Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)w...Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)were thought to play key roles during diapause,while few SPNs were functionally characterized.LmSPN2 was one of those genes differentially expressed between diapause and non-diapause eggs;however,its biological function remained to be explored.So,we conducted RNAi knockdown of LmSPN2,resulting in a significant decrease of the egg diapause rate by 29.7%.Using yeast two-hybrid assays,co-immunoprecipitation,and pull-down methods,we found an interaction between LmSPN2 and LmSPN3,which was proved to be mediated by a glutamate(E331)binding site of LmSPN2.RNAi knockdown of LmSPN3 resulted in a significant increase in diapause rate by 14.6%,indicating an inverse function of LmSPN2 and LmSPN3 on diapause regulation.Double knockdown of two SPN genes resulted in a 26.4%reduction in diapause rate,indicating that LmSPN2 was the dominant regulatory signal.Moreover,we found four Toll pathway genes(easter,spätzle,pelle,and dorsal)upregulated significantly after the knockdown of LmSPN2 while downregulated after the knockdown of LmSPN3.Therefore,we speculate that two SPNs regulate diapause through the Toll pathway.Our results indicated that LmSPN2 positively regulates locust egg entry into diapause,while LmSPN3 is a negative regulator of embryonic commitment to diapause.Their interaction is mediated by the binding site of E331 and influences egg diapause through the Toll pathway.This mechanistic understanding of diapause regulation expands our understanding of insect developmental regulation and provides functional targets for developing locust management strategies.展开更多
Maternal photoperiodic response is a key factor that affects offspring diapause in migratory locust,Locusta migratoria L.(Orthoptera:Acridoidea).Although many aspects of insect diapause have been studied,little is kno...Maternal photoperiodic response is a key factor that affects offspring diapause in migratory locust,Locusta migratoria L.(Orthoptera:Acridoidea).Although many aspects of insect diapause have been studied,little is known about the molecular mechanisms of maternal photoperiodic response that influence diapause regulation.To gain insight into the possible mechanisms of maternal photoperiod influence on diapause regulation,proteomics data by label-free quantification analysis were generated from non-diapause and diapause eggs.A total of 175 proteins were differentially expressed between diapause and non-diapause eggs.Among them,24 proteins were upregulated,and 151 proteins were downregulated.Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichments were performed on all differentially expressed proteins(DEPs)and showed that peroxisome,insect hormone biosynthesis,and longevity regulating pathway may be related to diapause of migratory locust.Furthermore,we used qRT-PCR to verify some results of the proteomic analysis.Proteins such as hexamerin-like protein 4,juvenile hormone epoxide hydrolase 1(JHEH1),cytochrome P450 and heat shock protein(HSP)20.7 were predicted to be involved in diapause.This study provides an important reference for future research that will explore the mechanisms of diapause induced by maternal effects in migratory locust.展开更多
The brine shrimp Artemia exhibits two reproductive modes: 1) oviparity, producing diapause embryos;and 2) ovoviviparity, producing free-swimming nauplii. Previous studies have suggested the existence of a critical sta...The brine shrimp Artemia exhibits two reproductive modes: 1) oviparity, producing diapause embryos;and 2) ovoviviparity, producing free-swimming nauplii. Previous studies have suggested the existence of a critical stage that determines the reproductive mode. Physicochemical factors, such as photoperiod, temperature, and salinity, have been suggested to irreversibly aff ect the reproductive mode of oocytes during this critical stage. In this study, experiments were carried out using a photoperiod and temperature-sensitive parthenogenetic Artemia clone where maternal Artemia were shifted bidirectionally between ovoviviparity (18 h L:6 h D, 27℃) and oviparity (6 h L:18 h D, 19℃) culture conditions. In the main experiment ( Artemia shifted at six diff erent stages including the post-larva Ⅱ to adult Ⅱ), the reproductive mode of fi rst brood was converted when shifting was performed on post-larva Ⅱ and Ⅲ but was not converted when females were shifted after post-larva Ⅲ. A supplementary experiment further revealed that the reproductive mode of fi rst brood could be altered when shifting females at an "early phase of postlarva Ⅳ", characterized by a developing ovisac reaching the middle of the third abdominal segment, ventral spines, and some oocytes growing larger than the others. In both experiments, reproductive modes of the second brood were signifi cantly aff ected when the shifting was performed on post-larva Ⅳ. These results suggest that the critical stage for inducing oviparity and embryonic diapause is at the previtellogenic stage of oocytes, or at maternal "early phase of post-larva Ⅳ" for the first-brood off spring. During this stage, diff erential gene expression patterns of the two destined oocytes may be triggered by the token stimuli signals received by the oocytes.展开更多
Diapause is a long-lived stage which has evolved into an important strategy for insects to circumvent extreme environments.In the pupal stage,Helicoverpa armigera can enter diapause,a state characterized by significan...Diapause is a long-lived stage which has evolved into an important strategy for insects to circumvent extreme environments.In the pupal stage,Helicoverpa armigera can enter diapause,a state characterized by significantly decreased metabolic activity and enhanced stress resistance,to survive cold winters.Previous studies have shown that reactive oxygen species(ROS)can promote the diapause process by regulating a distinct insulin signaling pathway.However,the source of ROS in the diapause-destined pupal brains and mechanisms by which ROS regulate diapause are still unknown.In this study,we showed that diapause-destined pupal brains accumulated high levels of mitochondrial ROS(mtROS)and total ROS during the diapause process,suggesting that mitochondria are the main source of ROS in diapause-destined pupal brains.In addition,injection of 2-deoxy-D-glucose(DOG),a glucose metabolism inhibitor,could delay pupal development by elevating mtROS levels in the nondiapause-destined pupal brains.Furthermore,the injection of a metabolite mixture to increase metabolic activity could avert the diapause process in diapause-destined pupae by decreasing mtROS levels.We also found that ROS could activate HSP60 expression and promote the stability of the HSP60-Lon complex,increasing its ability to degrade mitochondrial transcription factor A(TFAM)and decreasing mitochondrial activity or biogenesis under oxidative stress.Thus,this study illustrated the beneficial function of ROS in diapause or lifespan extension by decreasing mitochondrial activity.展开更多
The full-length cDNA encoding Larval serum protein 2 (LSp-2) in the onion maggot,Delia antiqua, was cloned and sequenced by rapid ampli?cation of cDNA ends methods. The result showed that the cDNA was 2203 bp long and...The full-length cDNA encoding Larval serum protein 2 (LSp-2) in the onion maggot,Delia antiqua, was cloned and sequenced by rapid ampli?cation of cDNA ends methods. The result showed that the cDNA was 2203 bp long and the open reading frame (ORF) of 2106 bp encoded 701 amino acid with a calculated molecular weight of 80.5 kDa and an isoelectric point of 5.87. The onion maggot LSp-2 shows highest homology (83%) to that ofCalliphora vicinaat amino acid level. Its signal peptides, domains and structures were predicted and analyzed by using bioinformatic methods. The amino acid sequence of LSP-2 suggests that it would be a typical hexamerin.展开更多
A hyperparasitic system with prolonged diapause for host is investigated. It is assumed that host prolonged diapause occur at larval stage, and parasitoid attack is limited to egg stage before the initiation of host d...A hyperparasitic system with prolonged diapause for host is investigated. It is assumed that host prolonged diapause occur at larval stage, and parasitoid attack is limited to egg stage before the initiation of host diapause. Such behavior has been reported for many ichneumons. Hyperparasite only attacks the parasitoids that parasitize the hosts. Hyperparasitic system is often used in biological control. The existence and stability of nonnegative fixed points are explored. Numerical simulations are carried out to explore the global dynamics of the system, which demonstrate appropriate prolonged diapause rate and appropriate intrinsic growth rate can stabilize the system. The reasons are explained according to the ecological perspective. Furthermore, many other complexities which include quasi-periodicity, period-doubling bifurcations leading to chaos, chaotic attractor, intermittent and supertransients are observed.展开更多
The forkhead box O(FoxO),as a conserved transcription factor,plays an indispensable role in regulating insect diapause.However,how FoxO is regulated to control diapause in insects remains unknown.In this study,we disc...The forkhead box O(FoxO),as a conserved transcription factor,plays an indispensable role in regulating insect diapause.However,how FoxO is regulated to control diapause in insects remains unknown.In this study,we discovered functional binding sites for miR-2765-3p in the 3′untranslated region of FoxO in Galeruca daurica.The luciferase reporter assay showed that miR-2765-3p targeted FoxO and suppressed its expression.The expression profiles of miR-2765-3p and FoxO displayed opposite patterns during the female developmental process.Overexpression of miR-2765-3p by the injection of the miR-2765-3p agomir into adult females reduced FoxO expression,leading to the suppression of lipid accumulation,promotion of ovarian development,and inhibition of reproductive diapause.This is similar to the phenotype that results from the depletion of FoxO by injecting dsFoxO into adult females.In addition,the repression of miR-2765-3p by injecting the miR-2765-3p antagomir increased the FoxO transcript level,leading to the stimulation of lipid accumulation,depression of ovarian development,and induction of reproductive diapause.A hormone injection assay showed that the juvenile hormone(JH)agonist(methoprene)upregulated miR-2765-3p and downregulated FoxO.Notably,injecting methoprene rescued ovarian development defects associated with miR-2765-3p inhibition.These findings indicate that the JH/miR-2765-3p/FoxO axis plays a vital role in the regulation of reproductive diapause in G.daurica.展开更多
The embryonic diapause of the silkworm, Bombyx mori, is induced by the diapause hormone (DH) which is secreted from the suboesophageal ganglion of pupae. The diapause nature of bivoltine strains uses environmental sti...The embryonic diapause of the silkworm, Bombyx mori, is induced by the diapause hormone (DH) which is secreted from the suboesophageal ganglion of pupae. The diapause nature of bivoltine strains uses environmental stimuli as the initial signal to determine the diapause nature. The experiments showed that DH gene expression is a direct response to the environmental stimulus, such as high incubation temperature. The cDNA from the embryonic stage was cloned and sequence analysis showed the cDNA encoding DH. Expression patterns of the DH gene in embryonic stage are different at incubation temperatures 15℃ and 25℃, suggesting that the incubation temperature as an environmental signal is kept within the body to control the DH gene expression at the pupal stage, so that the embryonic diapause of next generation can be determined.展开更多
Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adv...Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adverse environments.Ae.albopictus is the vital vector transmitting dengue virus in Guangzhou,but its diapause activities herein remain obscure.Methods:In the laboratory,yeast powder and food slurry were compared for a proper diapause determination method,and the critical photoperiod(CPP)was tested at illumination times of 11,11.5,12,12.5,13,and 13.5 h.A 4-parameter logistic(4PL)regression model was selected to estimate the CPP.In the field,the seasonal dynamics of the Ae.albopictus population,egg diapause,and hatching of overwintering eggs were investigated monthly,weekly,and daily,respectively.A distributed lag non-linear model(DLNM)was used to assess the associations of diapause with meteorological factors.Results:In the laboratory,both the wild population and the Foshan strain of Ae.albopictus were induced to diapause at an incidence greater than 80%,and no significant difference(P>0.1)was observed between the two methods for identifying diapause.The CPP of this population was estimated to be 12.312 h of light.In the field,all of the indexes of the wild population were at the lowest levels from December to February,and the Route Index was the first to increase in March.Diapause incidence displayed pronounced seasonal dynamics.It was estimated that the day lengths of 12.111 h at week2016,43 and 12.373 h at week2017,41 contributed to diapause in 50%of the eggs.Day length was estimated to be the main meteorological factor related to diapause.Conclusions:Photoperiodic diapause of Ae.albopictus in Guangzhou of China was confirmed and comprehensively elucidated in both the laboratory and the field.Diapause eggs are the main form for overwintering and begin to hatch in large quantities in March in Guangzhou.Furthermore,this study also established an optimized investigation system and statistical models for the study of Ae.albopictus diapause.These findings will contribute to the prevention and control of Ae.albopictus and mosquito-borne diseases.展开更多
Diapause hormone (DH) is a neurohormone which is secreted from suboesophageal ganglion and responsible for induction of embryonic diapause in many insects. Using rapid amplification of the cDNA ends (RACE) method, the...Diapause hormone (DH) is a neurohormone which is secreted from suboesophageal ganglion and responsible for induction of embryonic diapause in many insects. Using rapid amplification of the cDNA ends (RACE) method, the cDNA encoding diapause hormone in Helicoverpa armigera, a main kind of crops pest was cloned. The nucleotide sequence reveals that the mRNA encodes an open reading frame and the 25-aa DH peptide is localized at N-terminal region just after the signal peptide. A homology search showed that H. armigera DH has high homology with the diapause hormone of Bornbyx mori and Helicoverpa zea; and it also belongs to the FXPRL neuropeptide family. Thus, H. armigera DH seems to be a new type of diapause hormone molecule.展开更多
Juvenile hormone (JH) absence induces photoperiod-mediated reproductive diapause, which is characterized by reproductive cessation. Although the role of methoprene-tolerant (Met)-mediated JH signaling in photoperiod-m...Juvenile hormone (JH) absence induces photoperiod-mediated reproductive diapause, which is characterized by reproductive cessation. Although the role of methoprene-tolerant (Met)-mediated JH signaling in photoperiod-mediated female reproduction has been well documented, its role in male reproduction remains unclear. In this study, we investigated the role of JH in regulating photoperiod-mediated development of the male internal reproductive system (IRS) in the predatory ladybeetle Harmonia axyridis (Pallas). In a previous study, we found that adult male H. axyridis reared under either a short-day (SD) or long-day (LD) photoperiod had obvious differences in IRS development, but we were unable to identify the regulators of male reproductive diapause. In this study, we found that beetles reared under an SD photoperiod had significantly lower JH titer and a relatively undeveloped male IRS compared with those reared under an LD photoperiod. Additionally, application of the JH analog (JHA) methoprene promoted IRS development. Furthermore, Met knockdown strongly blocked JH signaling in males reared under the LD photoperiod, thereby slowing IRS development. Moreover, exogenous JHA did not reverse the suppressed development of the male IRS caused by Met knockdown. These results indicate that photoperiod regulates male IRS development in H. axyridis through a conserved Met-dependent JH signaling pathway.展开更多
Developmental diapause is a widespread strategy for animals to survive seasonal starvation and environmental harshness.Diapaused animals often ration body fat to generate a basal level of energy for enduring survival....Developmental diapause is a widespread strategy for animals to survive seasonal starvation and environmental harshness.Diapaused animals often ration body fat to generate a basal level of energy for enduring survival.How diapause and fat rationing are coupled,however,is poorly understood.The nematode Caenorhabditis elegans excretes pheromones to the environment to induce a diapause form called dauer larva.Through saturated forward genetic screens and CRISPR knockout,we found that dauer pheromones feed back to repress the transcription of ACOX-3,MAOC-1,DHS-28,DAF-22(peroxisomalβ-oxidation enzymes dually involved in pheromone synthesis and fat burning),ALH-4(aldehyde dehydrogenase for pheromone synthesis),PRX-10 and PRX-11(peroxisome assembly and proliferation factors).Dysfunction of these pheromone enzymes and factors relieves the repression.Surprisingly,transcription is repressed not by pheromones excreted but by pheromones endogenous to each animal.The endogenous pheromones regulate the nuclear translocation of HNF4αfamily nuclear receptor NHR-79 and its co-receptor NHR-49,and,repress transcription through the two receptors.The feedback repression maintains pheromone homeostasis,increases fat storage,decreases fat burning,and prolongs dauer lifespan.Thus,the exocrine dauer pheromones possess an unexpected endocrine function to mediate a peroxisome-nucleus crosstalk,coupling dauer diapause to fat rationing.展开更多
Diapause,an important strategy used by insects to avoid adverse environments,is regulated by various cell signaling pathways.The results of our previous studies demonstrated that the transforming growth factor-β(TGF-...Diapause,an important strategy used by insects to avoid adverse environments,is regulated by various cell signaling pathways.The results of our previous studies demonstrated that the transforming growth factor-β(TGF-β)signaling pathway regulated pupal diapause in Helicoverpa armigera,which was accompanied by downregulation of proteins in TGF-βsignaling.However,to date the mechanism underlying this phenomenon remains unknown.Here,we cloned the E3 ubiquitin ligases gene Smurf.In vitro experiments showed that Smurf directly bound to TGF-βreceptor type I(TGFβRI)and Smad2.Overexpressing Smurf promoted ubiquitination of TGFβRI and Smad2,thereby downregulating their protein levels.Conversely,silencing of the Smurf gene suppressed ubiquitination of TGFβRI and Smad2 thereby increasing their protein levels.Results from in vivo co-immunoprecipitation assays revealed that the binding of Smurf to TGFβRI or Smad2 was stronger in diapause pupae than in nondiapause pupae.Injection of Smurf inhibitor A01 into diapause pupae markedly upregulated expression of TGFβRI and Smad2 proteins,leading to resumption of development in diapause pupae.Taken together,these findings suggested that ubiquitin ligase E3 Smurf participated in H.armigera diapause by regulating TGF-βsignaling,and thus could be playing a crucial role in insect diapause.展开更多
The phenological response is among the most important traits affecting a species’sensitivity to climate.In insects,strongly seasonal environments often select for a univoltine life cycle such that one seasonal extrem...The phenological response is among the most important traits affecting a species’sensitivity to climate.In insects,strongly seasonal environments often select for a univoltine life cycle such that one seasonal extreme is avoided as an inactive stage.Through understanding the underlying mechanisms for univoltinism,and the consequences of its failure,we can better predict insect responses to climate change.Here we combine empirical data and simulation studies to investigate the consequences of an unusual diapause mechanism in a parthenogenetic matchstick grasshopper,Warramaba virgo,from arid southern Australia.Our field body temperature measurements indicate that this species is a thermoconformer and our laboratory studies of the thermal response of feeding rate imply strong constraints on winter activity.However,the species exhibits no obligate winter diapause,and eggs can develop in 1 month under constant temperatures approximating the mean soil temperature at the time of oviposition(summer).We show that diurnal temperature cycles exceeding a peak of 36℃ inhibit egg development in summer,and that this is sufficient to prevent autumnal hatching of eggs.Development is also strongly retarded below 24℃.Microclimate-driven simulation studies of egg development show that these thermal responses provide robust maintenance of a univoltine life cycle,thereby resulting in survival of heat stress as an egg(due to limited developmental state)and avoidance of cold stress as a nymph and adult(due to overwintering in the soil as an egg).展开更多
Envipnmental cues,mainly photoperiod and temperature,are known to control female adult reproductive diapause in several insect species.Diapause enhances female survival during adverse conditions and postpones progeny ...Envipnmental cues,mainly photoperiod and temperature,are known to control female adult reproductive diapause in several insect species.Diapause enhances female survival during adverse conditions and postpones progeny production to the favorable season.Male diapause(a reversible inability to inseminate receptive females)has been studied much less than female diapause.However,if the males maximized their chances to fertilize females while minimizing their energy expenditure,they would be expected to be in diapause at the same time as females.We investigated Drosophila montana male mating bchavior under short-day conditions that induce diapause in females and found the males to be reproductively inactive.We also found that males reared under long-day conditions(reproducing individuals)court reproducing postdiapause fermales,but not diapausing ones.The diapausing fies of both sexes had more long-chain and less short-chain hydrocarbons on their cuticle than the reproducing ones,which presumably increase their survival under stressful conditions,but at the same time decrease their attractiveness.Our study shows that the mating behavior of females and males is well coordinated during and afier overwintering and it also gives support to the dual role of insect cuticular hydrocarbons in adaptation and mate choice.展开更多
The paper investigates the existence of a relationship between the diapause duration and the temperature threshold of hatching,the variances in temperature and hatching time of the artificial six-month population of L...The paper investigates the existence of a relationship between the diapause duration and the temperature threshold of hatching,the variances in temperature and hatching time of the artificial six-month population of Lymantria dispar caterpillars.A half-year population gives two generations a year under artificial conditions.A comparative analysis of these parameters with similar parameters of the hybrid population of L.dispar,as well as studies by other authors,has been carried out.The Eigen quasispecies model was used for the mathematical formalization of the evolution process.The results of this work can be used to study the evolution of L.dispar.展开更多
In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facult...In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facultative diapause and prepares diapause can provide us new insights to study developmental and evolutionary biology.It has been shown that the circadian clock genes can participate in photoperiodic measurement and regulate reproductive diapause initiation through JH signaling in short-day-induced winter diapause.However,how circadian clock genes translate photoperiodic information into downstream JH signaling for diapause destiny and then affect diapause preparation remains largely unknown.In the present study,we investigate this in the cabbage beetle Colaphellus bowringi which undergoes reproductive diapause under long-day condition.We respectively knocked down two circadian clock negative regulators,period(per)and timeless(tim),in the 3-day-old larvae(most sensitive to photoperiod),and dsgfp treatment was served as a control.Under the diapause-inducing photoperiod(16L:8D),knocking down per and tim significantly decreased the rate of burrowing behavior.And mtany female beetles of the per and tim RNAi showed developed ovary,decreased lipid accumulation and downregulated expression of stress resistance genes.The JHinduced genes,Kr-h1,JHE1,Vg1,and Vg2, significantly increased in the females with suppression of per and tim.It implied that suppression of per and tim during diapause initiation phase(DIP)could activate the JH signaling in the female adults.Before the beetles enter into diapause preparation phase(DPP),we used RNA sequencing to analyize gene expression profiles after per and tim RNAi.It showed that many differentially expressed genes were enriched in environmental information processing,such as mTOR and TGF-beta signaling pathway.To ask whether per and tim also regulate diapause preparation,we knocked down these two genes in the female adults during DPP.It showed that the diapause destiny was not af-fected,but the lipid storage in diapause-destined females was significantly reduced after per and tim RNAi.Interestingly,per-and tim-regulated lipid storage during DPP was independent on JH signaling.We further found that per and tim promoted lipid storage by regulating the expression of genes that control lipogenesis and lipolysis.In summary,these results suggest that per and tim participate in photoperiodic measurement and initiate reproductive diapause through JH signaling during DIP in long-day-induced summer diapause.The mTOR and TGF-beta signaling pathways may be involved in the regulation of JH signaling by circadian clock genes.Meanwhile,per and tim transduce photoperiodic signal and promote lipid storage during DPP in a JH-independent manner.These results provide us new clues to study the molecular mechanism of photoperiod-regulated diapause induction in insects.展开更多
In insects, juvenile hormone (JH) decreases or has any effect upon the phenoloxidase (PO) activity, and favors or decreases the Antimicrobial Peptides (AMPs) expression. Although there is no information about the diff...In insects, juvenile hormone (JH) decreases or has any effect upon the phenoloxidase (PO) activity, and favors or decreases the Antimicrobial Peptides (AMPs) expression. Although there is no information about the differential effect of such hormone, two possibilities are that it depends on (a) the immune marker recorded and (b) sexual differences. Here, three commonly used immune markers, Phenoloxidase (PO), hydrogen peroxide (H2O2), and lytic activity, were measured 3, 6 and 24 hours after administration of methoprene (JHa, an analog of juvenile hormone) in male and female monarch butterflies (Danaus plexippus). At 3 and 6 h post-JHa administration, the PO activity increased in females but it only increased at 3 h in males, whereas H2O2 levels increased only in females at 3 h. For the remaining times the JHa had a null effect on POand H2O2. On the other hand, the JHa had a null effect for lytic activity in both sexes at 3, 6 and 24 h. To our knowledge, this is the first report of a positive effect of a JHa onPOand H2O2 and suggests that this effect is sex dependent.展开更多
Bathycoelia natalicola (Distant) is the dominant stink bug on macadamias in South Africa. This insect occurred throughout the year but was particularly numerous during summer months when developing macadamia nuts were...Bathycoelia natalicola (Distant) is the dominant stink bug on macadamias in South Africa. This insect occurred throughout the year but was particularly numerous during summer months when developing macadamia nuts were available on the trees. The presence of nymphs and adults throughout the winter as well as the absence of seasonal polyphenism indicates that true diapause may not occur in areas with mild subtropical climates. After harvest, during winter when no nuts were available, the winter stink bug complex consisting of Nezara pallidocons-persa Stal, Nezara prunasis Dallas and Atelocera raptoria Germarbecame was more numerous. The Nezara species do not breed in macadamias indicating that macadamia is possibly not a preferred host plant. Few individuals of the polyphagous pest, Pseudotheraptus wayi brown were recovered with the branch shaking technique suggesting that this technique is possibly not suitable to monitor for this insect. Considerable P. wayi damage levels were however, detected by dissecting prematurely aborted nuts.展开更多
This study aims to examine the following three hypotheses on the impact of global warming on the populations of the water strider, Aquarius paludum in the Kochi-Nankoku area (33。30'N) of Kochi prefecture, Japan t...This study aims to examine the following three hypotheses on the impact of global warming on the populations of the water strider, Aquarius paludum in the Kochi-Nankoku area (33。30'N) of Kochi prefecture, Japan through the recent data collected in 2009-2011. 1) Has the generation number increased? 2) Has aestivation appeared in adults? 3) Have overwintering adults stopped dispersing between the water surface and overwintering lands-sites far away from water and, instead, overwintered on/near the shore? Sampling data showed that the number of generations may have increased from three (1989-2002 strains) and four (2004-2008) to five (2009-2011) per year in Kochi (33。N). The ratio of adults having well developed flight muscles decreased from 45% in 1995 to 24% - 28% in 2009-2011 inoverwintering adults collected from the field in fall likely as a result of histolysis. “Mosaic-typed” wing morph group with long fore-wings and short hind-wings newly appeared in 2009-2011 in the Kochi-Nankoku overwintering populations. The mosaic-typed wings group cannot fly and the black and long fore wings might function as absorbing apparatus of sun-lights in the daytime of winter. Some overwintering adults seem to stop migrating between water bodies and overwintering sites on land far from the water bodies and overwinter, instead, near the shore. The use of Aquarius paludum as a biological indicator would be possible in the future, because this species can respond and change their reproductive and dispersal characteristics to the global change.展开更多
基金This work was supported by the National Key R&D Program of China(2022YFD1400500)the China Agriculture Research System of MOF and MARA(CARS-34-07)+1 种基金the Publicinterest Scientific Institution Basal Research Fund,China(Y2022GH12)the Central Public-interest Scientific Institution Basal Research Fund,China(S2021XM22 and S2022XM21)。
文摘Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)were thought to play key roles during diapause,while few SPNs were functionally characterized.LmSPN2 was one of those genes differentially expressed between diapause and non-diapause eggs;however,its biological function remained to be explored.So,we conducted RNAi knockdown of LmSPN2,resulting in a significant decrease of the egg diapause rate by 29.7%.Using yeast two-hybrid assays,co-immunoprecipitation,and pull-down methods,we found an interaction between LmSPN2 and LmSPN3,which was proved to be mediated by a glutamate(E331)binding site of LmSPN2.RNAi knockdown of LmSPN3 resulted in a significant increase in diapause rate by 14.6%,indicating an inverse function of LmSPN2 and LmSPN3 on diapause regulation.Double knockdown of two SPN genes resulted in a 26.4%reduction in diapause rate,indicating that LmSPN2 was the dominant regulatory signal.Moreover,we found four Toll pathway genes(easter,spätzle,pelle,and dorsal)upregulated significantly after the knockdown of LmSPN2 while downregulated after the knockdown of LmSPN3.Therefore,we speculate that two SPNs regulate diapause through the Toll pathway.Our results indicated that LmSPN2 positively regulates locust egg entry into diapause,while LmSPN3 is a negative regulator of embryonic commitment to diapause.Their interaction is mediated by the binding site of E331 and influences egg diapause through the Toll pathway.This mechanistic understanding of diapause regulation expands our understanding of insect developmental regulation and provides functional targets for developing locust management strategies.
基金funded by the earmarked fund of China Agriculture Research System (CARS-34-07)the National Natural Science Foundation of China (31672485)
文摘Maternal photoperiodic response is a key factor that affects offspring diapause in migratory locust,Locusta migratoria L.(Orthoptera:Acridoidea).Although many aspects of insect diapause have been studied,little is known about the molecular mechanisms of maternal photoperiodic response that influence diapause regulation.To gain insight into the possible mechanisms of maternal photoperiod influence on diapause regulation,proteomics data by label-free quantification analysis were generated from non-diapause and diapause eggs.A total of 175 proteins were differentially expressed between diapause and non-diapause eggs.Among them,24 proteins were upregulated,and 151 proteins were downregulated.Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichments were performed on all differentially expressed proteins(DEPs)and showed that peroxisome,insect hormone biosynthesis,and longevity regulating pathway may be related to diapause of migratory locust.Furthermore,we used qRT-PCR to verify some results of the proteomic analysis.Proteins such as hexamerin-like protein 4,juvenile hormone epoxide hydrolase 1(JHEH1),cytochrome P450 and heat shock protein(HSP)20.7 were predicted to be involved in diapause.This study provides an important reference for future research that will explore the mechanisms of diapause induced by maternal effects in migratory locust.
基金Supported by the Fundamental Research Funds for the Central Universities(No.201762017)the National Natural Science Foundation of China(No.31760626)
文摘The brine shrimp Artemia exhibits two reproductive modes: 1) oviparity, producing diapause embryos;and 2) ovoviviparity, producing free-swimming nauplii. Previous studies have suggested the existence of a critical stage that determines the reproductive mode. Physicochemical factors, such as photoperiod, temperature, and salinity, have been suggested to irreversibly aff ect the reproductive mode of oocytes during this critical stage. In this study, experiments were carried out using a photoperiod and temperature-sensitive parthenogenetic Artemia clone where maternal Artemia were shifted bidirectionally between ovoviviparity (18 h L:6 h D, 27℃) and oviparity (6 h L:18 h D, 19℃) culture conditions. In the main experiment ( Artemia shifted at six diff erent stages including the post-larva Ⅱ to adult Ⅱ), the reproductive mode of fi rst brood was converted when shifting was performed on post-larva Ⅱ and Ⅲ but was not converted when females were shifted after post-larva Ⅲ. A supplementary experiment further revealed that the reproductive mode of fi rst brood could be altered when shifting females at an "early phase of postlarva Ⅳ", characterized by a developing ovisac reaching the middle of the third abdominal segment, ventral spines, and some oocytes growing larger than the others. In both experiments, reproductive modes of the second brood were signifi cantly aff ected when the shifting was performed on post-larva Ⅳ. These results suggest that the critical stage for inducing oviparity and embryonic diapause is at the previtellogenic stage of oocytes, or at maternal "early phase of post-larva Ⅳ" for the first-brood off spring. During this stage, diff erential gene expression patterns of the two destined oocytes may be triggered by the token stimuli signals received by the oocytes.
基金supported by the China Postdoctoral Science Foundation (2017M622872)
文摘Diapause is a long-lived stage which has evolved into an important strategy for insects to circumvent extreme environments.In the pupal stage,Helicoverpa armigera can enter diapause,a state characterized by significantly decreased metabolic activity and enhanced stress resistance,to survive cold winters.Previous studies have shown that reactive oxygen species(ROS)can promote the diapause process by regulating a distinct insulin signaling pathway.However,the source of ROS in the diapause-destined pupal brains and mechanisms by which ROS regulate diapause are still unknown.In this study,we showed that diapause-destined pupal brains accumulated high levels of mitochondrial ROS(mtROS)and total ROS during the diapause process,suggesting that mitochondria are the main source of ROS in diapause-destined pupal brains.In addition,injection of 2-deoxy-D-glucose(DOG),a glucose metabolism inhibitor,could delay pupal development by elevating mtROS levels in the nondiapause-destined pupal brains.Furthermore,the injection of a metabolite mixture to increase metabolic activity could avert the diapause process in diapause-destined pupae by decreasing mtROS levels.We also found that ROS could activate HSP60 expression and promote the stability of the HSP60-Lon complex,increasing its ability to degrade mitochondrial transcription factor A(TFAM)and decreasing mitochondrial activity or biogenesis under oxidative stress.Thus,this study illustrated the beneficial function of ROS in diapause or lifespan extension by decreasing mitochondrial activity.
文摘The full-length cDNA encoding Larval serum protein 2 (LSp-2) in the onion maggot,Delia antiqua, was cloned and sequenced by rapid ampli?cation of cDNA ends methods. The result showed that the cDNA was 2203 bp long and the open reading frame (ORF) of 2106 bp encoded 701 amino acid with a calculated molecular weight of 80.5 kDa and an isoelectric point of 5.87. The onion maggot LSp-2 shows highest homology (83%) to that ofCalliphora vicinaat amino acid level. Its signal peptides, domains and structures were predicted and analyzed by using bioinformatic methods. The amino acid sequence of LSP-2 suggests that it would be a typical hexamerin.
文摘A hyperparasitic system with prolonged diapause for host is investigated. It is assumed that host prolonged diapause occur at larval stage, and parasitoid attack is limited to egg stage before the initiation of host diapause. Such behavior has been reported for many ichneumons. Hyperparasite only attacks the parasitoids that parasitize the hosts. Hyperparasitic system is often used in biological control. The existence and stability of nonnegative fixed points are explored. Numerical simulations are carried out to explore the global dynamics of the system, which demonstrate appropriate prolonged diapause rate and appropriate intrinsic growth rate can stabilize the system. The reasons are explained according to the ecological perspective. Furthermore, many other complexities which include quasi-periodicity, period-doubling bifurcations leading to chaos, chaotic attractor, intermittent and supertransients are observed.
基金supported by the National Natural Science Foundation of China(31760517).
文摘The forkhead box O(FoxO),as a conserved transcription factor,plays an indispensable role in regulating insect diapause.However,how FoxO is regulated to control diapause in insects remains unknown.In this study,we discovered functional binding sites for miR-2765-3p in the 3′untranslated region of FoxO in Galeruca daurica.The luciferase reporter assay showed that miR-2765-3p targeted FoxO and suppressed its expression.The expression profiles of miR-2765-3p and FoxO displayed opposite patterns during the female developmental process.Overexpression of miR-2765-3p by the injection of the miR-2765-3p agomir into adult females reduced FoxO expression,leading to the suppression of lipid accumulation,promotion of ovarian development,and inhibition of reproductive diapause.This is similar to the phenotype that results from the depletion of FoxO by injecting dsFoxO into adult females.In addition,the repression of miR-2765-3p by injecting the miR-2765-3p antagomir increased the FoxO transcript level,leading to the stimulation of lipid accumulation,depression of ovarian development,and induction of reproductive diapause.A hormone injection assay showed that the juvenile hormone(JH)agonist(methoprene)upregulated miR-2765-3p and downregulated FoxO.Notably,injecting methoprene rescued ovarian development defects associated with miR-2765-3p inhibition.These findings indicate that the JH/miR-2765-3p/FoxO axis plays a vital role in the regulation of reproductive diapause in G.daurica.
文摘The embryonic diapause of the silkworm, Bombyx mori, is induced by the diapause hormone (DH) which is secreted from the suboesophageal ganglion of pupae. The diapause nature of bivoltine strains uses environmental stimuli as the initial signal to determine the diapause nature. The experiments showed that DH gene expression is a direct response to the environmental stimulus, such as high incubation temperature. The cDNA from the embryonic stage was cloned and sequence analysis showed the cDNA encoding DH. Expression patterns of the DH gene in embryonic stage are different at incubation temperatures 15℃ and 25℃, suggesting that the incubation temperature as an environmental signal is kept within the body to control the DH gene expression at the pupal stage, so that the embryonic diapause of next generation can be determined.
基金This study was supported by the National Key Research and Development Program of China(2016YFC1200500)the Guangzhou Synergy Innovation Key Program for Health(201508020263)+1 种基金the Science and Technology Planning Project of Guangdong Province of China(2016A020251001)the Guangzhou International Science and Technology Cooperation Program(2012 J5100026).
文摘Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adverse environments.Ae.albopictus is the vital vector transmitting dengue virus in Guangzhou,but its diapause activities herein remain obscure.Methods:In the laboratory,yeast powder and food slurry were compared for a proper diapause determination method,and the critical photoperiod(CPP)was tested at illumination times of 11,11.5,12,12.5,13,and 13.5 h.A 4-parameter logistic(4PL)regression model was selected to estimate the CPP.In the field,the seasonal dynamics of the Ae.albopictus population,egg diapause,and hatching of overwintering eggs were investigated monthly,weekly,and daily,respectively.A distributed lag non-linear model(DLNM)was used to assess the associations of diapause with meteorological factors.Results:In the laboratory,both the wild population and the Foshan strain of Ae.albopictus were induced to diapause at an incidence greater than 80%,and no significant difference(P>0.1)was observed between the two methods for identifying diapause.The CPP of this population was estimated to be 12.312 h of light.In the field,all of the indexes of the wild population were at the lowest levels from December to February,and the Route Index was the first to increase in March.Diapause incidence displayed pronounced seasonal dynamics.It was estimated that the day lengths of 12.111 h at week2016,43 and 12.373 h at week2017,41 contributed to diapause in 50%of the eggs.Day length was estimated to be the main meteorological factor related to diapause.Conclusions:Photoperiodic diapause of Ae.albopictus in Guangzhou of China was confirmed and comprehensively elucidated in both the laboratory and the field.Diapause eggs are the main form for overwintering and begin to hatch in large quantities in March in Guangzhou.Furthermore,this study also established an optimized investigation system and statistical models for the study of Ae.albopictus diapause.These findings will contribute to the prevention and control of Ae.albopictus and mosquito-borne diseases.
文摘Diapause hormone (DH) is a neurohormone which is secreted from suboesophageal ganglion and responsible for induction of embryonic diapause in many insects. Using rapid amplification of the cDNA ends (RACE) method, the cDNA encoding diapause hormone in Helicoverpa armigera, a main kind of crops pest was cloned. The nucleotide sequence reveals that the mRNA encodes an open reading frame and the 25-aa DH peptide is localized at N-terminal region just after the signal peptide. A homology search showed that H. armigera DH has high homology with the diapause hormone of Bornbyx mori and Helicoverpa zea; and it also belongs to the FXPRL neuropeptide family. Thus, H. armigera DH seems to be a new type of diapause hormone molecule.
基金This study was funded by the National Natural Science Foundation of China(grant no.31701842)Hubei Provincial Natural Science Foundation of China(grant no.2019CFB475).
文摘Juvenile hormone (JH) absence induces photoperiod-mediated reproductive diapause, which is characterized by reproductive cessation. Although the role of methoprene-tolerant (Met)-mediated JH signaling in photoperiod-mediated female reproduction has been well documented, its role in male reproduction remains unclear. In this study, we investigated the role of JH in regulating photoperiod-mediated development of the male internal reproductive system (IRS) in the predatory ladybeetle Harmonia axyridis (Pallas). In a previous study, we found that adult male H. axyridis reared under either a short-day (SD) or long-day (LD) photoperiod had obvious differences in IRS development, but we were unable to identify the regulators of male reproductive diapause. In this study, we found that beetles reared under an SD photoperiod had significantly lower JH titer and a relatively undeveloped male IRS compared with those reared under an LD photoperiod. Additionally, application of the JH analog (JHA) methoprene promoted IRS development. Furthermore, Met knockdown strongly blocked JH signaling in males reared under the LD photoperiod, thereby slowing IRS development. Moreover, exogenous JHA did not reverse the suppressed development of the male IRS caused by Met knockdown. These results indicate that photoperiod regulates male IRS development in H. axyridis through a conserved Met-dependent JH signaling pathway.
基金supported by the National Natural Science Foundation of China(91857106 and 31770865)by the CGC,which is funded by NIH Office of Research Infrastructure Programs(P40 OD010440)of USAby the Mitani Lab through the National Bio-Resource Project of the MEXT of Japan。
文摘Developmental diapause is a widespread strategy for animals to survive seasonal starvation and environmental harshness.Diapaused animals often ration body fat to generate a basal level of energy for enduring survival.How diapause and fat rationing are coupled,however,is poorly understood.The nematode Caenorhabditis elegans excretes pheromones to the environment to induce a diapause form called dauer larva.Through saturated forward genetic screens and CRISPR knockout,we found that dauer pheromones feed back to repress the transcription of ACOX-3,MAOC-1,DHS-28,DAF-22(peroxisomalβ-oxidation enzymes dually involved in pheromone synthesis and fat burning),ALH-4(aldehyde dehydrogenase for pheromone synthesis),PRX-10 and PRX-11(peroxisome assembly and proliferation factors).Dysfunction of these pheromone enzymes and factors relieves the repression.Surprisingly,transcription is repressed not by pheromones excreted but by pheromones endogenous to each animal.The endogenous pheromones regulate the nuclear translocation of HNF4αfamily nuclear receptor NHR-79 and its co-receptor NHR-49,and,repress transcription through the two receptors.The feedback repression maintains pheromone homeostasis,increases fat storage,decreases fat burning,and prolongs dauer lifespan.Thus,the exocrine dauer pheromones possess an unexpected endocrine function to mediate a peroxisome-nucleus crosstalk,coupling dauer diapause to fat rationing.
基金supported by funds from the Technol-ogy Project of Guizhou Province(Qian Ke He Basic-ZK[2021]General 102)Youth Talents of Science and Tech-nology Projects from Guizhou Educational Department(Qian Jiao He KY Zi[2021]078)Talent Introduction Project of Guizhou University(Gui Da Ren Ji He[2019]04).
文摘Diapause,an important strategy used by insects to avoid adverse environments,is regulated by various cell signaling pathways.The results of our previous studies demonstrated that the transforming growth factor-β(TGF-β)signaling pathway regulated pupal diapause in Helicoverpa armigera,which was accompanied by downregulation of proteins in TGF-βsignaling.However,to date the mechanism underlying this phenomenon remains unknown.Here,we cloned the E3 ubiquitin ligases gene Smurf.In vitro experiments showed that Smurf directly bound to TGF-βreceptor type I(TGFβRI)and Smad2.Overexpressing Smurf promoted ubiquitination of TGFβRI and Smad2,thereby downregulating their protein levels.Conversely,silencing of the Smurf gene suppressed ubiquitination of TGFβRI and Smad2 thereby increasing their protein levels.Results from in vivo co-immunoprecipitation assays revealed that the binding of Smurf to TGFβRI or Smad2 was stronger in diapause pupae than in nondiapause pupae.Injection of Smurf inhibitor A01 into diapause pupae markedly upregulated expression of TGFβRI and Smad2 proteins,leading to resumption of development in diapause pupae.Taken together,these findings suggested that ubiquitin ligase E3 Smurf participated in H.armigera diapause by regulating TGF-βsignaling,and thus could be playing a crucial role in insect diapause.
基金This research was supported by Australian Research Council grants DP0450050 to MRK and DP160100279 to MRK and AAH.
文摘The phenological response is among the most important traits affecting a species’sensitivity to climate.In insects,strongly seasonal environments often select for a univoltine life cycle such that one seasonal extreme is avoided as an inactive stage.Through understanding the underlying mechanisms for univoltinism,and the consequences of its failure,we can better predict insect responses to climate change.Here we combine empirical data and simulation studies to investigate the consequences of an unusual diapause mechanism in a parthenogenetic matchstick grasshopper,Warramaba virgo,from arid southern Australia.Our field body temperature measurements indicate that this species is a thermoconformer and our laboratory studies of the thermal response of feeding rate imply strong constraints on winter activity.However,the species exhibits no obligate winter diapause,and eggs can develop in 1 month under constant temperatures approximating the mean soil temperature at the time of oviposition(summer).We show that diurnal temperature cycles exceeding a peak of 36℃ inhibit egg development in summer,and that this is sufficient to prevent autumnal hatching of eggs.Development is also strongly retarded below 24℃.Microclimate-driven simulation studies of egg development show that these thermal responses provide robust maintenance of a univoltine life cycle,thereby resulting in survival of heat stress as an egg(due to limited developmental state)and avoidance of cold stress as a nymph and adult(due to overwintering in the soil as an egg).
基金supported by The Academy of Finland(grant number 250999)。
文摘Envipnmental cues,mainly photoperiod and temperature,are known to control female adult reproductive diapause in several insect species.Diapause enhances female survival during adverse conditions and postpones progeny production to the favorable season.Male diapause(a reversible inability to inseminate receptive females)has been studied much less than female diapause.However,if the males maximized their chances to fertilize females while minimizing their energy expenditure,they would be expected to be in diapause at the same time as females.We investigated Drosophila montana male mating bchavior under short-day conditions that induce diapause in females and found the males to be reproductively inactive.We also found that males reared under long-day conditions(reproducing individuals)court reproducing postdiapause fermales,but not diapausing ones.The diapausing fies of both sexes had more long-chain and less short-chain hydrocarbons on their cuticle than the reproducing ones,which presumably increase their survival under stressful conditions,but at the same time decrease their attractiveness.Our study shows that the mating behavior of females and males is well coordinated during and afier overwintering and it also gives support to the dual role of insect cuticular hydrocarbons in adaptation and mate choice.
文摘The paper investigates the existence of a relationship between the diapause duration and the temperature threshold of hatching,the variances in temperature and hatching time of the artificial six-month population of Lymantria dispar caterpillars.A half-year population gives two generations a year under artificial conditions.A comparative analysis of these parameters with similar parameters of the hybrid population of L.dispar,as well as studies by other authors,has been carried out.The Eigen quasispecies model was used for the mathematical formalization of the evolution process.The results of this work can be used to study the evolution of L.dispar.
基金Funded by the National Natural Science Foundation of China(31701842)
文摘In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facultative diapause and prepares diapause can provide us new insights to study developmental and evolutionary biology.It has been shown that the circadian clock genes can participate in photoperiodic measurement and regulate reproductive diapause initiation through JH signaling in short-day-induced winter diapause.However,how circadian clock genes translate photoperiodic information into downstream JH signaling for diapause destiny and then affect diapause preparation remains largely unknown.In the present study,we investigate this in the cabbage beetle Colaphellus bowringi which undergoes reproductive diapause under long-day condition.We respectively knocked down two circadian clock negative regulators,period(per)and timeless(tim),in the 3-day-old larvae(most sensitive to photoperiod),and dsgfp treatment was served as a control.Under the diapause-inducing photoperiod(16L:8D),knocking down per and tim significantly decreased the rate of burrowing behavior.And mtany female beetles of the per and tim RNAi showed developed ovary,decreased lipid accumulation and downregulated expression of stress resistance genes.The JHinduced genes,Kr-h1,JHE1,Vg1,and Vg2, significantly increased in the females with suppression of per and tim.It implied that suppression of per and tim during diapause initiation phase(DIP)could activate the JH signaling in the female adults.Before the beetles enter into diapause preparation phase(DPP),we used RNA sequencing to analyize gene expression profiles after per and tim RNAi.It showed that many differentially expressed genes were enriched in environmental information processing,such as mTOR and TGF-beta signaling pathway.To ask whether per and tim also regulate diapause preparation,we knocked down these two genes in the female adults during DPP.It showed that the diapause destiny was not af-fected,but the lipid storage in diapause-destined females was significantly reduced after per and tim RNAi.Interestingly,per-and tim-regulated lipid storage during DPP was independent on JH signaling.We further found that per and tim promoted lipid storage by regulating the expression of genes that control lipogenesis and lipolysis.In summary,these results suggest that per and tim participate in photoperiodic measurement and initiate reproductive diapause through JH signaling during DIP in long-day-induced summer diapause.The mTOR and TGF-beta signaling pathways may be involved in the regulation of JH signaling by circadian clock genes.Meanwhile,per and tim transduce photoperiodic signal and promote lipid storage during DPP in a JH-independent manner.These results provide us new clues to study the molecular mechanism of photoperiod-regulated diapause induction in insects.
基金Lidia Ruth Ordones Espinosa provided help to collect the animals A Grant from CONACyT(152666)was provided to JCG.
文摘In insects, juvenile hormone (JH) decreases or has any effect upon the phenoloxidase (PO) activity, and favors or decreases the Antimicrobial Peptides (AMPs) expression. Although there is no information about the differential effect of such hormone, two possibilities are that it depends on (a) the immune marker recorded and (b) sexual differences. Here, three commonly used immune markers, Phenoloxidase (PO), hydrogen peroxide (H2O2), and lytic activity, were measured 3, 6 and 24 hours after administration of methoprene (JHa, an analog of juvenile hormone) in male and female monarch butterflies (Danaus plexippus). At 3 and 6 h post-JHa administration, the PO activity increased in females but it only increased at 3 h in males, whereas H2O2 levels increased only in females at 3 h. For the remaining times the JHa had a null effect on POand H2O2. On the other hand, the JHa had a null effect for lytic activity in both sexes at 3, 6 and 24 h. To our knowledge, this is the first report of a positive effect of a JHa onPOand H2O2 and suggests that this effect is sex dependent.
文摘Bathycoelia natalicola (Distant) is the dominant stink bug on macadamias in South Africa. This insect occurred throughout the year but was particularly numerous during summer months when developing macadamia nuts were available on the trees. The presence of nymphs and adults throughout the winter as well as the absence of seasonal polyphenism indicates that true diapause may not occur in areas with mild subtropical climates. After harvest, during winter when no nuts were available, the winter stink bug complex consisting of Nezara pallidocons-persa Stal, Nezara prunasis Dallas and Atelocera raptoria Germarbecame was more numerous. The Nezara species do not breed in macadamias indicating that macadamia is possibly not a preferred host plant. Few individuals of the polyphagous pest, Pseudotheraptus wayi brown were recovered with the branch shaking technique suggesting that this technique is possibly not suitable to monitor for this insect. Considerable P. wayi damage levels were however, detected by dissecting prematurely aborted nuts.
文摘This study aims to examine the following three hypotheses on the impact of global warming on the populations of the water strider, Aquarius paludum in the Kochi-Nankoku area (33。30'N) of Kochi prefecture, Japan through the recent data collected in 2009-2011. 1) Has the generation number increased? 2) Has aestivation appeared in adults? 3) Have overwintering adults stopped dispersing between the water surface and overwintering lands-sites far away from water and, instead, overwintered on/near the shore? Sampling data showed that the number of generations may have increased from three (1989-2002 strains) and four (2004-2008) to five (2009-2011) per year in Kochi (33。N). The ratio of adults having well developed flight muscles decreased from 45% in 1995 to 24% - 28% in 2009-2011 inoverwintering adults collected from the field in fall likely as a result of histolysis. “Mosaic-typed” wing morph group with long fore-wings and short hind-wings newly appeared in 2009-2011 in the Kochi-Nankoku overwintering populations. The mosaic-typed wings group cannot fly and the black and long fore wings might function as absorbing apparatus of sun-lights in the daytime of winter. Some overwintering adults seem to stop migrating between water bodies and overwintering sites on land far from the water bodies and overwinter, instead, near the shore. The use of Aquarius paludum as a biological indicator would be possible in the future, because this species can respond and change their reproductive and dispersal characteristics to the global change.
