Attraction of field-flying aphid males to synthetic sex pheromone

Summary Transparent plastic water traps, baited with the synthetic aphid sex pheromone components (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol or control lures, were placed in four semi-sheltered field sites at a height of 1.1 m. Although males of twenty-one aphid species were collected from the water traps, onlySitobion fragariae (Walker) was abundant. In total, 8 pheromone traps produced 102 males compared with only 10 males in 8 control traps. The sex pheromone released by sexual femaleS. fragariae was identified as the nepetalactone used in the lures. Aphid sex pheromones may be more species-specific than previously thought and the presence of a host plant is not essential for males to locate sexual females.     

Absolute configuration of the major sex pheromone component of the satin moth, Leucoma salicis, verified by field trapping test in Hungary

Summary. Male satin moths, Leucoma (Stilpnotia) salicis L. (Lepidoptera, Lymantriidae) were attracted only to (3Z,6R,7S,9R,10S)-isomer out of the four (3Z)-cis-6,7-cis-9,10-diepoxy-3-henicosenes (leucomalure). This was demonstrated by field trapping test with a bivoltine population in a mixed poplar-willow forest along the flood area of the river Danube at Adony, Hungary.     

Sex pheromone of the tea aphid,Toxoptera aurantii (Boyer de Fonscolombe) (Hemiptera: Aphididae)

The tea aphid, Toxoptera aurantii, also called the “black citrus aphid”, is one of the most destructive insect pests in commercial tea plantations and gardens in southern China. In autumn, declining day length triggers production of winged T. aurantii sexuparae, which produce both winged males and wingless oviparae. Oviparous females then release sex pheromone that attracts potential mates. GC–MS analysis of volatile headspace extracts of T. aurantii oviparae revealed that they emit (4aS,7S,7aR)-nepetalactone (I) and (1R,4aS,7S,7aR)-nepetalactol (II) in a ratio of 4.3–4.9:1. Field-trapping experiments with synthetic I and II singly or as two-component blends of different doses and ratios showed significant attraction of T. aurantii males, as well as weak attraction of sexuparae. Identification of the T. aurantii sex pheromone provides a new opportunity for developing a pheromone-based monitoring and management strategy for the sexual phase of tea aphids and, possibly, the alate sexparous generation in late summer and fall.     

Stereoisomeric composition of the sex pheromone of the pine sawfly <Emphasis Type="Italic">Microdiprion pallipes</Emphasis> (Hym., Diprionidae)

Summary. The basic chemical structure of the sex pheromone of the pine sawfly Microdiprion pallipes (Fallén) has earlier been identified as the propionate ester of (2S,3S,7R/S,11R/S)/(2R,3R,7R/S,11R/S)-3,7,11- trimethyl-2-tridecanol. We now report the results from further investigations on the male response to individual stereoisomers and to blends of stereoisomers, both in electroantennographic (EAG) recordings and in field trapping experiments. We also present our attempts to determine the stereochemistry of the compounds present in females of M. pallipes. By comparing gas chromatograms and mass spectra obtained from natural extracts with those from synthetic compounds it was found that the females contain one or more of the four (2S,3S,7R/S,11R/S)-3,7,11-trimethyl-2- tridecanol isomers (SS++-1). The active pheromone component is the corresponding propionate ester 2. In EAG experiments, males responded most strongly to five propionate ester samples, namely two four-isomer blends: SS++-2 and SR++-2, and three individual stereoisomers: SSSR-, SRRR- and SRSR-2. In a series of field trapping experiments it was found that males were attracted to the SR++-2 four-isomer blend and to the individual isomer SSSR-2. Based on the EAG-recordings and field responses of males and the stereoisomers found in the females, we suggest that the propionate ester of (2S,3S,7S,11R)-3,7,11-trimethyl-2- tridecanol (SSSR-2) is used as a main component of the sex pheromone in M. pallipes. Apparently the males react to other stereoisomers in addition to that or those produced by the females.     

Pheromone of the elm bark beetle Scolytus laevis (Coleoptera: Scolytidae): stereoisomers of 4-methyl-3-heptanol reduce interspecific competition

Stereoisomers of 4-methyl-3-heptanol (MH) are pheromone components of several Scolytus bark beetles. The elm bark beetle Scolytus laevis (Coleoptera: Scolytidae) has in previous studies been caught in traps baited with commercial MH containing all four stereoisomers, but the lure has been considered a weak attractant. In this study, we addressed the question whether stereospecific responses by S. laevis to stereoisomers of MH might contribute to its niche separation from other sympatric Scolytus species. Using GC–MS, we analyzed extracts of hindguts and abdomens from male and female S. laevis and the sympatric S. triarmatus. We also tested all four MH-stereoisomers individually and in combinations in the field to determine their role for S. laevis. All four stereoisomers were synthesized via a boronic ester method with 1,2-dicyclohexylethanediol as chiral director. In addition, the (3S,4R)-stereoisomer of MH was prepared through enantioselective, lipase-mediated transesterification of a mixture of the four stereoisomers of MH. Females of both species contained small amounts of syn-MH, and males contained trace amounts of anti-MH. The anti stereoisomer (3R,4S)-MH was attractive to male and female S. laevis, whereas the syn stereoisomer (3S,4S)-MH acted as an inhibitor or deterrent and reduced the catch when added to the attractive isomer. The syn isomer is the main aggregation pheromone component of the larger and sympatric S. scolytus and possibly also of S. triarmatus. The avoidance response of S. laevis to the (3S,4S)-stereoisomer may reduce interspecific competition for host trees.     

Identification and biological activity of sex pheromone components from females of the plum moth Illiberis rotundata Jordan (Lepidoptera: Zygaenidae: Procridinae)

The plum moth, Illiberis rotundata Jordan (Lepidoptera: Zygaenidae: Procridinae), is a pest of orchards in Japan and China. Few chemical ecological studies have been directed towards the Zygaenidae and particularly the Procridinae. To investigate the sex pheromone of this species, extracts of pheromone glands from adult female I. rotundata were analyzed by coupled gas chromatography-electroantennography (GC-EAG) and coupled gas chromatography-mass spectrometry (GC-MS). Whilst GC-EAG on male moths showed an active peak, identified as 2-butyl (7Z)-dodecenoate, GC-MS also revealed the presence of the homologue 2-butyl (9Z)-tetradecenoate. Electroantennographic investigations, as well as field tests, strongly suggested the natural compounds to have the (R)-configuration at the stereogenic centre. Field results demonstrate 0.2 mg of a 1:1-mixture of (2R)-butyl (7Z)-dodecenoate and (2R)-butyl (9Z)-tetradecenoate to be a powerful lure that may be used in pest control measures against I. rotundata. The chemical structures of the new pheromone components show the same features as those of other zygaenid species: unsaturated fatty acids esterified with a short chain chiral alcohol. This is the first example of a two-component blend constituting the pheromone of a procridinid species.     

Aggregation pheromone ofCarpophilus freemani (Coleoptera: Nitidulidae): A blend of conjugated triene and tetraene hydrocarbons

Summary Males ofCarpophilus freemani Dobson (Coleoptera: Nitidulidae) produce an aggregation pheromone to which both sexes fly in a wind-tunnel bioassay. The major pheromone component (ca. 30 ng per male per day in volatile collections) was identified as (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene. A minor component, (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-undecatetraene, was 3–10% as abundant as the major triene and was 5–20% as active when compared at relative doses ranging from natural proportions to 1:1. These compounds act synergistically: a mixture of major and minor components in natural proportions attracted more than twice as many beetles as the major component alone, and the mixture fully accounted for the activity of male-derived volatile collections. Six other male-derived conjugated hydrocarbons, ranging from 2% down to 0.04% as abundant as the major component, were also identified. These are (in order of decreasing bioassay activity when compared on an equal-weight basis): (3E,5E,7E)-6-ethyl-4-methyl-3,5,7-decatriene, (2E,4E,6E)-5-ethyl-3-me-thyl-2,4,6-octatriene, (3E,5E,7E,9E)-8-ethyl-4,6-dimethyl-3, 5,7,9-dodecatetraene, (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6, 8-undecatetraene, (3E,5E,7E)-5-ethyl-7-methyl-3,5,7-undecatriene, and (2E,4E,6E)-3,5-dimethyl-2,4,6-nonatriene. All structure identifications were confirmed by synthesis. In the wind tunnel, the pheromone acted synergistically with host-type volatiles such as propyl acetate, valeric acid, and ethanol. This concept was verified by fields tests in California, in which there was dramatic synergism between the pheromone and fermenting host materials. Pheromone biosynthesis is discussed.     

Neocembrene A, a major component of the trail-following pheromone in the genus Prorhinotermes (Insecta, Isoptera, Rhinotermitidae)

Summary. The diterpene neocembrene A or (1E,5E,9E,12R)-1,5,9-trimethyl-12-(1-methylethenyl)-1,5,9-cyclotetradecatriene, known as the trail-following pheromone of the advanced Termitidae Nasutitermitinae Nasutitermes exitiosus and Trinervitermes bettonianus, has been identified after SPME-GC/MS as the major component of the trail-following pheromone of the Rhinotermitidae Prorhinotermitinae, Prorhinotermes canalifrons and P. simplex. In all the other Rhinotermitidae studied until now, the major component of their trail pheromones is dodecatrienol ((3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol). This biochemical data further add to the anatomical and molecular characteristics that give a special status to the taxon Prorhinotermes among Rhinotermitidae. In Prorhinotermes canalifrons and P. simplex, neocembrene A was the only secretory compound specific to the sternal gland surface that could be detected after SPME. It elicited orientation as well as recruitment behavioral effects. However, the comparison of the respective biological activities triggered by neocembrene A and by sternal gland secretion suggests that minor components of the latter are acting in synergy with neocembrene A.     

Secondary metabolites of the leaf surface affected by sulphur fertilisation and perceived by the diamondback moth

Summary. Summary. Oilseed rape, Brassica napus L. (cv Express), plants were grown under three different sulphur regimes: sulphur-free (S₀), normal sulphur (S_n, normal field concentration) and a sulphur-rich (S₊, 2 × concentration of S_n). We performed dual choice oviposition assays with the diamondback moth, Plutella xylostella, using real plants and, for the first time with this insect, artificial leaves sprayed with methanolic leaf-surface extracts. The results mirrored those of a separate study of preferences for whole plants. Females laid more eggs on surrogate leaves that were treated with S_n extracts than on S₀ plants, while only a slight, not significant, difference was observed between extracts of normal and sulphur-rich plants. This shows that chemical compounds on the leaf surface mediate the oviposition preference and that the female insect can perceive the quality of the host-plants in terms of their fertilisation status.Since leaf volatiles are known to be oviposition stimulants, we investigated the effects of leaf-surface extracts on insect olfactory responses using electroantennograms (EAGs). In agreement with the behavioural data, we found that extracts of sulphur-treated plants yielded higher EAG amplitudes than the S₀ extracts. Since the leaf content of the volatiles isothiocyanates is influenced by sulphur nutrition, we analysed the extracts for these compounds. Above the detection threshold of our GC-MS system, no isothiocyanates were found. Thus, other compounds present in the surface extracts must be perceived by the antenna.However, the HPLC analysis revealed 11 different glucosinolates. Progoitrin (2-Hydroxy-3-butenyl) and gluconapoleiferin (2-Hydroxy-4-pentenyl), which belong to the hydroxy-alkene class of glucosinolates, were the most abundant compounds. The total glucosinolate content sharply increased from S₀ to S_n plants, whereas it was slightly lower in _n versus S₊ plants. Since it is known that glucosinolates can stimulate oviposition, it seems likely that the increased content we observed was influencing the insect preference in this study too.     

Marine diatoms grown in chemostats under silicate or ammonium limitation. III. Cellular chemical composition and morphology of Chaetoceros debilis,Skeletonema costatum,and Thalassiosira gravida

Three marine diatoms, Skeletonema costatum, Chaetoceros debilis, and Thalassiosira gravida were grown under no limitation and ammonium or silicate limitation or starvation. Changes in cell morphology were documented with photomicrographs of ammonium and silicate-limited and non-limited cells, and correlated with observed changes in chemical composition. Cultures grown under silicate starvation or limitation showed an increase in particulate carbon, nitrogen and phosporus and chlorophyll a per unit cell volume compared to non-limited cells; particulate silica per cell volume decreased. Si-starved cells were different from Si-limited cells in that the former contained more particulate carbon and silica per cell volume. The most sensitive indicator of silicate limitation or starvation was the ratio C:Si, being 3 to 5 times higher than the values for non-limited cells. The ratios Si:chlorophyll a and S:P were lower and N:Si was higher than non-limited cells by a factor of 2 to 3. The other ratios, C:N, C:P, C:chlorophyll a, N:chlorophyll a, P:chlorophyll a and N:P were considered not to be sensitive indicators of silicate limitation or starvation. Chlorophyll a, and particulate nitrogen per unit cell volume decreased under ammonium limitation and starvation. NH₄-starved cells contained more chlorophyll a, carbon, nitrogen, silica, and phosphorus per cell volume than NH₄-limited cells. N:Si was the most sensitive ratio to ammonium limitation or starvation, being 2 to 3 times lower than non-limited cells. Si:chlorophyll a, P:chlorophyll a and N:P were less sensitive, while the ratios C:N, C:chlorophyll a, N:chlorophyll a, C:Si, C:P and Si:P were the least sensitive. Limited cells had less of the limiting nutrient per unit cell volume than starved cells and more of the non-limiting nutrients (i.e., silica and phosphorus for NH₄-limited cells). This suggests that nutrient-limited cells rather than nutrient-starved cells should be used along with non-limited cells to measure the full range of potential change in cellular chemical composition for one species under nutrient limitation.Contribution No. 943 from the Department of Oceanography, University of Washington, Seattle, Washington 98195, USA.     

GC-EAD responses to semiochemicals by eight beetles in the subcortical community associated with Monterey pine trees in coastal California: similarities and disparities across three trophic levels

Summary.  Antennae of six sympatric bark and ambrosia beetles (Scolytidae), Dendroctonus valens LeConte, Gnathotrichus retusus (LeConte), Hylastes tenuis Eichhoff, Ips mexicanus (Hopkins), Ips plastographus maritimus Lanier, and Pseudohylesinus sericeus (Mannerheim), and two scolytid predators, Enoclerus sphegeus (F.) (Cleridae) and Lascontonus tuberculatus Kraus (Colydiidae), were analyzed by gas chromatographic-electroantennographic detection (GC-EAD) for their responses to synthetic Ips spp. pheromone components, and host and nonhost volatiles. The beetles emerged from cut logs of pitch canker-infected Monterey pine trees, Pinus radiata D. Don. There were significant disparities in EAD response patterns to the hemiterpene and monoterpene alcohol pheromone components that are typically produced by Ips spp. Antennae of I. p. maritimus responded strongly to ( ± )-ipsdienol, ( ± )-ipsenol, amitinol, and lanierone; antennae of I. mexicanus responded strongly to (1S,2S)-(–)-cis-verbenol, with weaker responses to ( ± )-ipsdienol, ( ± )-ipsenol, and amitinol; antennae of H. tenuis responded to (1S, 2R)-(–)-trans-ver-benol, with less pronounced responses to (–)-cis-verbenol and 2-methyl-3-buten-2-ol; and antennae of D. valens, G. retusus, and P. sericeus generally responded to all Ips spp. pheromone components except 2-methyl-3-buten-2-ol (D. valens and G. retusus) and E-myrcenol (G. retusus and P. sericeus). Ips mexicanus responded only to the (–)-enantiomers of ipsenol and ipsdienol, whereas I. p. maritimus responded to (–)-ipsenol, but to both the (+)- and (–)-enantiomers of ipsdienol. The antennae of the two predaceous insects (E. sphegeus and L. tuberculatus) responded to a range of the Ips spp. pheromone components. Host monoterpenes elicited no antennal responses from E. sphegeus, G. retusus, H. tenuis, and I. mexicanus, but several monoterpenes elicited various levels of responses from D. valens and I. p. maritimus antennae. Interestingly, antennae of female D. valens responded to (–), but not (+)-limonene. α- and β-Pinene elicited weak responses from L. tuberculatus antennae. EAD responses to selected nonhost volatiles were almost identical among the six scolytid species, with trans-conophthorin eliciting the strongest response in most cases, followed by three C₆- alcohols and two C₈-alcohols. The antennal responses by most of these species to linalool or geranylacetone were very weak; (E)-2-hexenal, (Z)-3-hexenyl acetate, and benzyl alcohol elicited almost no response. The response pattern of P. sericeus to nonhost volatiles differed slightly from the rest of the scolytids: a strong response to linalool, weaker response to the C₈-alcohols. The two predaceous Coleoptera generally had weak, but detectable, responses to nonhost volatiles, except for a relatively strong response to trans-conophthorin by L. tuberculatus. No notable differences in EAD responses were observed between males and females of the two Ips spp. Our results provide an electrophysiological baseline for future efforts to identify attractive and repellent semiochemicals (aggregation pheromones, host kairomones, or nonhost interruptants) for this guild of scolytids and their key predators that are associated with moribund and pitch canker- infected P. radiata.     

Aggregation pheromones of bark beetles, Pityogenes quadridens and P. bidentatus, colonizing Scotch pine: olfactory avoidance of interspecific mating and competition

The bark beetles Pityogenes bidentatus and Pityogenes quadridens (Coleoptera, Curculionidae, Scolytinae) are sibling species that feed and reproduce in bark areas on branches of Scotch pine, Pinus sylvestris. To identify aggregation pheromone components of both species, hindguts and head/thoraxes of males and females of both species feeding in hosts were extracted in pentane and analyzed by gas chromatography and mass spectrometry. Hindguts of male P. bidentatus contained grandisol as the major component along with small amounts of (4S)-cis-verbenol and other monoterpenes. Dose–response bioassays in the laboratory showed the components were attractive at 0.2 ng/min to walking beetles from a distance of ≥25 cm. In the field in southern Sweden, grandisol and (4S)-cis-verbenol were weakly attractive alone when released at rates of 0.05 and 0.5 mg/day, respectively, from a slow-rotating trap pair. Catch increased 3.6- to 13-fold when the two components were released together. The male proportion of the catch was 0.8 early in the flight period, declined to 0.5 on the peak flight day, and then declined further during the next 2 weeks to 0.2 on the last day of the flight period. Hindguts of male P. quadridens contained (2S,5R)- and (2S,5S)-chalcogran, as well as (E)-2-(3,3-dimethylcyclohexylidene)ethanol (E-grandlure 2) and E/Z-mixture of 2-(3,3-dimethylcyclohexylidene)acetaldehyde (grandlures 3 and 4), while female hindguts had only a trace amount of chalcogran. Laboratory studies proved E-grandlure 2 is an essential pheromone component for P. quadridens. Field bioassays with a slow-rotating trap pair in which the attractiveness of blends containing various candidate components were compared with that of less complete mixtures, showed that chalcogran and E-grandlure 2 were synergistic aggregation pheromone components of P. quadridens. Field tests also showed that grandisol (from P. bidentatus) reduced attraction of P. quadridens to its aggregation pheromone, whereas E-grandlure 2 and chalcogran (from P. quadridens) reduced response of P. bidentatus to its aggregation pheromone. Our results suggest that aggregation pheromone components from males of each species not only attract conspecifics but also aid individuals in avoiding interspecific mating and competition for food and spatial resources within the bark phloem layer.     

Electrophysiological responses of Dendroctonus armandi (Coleoptera: Curculionidae: Scolytinae) to volatiles of Chinese white pine as well as to pure enantiomers and racemates of some monoterpenes

To better understand the attractiveness of host tree, Chinese white pines (Pinus armandi Fr.) to Chinese white pine beetle (Dendroctonus armandi Tsai and Li), the antennal responses of D. armandi to the host volatile, as well as the pure enantiomers and racemates of some monoterpenes, were examined using an electroantennogram (EAG). EAG responses of male and female D. armandi to blended volatiles extracted from the host and some synthetic terpenes (α-phellandrene, (−)-β-pinene, (+)-α-pinene, (−)-α-pinene, (−)-camphene, β-myrcene, (S)-(−)-limonene, (+)-camphene and (R)-(+)-limonene) showed significant variation due to different compound concentrations and sex of the beetles. EAG responses to extracted blended volatiles were significantly greater in females than in males, but the EAG response was not always proportional to the volatile concentration. At lower concentrations, females responded strongly to α-phellandrene and males to (−)-β-pinene, while at higher concentrations, females responded most strongly to α-phellandrene and males to (+)-α-pinene. Females were significantly responsive to (−)-α-pinene, α-phellandrene and (−)-camphene, while males were more responsive to (S)-(−)-limonene, (+)-α-pinene and (R)-(+)-limonene. The EAG responses of the female D. armandi to the volatile oil were significantly higher than that of the males, and the infested pine volatiles could evoke higher EAG response. Most of the test compounds elicited similar responses, which suggested that several of the compounds may be used in combination by D. armandi in habitat and/or host community location at the Qinling forest ecosystem.     

The effects of temperature,body size and growth rate on energy losses due to metabolism in early life stages of haddock (<Emphasis Type="Italic">Melanogrammus aeglefinus</Emphasis>)

Rates of routine respiration (R _R, μl O₂ fish⁻¹ h⁻¹) and total ammonia nitrogen excretion (E _R, μg NH₄–N + NH₃–N fish⁻¹ h⁻¹) were measured on larval and juvenile haddock (Melanogrammus aeglefinus) to ascertain how energy losses due to metabolism were influenced by temperature (T), dry body mass (M _D, mg) and specific growth rate (SGR, % per day). R _R and E _R increased with M _D according to y = a  · M _D ^b with b-values of 0.96, 0.98, 1.14, and 0.89, 0.78, 0.74, respectively, at 10, 7, and 4°C, respectively. Multiple regressions explained 98% of the variability in the combined effects of M _D and T on R _R and E _R in larval haddock: R _R = 0.97 · M _D ^0.98  · e^0.092 · T ; E _R = 0.06 · M _D ^0.79  · e^0.092 · T . In young juvenile (24–30 mm standard length) haddock, R _R tended to decline (P = 0.06) and E _R significantly declined (P = 0.02) with increasing SGR. O:N ratios significantly increased with increasing SGR suggesting that N was spared in relatively fast-growing individuals. Our results for young larval and juvenile haddock suggest: (1) nearly isometric scaling of R _R with increasing body size, (2) allometric scaling of E _R with increasing body size, (3) Q ₁₀ values of 2.5 for both R _R and E _R, (4) metabolic differences in substrate utilization between relatively fast- and slow-growing individuals, and (5) that rates of routine energy loss and growth were not positively related. The measurements in this study will provide robust parameter estimates for individual-based models that are currently being utilized to investigate how variability in climatic forcing influences the vital rates of early life stages of haddock. Our results also stress that inter-individual differences in rates of energy loss should not be overlooked as a factor influencing growth variability among individuals.     

Electrophysiological and behavioural responses of Aphidius ervi (Hymenoptera: Braconidae) to tomato plant volatiles

Flight responses of the aphid parasitoid Aphidius ervi to tomato volatiles have recently demonstrated that different plant stresses can lead to increases in attractiveness for this parasitoid. For example, infestation of tomato plants by the aphid Macrosiphum euphorbiae results in the overexpression of defensive genes, as well as the release of volatile compounds that attract aphid parasitoids. Here, we determine which of the induced compounds elicit a significant electrophysiological response from parasitoid antennae. Compounds shown to be detected at the antennal level were then tested at a range of doses in a wind tunnel assay. A significant electroantennogram response was demonstrated for three compounds, (8S,9R)-(E)-caryophyllene, methyl salicylate, and (Z)-3-hexen-1-ol, over four concentrations. These compounds proved to be significantly attractive in the wind tunnel at a rate not always proportionally dependent upon the dose. The practical implications of these findings are discussed in the framework of sustainable control for pest aphids in agriculture.     

Sequestration of prenylated benzoic acid and chromenes by Naupactus bipes (Coleoptera: Curculionidae) feeding on Piper gaudichaudianum (Piperaceae)

The curculionid beetle Naupactus bipes (Germar, 1824) (Coleoptera: Curculionidae: Brachycerinae) has shown feeding preference for leaves of Piper gaudichaudianum, demonstrating an unexpected specificity for an insect considered to be a generalist. The leaves of P. gaudichaudianum contain the prenylated chromenes gaudichaudianic acid (4, major compound) and its methyl ester (5) in addition to a chromene (3) lacking one prenyl residue. In addition to 4, roots contain the chromone methyl ester (1) and methyl taboganate (2, major compound). Feeding on roots, larvae of N. bipes sequester exclusively the root-specific compounds 1 and 2. Adult beetles sequester the leaf-specific chromenes 3 and 4, but were found to also contain compounds 1 and 2 that are absent in leaves. Therefore, it is suggested that 1 and 2 are sequestered by larvae and can be found in the body of adult insects after long-term storage. In addition, 3 and 4, the major compounds in leaves were found to be associated with the eggs.     

Sex pheromone of the large aspen tortrix, Choristoneura conflictana(Lepidoptera: Tortricidae)

Summary. Three components that elicited antennal response from male Choristoneura conflictana were found from female gland extracts analyzed using a coupled gas chromatographic-electroantennographic detector system. The main component in gland extracts was (Z)-11-tetradecenal (Z11-14:Ald). Two minor components also elicited antennal response: (E)11-tetradecenal (E11-14:Ald) and (Z)-11- tetradecen-1-ol (Z11-14:OH). Analysis of effluvia indicated that calling virgin females release mostly Z11-14:Ald and trace amounts of Z11-14:OH. Field and wind tunnel behavioral studies showed that Z11-14:Ald alone attracted male moths in a dose response pattern. Tests comparing male response to blends of components detected in gland extracts showed that addition of 1.8% of E11-14:Ald to Z11-14:Ald did not influence male moths in the wind tunnel, but resulted in significantly lower trap captures in the field. The threecomponent blend [Z11-14:Ald (100), E11-14:Ald (1.8), Z11-14:OH (11)], was less attractive than Z11-14:Ald alone in both field and wind tunnel studies. Traps baited with two virgin female moths were equally attractive to males as traps baited with the three-component synthetic blend but less attractive than traps baited with Z11-14:Ald alone. Field tests of various blends of the two components (Z11-14:Ald, Z11-14:OH) detected in the females’ effluvia showed that the addition of 1–10% Z11-14:OH to Z11-14:Ald did not affect the males’ response to Z11-14:Ald. Our data demonstrate that female C. conflictana release sex pheromone components in a different ratio than they are stored in the pheromone gland. The sex pheromone is comprised of a single component, Z11-14:Ald, that can be used to monitor mated and virgin male C. conflictana throughout their flight period.     

Orientation ofRhizophagus grandis (Coleoptera: Rhizophagidae) to oxygenated monoterpenes in a species-specific predator-prey relationship

Summary The predator,Rhizophagus grandis, is linked to its specific prey,Dendroctonus micans, by semiochemical signals regulating oviposition and long range orientation. A mixture of simple oxygenated monoterpenes [(–)—fenchone, (–)—pinocamphone, rac. camphor, terpinene-4-ol, borneol, fenchol and verbenone], identified from the frass ofD. micans has been found to be extremely active in a flight windtunnel as a long—range attractant for the predator. The mixture elicited 84 % of the response to larval frass of the prey. Excluding pinocamphone from the mixture did not influence its activity. Also, changing the absolute configurations of some of the components (fenchol, terpinene-4-ol and borneol) did not influence the predators' response. However, the addition of (–)—-terpineol increased the attractivity of the synthetic blend to almost that of larval frass of the prey. Ecological implications of the identified semiochemicals and their use in pest management are discussed.     

Identification, synthesis and activity of sex pheromone gland components of the autumn gum moth (Lepidoptera: Geometridae), a defoliator of Eucalyptus

Summary. The autumn gum moth, Mnesampela privata (Guenée) (Lepidoptera: Geometridae), is native to Australia and can be a pest of plantation eucalypts. Field-collected and laboratory-reared female autumn gum moths were dissected to remove glands likely to contain components of the sex pheromone. Using gas chromatography (GC) and combined gas chromatography–mass spectrometry (GC-MS), three compounds were identified from female extracts, namely (3Z,6 Z,9 Z)-3,6,9-nonadecatriene, 1-hexadecanol and 1-octadecanol (confirmed by comparison with synthetic samples). Nonadecatriene elicited an antennal response in male autumn gum moth during gas chromatographic analyses combined with electroantennographic detection (GC-EAD). In electroantennogram (EAG) recording male M. privata antennae responded to the nonadecatriene. Nonadecatriene was synthesised via Kolbe electrolysis, starting with (9Z,12Z,15Z)-octadeca-9,12,15-trienoic acid (linolenic acid) and propanoic acid or via an alternative four-step method also starting from linolenic acid. In field trials (3Z,6Z,9Z)-3,6,9-nonadecatriene proved attractive to male moths. Thus, we conclude that (3Z,6Z,9Z)-3,6,9- nonadecatriene is a sex pheromone component of autumn gum moth. This component has been identified in extracts from other geometrids in the same subfamily, Ennominae. However, to our knowledge this is the first example where (3Z,6Z,9Z)-3,6,9-nonadecatriene has been found in females and also proved attractive to male moths when presented on its own. Our results are discussed in relation to other geometrid pheromones.     

Effects of temperature and body mass on metabolic rates of sprat, Sprattus sprattus L.

Sprat, Sprattus sprattus L., is a small schooling clupeid forming large stocks in several ecosystems. Despite its high trophodynamic impact, little is known about its energy consumption rates. As a central component of a bioenergetic budget, metabolic rates of sprat from 3.11 to 9.71 g wet weight (WW) were measured at nine different temperatures (T) ranging from 9 to 21°C using a computer-controlled intermittent-flow respirometer. Routine metabolism (R _R) was related to T (°C) and WW (g) by R _R = 0.074 WW^1.077 e^{0.080 T}. Standard metabolic rates (R _S) as calculated from the 10% percentiles of the repeated measurements were on average 12% lower and still influenced by continuous swimming activity: R _S = 0.069 WW^1.073 e^{0.078 T}. We interpret the deviation of the scaling exponent b from typically found exponents of b ~ 0.8 as a consequence of permanently elevated activity level. The high permanent swimming activities also indicated that the concept of standard metabolism may not be meaningful in schooling planktivorous fish. These results suggest that generally in bioenergetic models for clupeid schooling fish the activity multipliers should be chosen very conservatively.