature and photoperiod conditions in the laboratory. The "number of days exposed to cold temperatures" was the most significant factor that positively affected hatching of overwintering eggs. The time required for 50% of the egg population to hatch (T) was also negatively modulated by the duration of exposure to cold temperature. The temperature threshold for postdiapause eggs development collected from the field was estimated between 5 and 6 ºC in 2005 and 2007, respectively. Moreover, the degree-days required for post diapause development were estimated between 263.2 and 270.3, depending on the year of collection. Collectively, we provide additional information on the diapause termination and postdiapause development of the European red mite that may effectively contribute to optimize pest population models.
Topics: Animals; Tetranychidae; Diapause; Ovum; Temperature; Spain; Photoperiod; Cold Temperature; Female; Seasons
PubMed: 38637448
DOI: 10.1007/s10493-024-00904-9 -
Biology Letters Apr 2024In a previous study, an experimental oversight led to the accumulation of water filling a container housing diapausing bumblebee queens. Surprisingly, after draining the...
In a previous study, an experimental oversight led to the accumulation of water filling a container housing diapausing bumblebee queens. Surprisingly, after draining the water, queens were found to be alive. This observation raises a compelling question: can bumblebee queens endure periods of inundation while overwintering underground? To address this question, we conducted an experiment using 143 common eastern bumblebee () queens placed in soil-filled tubes and subjected to artificially induced diapause in a refrigerated unit for 7 days. Tap water was then added to the tubes and queens ( = 21 per treatment) were either maintained underwater using a plunger-like apparatus or left to float naturally on the water's surface for varying durations (8 h, 24 h or 7 days) while remaining in overwintering conditions. Seventeen queens served as controls. After the submersion period, queens were removed from water, transferred to new tubes with soil and kept in cold storage for eight weeks. Overall, queen survival remained consistently high (89.5 ± 6.4%) across all treatments and did not differ among submersion regimes and durations. These results demonstrate the remarkable ability of diapausing queens to withstand submersion under water for up to one week, indicating their adaptations to survive periods of flooding in the wild.
Topics: Bees; Animals; Resilience, Psychological; Soil; Water
PubMed: 38626803
DOI: 10.1098/rsbl.2023.0609 -
Journal of Economic Entomology Jun 2024In this study, we compared the growth, development, and fecundity of Arma chinensis (Fallou) reared on pupae of the geometrid Ectropis grisescens Warren fed on tea... (Comparative Study)
Comparative Study
Comparison of the effect of tea shoots during different seasons in Arma chinensis (Hemiptera: Pentatomidae) reared on Ectropis grisescens (Lepidoptera: Geometridae) pupae.
In this study, we compared the growth, development, and fecundity of Arma chinensis (Fallou) reared on pupae of the geometrid Ectropis grisescens Warren fed on tea shoots during different seasons of the year. The raw data on life history were analyzed using the age-stage, 2-sex life table. When reared on spring or winter geometrid pupae, the duration of the immature stage of A. chinensis was significantly longer than in those produced during the summer or autumn. The survival rate of immature A. chinensis reared on autumn geometrid pupae was significantly lower compared to other treatments. Reproductive diapause was observed in adult A. chinensis reared on winter geometrid pupae. The adult preoviposition period (APOP), total preoviposition period (TPOP), and total longevity were significantly longer in A. chinensis reared on winter pupae than in the other treatments. The fecundity of A. chinensis reared on spring geometrid pupae was significantly lower than in the other treatments. The higher intrinsic rate of increase of the A. chinensis reared on summer pupae (r = 0.0966 day-1) and autumn pupae (r = 0.0983 day-1) resulted in higher fecundity, shorter immature duration, and shorter TPOP compared to the winter and spring populations. These findings can be utilized to enhance and sustain biological control of E. grisescens in tea plantations.
Topics: Animals; Pupa; Seasons; Moths; Male; Female; Camellia sinensis; Heteroptera; Fertility; Pest Control, Biological; Longevity; Plant Shoots; Larva
PubMed: 38625052
DOI: 10.1093/jee/toae078 -
Frontiers in Aging 2024The gonad has become a central organ for understanding aging in , as removing the proliferating stem cells in the germline results in significant lifespan extension.... (Review)
Review
The gonad has become a central organ for understanding aging in , as removing the proliferating stem cells in the germline results in significant lifespan extension. Similarly, when starvation in late larval stages leads to the quiescence of germline stem cells the adult nematode enters reproductive diapause, associated with an extended lifespan. This review summarizes recent advancements in identifying the mechanisms behind gonad-mediated lifespan extension, including comparisons with other nematodes and the role of lipid signaling and transcriptional changes. Given that the gonad also mediates lifespan regulation in other invertebrates and vertebrates, elucidating the underlying mechanisms may help to gain new insights into the mechanisms and evolution of aging.
PubMed: 38605866
DOI: 10.3389/fragi.2024.1380016 -
Current Opinion in Genetics &... Jun 2024Embryonic diapause in mammals is a period of developmental pause of the embryo at the blastocyst stage. During diapause, the blastocyst has minimal cell proliferation,... (Review)
Review
Embryonic diapause in mammals is a period of developmental pause of the embryo at the blastocyst stage. During diapause, the blastocyst has minimal cell proliferation, metabolic activity and gene expression. At reactivation, blastocyst development resumes, characterised by increases in cell number, biosynthesis and metabolism. Until recently, it has been unknown how diapause is maintained without any loss of blastocyst viability. This review focuses on recent progress in the identification of molecular pathways occurring in the blastocyst that can both cause and maintain the diapause state. A switch to lipid metabolism now appears essential to maintaining the diapause state and is induced by forkhead box protein O1. The forkhead box protein O transcription family is important for diapause in insects, nematodes and fish, but this is the first time a conclusive role has been established in mammals. Multiple epigenetic modifications are also essential to inducing and maintaining the diapause state, including both DNA and RNA methylation mechanisms. Finally, it now appears that diapause embryos, dormant stem cells and chemotherapeutic-resistant cancer cells may all share a universal system of quiescence.
Topics: Animals; Blastocyst; Diapause; Embryonic Development; Epigenesis, Genetic; Gene Expression Regulation, Developmental; Humans; Lipid Metabolism; Forkhead Transcription Factors
PubMed: 38604005
DOI: 10.1016/j.gde.2024.102192 -
Development (Cambridge, England) Apr 2024Embryonic diapause can be induced by nutrient deprivation, but the molecular mechanisms underpinning this process are unclear. A new paper in Development shows that...
Embryonic diapause can be induced by nutrient deprivation, but the molecular mechanisms underpinning this process are unclear. A new paper in Development shows that protein and carbohydrate depletion can trigger embryonic diapause via the nutrient sensors Gator1 and Tsc2. To learn more about the story behind the paper, we caught up with first author Jiajia Ye and corresponding author Qiang Sun, professor and director of the Non-Human Primate Research Facility at the Institute of Neuroscience, Chinese Academy of Sciences.
Topics: Animals; Tuberous Sclerosis
PubMed: 38603797
DOI: 10.1242/dev.202869 -
Development (Cambridge, England) Apr 2024Embryonic diapause is a special reproductive phenomenon in mammals that helps embryos to survive various harsh stresses. However, the mechanisms of embryonic diapause...
Embryonic diapause is a special reproductive phenomenon in mammals that helps embryos to survive various harsh stresses. However, the mechanisms of embryonic diapause induced by the maternal environment is still unclear. Here, we uncovered that nutrient deficiency in uterine fluid was essential for the induction of mouse embryonic diapause, shown by a decreased concentration of arginine, leucine, isoleucine, lysine, glucose and lactate in the uterine fluid of mice suffering from maternal starvation or ovariectomy. Moreover, mouse blastocysts cultured in a medium with reduced levels of these six components could mimic diapaused blastocysts. Our mechanistic study indicated that amino acid starvation-dependent Gator1 activation and carbohydrate starvation-dependent Tsc2 activation inhibited mTORC1, leading to induction of embryonic diapause. Our study elucidates the essential environmental factors in diapause induction.
Topics: Animals; Female; Mice; Blastocyst; Diapause; Embryonic Development; Nutrients
PubMed: 38603796
DOI: 10.1242/dev.202091