Operative timing and the safety of emergency laparoscopic cholecystectomy: A retrospective analysis.

The ideal operative timing for laparoscopic cholecystectomy (LC) remains controversial, particularly in emergency patients. This study aimed to evaluate the necessity of operative timing for emergency LC. One hundred ninety-four patients who had undergone operative timings were classified into groups of <72h and >72h from the onset of symptoms to the operation. Baseline data, basic disease, operative bleeding, complications, and conversion rates were analyzed by Variance analysis and logistic regression analysis. The total morbidity of postoperative complication was 4.93% and 3.84% (P = .751) in the <72h and >72h groups respectively. The complication and conversion to LC were mainly influenced by age and gallbladder volume (odds ratio [OR] = 1.078, P = .013, and OR = 1.035, P = .031), but not by operative timing (P = .292). The intraoperative blood loss was closely correlated with the gallbladder volume (OR = 1.019, P = .025) by logit regression analysis, and correlation coefficient of R = 0.436, P < .01. Our results suggest that it is not necessary to confine the operative timing of LC to within 72h from the onset of symptoms, and gallbladder volume should be emphasized in the operative timing for emergency LC.

Influence of diverse storage conditions of double-stranded RNA in vitro on the RNA interference efficiency in vivo insect Tribolium castaneum.

BACKGROUND: A significant variation in RNA interference (RNAi) efficiency hinders further functional gene studies and pest control application in many insects. The available double-stranded RNA (dsRNA) molecules introduced into the target cells are regarded as the crucial factor for efficient RNAi response. However, numerous studies have only focused on dsRNA stability in vivo; it is uncertain whether different dsRNA storage conditions in vitro play a role in variable RNAi efficiency among insects. RESULTS: A marker gene cardinal, which leads to white eyes when knocked-down in the red flour beetle Tribolium castaneum, was used to evaluate the effects of RNAi efficiency under different dsRNA storage conditions. We demonstrated that the dsRNA molecule is very stable under typical cryopreservation temperatures (-80 and -20 °C) within 180 days, and RNAi efficiency shows no significant differences under either low temperature. Unexpectedly, while dsRNA molecules were treated with multiple freeze-thaw cycles up to 50 times between -80/-20 °C and room temperature, we discovered that dsRNA integrity and RNAi efficiency were comparable with fresh dsRNA. Finally, when the stability of dsRNA was further measured under refrigerated storage conditions (4 °C), we surprisingly found that dsRNA is still stable within 180 days and can induce an efficient RNAi response as that of initial dsRNA. CONCLUSION: Our results indicate that dsRNA is extraordinarily stable under various temperature storage conditions that did not significantly impact RNAi efficiency in vivo insects. © 2022 Society of Chemical Industry.

Clinicopathological difference between gastric cancer in the lesser curvature and gastric cancer in the greater curvature.

Gastric cancer (GC) is a heterogeneous disease; the tumor distribution and molecular subtype could affect the prognosis of patients with GC. However, the clinicopathological difference between GC in the lesser and that in the greater curvature remains unknown. In this study, we aimed to investigate the difference and provide new clues for the treatment of GC. Between January 2010 and August 2014, 1249 consecutive patients with GC in the lesser or greater curvature were treated in our surgery department; data related to the demographic characteristics, pathological type, tumor grade, tumor size, TNM stage, tumor markers, operative methods, complications, and follow-up were retrospectively analyzed using a univariate analysis and the Kaplan-Meier method. The tumor size in lesser curvature was larger than that in the greater curvature (4.95 ± 2.57 vs 4.43 ± 2.62 cm, P = .034); patients with GC in the lesser curvature had a higher incidence of total gastrectomy and a lower incidence of distal gastrectomy than those with GC in the greater curvature (60.2% vs 43.2%, and 34.8% vs 49.2%, P = .002). No significant differences were found in the 5-year survival rate between patients with GC in the greater curvature and those with GC in the lesser curvature (62.6% vs 66.1%, P = .496). The epidermal growth factor receptor (EGFR) expression rate of tumors in the lesser curvature was 40.55%, which was significantly higher than that of tumors in the greater curvature (25.92%, P = .024), while the 5-year survival rate of patients with EGFR-positive expression was 50.8%, which was significantly lower than that of patients with EGFR-negative expression (64.8%, P = .021). Significant differences were observed in the clinicopathological features between GC in the lesser curvature and that in the greater curvature. These differences contribute to the improvement in the treatment outcome.

Genome-Wide Identification of Neuropeptides and Their Receptors in an Aphid Endoparasitoid Wasp, Aphidius gifuensi.

In insects, neuropeptides and their receptors not only play a critical role in insect physiology and behavior but also are the potential targets for novel pesticide discoveries. Aphidius gifuensis is one of the most important and widespread aphid parasitoids, and has been successfully used to control aphid. In the present work, we systematically identified neuropeptides and their receptors from the genome and head transcriptome of A. gifuensis. A total of 35 neuropeptide precursors and 49 corresponding receptors were identified. The phylogenetic analyses demonstrated that 35 of these receptors belong to family-A, four belong to family-B, two belong to leucine-rich repeat-containing GPCRs, four belong to receptor guanylyl cyclases, and four belong to receptor tyrosine kinases. Oral ingestion of imidacloprid significantly up-regulated five neuropeptide precursors and four receptors whereas three neuropeptide precursors and eight receptors were significantly down-regulated, which indicated that these neuropeptides and their receptors are potential targets of some commercial insecticides. The RT-qPCR results showed that dopamine receptor 1, dopamine receptor 2, octopamine receptor, allatostatin-A receptor, neuropeptides capa receptor, SIFamide receptor, FMRFamide receptor, tyramine receptor and short neuropeptide F predominantly were expressed in the head whilst the expression of ion transport peptide showed widespread distribution in various tissues. The high expression levels of these genes suggest their important roles in the central nervous system. Taken together, our study provides fundamental information that may further our understanding of neuropeptidergic signaling systems in the regulation of the physiology and behavior of solitary wasps. Furthermore, this information could also aid in the design and discovery of specific and environment-friendly insecticides.

Abdominal-B regulates structure and development of the Harmonia axyridis cremaster.

The ladybird Harmonia axyridis is an insect that exhibits pupal attachment to plants, which facilitates development and environmental adaptation. The cremaster is highly specialized for this behavior. However, the underlying molecular regulation of the cremaster remains unclear; therefore, we performed experiments to investigate the transcriptional regulation of cremaster development. First, we examined the morphological structure of the cremaster to reveal its function in pupal attachment of H. axyridis. Next, we analyzed the Hox gene Ha-Abd-B using RNA interference (RNAi) to determine its function in regulating cremaster formation; Ha-Abd-B up-regulation promoted effective pupal attachment, whereas successful RNAi caused severe down-regulation of this gene, and pupae were unable to attach. Furthermore, successful RNAi and subsequent Ha-Abd-B down-regulation caused phenotypic changes in cremaster structure, including its complete disappearance from some individuals. Finally, we observed unique development of the cremaster and dynamic expression of Ha-Abd-B during pre-pupal development; consequently, we hypothesized that there was specific pre-pupal development of the cremaster. Overall, based on these results, the specialized cremasteric structure located on the posterior side of H. axyridis was determined to be a key organ for pupal attachment. Cremaster identification in H. axyridis is regulated by Ha-Abd-B and exhibits preferential development. Pupal attachment of H. axyridis reveals an environmental adaptation of this species; thus, this study and future molecular studies will help determine the role of Hox genes in regulation of insect attachment and further our understanding of the multiple functions of Hox genes.

Aspartate-ß-alanine-NBAD pathway regulates pupal melanin pigmentation plasticity of ladybird Harmonia axyridis.

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-ß-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-ß-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.

Candidate genetic determinants of intraspecific variation in pea aphid susceptibility to RNA interference.

RNA interference (RNAi) plays a key role in insect defense against viruses and transposable elements, and it is being applied as an experimental tool and for insect pest control. However, RNAi efficiency is highly variable for some insects, notably the pea aphid Acyrthosiphon pisum. In this study, we used natural variation in RNAi susceptibility of pea aphids to identify genes that influence RNAi efficiency. Susceptibility to orally-delivered dsRNA against the gut aquaporin gene AQP1 (ds-AQP1) varied widely across a panel of 83 pea aphid genotypes, from zero to total mortality. Genome-wide association between aphid performance on ds-AQP1 supplemented diet and aphid genetic variants yielded 103 significantly associated single nucleotide polymorphisms (SNPs), including variants in 55 genes, at the 10-4 probability cut-off. When ds-AQP1 was co-administered with dsRNA against six candidate genes, aphid mortality was reduced for three (50%) genes: the orthologs of the Drosophila genes trachealess (CG42865), headcase (CG15532) and a gene coding a peritrophin-A domain (CG8192), indicating that these genes function to promote RNAi efficiency against AQP1 in the pea aphid. Aphid susceptibility (quantified as mortality) to ds-AQP1 was correlated with RNAi against a further gene, snakeskin with essential gut function unrelated to AQP1, for some but not all aphid genotypes tested, suggesting that the determinants of RNAi efficiency may be partly gene-specific. This study demonstrates high levels of natural variation in susceptibility to RNAi and demonstrates the value of harnessing this variation to identify genes influencing RNAi efficiency.

The L-DOPA/Dopamine Pathway Transgenerationally Regulates Cuticular Melanization in the Pea Aphid Acyrthosiphon pisum.

Maternal phenotypic regulations between different generations of aphid species help aphids to adapt to environmental challenges. The pea aphid Acyrthosiphon pisum has been used as a biological model for studies on phenotypic regulation for adaptation, and its alternative phenotypes are typically and physiologically based on maternal effects. We have observed an artificially induced and host-related maternal effect that may be a new aspect to consider in maternal regulation studies using A. pisum. Marked phenotypic changes in the cuticular melanization of daughter A. pisum were detected via tyrosine hydroxylase knockdown in the mothers during their period of host plants alternations. This phenotypic change was found to be both remarkable and repeatable. We performed several studies to understand its regulation and concluded that it may be controlled via the dopamine pathway. The downregulation and phenotypes observed were verified and described in detail. Additionally, based on histological and immunofluorescence analyses, the phenotypic changes caused by cuticular dysplasia were physiologically detected. Furthermore, we found that this abnormal development could not be reversed after birth. Transcriptome sequencing confirmed that this abnormal development represents a systemic developmental failure with numerous transcriptional changes, and chemical interventions suggested that transgenerational signals were not transferred through the nervous system. Our data show that transgenerational regulation (maternal effect) was responsible for the melanization failure. The developmental signals were received by the embryos from the mother aphids and were retained after birth. APTH RNAi disrupted the phenotypic determination process. We demonstrate that non-neuronal dopamine regulation plays a crucial role in the transgenerational phenotypic regulation of A. pisum. These results enhance our understanding of phenotyping via maternal regulation in aphids.

Superficially Similar Adaptation Within One Species Exhibits Similar Morphological Specialization but Different Physiological Regulations and Origins.

Animals have developed numerous strategies to contend with environmental pressures. We observed that the same adaptation strategy may be used repeatedly by one species in response to a certain environmental challenge. The ladybird Harmonia axyridis displays thermal phenotypic plasticity at different developmental stages. It is unknown whether these superficially similar temperature-induced specializations share similar physiological mechanisms. We performed various experiments to clarify the differences and similarities between these processes. We examined changes in the numbers and sizes of melanic spots in pupae and adults, and confirmed similar patterns for both. The dopamine pathway controls pigmentation levels at both developmental stages of H. axyridis. However, the aspartate-ß-alanine pathway controls spot size and number only in the pupae. An upstream regulation analysis revealed the roles of Hox genes and elytral veins in pupal and adult spot formation. Both the pupae and the adults exhibited similar morphological responses to temperatures. However, they occurred in different body parts and were regulated by different pathways. These phenotypic adaptations are indicative of an effective thermoregulatory system in H. axyridis and explains how insects contend with certain environmental pressure based on various control mechanisms.

Isolation and characterization of Pseudomonas cedrina infecting Plutella xylostella (Lepidoptera: Plutellidae).

The diamondback moth, Plutella xylostella, is one of the most destructive pests worldwide and its management relies exclusively on frequent application of chemical insecticides. Resistance to common insecticides is now widespread, and novel classes of insecticides are needed. Entomopathogenic bacteria and their related products play an important role in the management of this pest. In the present work, one bacterial strain was separated from infected pupae of P. xylostella collected from field and its pathogenicity was evaluated. On the basis of the 16S ribosomal RNA sequencing, BLASTN, and phylogenetic analysis, this bacterial isolate was identified as Pseudomonas cedrina. Oral administration of P. cedrina at levels above 10,000 CFU/ml gave significant mortality to P. xylostella larvae. The pathogenicity was also observed by reduced longevity and fecundity in adult females. However, when live bacterial cells were removed, the cultured broth lost any pathogenicity. In response to the bacterial infection, P. xylostella expressed antimicrobial and stress-associated genes. A mixture treatment of P. cedrina and Bacillus thuringiensis showed an additive effect on larval mortality of P. xylostella. These results indicated that P. cedrina is an opportunistic entomopathogen without secretion of toxins. Furthermore, the additive effect of P. cedrina and B. thuringiensis provide a new insight to develop new strategy for controlling P. xylostella.

Infection of Powdery Mildew Reduces the Fitness of Grain Aphids (Sitobion avenae) Through Restricted Nutrition and Induced Defense Response in Wheat.

In natural ecological systems, plants are often simultaneously attacked by both insects and pathogens, which can affect each other's performance and the interactions can be extended to higher trophic levels, such as parasitoids. The English grain aphid (Sitobion avenae) and powdery mildew (Blumeria graminis f. sp. tritici) are two common antagonists that pose a serious threat to wheat production. Numerous studies have investigated the effect of a single factor (insect or pathogen) on wheat production. However, investigation on the interactions among insect pests, pathogens, and parasitoids within the wheat crop system are rare. Furthermore, the influence of the fungicide, propiconazole, has been found to imitate the natural ecosystem. Therefore, this study investigated the effects of B. graminis on the biological performance of grain aphids and the orientation behavior of its endoparasitic wasp Aphidius gifuensis in the wheat system. Our findings indicated that B. graminis infection suppressed the feeding behavior, adult and nymph weight, and fecundity and prolonged the developmental time of S. avenae. We found that wheat host plants had decreased proportions of essential amino acids and higher content of sucrose following aggravated B. graminis infection. The contents of Pro and Gln increased in the wheat plant tissues after B. graminis infection. In addition, B. graminis infection elicited immune responses in wheat: increase in the expression of defense genes, content of total phenolic compounds, and activity of three related antioxidant enzymes. Moreover, co-infection of B. graminis and S. avenae increased the attraction to A. gifuensis compare to that after infestation with aphids alone. In conclusion, our results indicated that B. graminis infection adversely affected the performance of S. avenae in wheat through restricted nutrition and induced defense response. Furthermore, the preference of parasitoids in such an interactive environment might provide an important basis for pest management control.

Volatile ß-Ocimene Can Regulate Developmental Performance of Peach Aphid Myzus persicae Through Activation of Defense Responses in Chinese Cabbage Brassica pekinensis.

In nature, plants have evolved sophisticated defense mechanisms against the attack of pathogens and insect herbivores. Plant volatile-mediated plant-to-plant communication has been assessed in multitrophic systems in different plant species and different pest species. ß-ocimene is recognized as an herbivore-induced plant volatile that play an important role in the chemical communication between plants and pests. However, it is still unclear whether ß-ocimene can active the defense mechanism of Chinese cabbage Brassica pekinensis against the peach aphid Myzus persicae. In this study, we found that treatment of Chinese cabbage with ß-ocimene inhibited the growth of M. persicae in terms of weight gain and reproduction. Moreover, ß-ocimene treatment negatively influenced the feeding behavior of M. persicae by shortening the total feeding period and phloem ingestion and increasing the frequency of stylet puncture. When given a choice, winged aphids preferred to settle on healthy Chinese cabbage compared with ß-ocimene-treated plants. In addition, performance of the parasitoid Aphidius gifuensis in terms of Y-tube olfaction and landings was better on ß-ocimene-treated Chinese cabbage than on healthy plants. Furthermore, ß-ocimene significantly increased the expression levels of salicylic acid and jasmonic acid marker genes and the accumulation of glucosinolates. Surprisingly, the transcriptional levels of detoxifying enzymes (CYP6CY3, CYP4, and GST) in aphids reared on ß-ocimene-treated Chinese cabbage were significantly higher than those of aphids reared on healthy plants. In summary, our results indicated that ß-ocimene can activate the defense response of Chinese cabbage against M. persicae, and that M. persicae can also adjust its detoxifying enzymes machinery to counter the host plant defense reaction.

Effect of Sublethal Doses of Imidacloprid on the Biological Performance of Aphid Endoparasitoid Aphidius gifuensis (Hymenoptera: Aphidiidae) and Influence on Its Related Gene Expression.

The integrated pest management (IPM) strategy was developed and used in combination with pesticides and beneficial biological control agents. To further develop IPM efficiency, it is important to evaluate the side effects of pesticides on biological control agents. Aphidius gifuensis is one of the most important aphid natural enemies and has been successfully used to control Myzys persicae and other aphid species. Imidacloprid (IMD) is a popular pesticide used worldwide and is highly toxic to non-target arthropods. Here, we investigated the short-term sublethal toxicity of IMD in Aphidius gifuensis and its impact on the biological performance and gene expression of this parasitoid. We found that sublethal IMD doses had a significant negative effect on the life history traits of female A. gifuensis, including shortening the lifespan and lowering parasitic capacity. Moreover, exposure to sublethal IMD also adversely affected the response of A. gifuensis to aphid-infested plant volatiles. Based on the transcriptome analysis, we found that the exposure to sublethal IMD doses significantly affected expression of genes involved in the central nervous system, energy metabolism, olfactory, and detoxification system of A. gifuensis. RT-qPCR also revealed that short term expose to sublethal IMD doses significantly induced the gene expression of genes related to the central nervous system (nAChRa7, nAChRa9, TbH, OAR1, NFR, TYR, and DAR1), olfactory system (OR28 and IR8a1), and detoxification system (CYP49p3, CYP6a2, and POD), while it suppressed the expression of genes involved in the central nervous system (nAChRa4 and nAChRb1), olfactory system (Orco1, IR8a2, and GR1), and detoxification system (GST2). Furthermore, exposure to sublethal doses of IMD also significantly increased the activities of CarEs and POD, whereas we observed no influence on the activities of CAT, GST, and SOD. Our results indicate that sublethal IMD doses might adversely affect the biological performance of A. gifuensis by altering gene expression related to the function of olfactory, nervous, energy metabolism, and detoxification systems. Thus, how the use of pesticides directly affect insect population should be considered when used in conjunction with natural pest parasitoids in IPM strategies.

The Potential Coordination of the Heat-Shock Proteins and Antioxidant Enzyme Genes of Aphidius gifuensis in Response to Thermal Stress.

Aphidius gifuensis is one of the most important aphid natural enemies and has been successfully used to control Myzys persicae and other aphid species. High temperature in summer is one of the key barriers for the application of A. gifuensis in the field and greenhouse. In this work, we investigated the biological performance of A. gifuensis and the response of heat-shock proteins and antioxidant enzymes under high temperature. The results showed that A. gifuensis could not survive at 40°C and female exhibited a higher survival in 35°C. Furthermore, the short term exposure to high temperature negatively affected the performance of A. gifuensis especially parasitism efficiency. Under short-term heating, the expression of AgifsHSP, Agifl(2)efl, AgifHSP70, AgifHSP70-4 and AgifHSP90 showed an increased trend, whereas AgifHSP10 initially increased and then decreased. In 35°C, the expressions of Agifl(2)efl, AgifHSP70-4 and AgifHSP90 in female were higher than those in male, whereas the expression of AgifHSP70 exhibited an opposite trend. Besides the HSPs, we also quantified the expression levels of 11 antioxidant enzyme genes: AgifPOD, AgifSOD1, AgifSOD2, AgifSOD3, AgifCAT1, AgifCAT2, AgifGST1, AgifGST2, AgifGST3, AgifGST4 and AgifGST5. We found that the sex-specific expression of AgifSOD2, AgifSOD3, AgifPOD, AgifGST1 and AgifGST3 were highly consistent with sex-specific heat shock survival rates at 35°C. Furthermore, when the temperature was above 30°C, the activities of GST, SOD, CAT and POD were significantly increased; however, there was no significant difference of the CAT activity between the male and female at 35°C. Collectively, all of these results suggested that the protection of thermal damage is coordinated by HSPs and antioxidant enzymes in A. gifuensis. Based on the heat tolerance abilities of many aphid natural enemies, we also discussed an integrated application strategy of many aphid enemies in summer.

Identification and expression analysis of chemosensory receptor genes in an aphid endoparasitoid Aphidius gifuensis.

Olfaction and gustation play critical roles during the host-location search process of insects. Several chemosensory receptor genes are thought to be involved in providing specificity to the olfactory sensory neuron responses. The aphid endoparasitoid, Aphidius gifuensis, has been used as a biological control agent against a variety of aphid species; this parasitoid is able to detect its target host(s) effectively during the parasitic process. To understand the mechanism of host detection in A. gifuensis, we assembled specific antennal transcriptomes of each sex through next generation sequencing technology to identify the major chemosensory receptor genes. Using a bioinformatics screen, we identified 100 olfactory receptors candidates (62 odorant receptors, 15 gustatory receptors, and 23 ionotropic receptors) from the sex-specific antennal transcriptome. In addition, combining with the demonstrated functions of chemosensory genes in other insects, the sex-, tissue-, and host-specific expression profile of chemosensory genes potentially revealed the candidate physiological functions. The identification and expression profile of chemosensory receptor genes in A. gifuensis provide valuable information for understanding and investigating the intraspecific or interspecific chemical communications in the solitary parasitic wasps.

Evaluation of the reference genes for expression analysis using quantitative real-time polymerase chain reaction in the green peach aphid, Myzus persicae.

The green peach aphid, Myzus persicae Sulzer (Hemiptera, Aphididae), is an important cosmopolitan pest. Real time qRT-PCR has been used for target gene expression analysis on M. persicae. Using real time qRT-PCR, the expression levels are normalized on the basis of the reliable reference genes. However, to date, the stability of available reference genes has been insufficient. In this study, we evaluated nine candidate reference genes from M. persicae under diverse experimental conditions. The tested candidate genes were comprehensively ranked based on five alternative methods (RefFinder, geNorm, Normfinder, BestKeeper and the comparative ΔCt method). 18s, Actin and ribosomal protein L27 (L27) were recommended as the most stable reference genes for M. persicae, whereas ribosomal protein L27 (L27) was found to be the least stable reference genes for abiotic studies (photoperiod, temperature and insecticide susceptibility). Our finding not only sheds light on establishing an accurate and reliable normalization of real time qRT-PCR data in M. persicae but also lays a solid foundation for further studies of M. persicae involving RNA interference and functional gene research.

Deciphering the Function of Octopaminergic Signaling on Wing Polyphenism of the Pea Aphid Acyrthosiphon pisum.

Aphids exhibit wing polyphenism (winged or wingless) for adaption to predictable or temporally heterogeneous environmental changes; however, the underlying mechanism is still unclear. This morphological change could be stimulated by high aphid density, which in turn could affect octopaminergic signaling in aphids. Octopamine is a neurotransmitter synthesized in insects that can modify their physiological metabolism, locomotion, and other behaviors. We designed experiments to determine whether octopamine functions in wing formation of the pea aphid, Acyrthosiphon pisum (Harris). We determined gene expression of tyramine ß-hydroxylase (TßH), a key enzyme in octopamine synthesis at different developmental stages, in different body parts, and in different densities of aphids. We also used TßH RNAi, octopamine receptor agonists (octopamine and synephrine), and an antagonist (mianserin) to modify octopaminergic signaling. We found that transcription of TßH was related to aphid density, which affected the proportion of winged offspring. By manually modifying the mother's octopaminergic signaling, TßH expression was suppressed, and TßH (enzyme) activity decreased. The proportion of winged offspring was also affected. Our results showed that octopamine could be a link in the wing determination system, as well as environmental stimulation. The RNAi results showed that the decrease of TßH expression increased aphid's reproduction; however, the decrease of TßH expression declined the numbers of winged-offspring producers, but did not affect the proportion of winged nymphs produced by the winged-offspring producer. In conclusion, the decline in the proportion of winged daughters in the next generation was caused by the decline of winged nymph producers.

Strategies used by two apterous strains of the pea aphid Acyrthosiphon pisum for passive dispersal.

Wingless forms of aphids are relatively sedentary, and have a limited ability to migrate or disperse. However, they can drop off hosts or walk away if disturbed, or their food quality or quantity become deteriorated. Earlier, we found that the pea aphid, Acyrthosiphon pisum (Harris, 1776), could use differed strategies to escape danger and locate new host plants. To determine the mechanisms behind the different strategies, we undertook a series of studies including the aphids' host location, energy reserves under starvation, glycogenesis, sugar assimilation, olfactory and probing behaviors. We found that in our controlled laboratory conditions, one strain (local laboratory strain) moved longer distances and dispersed wider ranges, and correspondingly these aphids assimilated more sugars, synthesized more glycogen, and moved faster than another strain (collected from Gansu Province, northwestern China). However, the latter strain could locate the host faster, probed leaves more frequently, and identified plant leaves more accurately than the former strain after they were starved. Our results explained how flightless or wingless insects adapt to fit biotic and abiotic challenges in the complex processes of natural selection.

Winged Pea Aphids Can Modify Phototaxis in Different Development Stages to Assist Their Host Distribution.

The pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), shows wing polyphenism (winged and wingless morphs) in its life cycle. The winged morph is adapted for dispersal; its two developmental adult stages (for dispersal and reproduction) are based on its breeding periods. The two morphs show different phototactic behavior and the winged can change its preference to light according to the developmental stages. To determine the mechanism and ecological functions of phototaxis for A. pisum, we first investigated the phototaxis of the two aphid morphs at different stages and analyzed the phototactic response to lights of different wavelengths; the correlation between alate fecundity and their phototactic behaviors were then studied. Finally, we focused on the possible functions of phototaxis in aphid host location and distribution in combination with gravitaxis behaviors. Negative phototaxis was found for breeding winged adults but all the other stages of both winged and wingless morphs showed positive phototaxis. The reactions of the aphids to different wavelengths were also different. Nymph production in winged adults showed negative correlation to phototaxis. The dopamine pathway was possibly involved in these behavior modifications. We speculated that winged adults can use light for dispersal in the early dispersal stage and for position holding in the breeding stage. Based on our results, we assume that light signals are important for aphid dispersal and distribution, and are also essential for the pea aphids to cope with environmental changes.

Pea aphid Acyrthosiphon pisum sequesters plant-derived secondary metabolite L-DOPA for wound healing and UVA resistance.

Herbivores can ingest and store plant-synthesized toxic compounds in their bodies, and sequester those compounds for their own benefits. The broad bean, Vicia faba L., contains a high quantity of L-DOPA (L-3,4-dihydroxyphenylalanine), which is toxic to many insects. However, the pea aphid, Acyrthosiphon pisum, can feed on V. faba normally, whereas many other aphid species could not. In this study, we investigated how A. pisum utilizes plant-derived L-DOPA for their own benefit. L-DOPA concentrations in V. faba and A. pisum were analyzed to prove L-DOPA sequestration. L-DOPA toxicity was bioassayed using an artificial diet containing high concentrations of L-DOPA. We found that A. pisum could effectively adapt and store L-DOPA, transmit it from one generation to the next. We also found that L-DOPA sequestration verity differed in different morphs of A. pisum. After analyzing the melanization efficiency in wounds, mortality and deformity of the aphids at different concentrations of L-DOPA under ultraviolet radiation (UVA 365.0 nm for 30 min), we found that A. pisum could enhance L-DOPA assimilation for wound healing and UVA-radiation protection. Therefore, we conclude that A. pisum could acquire L-DOPA and use it to prevent UVA damage. This study reveals a successful co-evolution between A. pisum and V. faba.