Toxicity of Dangerous Prey: Variation of Tetrodotoxin Levels Within and Among Populations of the Newt Taricha granulosa

The ability to identify and accurately measure traits at the phenotypic interface of potential coevolutionary interactions is critical in documenting reciprocal evolutionary change between species. We quantify the defensive chemical trait of a prey species, the newt Taricha granulosa, thought to be part of a coevolutionary arms race. Variation in newt toxicity among populations results from variation in levels of the neurotoxin tetrodotoxin (TTX). Individual variation in TTX levels occurs within populations. Although TTX exists as a family of stereoisomers, only two of these (TTX and 6-epi-TTX) are likely to be sufficiently toxic and abundant to play a role in the defensive ecology of the newt.     

Tetrodotoxin levels in eggs of the rough-skin newt,Taricha granulosa,are correlated with female toxicity

We quantified the amount of the neurotoxin tetrodotoxin (TTX) present in females and newly deposited eggs of the rough-skin newt, Taricha granulosa, to examine the relationship between the toxicity of an individual female and the toxicity of her eggs. We found high levels of TTX in individual eggs as well as substantial variation among clutches. Variation in the amount of TTX per egg within individual clutches was extremely low. Female skin toxicity was positively correlated with the mean egg toxicity of her clutch. Neither egg volume nor female size was significantly correlated with egg TTX levels. Tetrodotoxin stereoisomer–analog profiles were identical for females and their eggs. The presence of high levels of TTX in individual eggs coupled with the relationship between levels of TTX in female skin and levels of TTX in her eggs suggests that the TTX present in eggs of T. granulosa is maternally derived. The lack of correlation between egg size and TTX levels in individual eggs, as well as the low levels of within clutch variation, may indicate that deposition of TTX in eggs of T. granulosa is not linked to the deposition of other egg resources (e.g., lipids or other yolk components).     

A Resistant Predator and Its Toxic Prey: Persistence of Newt Toxin Leads to Poisonous (Not Venomous) Snakes

The common garter snake (Thamnophis sirtalis) preys upon the rough-skinned newt (Taricha granulosa), which contains the neurotoxin tetrodotoxin (TTX) in the skin. TTX is toxic, large quantities are present in a newt, and highly resistant snakes have the ability to ingest multiple newts; subsequently snakes harbor significant amounts of active toxin in their own tissues after consuming a newt. Snakes harbor TTX in the liver for 1 mo or more after consuming just one newt, and at least 7 wk after consuming a diet of newts. Three weeks after eating one newt, snakes contained an average of 42 microg of TTX in the liver. This amount could severely incapacitate or kill avian predators, and mammalian predators may be negatively affected as well.     

Semiochemicals from the Predatory Stink Bug Eocanthecona furcellata (Wolff): Components of Metathoracic Gland, Dorsal Abdominal Gland, and Sternal Gland Secretions

Volatile compounds from the metathoracic glands (MTG), dorsal abdominal glands (DAG), and sternal setae of the generalist predatory stink bug Eocanthecona furcellata (Wolff) were studied by gas chromatography–mass spectrometry. MTGs of both male and female bugs contained (E)-2-decenal as the major component, with lesser amounts of (E,E)-2,4-decadienal, (E,Z)-2,4-decadienal, and (E)-2,9-decadienal. The relative amount of (E)-2,9-decadienal in the MTGs of female bugs was higher than in male bugs. There was no dimorphism in the morphology of the DAGs of adults. However, the DAG contents of adult bugs were different between the sexes. Geraniol was found only in the DAGs of males, and limonene and -terpineol were found only in the DAGs of females, whereas linalool oxide isomers, linalool, neral, and geranial were found in DAGs of both sexes. The DAG contents of nymphs were also analyzed, with 4-oxo-(E)-2-hexenal, 4-oxo-(E)-2-octenal, tridecane, and tetradecanal being major components. Male bugs but not females possess sternal setae, and 6,10,13-trimethyltetradecyl isovalerate was detected from extracts of the sternal setae of males. The possible biological significance of dimorphism in the contents of the glands in adults is discussed.     

Isolation and Identification of Cellulolytic Bacteria from the Gut of Holotrichia parallela Larvae (Coleoptera: Scarabaeidae)

In this study, 207 strains of aerobic and facultatively anaerobic cellulolytic bacteria were isolated from the gut of Holotrichia parallela larvae. These bacterial isolates were assigned to 21 genotypes by amplified ribosomal DNA restriction analysis (ARDRA). A partial 16S rDNA sequence analysis and standard biochemical and physiological tests were used for the assignment of the 21 representative isolates. Our results show that the cellulolytic bacterial community is dominated by the Proteobacteria (70.05%), followed by the Actinobacteria (24.15%), the Firmicutes (4.35%), and the Bacteroidetes (1.45%). At the genus level, Gram-negative bacteria including Pseudomonas, Ochrobactrum, Rhizobium, Cellulosimicrobium, and Microbacterium were the predominant groups, but members of Bacillus, Dyadobacter, Siphonobacter, Paracoccus, Kaistia, Devosia, Labrys, Ensifer, Variovorax, Shinella, Citrobacter, and Stenotrophomonas were also found. Furthermore, our results suggest that a significant amount of bacterial diversity exists among the cellulolytic bacteria, and that Siphonobacter aquaeclarae, Cellulosimicrobium funkei, Paracoccus sulfuroxidans, Ochrobactrum cytisi, Ochrobactrum haematophilum, Kaistia adipata, Devosia riboflavina, Labrys neptuniae, Ensifer adhaerens, Shinella zoogloeoides, Citrobacter freundii, and Pseudomonas nitroreducens are reported to be cellulolytic for the first time in this study. Our results indicate that the scarab gut is an attractive source for the study of novel cellulolytic microorganisms and enzymes useful for cellulose degradation.     

The Involvement of Volatile Infochemicals from Spider Mites and from Food-Plants in Prey Location of the Generalist Predatory Mite <Emphasis Type="Italic">Neoseiulus californicus</Emphasis>

We investigated volatile infochemicals possibly involved in location of the generalist predatory mite Neoseiulus californicus to plants infested with spider mites in a Y-tube olfactometer. The predators significantly preferred volatiles from lima bean leaves infested with Tetranychus urticae to uninfested lima bean leaves. Likewise, they were attracted to volatiles from artificially damaged lima bean leaves and those from T. urticae plus their visible products. Significantly more predators chose infested lima bean leaves from which T. urticae plus their visible products had been removed than artificially damaged leaves, T. urticae, and their visible products. These results suggest that N. californicus is capable of exploiting a variety of volatile infochemicals originating from their prey, from the prey-foodplants themselves, and from the complex of the prey and the host plants (e.g., herbivore-induced volatiles). We also investigated predator response to some of the synthetic samples identified as volatile components emitted from T. urticae-infested lima bean leaves and/or artificially damaged lima bean leaves. The predators were attracted to each of the five synthetic volatile components: linalool, methyl salicylate, (Z)-3-hexen-1-ol, (E)-2-hexenal, and (Z)-3-hexenyl acetate. The role of each volatile compound in prey-searching behavior is discussed.     

Flavonoid Metabolites in the Hemolymph of European Pine Sawfly (Neodiprion sertifer) Larvae

Flavonoids in the hemolymph of European pine sawfly (Neodiprion sertifer) larvae that were feeding on Pinus sylvestris needles were identified. HPLC-ESI-MS analysis revealed that the main components in the hemolymph were flavonol di- and triglucosides and a catechin monoglucoside. These compounds were isolated from the larval hemolymph and their structures were established by HPLC-MS, GC-MS, and NMR spectroscopy. The isolated flavonoids were identified as (+)-catechin 7-O-β-glucoside, isorhamnetin 3,7,4'-tri-O-β-glucoside, kaempferol 3,7,4'-tri-O-β-glucoside, and quercetin 3,7,4'-tri-O-β-glucoside. The combined concentration of these four compounds in the hemolymph was 3.7 mg/ml. None of these compounds was present in the needles of P. sylvestris. Therefore, we propose that the flavonoid glucosides were produced by the larvae from flavonoid monoglucosides and (+)-catechin obtained from the pine needles.     

Olfactory Reactions of the Twelve-Spotted Lady Beetle, Coleomegilla maculata and the Green Lacewing, Chrysoperla carnea to Semiochemicals Released from Their Prey and Host Plant: Electroantennogram and Behavioral Responses

Electroantennograms (EAGs) were recorded from two predatory insect species, the twelve-spotted lady beetle, Coleomegilla maculata and the green lacewing, Chrysoperla carnea in response to semiochemicals emitted from one of their prey species, the pea aphid Acyrthosiphon pisum and their host plant. EAG responses were also recorded from C. maculata in response to extracts from individuals of the opposite sex and to extracts from an herbaceous plant, catnip Nepeta cataria. Extracts of catnip and two sex pheromone components of aphids, (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol, elicited significant EAG responses from the antennae of both predatory species. Of 10 corn volatile compounds tested, C. carnea adults responded most strongly to 2-phenylethanol and (E)--farnesene. A significant difference in EAG response to extracts of corn leaf collections was observed between male and female C. carnea. In C. maculata, significant EAG responses were elicited by most of the tested corn volatile compounds, except -pinene and (E)-2-hexenal. The highest EAG responses were observed in response to (E)--farnesene, -terpineol, 2-phenylethanol, and -caryophyllene. Sexual differences in EAG responses of C. maculata were only found in response to 1-octen-3-ol. Male antennae of C. maculata produced significant EAG responses to extracts from conspecific females, but not to males, which indicates that some chemicals from females could be involved in sexual communication. A significant EAG response also was recorded in response to the extracts of fluids produced during reflex bleeding. Male and female antennae of both species exhibited similar dose–response curves to most of the selected compounds, although female C. maculata antennae exhibited higher thresholds in response to several compounds including -terpineol, (Z)-3-hexenol, and (4aS,7S,7aR)-nepetalactone. Field tests showed that 2-phenylethanol was highly attractive to both sexes of the two investigated species. Only C. maculata was attracted to traps baited with -terpineol.     

Learned Recognition of Predation Risk by Enallagma Damselfly Larvae (Odonata, Zygoptera) on the Basis of Chemical Cues

We studied two populations of damselfly larvae (Enallagma boreale): one population cooccurred with a predatory fish (northern pike, Esox lucius); the other did not. Damselflies that cooccurred with pike adopted antipredator behavior (reduced activity) in response to chemical stimuli from injured conspecifics, and to chemical stimuli from pike, relative to a distilled water control. Damselflies from an area where pike do not occur responded only to chemical stimuli from injured conspecifics. In a second set of experiments, we conditioned pike-naive damselflies to recognize and respond to chemical stimuli from pike with antipredator behavior. Damselfly larvae that were previously unresponsive to pike stimuli learned to recognize pike stimuli after a single exposure to stimuli from pike and injured damselflies or pike and injured fathead minnows (Pimephales promelas). The response to injured fathead minnows was not a general response to injured fish because damselfly larvae did not respond to chemical stimuli from injured swordtails (Xiphophorus helleri), an allopatric fish. Taken together, these data suggest a flexible learning program that allows damselfly larvae to rapidly acquire the ability to recognize local predation risk based on chemical stimuli from predators, conspecifics, and heterospecific members of their prey guild.     

Sex Pheromones and Reproductive Behavior of Spodoptera litura (Fabricius) Moths Reared from Larvae Treated with Four Insecticides

When Spodoptera litura (Fabricius) larvae were treated with the insecticides deltamethrin, endosulfan, malathion, and carbaryl at dosages causing 30% mortality (LD30), female moths reared from survivors showed similar patterns in the frequency of calling behavior. However, females reared from larvae dosed with deltamethrin had significantly higher titers of sex pheromone than those treated with endosulfan, malathion, or carbaryl, or control individuals. The ratio of the sex pheromone blend, Z9,E12-14:OAc to Z9,E11-14:OAc in females from the deltamethrin treatment group differed significantly from that of female moths in other treatments. In a wind-tunnel bioassay, males reared from larvae treated with deltamethrin, malathion, or carbaryl were less likely to display behaviors resulting in the location of a sex pheromone source than males reared from larvae treated with endosulfan or a solvent control (acetone). Mating success was significantly decreased in pairs containing either males or females reared from larvae that survived treatment with deltamethrin.     

Toxicity of Certain Penta-Coordinated Organotin(IV) and Tetra-Coordinated Tin(II) Complexes of Heterocyclic beta-Diketones Against the Larvae of Aedes Aegypti (Liston)

Some organotin(IV) and tin(II) complexes of composition R(3)Sn[R'COC:CON(C(6)H(5))N:CCH(3)] (where R=C(4)H(9), R'=CH(3), C(3)H(5), p-ClC(6)H(4); R=C(6)H(5), R'=C(6)H(5) and p-ClC(6)H(4)) and Sn[p-ClC(6)H(4)COC:CON(C(6)H(5))N:CCH(3)](2) were screened for their toxicity against Aedes aegypti larvae. Organotin(IV) complexes were more active than tin(II) complexes.     

Purification Process,Physicochemical Properties,and Fatty Acid Composition of Black Soldier Fly (Hermetia illucens Linnaeus) Larvae Oil

This study presented a refining process and reported on fatty acid composition and the physicochemical properties of the oil from black soldier fly larvae (BSFL). Crude larvae oil was purified through four steps consisting of degumming, neutralization, bleaching, and deodorization. Optimum degumming conditions that give the highest phospholipid weight and oil consisted of water concentration of 7% (v/v), followed by addition of H₂SO₄ at a concentration of 0.5% (v/v). Optimum conditions for saponification that maximize saponification value and free fatty acid (FFA) value were 0.4 mg NaOH/100 g oil, 1 hour, and 80 °C of NaOH quantity, reaction time, and temperature, respectively. The oil was then dehydrated using 10 mg Na₂SO₄/g oil. The bleaching process that gives maximum oil yield consisted of activated carbon at concentration of 5% (w/w), followed by centrifugation at a speed of 5000 rpm (radius = 86 mm) for 30 min. The contents of lauric acid, linoleic acid, and linolenic acid in purified oil were 28.8%, 11.1%, and 0.4%, respectively. Physicochemical properties of the refined oil included viscosity of 96 ± 0.14 cP (measured at 20 °C), FFA value of 0.45 ± 0.017%, acid value of 0.9 ± 0.043 mg KOH g⁻¹, saponification value of 215.78 mg KOH g⁻¹, iodine value of 53.7 gI₂/100 g, and peroxide index of 133 mEq kg⁻¹.     

聚对苯硫醚、聚间苯硫醚及其共聚物的合成与表征

用硫磺、对二氯苯和间二氯苯为原料,在极性有机溶剂六甲基磷酰三胺中合成了聚对苯硫醚(p-PPS)、聚间苯硫醚(m-PPS)及其共聚物.用裂解气相色谱、红外光谱、X-射线衍射及热分析对所得聚合物的结构和热性能进行了初步研究.结果表明:p—PPS和m—PPS都是结晶性聚合物,间位结构引入到p-PSS的结构中明显地破坏了p-PPS的高度结晶性,降低了耐热性,但最大失重速率处温度却无多大变化.这一共聚改性途径可望用于改进p—PPS的刚性,提高其韧性.     

Olfactory Responses of the Predatory Mites (N eoseiulus cucumeris) and Insects (O rius strigicollis ) to Two Different Plant Species Infested with Onion Thrips (T hrips tabaci)

Responses of Neoseiulus cucumeris (a predatory mite) and the predatory insect Orius strigicollis to volatiles associated with two different plant species infested with onion thrips, Thrips tabaci, were examined in a Y-tube olfactometer. Both predators species showed a significant preference for volatiles from infested cucumber leaves without T. tabaci over clean air. However, they were not attracted to volatiles from uninfested cucumber leaves, artificially damaged cucumber leaves, or volatiles from T. tabaci plus their visible products collected from cucumber leaves. These results suggest that both predator species are capable of exploiting herbivore-induced volatiles from T. tabaci-infested cucumber leaves as a foraging cue. Neither predator was attracted to volatiles from uninfested spring onion leaves, infested spring onion leaves without T. tabaci, or volatiles from T. tabaci plus their visible products collected from spring onion leaves. Interestingly, they avoided volatiles from artificially damaged spring onion leaves. A possible explanation for the non-significant olfactory responses of the predator species to spring onion plants with infestation damage of T. tabaci is discussed.     

侵染马铃薯块茎蛾幼虫的球孢白僵菌对桃蚜的毒力测定

室内测定了从罹病马铃薯块茎蛾Phthorimaea operculella(Zeller)幼虫上分离到的球孢白僵菌Beauveris bassiana两菌株(Bb001，Bb004)对甘蓝桃蚜Myzus persicae(Sulzer)的毒力。运用时间-剂量-死亡率模型，对死亡率随时间和剂量的变化趋势，以及两种菌株在不同温度下对桃蚜的毒力作了分析。结果表明：两种菌株对桃蚜均具有毒杀作用，菌株Bb004在21℃下表现了较高的毒力，菌株Bb001在21℃～28℃下对桃蚜均有较强的致病力，2l℃～25℃下是两菌株共同发挥毒力最佳的温度。其中，Bb001有较宽的适宜温度范围，而Bb004适宜温度范围较小。     

Low-Temperature Oxidation, Hydrothermal Corrosion, and Their Effects on Properties of SiC (Tyranno) Fibers

The effects of oxidation in air and corrosion in high-temperature, high-pressure water on the mechanical properties of three commercially available amorphous Si-Ti-C-O (Tyranno) fibers with different oxygen contents (12%–18%) and diameters (8–11 μm) were investigated. The fibers were exposed to isothermal treatments at elevated temperatures and subsequently tested at room temperature. Structural changes in the fibers after oxidation and corrosion were also studied in order to understand better the degradation mechanisms of the fibers. Oxidation resulted in the formation of vitreous silica films and decreases of strength and Young's modulus of the fibers. Hydrothermal corrosion under 100 MPa water pressure started above 300°C and resulted in the formation of a carbon layer on the surface of the fibers. Dissolution of silica in water during the treatment was observed. Corrosion at temperatures above 400°C led to the formation of relatively thick carbon films which delaminated easily. It caused a decrease of strength and Young's modulus of the fibers. The hydrothermal method can be used for producing carbon coatings with thickness up to 2 μm on the surface of silicon carbide fibers. The degrading of the mechanical properties after oxidation and corrosion was controlled by the thickness of the oxide or carbon layer. Based on this fact, it is possible to predict changes in the mechanical properties from the oxidation data.     

Synthesis and Characterization of Diepoxyalkenes Derived from (3Z,6Z,9Z)-Trienes: Lymantriid Sex Pheromones and Their Candidates

All stereoisomers of three diepoxyalkenes derived from (3Z,6Z,9Z)-trienes with a C₂₁, C₁₉, or C₁₈ straight chain, lymantriid sex pheromones and their candidates, were synthesized by MCPBA oxidation of optically active epoxyalkadienes. Their chromatographic behaviors were examined with GC and LC equipped with achiral and chiral columns. Detailed inspection of the mass spectra of these epoxides indicated the following diagnostic ions for determining the chemical structures: m/z 128, 167, M-87 and M-85 for (Z)-cis-3,4-cis-6,7-diepoxy-9-enes; m/z 111, M-125 and M-69 for (Z)-cis-6,7-cis-9,10-diepoxy-3-enes; and m/z M-125 and M-139 for (Z)-cis-3,4-cis-9,10-diepoxy-6-enes. Mass chromatographic analysis that monitored these fragment ions revealed the existence of a new pheromonal compound with a C₂₁ chain in an extract from virgin females of a lymantriid species, Perina nuda F. The three diepoxyalkenes were converted into the corresponding DMDS adducts, which showed characteristic ions from fragmentation between the two thiomethyl groups, reflecting the position of an original double bond.     

Genome-Wide Analysis of the Late Embryogenesis Abundant (LEA) and Abscisic Acid-, Stress-, and Ripening-Induced (ASR) Gene Superfamily from Canavalia rosea and Their Roles in Salinity/Alkaline and Drought Tolerance

Canavalia rosea (bay bean), distributing in coastal areas or islands in tropical and subtropical regions, is an extremophile halophyte with good adaptability to seawater and drought. Late embryogenesis abundant (LEA) proteins typically accumulate in response to various abiotic stresses, including dehydration, salinity, high temperature, and cold, or during the late stage of seed development. Abscisic acid-, stress-, and ripening-induced (ASR) genes are stress and developmentally regulated plant-specific genes. In this study, we reported the first comprehensive survey of the LEA and ASR gene superfamily in C. rosea. A total of 84 CrLEAs and three CrASRs were identified in C. rosea and classified into nine groups. All CrLEAs and CrASRs harbored the conserved motif for their family proteins. Our results revealed that the CrLEA genes were widely distributed in different chromosomes, and all of the CrLEA/CrASR genes showed wide expression features in different tissues in C. rosea plants. Additionally, we introduced 10 genes from different groups into yeast to assess the functions of the CrLEAs/CrASRs. These results contribute to our understanding of LEA/ASR genes from halophytes and provide robust candidate genes for functional investigations in plant species adapted to extreme environments.