Insect chemical communication: Pheromones and exocrine glands of ants

Summary Chemical communication plays a very important role in the lives of many social insects. Several different types of pheromones (species-specific chemical messengers) of ants have been described, particularly those involved in recruitment, recognition, territorial and alarm behaviours. Properties of pheromones include activity in minute quantities (thus requiring sensitive methods for chemical analysis) and specificity (which can have chemotaxonomic uses). Ants produce pheromones in various exocrine glands, such as the Dufour, poison, pygidial and mandibular glands. A wide range of substances have been identified from these glands.     

Species-specificity in trail pheromones and Dufour's gland contents ofCamponotus atriceps andC. floridanus (Hymenoptera: Formicidae)

Summary By means of gas chromatography, gas chromatographic coupled mass spectrometry, trail-following experiments and electrophysiological recordings from worker antennae, the major trail pheromone components from the hindgut of the formicine speciesCamponotus atriceps andC. floridanus were identified as 3,5-dimethyl-6-(1-methylpropyl)-tetrahydropyran-2-one and nerolic acid, respectively. The Dufour's gland contents of both species, investigated by gas chromatographic coupled mass spectrometry, show significant differences.Pheromones 104: Janssen E, Übler E, Bauriegel L, Kern F, Bestmann H-J, Attygalle AB, Steghaus-Kovacs S, Maschwitz U: Trail pheromone of the Ponerinae antLeptogenys peuqueti (Hymenoptera: Formicidae): a multicomponent mixture of related compounds     

单壁碳纳米管对太平洋牡蛎(Crassostrea gigas)的毒性效应及生物体防御机制研究

碳纳米管的生态安全和健康风险日益受到人们的广泛关注。本文采用典型的海洋底栖生物——太平洋牡蛎(Crassostrea gigas, C. gigas)作为受试生物,研究了单壁碳纳米管(Single-Walled Carbon Nanotubes, SWCNTs)暴露对其造成的毒性效应及牡蛎自身的防御机制,以期为碳纳米管的海洋生态风险评价提供科学依据。在0.1～10 mg·L~(-1)的SWCNTs暴露96 h后,太平洋牡蛎鳃和消化腺中的丙二醛(malondialdehyde, MDA)含量显著增加(P≤0.05),总超氧化物歧化酶(superoxide dismutase, SOD)和过氧化氢酶(catalase, CAT)活性呈现显著的剂量依赖性升高(P≤0.05),cat、hsp70、aox及caspase-7等基因的相对表达量显著上调(P≤0.05)。相比于单独暴露,P-gp蛋白抑制剂Tariquidar与SWCNTs的复合暴露显著增加了鳃和消化腺中MDA含量,产生了更严重的氧化损伤。这些结果表明,SWCNTs暴露对太平洋牡蛎的鳃和消化腺造成了一定程度的氧化损伤,而牡蛎体内的抗氧化系统和多外源性物质抗性机制在防御SWCNTs的过程中起到了至关重要的作用。     

The chemical basis for trail recognition in Lasius nipponensis (Hymenoptera: Formicidae)

Summary. In this paper we report on the chemical basis for trail recognition in Lasius nipponensis. On and near trails in the field, workers became aggressive against conspecific intruders and succeeded in protective contests, while intruders usually avoided confrontation. Such asymmetric interactions were also observed in the laboratory when two non-nestmate workers were sequentially placed in a clean glass dish, while mutual aggression was observed when they were placed simultaneously. Asymmetric aggression was also observed when the workers were placed in a dish previously conditioned by other workers, or when the dish was treated with the hexane rinse of the conditioned dish. The rinse contained a series of hydrocarbons, in which components and proportion were almost identical to those of the cuticular hydrocarbons of the workers, except for a lack of n-alkanes. Amounts of the hydrocarbons that remained on the dish were very small when all the tarsi of the workers were incapacitated. We therefore consider that the hydrocarbons are not adhesion of the cuticular hydrocarbons but secretion from the tarsi of workers, and serve as a key signal for trail recognition in this ant.     

The trail pheromone of the ant <Emphasis Type="Italic">Crematogaster castanea</Emphasis>

Summary. The major component of the trail pheromone of the myrmicine ant Crematogaster castanea has been identified as (R)-2-dodecanol from the tibial glands of the hind legs. The substance gave activity comparable to the contents of 8 tibial glands at a concentration of 1 pg per 32 cm trail.     

Information transfer during recruitment in the ant<Emphasis Type="Italic"> Lasius niger</Emphasis> L. (Hymenoptera: Formicidae)

In this paper, we used the food-correlated search behavior observed in foraging ants returning to a previously rewarding site to study information transfer during recruitment in the ant Lasius niger. We hypothesized that, if information about the characteristics of the food is conveyed during recruitment, food-correlated search tactics should also be observed in recruited workers. Our results show that the characteristics of the trajectories of recruited workers are comparable to those of scout ants returning to a site or prior food find and depend more on the type (prey/sugar) than on the quality (sugar concentration) of the food discovered by the scouts. Independent of sugar concentration, workers recruited to a source of sugar search with a greater sinuosity than workers recruited to a prey. Experimental manipulation of the recruitment signals (chemical trail and contact between ants) shows that the trail pheromone laid down by recruiting ants does not play a role in the modification of trajectory sinuosity. This change appears to be most likely triggered by a direct perception of the residue of sugar smeared on the body of the recruiting workers coming back to the nest.Communicated by J. Heinze     

Trail discrimination signal of Lasius japonicus (Hymenoptera: Formicidae)

Summary. Trail-following behavior of Lasius japonicus was colony-specific in the field, while trail pheromone activity was not. We found that the footprint substance caused colony-specific trail-following behavior only when working in conjunction with the trail pheromone. The footprint substance alone did not lead the workers to follow trails. The substance consisted mainly of hydrocarbons with composition almost identical to that of cuticular hydrocarbons, except for the absence of n-alkanes. Nestmate workers shared footprint hydrocarbon profiles as well as cuticular hydrocarbons, but the profiles differed among colonies. We therefore consider that the footprint hydrocarbon profiles serve as the trail discrimination signal in L. japonicus.     

Chemistry of the postpharyngeal gland secretion and its implication for the phylogeny of IberianCataglyphis species (Hymenoptera: Formicidae)

Summary A comparative morphological and chemical study of six endemic species ofCataglyphis from the Iberian Peninsula:C. ibericus, C. rosenhaueri, C. hispanicus, C. humeya, C. velox andC. floricola and the Moroccan speciesC. bombycinus is described. The morphological study relied primarily on genitalia characteristics, whereas the chemical study concentrated on the postpharyngeal gland constituents. Cladograms based on the morphological and chemical data were performed using Ward's method. The dendrogram based on morphological features revealed that the IberianCataglyphis can be classified into three species groupsalbicans, altisquamis andemmae. The same pattern occurred when the dimethylalkanes constituents of the postpharyngeal gland were utilised as character states, with a slight displacement of species within thealtisquamis group. However, when the complete hydrocarbon blend was utilised major discrepancies in the dendrograms occurred.Cataglyphis velox proved to be very similar toC. bombycinus, whereasC. floricola clustered with the other two species of thealtisquamis group. Based on the geographical distribution and paleontological data (Tinaut 1993) it is assumed thatC. floricola recently invaded the Iberian Peninsula. Based on the chemical findings we postulate that chemical character displacement occurred inC. floricola as a result of its sympatry withC. velox after the former colonized the Iberian Peninsula. We further discuss the possible reason for the different dendrograms obtained when only the dimethylalkanes are considered and its implication for the communicative role of the postpharyngeal gland secretion in these ants.     

Co-evolution-driven cuticular hydrocarbon variation between the slave-making ant Rossomyrmex minuchae and its host Proformica longiseta (Hymenoptera: Formicidae)

Summary. Proformica longiseta exists as two populations in the Sierra Nevada Mountains in Spain, only one of which is parasitized by the slave-maker ant Rossomyrmex minuchae. To investigate the possible effect of co-evolutionary pressures on cuticular hydrocarbon (CHC) profiles (the presumed nestmate recognition cues), we performed a comparative analysis of the CHC of R. minuchae and P. longiseta colonies from both the allopatric and sympatric populations; the latter includes samples of enslaved as well as free-living workers. Discriminant analyses based on these chemical profiles showed two clear profile groups: the first comprised R. minuchae and both enslaved and free-living P. longiseta from the sympatric population; and the second the allopatric P. longiseta workers. As expected, the profiles of the two sympatric P. longiseta groups (enslaved and free-living) were distinct; but, interestingly, those of the enslaved P. longiseta and its parasite R. minuchae were also distinguishable. This indicates that despite their cohabitation each species maintains its own chemical identity. Profile similarity between the sympatric free-living P. longiseta and its parasite may explain the lower than expected aggression observed during raids. We further speculate that in view of the differences between the sympatric and allopatric population of P. longiseta, co-evolutionary pressures have driven changes in the profile of the former to better match that of its parasite R. minuchae. Such an adjustment may have enabled nests of the sympatric P. longiseta to endure multiple raids by the parasite (due to the reduced aggression) and thus to continue to reproduce despite the damage inflicted by the raids.     

The iridoid glycoside,catalpol, as a deterrent to the predatorCamponotus floridanus (Formicidae)

Summary We investigated the role of the iridoid glycoside, catalpol, as a deterrent to the predator,Camponotus floridanus. Four laboratory colonies of this ant were offered buckeye caterpillars (Junonia coenia: Nymphalidae) raised on diets with and without catalpol. The same colonies were offered sugar-water solutions containing varying concentrations of catalpol, in both no-choice and choice tests. Regardless of diet, buckeye caterpillars appeared to be morphologically protected from predation by the ants, possibly because of their large spines or tough cuticle. However, buckeyes raised on diets with catalpol had high concentrations of catalpol in their hemolymph; extracts of this high-catalpol hemolymph proved to be an effective deterrent to the ants. When starved ants were not given the choice of food items, they were more likely to consume sucrose solutions that contained 5 mg catalpol/ml or 10 mg catalpol/ml than they were to consume solutions with 20 mg catalpol/ml. When they were given a choice of sugar solution or a sugar solution containing catalpol, the ants avoided solutions with catalpol at any of these concentrations. Ant colony responses to catalpol in sucrose solutions varied considerably over time and among colonies.     

重金属和聚苯乙烯微球对卤虫的复合毒性效应研究

微塑料是一类重要的海洋污染物,由于其性质稳定、难以降解,对海洋生态系统具有潜在的危害。微塑料粒径小,比表面积大,容易吸附海洋中的重金属等污染物产生二次危害,因此研究微塑料与重金属的复合毒性效应对于正确评价微塑料的生态风险具有重要意义。本文以卤虫(Artemia parthenogenetica)作为研究对象,考察了10μm聚苯乙烯微球与2种重金属(Cu~(2+)和Cd~(2+))对卤虫无节幼体的单一及复合急性毒性。同时使用电感耦合等离子体质谱仪(ICP-MS)测定了卤虫体内Cu~(2+)和Cd~(2+)浓度随时间的变化情况,比较分析了聚苯乙烯微球对重金属在卤虫体内富集的影响。研究发现,Cu~(2+)和Cd~(2+)单一暴露时对卤虫无节幼体的24 h半数致死浓度(24 h-LC_(50))分别为(1.26±0.15) mg·L~(-1)和(164.5±27.3) mg·L~(-1),与聚苯乙烯微球共同作用时24h-LC_(50)分别为(1.38±0.23) mg·L~(-1)和(178.3±36.4) mg·L~(-1),聚苯乙烯微球的存在显著促进了卤虫对Cu~(2+)和Cd~(2+)的摄入和排出,但并未影响二者急性毒性。研究结果可为海洋环境中微塑料和重金属的生态风险评价提供理论依据。     

四溴双酚A对太平洋真宽水蚤的急性毒性及氧化胁迫

为了研究四溴双酚A(tetrabromobis-phenol A,TBBPA)对海洋桡足类的急性毒性和氧化胁迫效应,以太平洋真宽水蚤为受试生物,测定了TBBPA对其96 h急性毒性和对其体内抗氧化防御系统的影响。结果表明,TBBPA对太平洋真宽水蚤的96 h半数致死浓度(96 h-LC50)为178μg·L~(-1),95%可信区间为91~306μg·L~(-1),表现为极毒。亚致死浓度下,TBBPA能够不同程度影响太平洋真宽水蚤的抗氧化防御酶活力以及非酶物质含量。其中SOD和GST活性的变化趋势较为一致,暴露初期SOD和GST活性显著上升(P0.05),随暴露时间延长酶活性有所下降,最终趋向对照组水平;GPx活性水平始终维持在对照组以上并且差异显著(P0.05);暴露初期,GSH含量受轻微氧化压力而轻微升高,暴露48 h后GSH含量急剧下降并显著低于对照组(P0.05)。太平洋真宽水蚤体内SOD、GST、GPx活性和GSH含量对TBBPA暴露均十分敏感,能够为海洋环境的TBBPA监测提供生化指标参考。     

(S)-2-Methyl-1-hexanol,characteristic mandibular gland substance of ants of theCataglyphis bicolor group

Summary In all the species of theCataglyphis bicolor group examined yet, i.e.C. bicolor, C. diehli, C. isis, C. nodus, andC. viaticus, 2-methyl-1-hexanol is the characteristic substance and almost the only substance found in the mandibular glands. Its chirality has been determined inC. bicolor and shown to be exclusively (S)-2-methyl-1-hexanol.     

氟虫双酰胺对蚯蚓的生化毒性与细胞毒性研究

双酰胺类杀虫剂已成为全世界第4大类最常用的杀虫剂,具有非常广阔的应用前景。然而,目前关于双酰胺类杀虫剂生态毒性评估方面的研究还比较少。为探究双酰胺类杀虫剂对非靶标生物的毒性作用,选取赤子爱胜蚓(Eisenia fetida)为受试生物,研究了典型双酰胺类杀虫剂氟虫双酰胺对非靶标动物蚯蚓的生化毒性和细胞毒性以及其在人工土和蚯蚓体内的浓度变化情况。结果表明,氟虫双酰胺在人工土壤中十分稳定,在整个暴露期间氟虫双酰胺的浓度变化不超过20%。氟虫双酰胺在蚯蚓体内的含量随染毒浓度的升高和暴露时间的推移而增加,呈明显的时间和剂量-效应关系;在染毒浓度为0.1和1.0 mg·kg-1的处理组中,氟虫双酰胺未对蚯蚓产生明显的氧化胁迫效应。在染毒浓度为5.0和10.0 mg·kg-1的处理组中,蚯蚓体内活性氧(ROS)含量显著高于其他处理组,过量的ROS诱导蚯蚓体内各种抗氧化酶活性发生异常变化,并在蚯蚓体内造成了脂质过氧化、蛋白质羰基化和DNA损伤。研究表明,当土壤中氟虫双酰胺的浓度为5.0和10.0 mg·kg-1时可能会对蚯蚓产生很高的风险。此外,彗星实验对氟虫双酰胺诱导的氧化胁迫较为敏感,可以作为敏感生物标志物对氟虫双酰胺造成的土壤污染进行预警。     

页岩气压裂返排液的水生生态毒性效应研究

页岩气压裂作业过程产生大量压裂返排液,这类废液富含有毒且致癌的芳香烃、有毒金属和铀、钍、镭等放射性物质、石油类添加剂等,具有可生化性差和难处理的特点。这类废液若不经任何处理就进行排放,将给环境和人群健康带来潜在的危害和风险。目前尚不清楚它们的生态毒性效应。论文从涪陵页岩气开采基地采集了4口开采井(2号井、6号井-1、6号井-2和9号井)的压裂返排液,采用国家废水测试标准分析4种压裂返排液的水质理化指标,采用斜生栅藻(Scenedesmus obliquus)、大型溞(Daphnia magna)等标准毒性试验生物探究压裂返排液污染物体系的水生生态毒性效应,并研究水质理化指标与压裂返排液综合毒性的关系。结果表明,采集的所有压裂返排液样品均具备较大的水生生态毒性效应。以斜生栅藻的96 h的半数效应浓度(96 h-EC_(50))或大型溞的96 h的半数致死浓度(96 h-LC_(50))和毒性单位(TUa)为评价指标进行生态毒性分级,4个位点压裂返排液的生态毒性均为中毒及以上。压裂返排液的重金属、阴阳离子及有机物含量与其综合毒性的相关性结果表明,这些污染物成分与其藻类综合毒性无显著相关性。但Li、V、Cu、Ga、Rb、Ba等6种重金属及Na+、Cl-等2种阴阳离子对压裂返排液的溞类综合毒性有显著影响,影响程度依次为LiGaBaCl-VNa+RbCu。因此,在对压裂返排液进行处理时,这些与毒性相关的污染物是需要重点考虑的化学成分。     

12种杀菌剂制剂对半闭弯尾姬蜂的急性毒性及安全性评价

采用试管药膜法测定了12种杀菌剂制剂对半闭弯尾姬蜂成蜂的急性接触毒性,结合安全性系数评价了供试药剂对半闭弯尾姬蜂的安全性。急性毒性测定结果表明,氟硅唑和啶菌噁唑对半闭弯尾姬蜂成蜂的接触毒性最高,LC50值分别为220.022和223.115 mg·L-1;其次为多抗霉素、丙森锌和戊唑醇,LC50值分别为436.496、472.358和638.638 mg·L-1;其余7种杀菌剂制剂嘧霉胺、啶酰菌胺、苯醚甲环唑、多菌灵、嘧菌酯、嘧菌环胺和异菌脲对半闭弯尾姬蜂成蜂的触杀毒性都较低,LC50值均大于1 000 mg·L-1。安全性评价结果表明,丙森锌和啶菌噁唑对半闭弯尾姬蜂成蜂具有高风险性,安全系数分别为0.16和0.42;嘧霉胺、多抗霉素、氟硅唑和戊唑醇为中等风险性,安全系数分别为1.43、1.56、2.20和3.23;其余6种杀菌剂制剂啶酰菌胺、苯醚甲环唑、多菌灵、嘧菌酯、嘧菌环胺和异菌脲对半闭弯尾姬蜂表现为低风险性,安全系数均大于5。结果显示:甾醇脱甲基抑制剂氟硅唑、戊唑醇和啶菌噁唑以及苯胺基嘧啶类杀菌剂嘧霉胺、有机硫杀菌剂丙森锌和抗菌素多抗霉素对半闭弯尾姬蜂成蜂具有急性毒性风险,在有害生物综合治理中应谨慎使用,特别是啶菌噁唑和丙森锌,以免对半闭弯尾姬蜂造成不良影响和危害。     

Queen dimorphism and reproductive strategies in the fire ant Solenopsis geminata (Hymenoptera: Formicidae)

Alate trapping studies of a monogyne population of the fire ant Solenopsis geminata indicate that two sizes of gynes are produced. Macrogynes, which participate in late spring and summer mating flights, are larger, fattier, and more than twice as heavy as microgynes, which participate in fall mating flights. Three patterns of gyne production were observed in 51 colonies studied: 35 produced macrogynes only, 9 produced microgynes only, and 7 produced both morphs, contributing to both summer and fall mating flights. Behavioral evidence and rearing studies suggest that macrogynes found new colonies independently, whereas microgynes achieve colony queen status by infiltrating or being adopted by established colonies. Of the total number of female alates collected from the trapped colonies, 56% were microgynes. However, because of their smaller size and lower fat content, microgynes made up only one-third of the caloric investment in female alates. By measuring the thorax lengths of queens from mature colonies, we determined that at least 56% were macrogynes and 35% or more were microgynes. These results indicate that as a reproductive strategy, colony investment in microgyne production may have at least as high a payoff as investment in macrogyne production.This is publication #24 of the Fire Ant Research Team     

土壤Cd污染对跳虫Folsomia candida的生态毒性

采矿及冶炼等行为造成了严重的土壤重金属污染,其中Cd污染及其带来的健康风险近年来引起人们的高度重视。利用弹尾目跳虫开展土壤Cd污染的生态毒理研究,对Cd污染土壤的生态风险评价具有重要意义。本研究将跳虫Folsomia candida(F.candida)暴露在不同Cd浓度污染的人工土壤中,利用跳虫存活数量、繁殖数量及回避行为实验来评价重金属Cd污染对跳虫的生态毒性。结果表明,Cd对F.candida的急性毒性LC50值为2 086.93 mg·kg~(-1),慢性毒性的繁殖抑制(28 d)EC50值为224.95 mg·kg~(-1)。此外,Cd对跳虫回避行为影响的EC50(48 h)为721.26 mg·kg~(-1)。可以看出,慢性毒性的EC50值与Cd对回避行为影响的EC50值近似,但远低于急性毒性LC50值。因此,跳虫F.candida的回避行为和繁殖率对Cd污染土壤有较高的灵敏度,可用来表征土壤中Cd的生态毒性。     

全氟烷基磺酸盐(PFOS)及其替代品对两栖类胚胎的发育毒性

用非洲爪蟾胚胎致畸实验和黑斑蛙胚胎发育毒性实验,比较研究了PFOS及其4种替代品对两栖动物胚胎的发育毒性。结果发现,用调聚法合成的织物三防整理剂和50%的全氟丁基有机铵盐阳离子表面活性剂同PFOS一样对非洲爪蟾胚胎有明显毒性,且织物三防整理剂和表面活性剂的毒性强于PFOS;电解氟化法合成的C4织物及C6织物三防整理剂(以下简称C4及C6织物三防整理剂)对非洲爪蟾胚胎没有明显毒性。与非洲爪蟾不同,PFOS和4种替代品对黑斑蛙胚胎没有明显毒性。结果显示,从生物安全性的角度分析,C4和C6织物三防整理剂可作为PFOS的替代品使用,而织物三防整理剂和表面活性剂的毒性比PFOS大,作为PFOS替代品使用需要慎重考虑。     

全氟辛烷磺酸盐(PFOS)及替代品对两栖类蝌蚪的急性毒性

PFOS及其4种替代品对两栖动物非洲爪蟾和黑斑蛙蝌蚪的急性毒性结果为:用调聚法合成的织物三防整理剂对非洲爪蟾蝌蚪和黑斑蛙蝌蚪的96h-LC50分别为8和21mg·L-1,而PFOS对两种蝌蚪的96h-LC50分别为92和81mg·L-1。此实验结果说明织物三防整理剂的急性毒性高于PFOS。用电解氟化法合成的C4、C6织物三防整理剂和50%的全氟丁基有机铵盐阳离子表面活性剂浓度在100mg·L-1时,对两种蝌蚪都没有毒性。这说明,从急性毒性的角度,C4、C6织物三防整理剂和表面活性剂可作为PFOS的替代品使用,但是织物三防整理剂的急性毒性比PFOS大,作为替代品使用应慎重考虑。另外,PFOS和织物三防整理剂对黑斑蛙蝌蚪的急性毒性与对非洲爪蟾蝌蚪的急性毒性存在差异。出于保护我国本土两栖动物的目的,使用黑斑蛙开展毒性评价比使用非洲爪蟾更有现实意义。