EAG and behavioral responses of workers of the red imported fire ant,Solenopsis invicta Buren (Hymenoptera: Formicidae) to its trail pheromones

[目的]测定红火蚊Solenopsis invicta Buren工蚊对其跟踪信息素的触角电位(EAG)及行为反应.[方法]解剖红火蚁工蚁的杜氏腺,用正己烷溶剂提取其分泌的跟踪信息素进行气相色谱-质谱(GC-MS)分析,并测定了红火蚁工蚁对杜氏腺提取物、工蚁提取物和合成的法尼烯混合物的EAG和招募行为反应.[结果]通过与合成的法尼烯混合物的气相色谱(GC)保留时间和质谱图比对,发现杜氏腺提取物的主要成分并不是Z,E-α-法尼烯.EAG测定结果表明,红火蚁工蚁对杜氏腺提取物、工蚁提取物及100 μg的法尼烯混合物均有较强的EAG反应,其次为10μg和1 μg的法尼烯混合物.在招募行为测定中,杜氏腺提取物和工蚁提取物招募作用明显,而10,1,0.1和0.01 μg法尼烯混合物的作用均不显著.[结论]Z,E-α-法尼烯不是红火蚁跟踪信息素的主要成分;红火蚁工蚁对杜氏腺提取物、工蚁提取物有较强的EAG反应和明显的招募行为反应.     

红火蚁工蚁对棉蚜诱导的棉花挥发物的嗅觉和行为反应

【目的】红火蚁 Solenopsis invicta 与棉蚜 Aphis gossypii 存在兼性共生关系,红火蚁可能利用棉蚜危害诱导棉花释放的挥发物定位棉蚜。本研究将测试红火蚁工蚁对棉花挥发物的嗅觉和行为反应。【方法】使用Y型管实验测试红火蚁工蚁对棉花气味的行为反应;以红火蚁告警信息素2-乙基-3,5(6)-二甲基吡嗪为阳性对照,测试红火蚁工蚁对不同剂量(100, 10, 1 和0.1 μg)的9种棉花挥发物组分[α-蒎烯、β-蒎烯、β-石竹烯、( E, E )-4,8,12-三甲基-1,3,7,11-十三碳四烯(TMTT)、( E )-4,8-二甲基-1,3,7-壬三烯(DMNT)、辛醛、6-甲基-5-庚烯-2-酮、顺-3-己烯基乙酸酯和水杨酸甲酯]的触角电位反应;再利用Y型嗅觉仪测试这些挥发物对红火蚁工蚁的行为选择影响。【结果】结果表明,受棉蚜为害的棉花较健康棉花对红火蚁工蚁具有极显著的引诱效果。红火蚁对9种挥发物组分的EAG反应随着剂量升高而升高。各化合物在100 μg剂量时EAG反应值最大,其中,工蚁对水杨酸甲酯和6-甲基-5-庚烯-2-酮这两个化合物反应最强。在行为选择实验中,化合物水杨酸甲酯、6-甲基-5-庚烯-2-酮和DMNT对红火蚁工蚁均具有显著的引诱效果。【结论】棉蚜诱导的棉花挥发物中水杨酸甲酯和6-甲基-5-庚烯-2-酮对红火蚁有显著的引诱效果,这2种化合物可能在红火蚁定位棉蚜、建立共生关系中起着关键的作用。     

室内饲养的红火蚁工蚁毒腺生物碱含量动态分析

【目的】分析红火蚁 Solenopsis invicta 工蚁在室内长时间饲养时,体内生物碱主要成分的含量变化。【方法】每10 d取0.5 g红火蚁工蚁用正己烷溶剂浸提48 h,浸提液通过硅胶柱分离,经气相色谱（GC）和气相色谱 质谱联用仪（GC-MS）鉴定其生物碱的主要成分,并用外标法测其生物碱各个主要成分的含量。【结果】红火蚁工蚁体内生物碱主要成分为9种顺式生物碱和5种反式生物碱,并测出90 d内这14种化合物在红火蚁工蚁体内的含量变化。其中,反式生物碱2-甲基-6-（4′-十三烯）哌啶的含量最高,第1天为3 391.57 μg/g,90 d后为556.70 μg/g;顺式生物碱2-甲基-6-十五烷基哌啶的含量最低,第1天为10.27 μg/g,90 d后为2.93 μg/g。【结论】红火蚁工蚁在室内长时间饲养时,体内生物碱的含量开始时持续下降,当生物碱含量下降到一个极低的水平后,基本不再变化,处于平衡状态。结合室内饲养时红火蚁工蚁死亡情况,可推测出当红火蚁蚁巢中生物碱含量很低时,蚁巢中体型较大的工蚁数量会比较少。     

红火蚁告警信息素的GC-EAD分析

【背景】2-乙基-3,6-二甲基吡嗪是红火蚁告警信息素的主要成分,本研究旨在分离、鉴定红火蚁工蚁浸提液中告警信息素成分,分析红火蚁工蚁对告警信息素合成样品混合物的电生理反应。【方法】200 g红火蚁工蚁的正己烷浸提液过硅胶柱,正己烷—丙酮体系洗脱,气相色谱(GC)和气相色谱—质谱联用(GC-MS)分析检测浸提液中含告警信息素的流分,气相色谱—触角电位联用仪(GC-EAD)分析红火蚁工蚁对2-乙基-3,5(6)-二甲基吡嗪混合物的电生理活性。【结果】红火蚁工蚁正己烷浸提液硅胶柱层析分离能够得到含2-乙基-3,6-二甲基吡嗪的流分,GC-MS分析的保留时间在11.45 min。经过GC-EAD分析,发现红火蚁工蚁对2-乙基-3,5(6)-二甲基吡嗪混合物有显著的电生理反应。【结论与意义】红火蚁工蚁对2-乙基-3,6-二甲基吡嗪的电生理反应比2-乙基-3,5-二甲基吡嗪高。     

红火蚁告警信息素的GC-EAD分析

[背景]2-乙基-3,6-二甲基吡嗪是红火蚁告警信息素的主要成分,本研究旨在分离、鉴定红火蚁工蚁浸提液中告警信息素成分,分析红火蚁工蚁对告警信息素合成样品混合物的电生理反应。[方法]200 g红火蚁工蚁的正己烷浸提液过硅胶柱,正己烷—丙酮体系洗脱,气相色谱（GC）和气相色谱—质谱联用（GC-MS）分析检测浸提液中含告警信息素的流分,气相色谱—触角电位联用仪（GC-EAD）分析红火蚁工蚁对2-乙基-3,5（6）-二甲基吡嗪混合物的电生理活性。[结果]红火蚁工蚁正己烷浸提液硅胶柱层析分离能够得到含2-乙基-3,6-二甲基吡嗪的流分,GC-MS分析的保留时间在11.45 min。经过GC-EAD分析,发现红火蚁工蚁对2-乙基-3,5（6）-二甲基吡嗪混合物有显著的电生理反应。[结论与意义]红火蚁工蚁对2-乙基-3,6-二甲基吡嗪的电生理反应比2-乙基-3,5-二甲基吡嗪高。     

土垅大白蚁Macrotermes annandalei(Silvestri)采食品级的踪迹信息素

【目的】解析土垅大白蚁Macrotermes annandalei(Silvestri)采食行为中的踪迹信息交流机制。【方法】通过对其踪迹信息素进行化学和行为活性分析。【结果】土垅大白蚁兵蚁腹板腺源踪迹信息素的主要成分为顺-3-十二碳单烯醇-1((3Z)-dodec-3-en-l-ol,DOE),与工蚁的踪迹信息素化学结构完全相同。大兵蚁腺体当中DOE的含量最高,分别是大、小工蚁品级和小兵蚁品级DOE含量的3.88倍和3.78倍,与其在采食行为中的功能相适应。尽管小兵蚁的位置处于采食队伍的先锋,但小兵蚁的踪迹信息素含量与工蚁相当,不能起到召募采食的作用。行为观察和跟踪信息素行为活性表明大兵蚁具有通过分泌大量踪迹信息素召募工蚁品级的能力。【结论】土垅大白蚁依靠大兵蚁分泌大量踪迹信息素单一组分及其在采食队伍中的位置的变化来实现采食行为中的方向信息的快速传递交流。     

脂肪酸对红火蚁搬尸行为的影响

【目的】工蚁死亡后易受病原菌的侵染,进而危害蚁巢的健康。为了避免病菌横向传播,活工蚁根据尸体体内特定的化学物质的变化来识别尸体并将其搬运到弃尸堆。本实验旨在研究6种脂肪酸(油酸、亚油酸、棕榈油酸、棕榈酸、硬脂酸和肉豆蔻酸)对红火蚁Solenopsis invicta工蚁搬尸行为的影响,明确不同脂肪酸在其搬尸行为中发挥的作用。【方法】本实验利用GC-MS分析了工蚁活体和尸体提取物的脂肪酸成分,并在室内用滤纸片法测定了红火蚁对6种脂肪酸(10 μg/μL)、不同浓度(0.75和3 μg/μL)的单组分油酸或亚油酸以及不同浓度(0.01, 0.1, 1和10 μg/μL)的这两种酸的混合液的反应。【结果】结果表明,红火蚁尸体仅含有亚油酸和油酸两种脂肪酸;另外4种脂肪酸(棕榈油酸、棕榈酸、硬脂酸和肉豆蔻酸)对红火蚁的搬尸行为无显著影响;单组分的油酸和亚油酸均能促进红火蚁的搬尸行为,浓度越高,搬尸行为越显著。10 μg/μL的油酸和亚油酸混合液对工蚁的搬尸行为也具有显著的促进效果,低浓度的混合液对其无明显的促进作用(P>0.05)。【结论】结果提示油酸和亚油酸可调控红火蚁的搬尸行为,其他脂肪酸对红火蚁搬尸行为不产生影响。     

Bt毒素对棉铃虫雄蛾感受雌蛾性信息素EAG反应的影响

用含Bt毒素的人工饲料饲养棉铃虫Helicoverpa armigera 3龄幼虫至成虫(死亡率为40%～50%),采用触角电位 (electroantennogram, EAG) 技术,测定了雄蛾对雌蛾性信息素2种组分顺9-十六碳烯醛(Z9-16:Ald)、顺11-十六碳烯醛(Z11-16:Ald)及其混合物(Z11-16:Ald∶Z9-16:Ald=97∶3)的EAG反应。结果表明,Bt毒素对雄蛾感受性信息素单一组分和混合物的EAG反应均具促进作用;且随信息素剂量的增加,这种促进作用也随之增强。这一结果对于评价和实施延缓棉铃虫对Bt棉抗性的“庇护所"策略,具有一定的参考意义。     

甘薯蚁象对不同甘薯品种植物挥发物的EAG和嗅觉反应

【目的】为筛选对甘薯蚁象Cylas formicarius(Fabricius)有引诱作用的植物挥发性物质。【方法】采用顶空气体采样法收集5个甘薯品种的植物挥发物,通过气相-质谱联用系统(GC-MS)进行物质鉴定及定量分析,测定甘薯蚁象成虫对候选挥发物的触角电位(EAG)反应和嗅觉趋向选择行为。利用Y型嗅觉仪测定甘薯蚁象成虫对5个甘薯品种茎叶的嗅觉反应。【结果】5种甘薯品种的植物挥发物种类和含量有所差异。7种候选挥发物(罗勒烯、柠檬烯、壬醛、β-石竹烯、葎草烯、法尼烯和乙酸-顺-3-己烯酯)均引起甘薯蚁象雌、雄成虫的EAG反应。其中,雌虫对柠檬烯、壬醛和β-石竹烯的反应相对值较大;而引起雄虫反应相对值较大的挥发物为罗勒烯、柠檬烯、葎草烯。在趋向行为反应中,柠檬烯和壬醛对甘薯蚁象雄虫的吸引作用高于对照,而雌虫对葎草烯、柠檬烯有极显著的趋向选择。甘薯蚁象成虫对5种茎叶的反应率为40.90%~65.21%,且5个甘薯品种的茎叶挥发物均没有显著的引诱作用(P0.05)。【结论】甘薯蚁象雌、雄成虫对甘薯植物挥发物具有不同的EAG及趋向行为反应,气味化合物柠檬烯与甘薯蚁象偏爱选择密切相关。     

笋秀夜蛾雄蛾对性信息素化合物的电生理和行为反应

利用气质联用仪对笋秀夜蛾雌蛾性腺体粗提物成分进行了分析比对,通过触角电位(EAG)试验研究了笋秀夜蛾雄成虫对性信息素组分的电生理反应,以Y形嗅觉仪进行了室内和林间的行为生测.结果表明： 雌蛾性腺体粗提物中顺11-十六碳乙酸酯(Z11-16:Ac)和顺11-十六碳烯醇(Z11-16:OH)为笋秀夜蛾性信息素活性组分,性腺粗提物、两种化合物及其混合物均能激发雄蛾明显的EAG反应,且EAG反应值随性信息素组分浓度增加而增加.Z11-16:Ac和Z11-16:OH按57∶43配置成的二元混合物所激发的EAG反应强于同等剂量下的单一组分.室内的行为生测和林间诱捕试验结果与EAG反应基本一致,Z11-16:Ac+Z11-16:OH(57∶43)混合物对雄蛾引诱力最强,在林间单诱捕器(诱芯浓度为10⁴ng·μL^-1)的平均诱捕量达到(48.5±6.7)头.     

Behavioral and Electroantennogram Responses of Phorid fly <Emphasis Type="Italic">Pseudacteon tricuspis</Emphasis> (Diptera: Phoridae) to Red Imported Fire Ant <Emphasis Type="Italic">Solenopsis invicta</Emphasis> Odor and Trail Pheromone

The phorid fly, Pseudacteon tricuspis is an introduced parasitoid of the red imported fire ant, Solenopsis invicta in the United States. Previous studies show that phorid flies are attracted to host ant workers at disturbed colonies, to colonies exhibiting aggressive interspecific interactions, and to fire ant mating flights. In a series of behavioral and electroantennogram (EAG) experiments, we confirm the possible use of fire ant odor as cues for host location by P. tricuspis. We tested the response of P. tricuspis of different sex and mating status to several host-related odor stimuli including live fire ant workers, extracts of worker whole body, head, thorax, and abdomen, and (E,E)-α-farnesene, a trail pheromone component of Solenopsis fire ants. Results from Y-tube olfactometer bioassays demonstrated the attraction of mated female P. tricuspis to live S. invicta workers. In addition, extracts of S. invicta worker whole body and thorax elicited strong olfactometer response in female flies (mated and unmated) and mated males, but not in unmated males. Pseudacteon tricuspis did not show significant attraction to extracts of S. invicta worker head and abdomen, or to (E,E)-α-farnesene, irrespective of sex and mating status. In EAG experiments, female and male P. tricuspis showed significant EAG response to extracts of worker whole body, head, and abdomen, and to a less extent, thorax extract, but not to (E,E)-α-farnesene. Females showed slightly greater EAG response than males, but EAG response was not affected by mating status. These results suggest that fire ant thorax is likely the source of kairomones used as host location cues by P. tricuspis, and support the hypothesis that fire ant worker trail pheromones are not likely used by P. tricuspis for host location.     

Behavioral and olfactory antennal responses of Solenopsis geminata (Fabricius) (Hymenoptera: Formicidae) workers to their dufour gland secretion

Behavioral and electrophysiological tests were performed to evaluate the responses of workers of the ant Solenopsis geminata (Fabricius) from different size categories to Dufour gland extracts. Morphometric measures based in head widths across eyes were used to determine worker sizes. Trail following response of different worker sizes to Dufour gland extract from workers of different sizes was assessed. For each worker size category olfactory responses to Dufour gland extracts were determined using electroantennography (EAG). Gas chromatography and mass spectrometry (GC-MS) were used to determine the chromatographic profile of Dufour gland secretion for each worker size. Morphometric measures permitted to classify the workers of S. geminata as large, medium and small workers. Medium S. geminata workers displayed a significantly higher behavioral response to Dufour gland extracts produced by medium size workers. Similarly, medium workers showed a significantly higher EAG response to Dufour gland extracts produced by medium sized workers. Chromatographic profile of Dufour gland secretions produced by workers showed that each size category exhibited a characteristic profile of the three main components considered as potential trail pheromone constituents. This work showed that medium workers of S. geminata exhibited a high trail-following behavior as well as a high antennal response to Dufour gland secretion. This and their relative abundance in field foraging areas, suggest that medium-sized workers are specialized in foraging activities.     

棉铃虫齿唇姬蜂对植物挥发物和寄主性信息素腺体化合物的EAG反应

测试了棉铃虫齿唇姬蜂Campoletis chlorideae Uchida对58种植物挥发物和5种寄主性信息素腺体化合物的EAG反应。在100 μg的刺激剂量下,棉铃虫齿唇姬蜂对C₅～C₇脂肪醇的EAG反应最强,碳链延长或缩短都将导致反应的降低;对脂肪醛、酮、酸和酯都有一定的反应。棉铃虫齿唇姬蜂对萜烯的EAG反应很低,对氧化萜的反应普遍升高。3种芳香化合物均可激起棉铃虫齿唇姬蜂较强的EAG反应。剂量反应曲线表明,具有EAG活性的化合物激起的反应强度与化合物的剂量呈正相关,而2种萜烯——α-蒎烯和反式石竹烯,在测定的剂量范围内EAG活性都很低。棉铃虫齿唇姬蜂对寄主性信息素腺体化合物也有EAG反应,用100 μg和1 000 μg的寄主性信息素刺激,雄蜂的反应可比雌蜂的反应高出1倍。对植物挥发物在棉铃虫齿唇姬蜂寻找寄主中的作用进行了讨论。     

Contents of the poison apparatus of some species of Pheidole ants

Four Old World species of Pheidole ants contain different mixtures of farnesene-type hydrocarbons in their poison apparatus, and the mixture is different between the minor and major workers within a species. A bishomofarnesene (C₁₇H₂₈) provides approximately half of the secretion of the Dufour glands of minor workers of Pheidole pallidula. (Z,E)-α-Farnesene constituted 96% of the Dufour secretion of major workers of P. pallidula, but only 20% of that of minors. The Dufour glands of minor workers of Pheidole sinaitica contain a mixture of farnesene homologues with (Z,E)-α-farnesene and the bishomofarnesene also found in P. pallidula predominant. The mixture in major workers was similar but had, in addition, a small amount of (E)-β-farnesene. The Dufour glands of Pheidole teneriffana minors contain chiefly the same bishomofarnesene found in P. pallidula and P. sinaitica while major workers contain (Z,E)-α-farnesene. Pheidole megacephala minor workers contained small amounts of eight farnesenes, while major workers contained essentially no farnesenes. The poison glands of minor workers of P. pallidula contain 3-ethyl-2,5-dimethylpyrazine. No pyrazine compounds were found in the major workers of P. pallidula or the minor workers of P. sinaitica. The poison glands of the major workers of P. sinaitica contained larger amounts of tetra-substituted pyrazines. No pyrazines were found in the poison reservoirs of major or minor workers of P. teneriffana or P. megacephala.     

Comparing electroantennogram and behavioral responses of two Pseudacteon phorid fly species to body extracts of Black, Red and Hybrid imported fire ants, Solenopsis spp

Several phorid fly species were introduced to the southern United States for biological control of the invasive imported fire ants, Solenopsis richteri (Black), Solenopsis invicta (Red), and their Hybrid S. richteri×S. invicta (Hybrid). It has been previously reported that the Jaguariuna biotype of Pseudacteon tricuspis and the Formosan biotype of Pseudacteon curvatus could distinguish among the three fire ant species with greater preference for Hybrid and Red fire ants. We hypothesized that phorid flies might use host derived chemical cues to differentiate ant species. To determine possible differential olfactory sensitivity of phorid fly species to different fire ant species, we compared electroantennogram (EAG) and behavioral responses of both sexes of P. tricuspis and P. curvatus to body extracts of Black, Red and Hybrid fire ants. As worker sizes of Black and Hybrid fire ants used in this study were much larger than that of Red fire ant (the average weight for Black, Red and Hybrid workers was 1.707, 0.863, 1.223mg per ants, respectively), at doses of 0.01, 0.1, 1 worker equivalent, body extracts of Black and Hybrid fire ant elicited significantly greater EAG response in both sexes of P. tricuspis than that of Red fire ant. Similarly, the EAG response in female P. curvatus to body extract of Black fire ant was significantly greater than to body extract of Red fire ant. To eliminate worker size influence on EAG response in phorid flies, we conducted a second EAG study using a dose of 1mg ant equivalent (body extract from 1mg of worker). No difference in EAG responses was recorded to body extract obtained from the same amount of workers among the three fire ant species (we consider viable Hybrid fire ant as a species in this paper), suggesting that worker size differences contributed to difference in EAG response in the first EAG study. In both EAG studies, male P. tricuspis showed significantly greater EAG responses than male P. curvatus to all three fire ant species. In four-way olfactometer bioassay, worker body extracts of all three fire ant species were equally attractive to P. tricuspis and P. curvatus (i.e. both phorid fly species did not show any preferences among the three fire ant species). Together, the results of the EAG and behavior studies suggest that parasitic phorid flies utilize host derived non-polar compounds from worker ants extracted out by hexane for host location but not for host preference, since both fly species are not able to distinguish among the body extracts of the three fire ant species. Future study will investigate possible involvement of polar compounds and/or non-chemical cues in mediating host preference by phorid flies.     

Worker size polymorphism and ethological role of sting associated glands in the harvester ant Messor barbarus

Summary: Though harvester ants are closely similar in ecology, species differ in their worker size polymorphism as well as in the glandular source of their trail pheromones and defensive compounds. In the harvester ant Messor barbarus, we find that the recruitment trail pheromone is located in the Dufour gland, while defence-alarm substances are produced in the poison gland. We also investigated how the glandular development and the ethological response to these abdominal glands are related to worker body size. For both glands, M. barbarus workers show monophasic and nonisometric growths with slopes of allometric regression lines lower than 1. The highest trail-following response is elicited by the Dufour gland secretion from media workers, responsible for most foraging activities in M. barbarus. Aggressive behaviour is more frequently observed in the presence of poison gland secretions from medium and large-sized workers. Differences between species and between worker size classes in the ethological role of sting associated glands are discussed in relation to the foraging ecology and defensive characteristics of harvester ants.     

不同温度下白僵菌Bb04菌株对红火蚁工蚁的致病力

[背景[白僵菌是一种应用最广泛的虫生真菌,已被用于工厂化大量生产,可防治多种农林害虫。[方法]试验设置17、21、25、29和33℃5个温度水平,采用喷雾法,将浓度为1×105和1×108个·mL-1的白僵菌孢子悬浮液分别感染红火蚁工蚁,以测试不同温度下白僵菌菌株对红火蚁工蚁的致病力。[结果]当浓度为1×108个·mL-1时,在21、25和29℃条件下,红火蚁工蚁在15 d的累计死亡率均达到了100%,在17和33℃下分别为99.36%和98.74%。当浓度为1×105个·mL-1时,在21、25、29和33℃下,红火蚁工蚁在15 d的累计死亡率分别为29.42%、36.18%、33.17%和27.21%,显著高于17℃的累计死亡率。2个浓度处理在17～25℃时,白僵菌对红火蚁工蚁的致死中时（LT50）随着温度的升高而缩短,当温度为29和33℃时,红火蚁的LT50不减少反而增加。25℃时白僵菌Bb04菌株对红火蚁工蚁的LT50最短,死亡速度最快,致病力最强。[结论与意义]该研究可为制定田间利用白僵菌防治红火蚁的最佳时期奠定基础。     

EAG and behavioral responses of the wingless tea aphid Toxoptera aurantii (Homoptera: Aphididae) to tea plant volatiles

Electrophysiological and behavioral responses of the wingless tea aphid, Toxoptera aurantii (Boyer), to 14 synthetic volatiles identified from tea shoots, their partial (GLV mixture) and full (ACB mixture) blends, and fresh young tea leaves, buds, tender stems, adult tea leaves and tea aphid-damaged young leaves (ADYL) were studied by using an electroantennography (EAG) and a four-arm olfactometer. ACB elicited the largest EAG responses. Major volatile components, Z-3-hexen-1-ol, E-2-hexenal, n-hexanol, methyl salicylate and benzylalcohol, from the tea shoots were strongly EAG active. All the 4 tested tea shoot tissues also elicited significant EAG responses, with the young tea leaves being the strongest, followed by buds, tender stems and adult tea leaves. Surprisingly, ADYL elicited a weakly negative EAG response. In the olfactory assays, the fresh and tender tea leaves, as well as the individual major volatile components, e.g. Z-3-hexenyl acetate, methyl salicylate, E-2-hexen-1-ol and Z-3-hexen-1-ol, from the tender shoots (EAG-active) were all attractive. This result might indicate that the wingless tea aphids may use tea shoot volatiles as kairomone to find their optimal feeding sites, e.g. fresh tender tea shoots.