The melon fly, Zeugodacus cucurbitae, and the oriental fruit fly, Bactrocera dorsalis, are economically important tephritid pests whose sympatric distribution and overlapping host ranges precipitate intense interspecific competitive interactions. To explore the interspecific competition during larval development between these two species, we conducted a comparative study under controlled laboratory conditions. Larvae were evaluated on five host fruits—pumpkin (Cucurbita moschata), cucumber (Cucumis sativus), winter melon (Benincasa hispida), bitter gourd (Momordica charantia), and guava (Psidium guajava)—across six larval density gradients (4.0, 1.33, 0.8, 0.57, 0.44, and 0.36 larvae g−1 of host tissue). In mixed-species treatments, Z. cucurbitae exhibited significantly higher survival rates and greater adult dry weights than B. dorsalis on all cucurbit hosts except guava, indicating a consistent competitive advantage. Under high-density conditions, mixed-species treatments displayed stronger competitive effects than single-species treatments. Survival rate and adult dry weight of both species were significantly affected by the interactive effects of host plant species and larval density, with these factors jointly determining competitive outcomes. These findings improve our understanding of interspecific competition in tephritid fruit flies and provide a scientific basis for developing more effective management strategies for these economically important pests.

Chemical control is the main method used to manage the oriental fruit fly (Bactrocera dorsalis) in orchards. However, the oriental fruit fly has gradually developed resistance to multiple insecticides, posing significant challenges for pest resistance management. This study investigated changes in insecticide resistance in oriental fruit flies under different selection pressures. We identified resistance-related genes and their mutation sites using cDNA probes. Our results showed that resistance to trichlorfon decreased significantly in the absence of selection pressure. However, resistance increased when selection pressures were applied every 30 or 60 days. Although the resistance ratio showed a decreasing trend at every 90 and 120 days, a risk of a rebound remained. A large number of homologous sequences were identified in the suppression subtractive hybridization library of insecticide-resistant strains. Resistance to trichlorfon and alphamethrin primarily involves detoxification and metabolic genes, which are often associated with cross-resistance. A single gene may detoxify multiple pesticides, leading to cross-resistance. The four acetylcholinesterase mutations identified in this study are consistent with previous research findings. Moreover, resistance results from the combined action of multiple genes. Based on these findings, this study recommends avoiding continuous use of trichlorfon and maintaining an interval of more than 80 days between applications. It also emphasizes the importance of incorporating pesticide application intervals into integrated pest management strategies. This study provides a theoretical foundation for delaying resistance development in the oriental fruit fly, offers guidance on proper pesticide application intervals in the field, and contributes practical insights for pest resistance management.

The Zeugodacus cucurbitae and Bactrocera dorsalis are economically significant pests that share similar habitats and host plants, leading to intense interspecific competition. To elucidate their competitive interactions, this study investigated the oviposition competition behavior of mixed laboratory populations on five common host plants: pumpkin (Cucurbita moschata), cucumber (Cucumis sativus), winter melon (Benincasa hispida), bitter melon (Momordica charantia) and guava (Psidium guajava). The results exhibited that among the five hosts tested, B. dorsalis exhibited a significant competitive advantage in oviposition on pumpkin and bitter melon, with its fecundity greater than that of Z. cucurbitae across all ratios. Conversely, Z. cucurbitae showed a clear preference for cucumber. Except at the extreme ratio of 16:4, where B. dorsalis laid slightly more eggs than that of Z. cucurbitae, Z. cucurbitae laid more eggs at all ratios. The results can provide a reference for further investigation on the oviposition selectivity and interspecific competition between the adults of Z. cucurbitae and B. dorsalis.

Bactrocera dorsalis (Hendel) (B. dorsalis) is an important agricultural invasive pest that causes significant economic losses in tropical and subtropical fruit and vegetable crops. In this study, the proteins related to the sense of smell and taste of B. dorsalis, such as OBP, PBP, OR, IR, SNMP and CSP, were screened based on B. dorsalis transcriptome data. By integrating the compounds that were reported to be attractive to B. dorsalis, similar compounds of hydrocarbon compounds were obtained. Molecular docking was used to predict the binding between the similar compounds and the OBP, PBP, OR, IR, SNMP and CSP proteins. Network pharmacology was used to screen the potentially attractive compounds, and ecological experiments with B. dorsalis were finally conducted to verify the effect of these potentially attractive compounds on B. dorsalis. The results showed that the G protein-coupled receptor [BR: KO04030] and ion channel [BR: KO04040] pathways were closely related to the odor tropism of B. dorsalis. A total of 84 compounds, such as mitemcinal, exemestane and midecamycin, have potential binding effects on the B. dorsalis odor receptor proteins. The results of the ecological experiments showed that 1 mg/mL and 0.1 mg/mL 19-norandrostenedione, 1 mg/mL progesterone compounds was significantly attractive to B. dorsalis males, while 0.1 mg/mL exemestane was significantly attractive to B. dorsalis females. In this study, network pharmacology technology was used to discover the potential attractive compounds for B. dorsalis, which is important for the development and subsequent prevention and control of B. dorsalis. It can provide a reference in improving the success rates of clinical trials of new pest control products and in reducing the time and cost of drug development.

为明确食品级惰性粉对仓储害虫土耳其扁谷盗成虫的致死作用,采用拌粮法研究不同剂量食品级惰性粉对土耳其扁谷盗成虫的致死效果,结合扫描电镜观察惰性粉对其体壁形态结构的影响.结果 表明,惰性粉对土耳其扁谷盗成虫有较强的致死作用,且随着使用剂量的增加和处理时间的延长,土耳其扁谷盗成虫的死亡率逐渐上升.当处理时间分别为24、48、72 h时,惰性粉的致死中量分别为8.3、5.6、4.1 mg/kg.扫描电镜观察结果表明,惰性粉能对土耳其扁谷盗成虫体壁形态结构造成明显的物理损伤.经惰性粉处理的土耳其扁谷盗成虫体表均匀粘附有惰性粉颗粒,体表刚毛出现损伤、缺失,体节及相关附肢关节,如头部与前胸、前胸与中胸、足的基节窝等处,发生明显的缢缩、间隙闭合.而对照组虫体体壁干净,各体节连接处舒展、正常.

Exotic invasive species can influence the behavior and ecology of native and resident species, but these changes are often overlooked. Here we hypothesize that the ghost ant, Tapinoma melanocephalum, living in areas that have been invaded by the red imported fire ant, Solenopsis invicta, displays behavioral differences to interspecific competition that are reflected in both its trophic position and symbiotic microbiota. We demonstrate that T. melanocephalum workers from S. invicta invaded areas are less aggressive towards workers of S. invicta than those inhabiting non-invaded areas. Nitrogen isotope analyses reveal that colonies of T. melanocephalum have protein-rich diets in S. invicta invaded areas compared with the carbohydrate-rich diets of colonies living in non-invaded areas. Analysis of microbiota isolated from gut tissue shows that T. melanocephalum workers from S. invicta invaded areas also have different bacterial communities, including a higher abundance of Wolbachia that may play a role in vitamin B provisioning. In contrast, the microbiota of workers of T. melanocephalum from S. invicta-free areas are dominated by bacteria from the orders Bacillales, Lactobacillales and Enterobacteriales that may be involved in sugar metabolism. We further demonstrate experimentally that the composition and structure of the bacterial symbiont communities as well as the prevalence of vitamin B in T. melanocephalum workers from S. invicta invaded and non-invaded areas can be altered if T. melanocephalum workers are supplied with either protein-rich or carbohydrate-rich food. Our results support the hypothesis that bacterial symbiont communities can help hosts by buffering behavioral changes caused by interspecies competition as a consequence of biological invasions.

The oriental fruit fly Bactrocera dorsalis (Hendel) is a worldwide pest leading to crop production. The management of B. dorsalis is becoming more and more difficult because of the emerging insecticide resistance. Searching for new and effective methods in managing this pest has become an urgent task. Here, we explored the relationship between pigmentation and insecticide resistance through conducting studies on 5 strains of B. dorsalis (CK, CZ, CB, LC and LX) with various traits of pigmentation and insecticide resistance. Strain CK was a wild strain with brown pupae coloration while strain CZ was a beta-cypermethrin-resistant strain with pupae coloration was brown. Strain CB was a pigmentation mutation strain with white pupae coloration. Strain LC was the female of pigmentation sex genetic strain whose pupae coloration was white. Strain LX was the male of pigmentation sex genetic strain whose pupae coloration was brown. Efficacy tests were employed to evaluate the resistance performance of the 5 trains, transcriptome sequencing and gene quantifications were used to explore the potential genes in both pigmentation and detoxification pathway. The brief of results were as follow: Results of efficacy tests of the 5 strains with beta-cypermethrin, abamectin and trichlorfon respectively showed that resistances to these three insecticide of strains LX and LC were very low. The corrective mortalities of strains LX and LC in 128 ug/ml of abamectin were 49.48±3.01%, 59.06±1.89% respectively while that of strain CK was 11.80%±1.37. The corrective mortality of strain CZ were lowest in all concentrations level of all test reagent. The resistance of strain CK was similar to CB. Transcriptomic analysis showed that 24 genes and 165 genes were associated with pigmentation and detoxification. Gene expression pattern of strain CK was similar to strain CB while these two strains were different to strains LC and LX, and the gene expression pattern of strain CZ was more similar to strains LC and LX. Results of gene quantifications in B. dorsalis pupae showed that the relative expressions of yellow gene MK529913, DDC gene MK515141, laccase2 gene MK515143 and PO gene MK515140 in brown pupae (CK, CZ, LX) were significantly higher than those in white pupae (CB, LC) while the relative expressions of AANAT gene MK515144 in white pupae were significantly higher than those in yellow pupae. In summary, analyses of gene quantifications and efficacy tests indicated that high expressions of P450 gene, AANAT gene might contribute to resistances of adults of B. dorsalis to beta-cypermethrin and a bamectin; high expression of yellow gene might contribute to resistances of adults which emergenced from brown pupae to beta-cypermethrin and abamectin; high expressions of yellow genes, laccase2 gene, PO gene and DDC gene might contribute to the resistance of B. dorsalis to trichlorfon.

本文通过使用甲醇浸泡浸提和气相色谱-质谱连用(GC-MS)方法,对黄龙病易感寄主椪柑Citrus reticulata Blanco cv.Ponkan的健叶、 病叶以及隐症寄主九里香Murraya paniculata(L.)Jack健叶中部分次生化合物的种类及相对含量进行了差异分析.结果显示:椪柑的健康叶片鉴定出32种次生化合物,感病叶片有31种,九里香健康叶片有21种.其中脂肪酸类和简单芳香族类化合物在3样本之间未显示差异;烷烃类化合物在椪柑健叶中含量较高,椪柑病叶和九里香健叶中相对较少;萜类、 黄酮类和香豆素类化合物在椪柑健病间的含量相差无几,其中萜类和黄酮类显著多于九里香,而香豆素类则相反.萜类化合物α-石竹烯在椪柑健叶中未检出,但在其病叶和九里香健叶之间无显著差异,此外九里香中特有的萜类有 α-姜黄烯(0.15％)、 左旋-姜烯(1.00％)、 β-倍半水芹烯(0.26％);特有且含量较高的香豆素类化合物主要为蛇床子素(13.97％);而黄酮类化合物在九里香中未检出.两种寄主植物之间以及同种植物在感病与不感病的状态下,次生化合物的种类及相对含量均有显著差异,并初步探讨了其与寄主抗性的相关性.

截至2019年,我国大陆发现红火蚁Solenopsis invicta Buren发生危害已经15年了.在有关部门/机构的支持下,围绕着种群控制理论和技术,华南农业大学红火蚁研究中心坚持开展红火蚁相关基础研究和防控应用工作.本文系统总结了我国大陆红火蚁入侵、传播和扩张的时空规律,阐明了红火蚁暴发灾变的生物学基础和规律以及入侵对农业生态系统的影响,明确了其入侵优势和生态学效应,阐释了红火蚁的化学防治理论基础;介绍了监测技术体系、检疫除害技术体系和应急防控、根除与治理技术体系的创建,以及推广应用.研究成果可为我国红火蚁的防治提供重要科技支撑与保障.

The Diaphorina citri Kuwayama (Hemiptera: Liviidae) also known as Asian citrus psyllid transmits 'Candidatus Liberibacter asiaticus' (CLas) associated with the citrus Huanglongbing (HLB). Minimizing Asian citrus psyllid populations is one of the most important methods for HLB control. The development and survival of Asian citrus psyllid were evaluated on CLas+ and CLas- plants of Citrus reticulate Blanco. cv. Mashuiju (Sapindales: Rutaceae) or Citrus sunki Hort. ex Tanaka (Sapindales: Rutaceae) to assess the effects of CLas infection on vector populations. The development times were unaffected between CLas+ and CLas- plants for eggs and first to third instar nymphs but decreased for fourth instars, fifth instars, and total nymphal life on CLas+ plants. The survival rates of eggs and first and second instar nymphs were significantly lower, while those of third to fifth instar nymphs were significantly higher on CLas+ plants. However, overall nymphal survival did not differ between CLas+ and CLas- plants. The pre-oviposition period of Asian citrus psyllid on CLas+ plants decreased, while oviposition period increased, resulting in significantly higher fecundity and population trend index compared with those on CLas- plants, illustrating an overall fitness benefit of CLas infection to Asian citrus psyllid. On the other hand, the longevity and resistance to starvation and lower temperatures of adults from CLas+ plants were significantly lower than those from CLas- plants suggesting that there may be a fitness cost for Asian citrus psyllid on CLas+ plants. The development time of eggs and nymphs and adult longevity were always shorter on C. reticulate regardless of infection status. This knowledge of host plant, pathogen, and vector interactions is useful for developing Asian citrus psyllid-HLB management programs.

Charantins A is cucurbitane-type triterpene glycoside secondary metabolites derived from Momordica charantia. Here, biological activities of charantin A and mode of action to Spodoptera litura ovary cell line (SpLi-221) were evaluated. We investigated the effects of charantins A on cell growth inhibition compared with charantins B, momordicin I and azadirachtin A. Among them, charantins A showed the most potent activity against SpLi-221 cells with the lowest IC50 values, and in a time- and dose-dependent manner. Moreover, the cell morphology changed after charantin A treatment, including cytoplasm leakage, irregular morphology, and apoptotic bodies. In addition, the flow cytometry assay confirmed that charantin A promoted the occurrence of cells' G2/M block and apoptosis, as evidenced by an increased ratio of cells in the sub-G1 phase. Furthermore, cell membrane disruption and increase of intracellular calcium levels were observed following charantin A treatment. These findings provide new clues regarding the role of cucurbitane-type triterpene glycosides as potential novel pesticides for pest control.

Mutualistic interaction between invasive ants and honeydew-producing hemipterans has been extensively examined in many studies. Laboratory experiments showed that invasive ant Solenopsis mvicia (Hymenoptera Formicidae) suppress ghost ants Tapmoma melanocephalum (Hymenoptera: Fonnicidae) through interference competition. However, relatively less testing have been done to evaluate the competition for mutual exploitation between the two ant species in the field. Here, we investigated the interference of the fire ant S. mvicia on the interactions between the ghost ant 7: melanocephalum and the invasive mealybug Phenacoccus solenopsis (Hemiptera Pseudococcidae) in the field The results showed that fire ant invasion significantly suppressed honeydew exploitation by ghost ant. Fire ant suppression markedly increased the ghost ant foraging activity both on plants and the ground Ant diversity in fire ant-infested plots was significantly reduced compared with in fire ant-free plots. Compared with in the no-ant plots, the colony growth rate of mealybug significantly increased, and the parasitism of mealybug was obviously decreased, both in fire ant-infested plots and in fire ant-free plots. Colony growth rate of mealybug in fire ant infested plots was greater than fire ant-free plots. These results suggest that S invicia suppresses the exploitation of honeydew producing hemipterans by ghost ant and occupies most of the honeydew resource.

The fumigant toxicity of 23 essential oils on adults of rusty grain beetle,Cryptolestes ferrugineus (Stephens) was investigated with the method of mixing oils with diet.The results proved that the fumigant toxicity activity of the essential oils of Allium sativum and Brassica nigra were better than that of the other 21 essential oils.The LC50 of rusty grain beetle fumigated by the essential oils of A.sativum under the exposure time of 24,48 and 72 hours were 0.7827,0.7222 and 0.6478 μL/L,respectively.While the LC50 of B.nigra under the same exposure time were 2.7581,2.6117 and 2.4619 μL/L,respectively.The fumigant toxicity of A.sativum on adults of rusty grain beetle was stronger than that of B.nigra.

In order to clarify the effects of temperature on the instar survival rate,developmental duration,egg hatchability and protective enzyme activity of Eupolyphaga sinensis Walker.The instar survival rate,developmental duration,egg hatchability and the activities of three protective enzymes (superoxide dismutase,SOD;catalase,CAT;peroxidase,POD) in E.sinensis at different temperature were assayed and analyzed.The results showed that the temperature has significant influence on the survival rate and developmental duration of E.sinensis (P ＜ 0.05).the survival rate of E.sinensis was significantly higher at 18;22;26;30℃ than at 34℃ (df=4,20;F =7.414;P =0.001).The developmental duration of female larvae was longer than male larvae at the same temperature.The developmental duration of eggs was 74.6;65.9;53.3;44.5;39.4 d (F =24.251;df =4,20;P ＜ 0.05),developmental duration of female nymph was 286.2;258.6;228.2;198.6;182.5 d (F =72.846;df =4,20;P ＜ 0.05) and developmental duration of male nymph was 263.3;232.6;216.2;186.4;169.3 d (F =38.332;df=4,20;P ＜ 0.05) respectrively at above five temperatures.There were protective enzymes (superoxide dismutase,SOD;catalase,CAT;peroxidase,POD) in E.sinensis and different temperature had significant impact on the activities (P ＜ 0.05).The CAT activity was highest at 26℃ and lowest at 34℃.The POD activity was highest at 26℃ or 30℃ and lowest at 34℃.The SOD activity was highest at 30℃ and lowest at 34℃.Considering the developmental duration and the survival rate and hatching rate,26℃ and 30℃ can be used as the reference temperature of artificial feeding.

To study on the resistance dynamic of Bactrocera dorsalis (Hendel) high-resistant strain under using beta-cypermethrin with different frequency, for purpose of providing the basis for scientific and rational usage of beta-cypermethrin to control this pest in the fields, B. dorsalis adults with high resistance to beta-cypermethrin selected under the laboratory conditions were tested, and the toxicity of beta-cypermethrin to the susceptible strain was toxicity baseline. Depending on the time interval length of selection with beta-cypermethrin, four treatments including 30 d, 60 d, 90 d and 120 d were set. The high resistance strain without contacting pesticides kept continuously under normal conditions was as control. The resistance-selection and toxicity assay both with the pesticide film method were determined once every 30 days, and these tests reached ten times totally. The analysis of the relationship between the resistance dynamics and the selection time intervals was based on the median lethal concentration (LC50) and resistant multiple (Rm). The results showed that, 270 days after treatment, there were obvious differences among the resistance development for B. dorsalis strains to beta-cypermethrin at different time interval selections, and as the selected time interval was shorter, the resistance increased faster. At the treatment of once selection every 30 days, LC50 of B. dorsalis adults to beta-cypermethrin rose to 1133.6 mg/L from the first time 582.7 mg/L, and Rm also rose to 190.7 folds from 98.0 folds. When the selection was taken once every 60 days, LC50 and Rm were 828.0 mg/L and 139.3 folds, respectively. LC50 was 529.2 mg/L and Rm was 89.0 folds at the treatment of once every 90 days. LC50 and Rm were 511.3 mg/L and 86.0 folds, respectively, at the treatment of once every 120 days. LC50 of the resistant strain without resistance-selection decreased to 368.1 mg/L from the first time 582.7 mg/L, and Rm also decreased to 61.9 folds from 98.0 folds. The equation Y=11.427X-0.529 can well describe the relationship between the selection time interval of beta-cypermethrin and the growth rate of B. dorsalis adult resistance in 270 days. According to those results, it was predicted that the resistance of B. dorsalis to beta-cypermethrin would not rise in 270 days, when the time interval between the two successive usages for that insecticide in the orchards was over 99 days.

A white pupa mutant strains of the oriental fruit fly was found in the laboratory population. According to the genetic laws of Mendel, the experiments of wild type and mutant hybrid (reciprocal cross), F1 generation backcross with mutant type, F1 generation self-fertilize and F2 generation of mutant self-fertilize were designed and carried out, and the genetic regulation of white pupa mutant character was observed and analyzed. The results showed that the proportion of the wild type in F1 generation of reciprocal crosses between wild and mutant parents was 100%, the ratio of F2 segregation between wild and mutant types was 2.98∶1, and the ratio in backcrosses was 1.19∶1. In addition, progenies of self-crossed F2 mutants all were mutant type. The results indicated that this kind of white pupa mutant strains was consistent with Mendelian monogenic autosomal recessive inheritance.

Asian citrus psyllid (ACP, Diaphorina citri Kuwayama) transmits “Candidatus Liberibacter asiaticus” (CLas), an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB). CLas has recently been found in California. Understanding ACP population diversity is necessary for HLB regulatory practices aimed at reducing CLas spread. In this study, two circular ACP mitogenome sequences from California (mt-CApsy, ~15,027 bp) and Florida (mt-FLpsy, ~15,012 bp), USA, were acquired. Each mitogenome contained 13 protein coding genes, 2 ribosomal RNA and 22 transfer RNA genes, and a control region varying in sizes. The Californian mt-CApsy was identical to the Floridian mt-FLpsy, but different from the mitogenome (mt-GDpsy) of Guangdong, China, in 50 single nucleotide polymorphisms (SNPs). Further analyses were performed on sequences in cox1 and trnAsn regions with 100 ACPs, SNPs in nad1-nad4-nad5 locus through PCR with 252 ACP samples. All results showed the presence of a Chinese ACP cluster (CAC) and an American ACP cluster (AAC). We proposed that ACP in California was likely not introduced from China based on our current ACP collection but somewhere in America. However, more studies with ACP samples from around the world are needed. ACP mitogenome sequence analyses will facilitate ACP population research.

34 kinds of plant essential oils were used to test the repellent and fumigation activity against Cryptolestes turcicus Grouville. Results showed that the cinnamon oil had strong repellent activity to C. turcicus, about 75% individuals chose the control within 24-48 h, then dropped to 63. 33% after exposed 72 h, but still showed significant repellent activity according to Chi-square test. While essential oils of cumin seeds, pine, and black pepper showed attraction activity to C. turcicus. Among the tested 34 kinds of plant essential oils, garlic and mustard essential oil showed the strongest fuming toxicity to C. turcicus. Corrected mortality of C. turcicus was kept above 98% when exposed to garlic and mustard essential oil at the concentration of 10 μL/L within 48 h. The LC50 of C. turcicus fumigated by the essential oils of garlic under the exposure time of 24, 48 and 72 h were 0. 61, 0. 59 and 0. 49μL/L, respectively. While the LC50 of mustard essential oil under the same exposure time were 4. 35, 4. 28 and 4. 16 μL/L, respectively. The fumigant toxicity of garlic essential oil on adults of C. turcicus was stronger than that of mustard essential oil.

Symbionts are associated with many insects and play several multifunctional roles in insect-microorganism mutualistic relationships. The trichlorphon-degrading symbiont Citrobacter freundii (CF-BD) of the oriental fruit fly Bactrocera dorsalis was recently discovered; however, its intraspecies transmission pathway among flies remains unknown. Here, we use fluorescence in situ hybridization (FISH), PCR detection, and a series of ingenious experiments to reveal that CF-BD was aggregated in rectal pads associated with the female ovipositor, and the CF-BD symbiont was vertically transmitted via egg surface contamination. Although CF-BD was not detected in ovaries, it was found in deposited eggs. In addition, CF-BD was readily acquired horizontally between larvae or adults via oral uptake, although it was not transferred via mating behavior. Surface sterilization of eggs had a negative effect on the insects, which exhibited a lower body weight and a sharp decrease in fecundity, suggesting important biological roles of CF-BD in the fitness of the host insects. Our findings may also help to explain the high pesticide resistance levels of B. dorsalis. Furthermore, identifying a clear transmission pathway of this organophosphorus-degrading symbiont will be useful for pesticide resistance management and future pest control technologies.