The olfactory system of insects is crucial in modulating behaviors such as host seeking,mating,and oviposition.Odorantbinding proteins(OBPs)are involved in semiochemical recognition.OBPs recognize and bind odorants an...The olfactory system of insects is crucial in modulating behaviors such as host seeking,mating,and oviposition.Odorantbinding proteins(OBPs)are involved in semiochemical recognition.OBPs recognize and bind odorants and transport them to odorant receptors located in olfactory neurons.Harmonia axyridis(Coleoptera:Coccinellidae)is a widely used predacious biological control agent for many agricultural and forestry pests.This study identified 19 OBPs in H.axyridis based on the antennal and whole-body transcriptomes of adults and obtained all the full-length open reading frames,including 11‘Classic’OBPs,7‘Minus-C’OBPs and 1‘Plus-C’OBP.They encoded 125 to 241 amino acid proteins with molecular weights ranging from 13.75 to 27.75 kDa and isoelectric points ranging from 4.15 to 8.80.Phylogenetic analyses were used to study the relationships between H.axyridis OBPs and OBPs from other species of Coleoptera.Quantitative real-time PCR(qPCR)analysis showed that HaxyOBP2,3,5,8,10,12,13,14,and 15 were highly expressed in antennae of both adult females and males.Moreover,HaxyOBP2,3,5,12,and 15 were more abundantly expressed in antennae than other body parts,while HaxyOBP13 and HaxyOBP14 were expressed predominantly,and at similar levels,in the head and antennae.The other OBP genes were highly expressed in non-olfactory tissues including the thorax,abdomen,legs,and wings.These results provide valuable information for further study of H.axyridis olfaction,which may ultimately enhance its use as a biocontrol agent.展开更多
In this study, the Harmonia axyridis vitellogenin gene 2 (HmVg2) sequence was identified from transcriptomic databases of female adult H. axyridis and cloned into pMD18-T vector. The HmVg2 gene was 5 460 bp in length,...In this study, the Harmonia axyridis vitellogenin gene 2 (HmVg2) sequence was identified from transcriptomic databases of female adult H. axyridis and cloned into pMD18-T vector. The HmVg2 gene was 5 460 bp in length, and formed with an open reading frame (ORF) of 5 361 nucleotides (GenBank accession no. KY794939). The putative molecular weight of the primary HmVg2 protein was 203.459 kDa and the predicted isoelectric point (pI) was 8.59. HmVg2 contained a signal peptide, vitellogenin N-terminal (vitellogenin-N) domain, domain of unknown function 1943 (DUF1934) domain and von Willebrand factor type D (VWD) domain. The developmental expression profiling showed that HmVg2 was extremely highly expressed in female insects, but was expressed at lower levels in male insects. In female insects, HmVg2 was mainly expressed in the wing and fat body. The double-stranded RNA-HmVg2/-GFP was injected into H. axyridis, and qRT-PCR results showed that the HmVg2 gene was specifically silenced. The eggs laid during the first five days and the hatching rate of eggs was lower than controls after dsHmVg2 injection. This investigation demonstrated that the HmVg2 gene plays an important role in H. axyridis reproduction and enriches the function of the insect vitellogenin gene.展开更多
Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti (Panzer), feeding on transgenic poplar (P. alba × P. glandulosa) varieties C13-5 and C013-5, were carried out to study the effect of...Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti (Panzer), feeding on transgenic poplar (P. alba × P. glandulosa) varieties C13-5 and C013-5, were carried out to study the effect of transgenic poplar on the ladybird Harmonia axyridis (Pallas). The mortality and development time of the immature stages, the eclosion rate and body mass of H. axyridis were measured. The results indicated that C. populeti feeding on different varieties of transgenic plants had no statistically significant ef- fect on the mortality ofH. axyridis larvae. The development time of larval and pupal stages were not significantly different between the two transgenic poplars and a non-transgenic poplar. Furthermore, the body mass and eclosion rate did not show any difference between the H. axyridis feeding on aphids reared on transgenic plants and those from non-transgenic plants. It is suggested that transgenic plants have no deleterious effect on the predatory ladybird.展开更多
These last few years the multicolored Asian ladybird, Harmonia axyridis (Pallas), previously introduced in Europe and North America as a biological control agent, has swiftly spread out on those territories and turns ...These last few years the multicolored Asian ladybird, Harmonia axyridis (Pallas), previously introduced in Europe and North America as a biological control agent, has swiftly spread out on those territories and turns out to be a pest in several ways. In order to improve understanding of several key points of the biology of this ladybird, a novel fast-GC method of quantification of harmonine, the main defense alkaloid of H. axyridis, has been designed and validated using the accuracy profile concept for concentrations ranging from 13 to 264 μg/individual. This method allows quantifying harmonine in a single insect with a maximal error risk of 20%. For ladybirds collected in spring, mean harmonine concentration observed was 106.6 μg/individual with a very high standard deviation of 80.2 μg/individual, which can easily be explained by the strong asymmetry of the results distribution. Males and females seem equally chemically protected as the harmonine concentration did not significantly differ between sexes. This method is currently used to improve our comprehension of several key points of H. axyridis biology including aggregation behavior and aposematism.展开更多
Five sampling points for Harmonia axyridis (Pallas) were set in Sifeng Mountain scenic spot and four school districts of Jiamusi University, and diversity of color pattern of overwintering H. axyridis was surveyed f...Five sampling points for Harmonia axyridis (Pallas) were set in Sifeng Mountain scenic spot and four school districts of Jiamusi University, and diversity of color pattern of overwintering H. axyridis was surveyed from October to December in 2010. Survey results found that there were 16 color patterns of H. axyridis in southern suburb of Jiamusi, 11 species showed yellow background, while the other 5 species were black background, accounting for 68.75% and 31.25% of all the species, respectively. The majority of H. axyridis with yellow background had 18 or 19 spots. Compared with the sampling data in 2006 and 2008, the propor- tions of the color patterns had no significant difference in different years, but it slightly varied with the changes of environment.展开更多
Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of ...Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids (Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene), from coccinellids ([-]-β-earyophyllene) and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds ([Z]-3- hexenol and [E]-2-hexenal) were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while (-)-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the (Z)-3-hexenol oriented both males and females to the odor source. The (E)-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.展开更多
The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoi...The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-l-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vieia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds (3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene) were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonene was the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals as well as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis.展开更多
The multicolored Asian lady beetle,Harmonia axyridis(Pallas)(Coleoptera:Coccinellidae),is an important natural enemy in agricultural ecosystems.In spite of being a carnivore consuming protein-rich preys,the lady beetl...The multicolored Asian lady beetle,Harmonia axyridis(Pallas)(Coleoptera:Coccinellidae),is an important natural enemy in agricultural ecosystems.In spite of being a carnivore consuming protein-rich preys,the lady beetles often consume carbohydrate-rich food like nectar or honeydew.However,most studies on nutrition regulation of carnivores mainly focus on protein and lipid,two major macronutrients in preys.In this study,nutrition regulation of protein and carbohydrate has been investigated in the 4th instar larvae of H.axyridis using Geometric Framework.We provided the insects two pairs of foods,one a protein-biased one and the second carbohydrate-biased,to determine the intake target.We then confined them to nutritionally imbalanced foods to examine how they regulated food intake to achieve maximal performance.The larvae performed well on the 2 foods that containing the closest P:C ratios to the intake target,but,surprisingly,the lipid content was much lower than that in the choice experiment.The lady beetles seemed to maintain the optimal lipid content by consuming carbohydrate-rich food.Moreover,consuming the carbohydrate-rich food was less metabolically expensive than the protein-rich food.Therefore,switching behavior between plant and animal foods actually reflects their nutritive needs.These findings extended our understanding of predator forage behavior and its influence on food web in ecosystems,and shed light on the role of agri-environment schemes in meeting the nutritional need of predators in field.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
Phenotypic plasticity is observed in many animal species and it is effective for them to cope with many types of environmental threats.The multicolored Asian ladybird Harmonia axyridis shows a cuticular pigmentation p...Phenotypic plasticity is observed in many animal species and it is effective for them to cope with many types of environmental threats.The multicolored Asian ladybird Harmonia axyridis shows a cuticular pigmentation plasticity that can be rapidly induced by temperature changes,and in the form of changeable melanin spot patterns to adjust heat-absorbing.Here,H.axyridis with thermal stimulation were selected for determining the molecular regulations behind it.First,we confirmed the melanin level changes of H.axyridis pupa could be induced by temperature,and then screened the efficient time window for thermal sensing of H.axyridis pre-pupa;it is suggested that the late stage of pre-pupa(late stage of 4th instar larva)is the critical period to sense thermal signals and adjust its pupal melanin spot area size to adapt to upcoming thermal conditions.The Ha-ADC(aspartate decarboxylase)and Ha-ebony(NBAD synthase)of aspartate-β-alanine-NBAD pathway were then proved in regulation of cuticular melanization for pupa through RNA interference experiments;knockdown of these two genes enlarged the melanin spot size.Finally,we designed a random injection of Ha-ADC at different pre-pupal stages,to further study the regulation window during this process.Combined with all evidence observed,we suggested the spot size determination can be regulated very close to the time point of pupation,and genes of the aspartate-β-alanine-NBAD pathway play an important role at the molecular level.In brief,H.axyridis exhibits a flexible active physiological regulation through transcriptional modification to thermal changes.展开更多
Glucose is vital to embryogenesis,as are glucose transporters.Glucose transporter 4(Glut4)is one of the glucose transporters,which is involved in rapid uptake of glucose by various cells and promotes glucose homeostas...Glucose is vital to embryogenesis,as are glucose transporters.Glucose transporter 4(Glut4)is one of the glucose transporters,which is involved in rapid uptake of glucose by various cells and promotes glucose homeostasis.Although energy metabolism in insect reproduction is well known,the molecular mechanism of Glut4 in insect reproduction is poorly understood.We suspect that Glut4 is involved in maintaining glucose concentrations in the ovaries and affecting vitellogenesis,which is critical for subsequent oocyte maturation and insect fertility.Harmonia axyridis(Pallas)is a model organism for genetic research and a natural enemy of insect pests.We studied the influence of the Glut4 gene on the reproduction and development of H.axyridis using RNA interference technology.Reverse transcription quantitative polymerase chain reaction analysis revealed that HaGlut4 was most highly expressed in adults.Knockdown of the HaGlut4 gene reduced the transcript levels of HaGlut4,and the weight and number of eggs produced significantly decreased.In addition,the transcript levels of vitellogenin receptor and vitellogenin in the fat bodies and the ovaries of H.axyridis decreased after the interference of Glut4,and decreased the triglyceride,fatty acid,total amino acid and adenosine triphosphate content of H.axyridis.This resulted in severe blockage of ovary development and reduction of yolk formation;there was no development of ovarioles in the developing oocytes.These changes indicate that a lack of HaGlut4 can impair ovarian development and oocyte maturation and result in decreased fecundity.展开更多
基金This work was supported by the National Key Research and Develop Program of China(2017YFD0200400)the Shandong Province Modern Agricultural Technology System Peanut Innovation Team,China(SDAIT-04-08)the Beijing Leafy Vegetables Innovation Team of Modern Agroindustry Technology Research System,China(BAIC07-2020).
文摘The olfactory system of insects is crucial in modulating behaviors such as host seeking,mating,and oviposition.Odorantbinding proteins(OBPs)are involved in semiochemical recognition.OBPs recognize and bind odorants and transport them to odorant receptors located in olfactory neurons.Harmonia axyridis(Coleoptera:Coccinellidae)is a widely used predacious biological control agent for many agricultural and forestry pests.This study identified 19 OBPs in H.axyridis based on the antennal and whole-body transcriptomes of adults and obtained all the full-length open reading frames,including 11‘Classic’OBPs,7‘Minus-C’OBPs and 1‘Plus-C’OBP.They encoded 125 to 241 amino acid proteins with molecular weights ranging from 13.75 to 27.75 kDa and isoelectric points ranging from 4.15 to 8.80.Phylogenetic analyses were used to study the relationships between H.axyridis OBPs and OBPs from other species of Coleoptera.Quantitative real-time PCR(qPCR)analysis showed that HaxyOBP2,3,5,8,10,12,13,14,and 15 were highly expressed in antennae of both adult females and males.Moreover,HaxyOBP2,3,5,12,and 15 were more abundantly expressed in antennae than other body parts,while HaxyOBP13 and HaxyOBP14 were expressed predominantly,and at similar levels,in the head and antennae.The other OBP genes were highly expressed in non-olfactory tissues including the thorax,abdomen,legs,and wings.These results provide valuable information for further study of H.axyridis olfaction,which may ultimately enhance its use as a biocontrol agent.
基金supported by the National Natural Science Foundation of China (31272095)the National Key Research and Development Program of China (2017YFD0201004)the Hebei Modern Agriculture Industry Technology System, China (HBCT2018060204)
文摘In this study, the Harmonia axyridis vitellogenin gene 2 (HmVg2) sequence was identified from transcriptomic databases of female adult H. axyridis and cloned into pMD18-T vector. The HmVg2 gene was 5 460 bp in length, and formed with an open reading frame (ORF) of 5 361 nucleotides (GenBank accession no. KY794939). The putative molecular weight of the primary HmVg2 protein was 203.459 kDa and the predicted isoelectric point (pI) was 8.59. HmVg2 contained a signal peptide, vitellogenin N-terminal (vitellogenin-N) domain, domain of unknown function 1943 (DUF1934) domain and von Willebrand factor type D (VWD) domain. The developmental expression profiling showed that HmVg2 was extremely highly expressed in female insects, but was expressed at lower levels in male insects. In female insects, HmVg2 was mainly expressed in the wing and fat body. The double-stranded RNA-HmVg2/-GFP was injected into H. axyridis, and qRT-PCR results showed that the HmVg2 gene was specifically silenced. The eggs laid during the first five days and the hatching rate of eggs was lower than controls after dsHmVg2 injection. This investigation demonstrated that the HmVg2 gene plays an important role in H. axyridis reproduction and enriches the function of the insect vitellogenin gene.
基金supported by the National Premier Special Funds for Study and Industrialization of Transgenic Plants (J2002-B-004)the National Natural Science and Technology Support Plan of China "the technology researchdemonstration of forestry-paper integrate project" (Grant No. 2006BAD32B)
文摘Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti (Panzer), feeding on transgenic poplar (P. alba × P. glandulosa) varieties C13-5 and C013-5, were carried out to study the effect of transgenic poplar on the ladybird Harmonia axyridis (Pallas). The mortality and development time of the immature stages, the eclosion rate and body mass of H. axyridis were measured. The results indicated that C. populeti feeding on different varieties of transgenic plants had no statistically significant ef- fect on the mortality ofH. axyridis larvae. The development time of larval and pupal stages were not significantly different between the two transgenic poplars and a non-transgenic poplar. Furthermore, the body mass and eclosion rate did not show any difference between the H. axyridis feeding on aphids reared on transgenic plants and those from non-transgenic plants. It is suggested that transgenic plants have no deleterious effect on the predatory ladybird.
基金financially supported by a PhD grant from the Fonds pour la formation a la Recherche dans l’Industrie et dans l’Agriculture(FRIA)(Belgium).
文摘These last few years the multicolored Asian ladybird, Harmonia axyridis (Pallas), previously introduced in Europe and North America as a biological control agent, has swiftly spread out on those territories and turns out to be a pest in several ways. In order to improve understanding of several key points of the biology of this ladybird, a novel fast-GC method of quantification of harmonine, the main defense alkaloid of H. axyridis, has been designed and validated using the accuracy profile concept for concentrations ranging from 13 to 264 μg/individual. This method allows quantifying harmonine in a single insect with a maximal error risk of 20%. For ladybirds collected in spring, mean harmonine concentration observed was 106.6 μg/individual with a very high standard deviation of 80.2 μg/individual, which can easily be explained by the strong asymmetry of the results distribution. Males and females seem equally chemically protected as the harmonine concentration did not significantly differ between sexes. This method is currently used to improve our comprehension of several key points of H. axyridis biology including aggregation behavior and aposematism.
基金Supported by General Science and Technology Project of Department of Education of Heilongjiang Province(11531384)~~
文摘Five sampling points for Harmonia axyridis (Pallas) were set in Sifeng Mountain scenic spot and four school districts of Jiamusi University, and diversity of color pattern of overwintering H. axyridis was surveyed from October to December in 2010. Survey results found that there were 16 color patterns of H. axyridis in southern suburb of Jiamusi, 11 species showed yellow background, while the other 5 species were black background, accounting for 68.75% and 31.25% of all the species, respectively. The majority of H. axyridis with yellow background had 18 or 19 spots. Compared with the sampling data in 2006 and 2008, the propor- tions of the color patterns had no significant difference in different years, but it slightly varied with the changes of environment.
文摘Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids (Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene), from coccinellids ([-]-β-earyophyllene) and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds ([Z]-3- hexenol and [E]-2-hexenal) were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while (-)-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the (Z)-3-hexenol oriented both males and females to the odor source. The (E)-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.
文摘The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-l-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vieia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds (3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene) were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonene was the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals as well as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis.
基金supported by the National Key R&D Program of China(2017YFD0200400)the Introduction of Tal-ent Research Start-up Fund of Northwest A&F University(2452017323)Shaanxi Province(A279021711).
文摘The multicolored Asian lady beetle,Harmonia axyridis(Pallas)(Coleoptera:Coccinellidae),is an important natural enemy in agricultural ecosystems.In spite of being a carnivore consuming protein-rich preys,the lady beetles often consume carbohydrate-rich food like nectar or honeydew.However,most studies on nutrition regulation of carnivores mainly focus on protein and lipid,two major macronutrients in preys.In this study,nutrition regulation of protein and carbohydrate has been investigated in the 4th instar larvae of H.axyridis using Geometric Framework.We provided the insects two pairs of foods,one a protein-biased one and the second carbohydrate-biased,to determine the intake target.We then confined them to nutritionally imbalanced foods to examine how they regulated food intake to achieve maximal performance.The larvae performed well on the 2 foods that containing the closest P:C ratios to the intake target,but,surprisingly,the lipid content was much lower than that in the choice experiment.The lady beetles seemed to maintain the optimal lipid content by consuming carbohydrate-rich food.Moreover,consuming the carbohydrate-rich food was less metabolically expensive than the protein-rich food.Therefore,switching behavior between plant and animal foods actually reflects their nutritive needs.These findings extended our understanding of predator forage behavior and its influence on food web in ecosystems,and shed light on the role of agri-environment schemes in meeting the nutritional need of predators in field.
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.
文摘Phenotypic plasticity is observed in many animal species and it is effective for them to cope with many types of environmental threats.The multicolored Asian ladybird Harmonia axyridis shows a cuticular pigmentation plasticity that can be rapidly induced by temperature changes,and in the form of changeable melanin spot patterns to adjust heat-absorbing.Here,H.axyridis with thermal stimulation were selected for determining the molecular regulations behind it.First,we confirmed the melanin level changes of H.axyridis pupa could be induced by temperature,and then screened the efficient time window for thermal sensing of H.axyridis pre-pupa;it is suggested that the late stage of pre-pupa(late stage of 4th instar larva)is the critical period to sense thermal signals and adjust its pupal melanin spot area size to adapt to upcoming thermal conditions.The Ha-ADC(aspartate decarboxylase)and Ha-ebony(NBAD synthase)of aspartate-β-alanine-NBAD pathway were then proved in regulation of cuticular melanization for pupa through RNA interference experiments;knockdown of these two genes enlarged the melanin spot size.Finally,we designed a random injection of Ha-ADC at different pre-pupal stages,to further study the regulation window during this process.Combined with all evidence observed,we suggested the spot size determination can be regulated very close to the time point of pupation,and genes of the aspartate-β-alanine-NBAD pathway play an important role at the molecular level.In brief,H.axyridis exhibits a flexible active physiological regulation through transcriptional modification to thermal changes.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2017YFD0201000)the Hangzhou Science and Technology Development Program of China(Grant No.20190101A01).
文摘Glucose is vital to embryogenesis,as are glucose transporters.Glucose transporter 4(Glut4)is one of the glucose transporters,which is involved in rapid uptake of glucose by various cells and promotes glucose homeostasis.Although energy metabolism in insect reproduction is well known,the molecular mechanism of Glut4 in insect reproduction is poorly understood.We suspect that Glut4 is involved in maintaining glucose concentrations in the ovaries and affecting vitellogenesis,which is critical for subsequent oocyte maturation and insect fertility.Harmonia axyridis(Pallas)is a model organism for genetic research and a natural enemy of insect pests.We studied the influence of the Glut4 gene on the reproduction and development of H.axyridis using RNA interference technology.Reverse transcription quantitative polymerase chain reaction analysis revealed that HaGlut4 was most highly expressed in adults.Knockdown of the HaGlut4 gene reduced the transcript levels of HaGlut4,and the weight and number of eggs produced significantly decreased.In addition,the transcript levels of vitellogenin receptor and vitellogenin in the fat bodies and the ovaries of H.axyridis decreased after the interference of Glut4,and decreased the triglyceride,fatty acid,total amino acid and adenosine triphosphate content of H.axyridis.This resulted in severe blockage of ovary development and reduction of yolk formation;there was no development of ovarioles in the developing oocytes.These changes indicate that a lack of HaGlut4 can impair ovarian development and oocyte maturation and result in decreased fecundity.