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Pest Management Science Feb 2024Anastatus japonicus Ashmead, a biological control agent utilized in China to control fruit bugs and forest caterpillars, is efficiently raised on large Chinese oak...
BACKGROUND
Anastatus japonicus Ashmead, a biological control agent utilized in China to control fruit bugs and forest caterpillars, is efficiently raised on large Chinese oak silkworm (Antheraea pernyi) eggs. Here, we investigated the biological parameters of non-diapaused and diapaused Anastatus japonicus after long-term storage within eggs of the host, Antheraea pernyi, under laboratory conditions.
RESULTS
Diapaused mature larvae of Anastatus japonicus were more cold-tolerant than non-diapaused mature larvae, as reflected by a lower supercoiling point, lower freezing point, and higher survival rate at cold temperatures. Diapause induction enhanced the lifespan, fecundity and oviposition period of Anastatus japonicus than non-diapaused Anastatus japonicus when refrigerated for 6 months. However, after 12 months of refrigeration, the fecundity and oviposition period of Anastatus japonicus were significantly reduced with and without diapause. No difference in the progeny sex ratio of Anastatus japonicus was observed between diapause-induction treatment and those of non-diapaused. With the extension of refrigeration period from 6 months to 12 months, the lifespan, fecundity and oviposition period of Anastatus japonicus which were treated with diapause induction showed a sharp decrease. No significantly difference in the lifespan, fecundity and oviposition period of Anastatus japonicus was observed between diapause-induction treatment and those of non-diapaused when refrigerated for 12 months.
CONCLUSION
These results suggest that the induction of diapause is an applicable technique to achieve mass production of Anastatus japonicus in long-term storage using eggs of the factitious host Antheraea pernyi, without compromising the quality of the parasitoid. The refrigeration period of diapaused Anastatus japonicus should not exceed 6 months. © 2023 Society of Chemical Industry.
Topics: Animals; Female; Bombyx; Moths; Hymenoptera; Larva; Diapause
PubMed: 37774138
DOI: 10.1002/ps.7807 -
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 -
Comparative Biochemistry and... Dec 2023Culex pipiens demonstrates robust circadian rhythms in adult eclosion, flight activity, mating, and development. These rhythmic patterns are believed to be controlled by...
Culex pipiens demonstrates robust circadian rhythms in adult eclosion, flight activity, mating, and development. These rhythmic patterns are believed to be controlled by the endogenous light-entrainable circadian clock that consists of positive and negative regulators working in a transcription-translation feedback loop. Moreover, these mosquitoes undergo seasonal diapause in exposure to the short photoperiod of late summer or early fall. However, the exact genetic and cellular mechanism behind the clock gene-mediated activity pattern, seasonal time measurement, and subsequent diapause initiation still need to be unraveled. To determine the possible linkage between clock genes and downstream processes, here we employed ChIP-sequencing to identify the direct targets of one of the core clock proteins, Cycle (CYC). The nearest genes with peaks mapping to their 1Kb upstream region of the transcription start site were extracted and scanned for consensus E box sequences, resulting in a dataset comprising the target genes possibly regulated by CYC. Based on the highest fold enrichment and functional relevance, we identified genes relating to five gene categories of potential interest, including peptide/receptors, neurotransmission, olfaction, immunity, and reproductive growth. Of these, we validated fourteen genes with ChIP-qPCR and qRT-PCR. These genes showed a significantly high expression in dusk compared to dawn in concert with the activity level of the CYC transcription factor and are thus strong candidates for mediating circadian rhythmicity and possibly regulating seasonal shifts in mosquito reproductive activity.
Topics: Animals; Culex; Culicidae; Circadian Rhythm; Gene Expression Regulation; Circadian Clocks
PubMed: 37690215
DOI: 10.1016/j.cbd.2023.101140 -
The Science of the Total Environment May 2024Recently, the effect of artificial light at night (ALAN) on the physiology and behavior of insects has gradually attracted the attention of researchers and has become a...
BACKGROUND
Recently, the effect of artificial light at night (ALAN) on the physiology and behavior of insects has gradually attracted the attention of researchers and has become a new research topic. Aedes albopictus is an important vector that poses a great public health risk. Further studies on the diapause of Ae. albopictus can provide a basis for new vector control, and it is also worth exploring whether the effect of ALAN on the diapause of Ae. albopictus will provide a reference for the prevention and control of infectious diseases mediated by Ae. albopictus.
METHODS
In this study, we experimentally studied the diapause characteristics of different geographical strains of Ae. albopictus under the interference of ALAN, explored the effect of ALAN on the diapause of Ae. albopictus and explored the molecular mechanism of ALAN on the diapause process through RNA-seq.
RESULTS
As seen from the diapause incidence, Ae. albopictus of the same geographic strain showed a lower diapause incidence when exposed to ALAN. The differentially expressed genes (DEGs) were mainly enriched in signaling and metabolism-related pathways in the parental females and diapause eggs of the ALAN group.
CONCLUSIONS
ALAN inhibits Ae. albopictus diapause. In the short photoperiod induced diapause of Ae. albopictus in temperate strain Beijing and subtropical strain Guangzhou, the disturbance of ALAN reduced the egg diapause rate and increased the egg hatching rate of Ae. albopictus, and the disturbance of ALAN also shortened the life cycle of Ae. albopictus eggs after hatching.
Topics: Animals; Female; Light Pollution; Diapause; Aedes; Photoperiod
PubMed: 38461989
DOI: 10.1016/j.scitotenv.2024.171594 -
Chemistry & Biodiversity Mar 2024Plant-insect interactions are a driving force into ecosystem evolution and community dynamics. Many insect herbivores enter diapause, a developmental arrest stage in...
Plant-insect interactions are a driving force into ecosystem evolution and community dynamics. Many insect herbivores enter diapause, a developmental arrest stage in anticipation of adverse conditions, to survive and thrive through seasonal changes. Herein, we investigated the roles of medium- to non-polar metabolites during larval development and diapause in a specialist insect herbivore, Chlosyne lacinia, reared on Aldama robusta leaves. Varying metabolites were determined using gas chromatography-mass spectrometry (GC-MS)-based metabolomics. Sesquiterpenes and steroids were the main metabolites putatively identified in A. robusta leaves, whereas C. lacinia caterpillars were characterized by triterpenes, steroids, fatty acids, and long-chain alkanes. We found out that C. lacinia caterpillars biosynthesized most of the identified steroids and fatty acids from plant-derived ingested metabolites, as well as all triterpenes and long-chain alkanes. Steroids, fatty acids, and long-chain alkanes were detected across all C. lacinia instars and in diapausing caterpillars. Sesquiterpenes and triterpenes were also detected across larval development, yet they were not detected in diapausing caterpillars, which suggested that these metabolites were converted to other molecules prior to the diapause stage. Our findings shed light on the chemical content variation across C. lacinia development and diapause, providing insights into the roles of metabolites in plant-insect interactions.
Topics: Animals; Gas Chromatography-Mass Spectrometry; Ecosystem; Metabolomics; Lepidoptera; Diapause; Steroids; Sesquiterpenes; Fatty Acids; Alkanes; Triterpenes; Larva
PubMed: 38426669
DOI: 10.1002/cbdv.202301779 -
Insect Biochemistry and Molecular... Mar 2024The solitary bee Osmia lignaria is a native pollinator in North America with growing economic importance. The life cycle of O. lignaria provides a unique opportunity to...
The solitary bee Osmia lignaria is a native pollinator in North America with growing economic importance. The life cycle of O. lignaria provides a unique opportunity to compare the physiological and molecular mechanisms underlying two ecologically contrasting dormancies within the same species. O. lignaria prepupae become dormant during the summer to avoid high temperatures. Shortly after adult eclosion, they enter a second dormancy and overwinter as diapausing adults. To compare these two dormancies, we measured metabolic rates and gene expression across development as bees initiate, maintain, and terminate both prepupal (summer) and adult (overwintering) dormancies. We observed a moderate temperature-independent decrease in gas exchange during both the prepupal dormancy after cocoon spinning (45 %) and during adult diapause after eclosion (60 %). We sequenced and assembled a high-quality reference genome from a single haploid male bee with a contiguous n50 of 5.5 Mbp to facilitate our transcriptomic analysis. The transcriptomes of dormant prepupae and diapausing adults clustered into distinct groups more closely associated with life stage than dormancy status. Membrane transport, membrane-bound cellular components, oxidoreductase activity, glutathione metabolism, and transcription factor activity increased during adult diapause, relative to prepupal dormancy. Further, the transcriptomes of adults in diapause clustered into two groups, supporting multiple phases of diapause during winter. Late adult diapause was associated with gene expression profiles supporting increased insulin/IGF, juvenile hormone, and ecdysone signaling.
Topics: Bees; Male; Animals; Transcriptome; Temperature; Gene Expression Profiling; Life Cycle Stages; Diapause
PubMed: 38228213
DOI: 10.1016/j.ibmb.2024.104074 -
The American Naturalist Jun 2024AbstractPhysiological time is important for understanding the development and seasonal timing of ectothermic animals but has largely been applied to developmental...
AbstractPhysiological time is important for understanding the development and seasonal timing of ectothermic animals but has largely been applied to developmental processes that occur during spring and summer, such as morphogenesis. There is a substantial knowledge gap in the relationship between temperature and development during winter, a season that is increasingly impacted by climate change. Most temperate insects overwinter in diapause, a developmental process with little obvious morphological change. We used principles from the physiological time literature to measure and model the thermal sensitivity of diapause development rate in the apple maggot fly , a univoltine fly whose diapause duration varies substantially within and among populations. We show that diapause duration can be predicted by modeling a relationship between temperature and development rate that is shifted toward lower temperatures compared with typical models of morphogenic, nondiapause development. However, incorporating interindividual variation and ontogenetic variation in the temperature-to-development rate relationship was critical for accurately predicting fly emergence, as diapause development proceeded more quickly at high temperatures later in diapause. We conclude that the conceptual framework may be flexibly applied to other insects and discuss possible mechanisms of diapause timers and implications for phenology with warming winters.
Topics: Animals; Diapause, Insect; Tephritidae; Temperature; Seasons; Larva; Models, Biological; Female
PubMed: 38781522
DOI: 10.1086/729515 -
BioRxiv : the Preprint Server For... Nov 2023How mosquitoes may respond to rapid climate warming remains unknown for most species, but will have major consequences for their future distributions, with cascading...
How mosquitoes may respond to rapid climate warming remains unknown for most species, but will have major consequences for their future distributions, with cascading impacts on human well-being, biodiversity, and ecosystem function. We investigated the adaptive potential of a wide-ranging mosquito species, , across a large climatic gradient by conducting a common garden experiment measuring the thermal limits of mosquito life history traits. Although field-collected populations originated from vastly different thermal environments that spanned over 1,200 km, we found remarkably limited variation in upper thermal tolerance between populations, with the upper thermal limits of fitness varying by <1°C across the species range. For one life history trait-pupal development rate-we did detect significant variation in upper thermal limits between populations, and this variation was strongly correlated with source temperatures, providing evidence of local thermal adaptation for pupal development. However, we found environmental temperatures already regularly exceed our highest estimated upper thermal limits throughout most of the species range, suggesting limited potential for mosquito thermal tolerance to evolve on pace with warming. Strategies for avoiding high temperatures such as diapause, phenological shifts, and behavioral thermoregulation are likely important for mosquito persistence.
PubMed: 37961581
DOI: 10.1101/2023.03.02.530886 -
Journal of Comparative Physiology. A,... Jun 2024Drosophila ezoana is a virilis group Drosophila species inhabiting northern latitudes. The flies enter adult reproductive diapause to survive winter upon exposure to...
Drosophila ezoana is a virilis group Drosophila species inhabiting northern latitudes. The flies enter adult reproductive diapause to survive winter upon exposure to short photoperiod conditions (short-day) over several consecutive days. Insect pre-diapause phase - the duration between the beginning of exposure to short days and expression of diapause is thought to be comprised of two distinct phases - (a) photoperiodic time measurement that detects short-days, followed by (b) physiological events leading to the expression of diapause phenotype. A short-day dependent segment of the pre-diapause phase thus approximates the process of photoperiodic time measurement. Continuous darkness has been found to be a neutral condition with respect to diapause regulation in many insect species. The effect of variable number of short-days followed by continuous darkness on diapause incidence thus allows identification of short-day dependent segment of pre-diapause phase thereby mapping the process of photo-periodic time measurement. Although, few weeks of exposure to short-days in adult stage is known to be sufficient for the expression of diapause in D. ezoana, the number of short days required for the completion of photo-periodic time measurement has never been systematically analysed. Our experiments show that continuous darkness is a neutral condition for diapause regulation also in D. ezoana. We utilized the neutral nature of continuous darkness to map the process of photoperiodic time measurement in the D. ezoana strain 124OJ8 which showed that integration of short-day photic cues over the first 10 days of pre-diapause phase is essential for diapause induction.
PubMed: 38916659
DOI: 10.1007/s00359-024-01707-4 -
Journal of Visualized Experiments : JoVE Nov 2023One of the major pests of potato Solanum tuberosum L. in the temperate zone is the insect Colorado potato beetle (CPB). Most studies on the immunity and diseases of the...
One of the major pests of potato Solanum tuberosum L. in the temperate zone is the insect Colorado potato beetle (CPB). Most studies on the immunity and diseases of the CPB are conducted during active feeding stages. Nonetheless, there are fewer studies on resting stages, although these beetles spend most of their life cycle in a state of winter diapause (hibernation). In this work, a method for investigating CPB hibernation under natural conditions was developed and tested, offering an opportunity to collect a sufficient number of individuals in winter. In this article, CPB survival was assessed, and infectious agents at different stages of hibernation were identified. CPB mortality increased during the hibernation, reaching a maximum in April-May. Entomopathogenic fungi (Beauveria, Isaria, and Lecanicillium) and bacteria Bacillus, Sphingobacterium, Peribacillus, Pseudomonas, and Serratia were isolated from the dead insects. The survival rate of the beetles for the entire hibernation period was 61%. No frozen or desiccated beetles were found, indicating the success of the presented method.
Topics: Animals; Coleoptera; Solanum tuberosum; Hibernation; Larva; Colorado
PubMed: 38047559
DOI: 10.3791/65862