Sex pheromone communication of tentiform leaf-miners <Emphasis Type="Italic">Phyllonorycter insignitella</Emphasis> and <Emphasis Type="Italic">Ph. nigrescentella</Emphasis> from two related species groups

Summary.  Females of both species start their pheromone-releasing activity on the second day after emergence at the beginning of the photophase. During the present work, a peak of calling activity with close to 100% of active Ph. nigrescentella females was registered 1.5 hour after the light had been put on. The high pheromone release behaviour with 50% active females lasted for 3 hours. The calling activity of the group of females was about 6 h/day. The beginning of a photophase under laboratory conditions or an early morning in nature is a common period for sex pheromone release in the genus Phyllonorycter. (8Z,10E)-tetradecadien-1-yl acetate (8Z,10E-14:Ac), (8Z,10E)-tetradecadien-1-ol (8Z,10E-14:OH) and (8E,10Z)-tetradecadien-1-yl acetate (8E,10Z-14:Ac) in the ratio 96:4:traces as well as 8Z,10E-14:Ac and 8Z,10E-14:OH in the ratio 88:12 collected by Solid Phase Micro Extraction (SPME) were found to be specific for the calling periods of virgin Phyllonorycter insignitella and Ph. nigrescentella females respectively. Field trapping experiments demonstrated that all three compounds are important for the attraction of Ph. insignitella males while only 8Z,10E-14:Ac is the essential sex pheromone component for Ph. nigrescentella. The pheromone activity of all three compounds is reported for the first time. Addition of either 8Z,10E-14:OH or 8E,10Z-14:Ac to 8Z,10E-14:Ac did not have a significant effect on the attraction of Ph. nigrescentella males, while the efficiency of the three component blend was 5 times lower as compared to that of 8Z,10E-14:Ac. Our data demonstrate that 8Z,10E-14:OH and 8E,10Z-14:Ac play a dual function, they are minor sex pheromone components of Ph. insignitella essential for attraction of conspecific males and show an allelochemical, antagonistic effect on Ph. nigrescentella males and, thus, ensuring specificity of the mate location signal in two related Phyllonorycter species.     

Female sex pheromone of Ostrinia orientalis – throwing a light on the relationship between O. orientalis and the European corn borer, O. nubilalis

Summary. The sex pheromone of Ostrinia orientalis (Lepidoptera: Crambidae) was analyzed by gas chromatography–electroantennographic detection (GC–EAD), GC–mass spectrometry and a series of bioassays. Three EAD-active compounds were detected in the female sex pheromone gland extract, and identified as tetradecyl acetate (14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (E)-11-tetradecenyl acetate (E11-14:OAc). The titers (ratio) of 14:OAc, Z11-14:OAc and E11-14:OAc in 3-day-old virgin females were 0.49 ng (10), 4.86 ng (98) and 0.10 ng (2), respectively. In a wind-tunnel bioassay, the 98:2 blend of Z11- and E11-14:OAc, but not Z11-14:OAc alone, elicited the same male behavioral responses as virgin females and crude gland extracts. 14:OAc was inactive by itself, and did not show any synergistic effect on the binary blend. Field trapping experiments also confirmed the attractiveness of the binary blend to O. orientalis males. Based on these results, we concluded that the sex pheromone of O. orientalis is a 98:2 mixture of Z11-14:OAc and E11-14:OAc. This sex pheromone is very similar to that of the Z-type European corn borer, O. nubilalis. The present finding raises the question of whether O. orientalis , which is indistinguishable from O. nubilalis based on external morphology, is a biologically distinct species independent from O. nubilalis.     

Comparative studies on the sex pheromones of Ostrinia spp. in Japan: the burdock borer, Ostrinia zealis

Summary. To gain insight into the evolution of the sex pheromone communication system in Ostrinia (Lepidoptera Pyralidae), the sex pheromone of the burdock borer, O. zealis was analyzed by means of gas chromatography-electroantennographic detection (GC-EAD), GC-mass spectrometry and a series of bioassays. Four EAD-active compounds were detected in the female sex pheromone gland extract, and these were identified as tetradecyl acetate (14:OAc), (Z)-9-tetradecenyl acetate (Z9–14:OAc), (E)-11-tetradecenyl acetate (E11-14:OAc) and (Z)-11-tetradecenyl acetate (Z11-14:OAc). The average amounts (ratio) of the four compounds in single sex pheromone glands were 2.5 ng (13%), 11.6 ng (61%), 4.1 ng (21%) and 0.9 ng (5%), respectively. In a wind-tunnel bioassay, the ternary blend of Z9-, E11- and Z11-14:OAc at a ratio found in the sex pheromone gland elicited the same behavioral responses from the males as did virgin females. 14:OAc did not show any enhancement or inhibition of the males’ behavioral responses when added to the ternary blend. The attractiveness of the 3-component lure to O. zealis males was also confirmed by field trapping experiments. Based on these results, we concluded that the sex pheromone of O. zealis is composed of Z9-14:OAc, E11-14:OAc and Z11-14:OAc at a ratio of 70:24:6. The evolutionary changes of the sex pheromones in Ostrinia are also discussed based on the presently available information on the sex pheromones and phylogenetic relationships of Ostrinia spp. Received 25 September 1998; accepted 2 December 1998.     

Sex pheromones and their potential role in the evolution of reproductive isolation in small ermine moths (Yponomeutidae)

Summary Sex pheromone communication in the nine European species of small ermine moths (Yponomeuta) is reviewed in regard to the potential role of pheromones in the speciation process. Six of the nine species studied (viz.,Y. evonymellus, Y. cagnagellus, Y. padellus, Y. irrorellus, Y. plumbellus, andY. vigintipunctatus) use a mixture of (E)-11-and (Z)-11-tetradecenyl acetate in different ratios as primary pheromone components, with combinations of tetradecyl acetate, (Z)-9-tetradecenyl acetate, (Z)-11-hexadecenyl acetate and the corresponding alcohols of the acetates as additional pheromone components. Analysis of (Z)- to (E)-11-tetradecenyl acetate ratios produced by individual females of these species demonstrated significant variation among females of all species. However, the ranges of ratios produced byY. cagnagellus, Y. irrorellus, andY. plumbellus, sharing the same host-plant species, spindle tree, did not overlap. Niche separation of all six species mentioned required consideration of at least one additional pheromone component or of temporal aspects. The remaining three species,i.e. Y. malinellus, Y. mahalebellus andY. rorellus, have pheromones that differ qualitatively.Biosynthetic routes to the pheromone components identified are proposed on the basis of fatty acid pheromone precursors found in the pheromone glands. A phylogenetic tree for the genus is constructed based on allozyme frequency data and changes in pheromone composition are superimposed on this tree. We suggest that the ancestral ermine moth pheromone is a mixture of (Z)-11- and (E)-11-tetradecenyl acetate and the corresponding alcohols, and a scenario of how present-day patterns evolved is outlined. The pheromone differences among the three species using spindle tree as their host-plant might have evolved throughreproductive character displacement upon secondary contact between populations that had already diverged genetically in allopatry. Pheromone differences within the so-calledpadellus-complex (includingY. cagnagellus, Y. mahalebellus, Y. malinellus, Y. padellus, andY. rorellus) in which species might have originated sympatrically, may have evolved byreinforcing selection as these species still hybridise and produce viable offspring when confined in cages. The role of pheromones in reproductive isolation amongYponomeuta species is emphasised by (1) the function of pheromone components of some of the species as behavioural antagonists to other species, (2) the cross-attraction under experimental conditions between allochronic species with similar pheromones, and (3) the formation of hybrids in the laboratory between species that are isolated in nature by pheromone differences.     

Heritable pheromone blend variation in a local population of the butterbur borer moth Ostrinia zaguliaevi (Lepidoptera: Crambidae)

Summary. In a local population of Ostrinia zaguliaevi Mutuura & Munroe (Lepidoptera: Crambidae), extensive variation was found in the blend ratio of three sex pheromone components, (Z)-9-tetradecenyl acetate (Z9-14:OAc, 10.2-63.8%), (Z)-11-tetradecenyl acetate (Z11-14:OAc, 32.2-86.8%), and (E)-11-tetradecenyl acetate (E11-14:OAc, 2.1-11.9%). The variation was observed over a three-year period (2002-2004). Mother-daughter regression analyses have shown that although the heritability of the minor component E11-14:OAc was not significant, the heritability of the proportions of Z9-14:OAc and Z11-14:OAc were substantial (0.5–0.6). In artificial selection experiments, the mean % Z9-14:OAc in the sex pheromone changed significantly within three generations (37% in the control line, 48 and 52% for two lines selected for increase, and 23 and 30% for two lines selected for decrease). Despite these changes, the amounts of fatty acyl pheromone precursors, (Z)-9-, (Z)-11- and (E)-11-tetradecenoate, in the pheromone gland were not significantly affected by the selection. Taken together, variation in the pheromone blend of O. zaguliaevi is likely to be attributable to a few genes involved in the reduction or acetylation of fatty acyl pheromone precursors, the last two steps in pheromone biosynthesis.     

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.     

New repellent semiochemicals for three species of <Emphasis Type="Italic">Dendroctonus</Emphasis> (Coleoptera: Scolytidae)

Summary. Nine compounds identified from captured volatiles of the Douglas-fir beetle, Dendroctonus pseudotsugae, the mountain pine beetle, D. ponderosae, and the spruce beetle, D. rufipennis, that elicited antennal responses in males and females of one or more of these species were tested in the field to determine behavioural activity. 1-Octen-3-ol, found in the volatiles of females of all three species decreased the response of male and female coastal and male interior D. pseudotsugae and both sexes of D. ponderosae to their aggregation pheromones. Acetophenone, identified in the volatiles of females of all three species, significantly decreased the response of interior female D. pseudotsugae. trans-Verbenol, a potent aggregation pheromone of D. ponderosae, decreased the response of both sexes of D. pseudotsugae, while 3-methyl-2-cyclohexen-1- one (MCH), the antiaggregation pheromone of D. pseudotsugae and D. rufipennis decreased the response of both sexes of D. ponderosae. While it has been demonstrated that semiochemical mediated interspecific communication occurs among bark beetles infesting the same host, this study demonstrates that beetles can perceive signals emitted by heterospecifics attacking nonhosts and can potentially use them to avoid attacking the wrong species of conifer.     

Communication ecology of webbing clothes moth: 4. Identification of male- and female-produced pheromones

Summary. We investigated the hypothesis that aggregation signals produced by male webbing clothes moths (WCM), Tineola bisselliella (Hum.) (Lepidoptera: Tineidae), and close-range male attractant signals produced by females have a pheromonal basis, at least in part. Gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric analyses of bioactive methanolic extracts of male WCM disclosed three candidate pheromone components: hexadecanoic acid methyl ester (16:Ester), (Z)-9-hexadecenoic acid methyl ester (Z9—16:Ester), and octadecanoic acid methyl ester (18:Ester). In bioassay experiments in a large Plexiglas™ arena, a blend of synthetic 16:Ester plus Z9—16:Ester was attractive to male and virgin (but not mated) female WCM; the 18:Ester was inactive. GC-EAD analyses of pheromone gland extracts from female WCM revealed (E,Z)-2,13-octadecadienal (E2Z13—18:Ald) and (E,Z)-2,13-octadecadienol (E2Z13—18:OH) as candidate sex pheromone components. In arena bioassay experiments, 1—5 female equivalents of synthetic E2Z13—18:Ald (0.2 ng) and E2Z13—18:OH (0.1 ng) were more attractive to male WCM than were two virgin female WCM. We anticipate that the combination of aggregation and sex pheromones, male-produced sonic aggregation signals, and habitat-derived semiochemicals will be highly effective in attracting male and female WCM to commercial traps. Received 12 January 2001; accepted 8 June 2001.     

Temporal accumulation of phenylpropanoids in male fruit flies, <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis> and <Emphasis Type="Italic">B. carambolae</Emphasis> (Diptera: Tephritidae) following methyl eugenol consumption

Summary. Males of dacine tephritids, Bactrocera carambolae and B. dorsalis are strongly attracted to, and compulsively feed on methyl eugenol (ME), a potent attractant for many Bactrocera species. While ME was shown to be biotransformed into phenylpropanoids, 2-allyl-4,5-dimethoxyphenol and (E)-coniferyl alcohol, and temporarily stored in the rectal gland of male B. dorsalis prior to release during courtship at dusk, B. carambolae male produces only the latter compound along with its de novo synthesized pheromone components. Both species were also shown to have different age-related response, sensitivity and consumption levels of ME. Here, we monitored and compared temporal changes in the accumulation profiles of these phenylpropanoids by the two sibling species, with male rectal glands being individually excised at different time intervals from 15 minutes to 20 days after initial ME feeding and analysed quantitatively. Results are discussed in light of plant-fruit fly co-evolution relationship.     

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.     

Triterpenoid and caffeic acid derivatives in the leaves of ragweed, <Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> L. (Asterales: Asteraceae), as feeding stimulants of <Emphasis Type="Italic">Ophraella communa</Emphasis> LeSage (Coleoptera: Chrysomelidae)

Summary. The leaf beetle Ophraella communa infests almost exclusively Ambrosia artemisiifolia in the fields of Japan, even though it normally feeds on several Asteraceous plants. A filter paper bioassay showed that the feeding of O. communa is strongly stimulated by methanolic extracts of A. artemisiifolia. The feeding stimulants for O. communa have been isolated from methanolic extracts of A. artemisiifolia. -Amyrin acetate, -amyrin acetate, 5-caffeoylquinic acid (chlorogenic acid) and 3,5-dicaffeoylquinic acid from A. artemisiifolia have been identified as feeding stimulants for O. communa. Triterpenoid derivatives (-amyrin acetate or -amyrin acetate) and caffeic acid derivatives (3, 5-dicaffoylquinic acid or 5-caffeoylquinic acid) showed feeding stimulant activity when mixed together.     

(Z)-11-Pentacosene is the major sex pheromone component inDrosophila virilis (Diptera)

Summary A crude cuticular extract from 3450 virgin 9–13 day old female fruit flies(Drosophila virilis), was subjected to chromatography accompanied by bioassay for sex pheromone activity. After three chromatographic steps, fractions containing active monoenes and dienes were obtained. Chemical analysis by infrared absorption, gas liquid chromatography and gas chromatography/mass spectrometry of the active fraction indicated that active monoenes were comprised chiefly of (Z)-11-pentacosene (abbreviated (Z)-11-C_25:1), (Z)-13-C_27:1, (Z)-13- and (Z)-14-C_29:1. Synthetic monoenes were made, and only (Z)-11-C_25:1 elicited good courtship behaviour in maleD. virilis. Therefore it was concluded that (Z)-11-C_25:1 was a major sex pheromone. A total of 16.2±1.32 µg of cuticular hydrocarbons was isolated from 10 day old females, including 5.9±0.56 µg of (Z)-11-C_25:1. An additive effect was suggested from the higher observed courtship response when using a mixture of active dienes with the active monoene.     

Sexually differentiated functions of female-produced pheromone of the black chafer <Emphasis Type="Italic">Holotrichia loochooana loochooana</Emphasis> (Sawada) (Coleoptera: Scarabaeidae)

Summary. Both male and female Holotrichia loochooana loochooana (Sawada) (Coleoptera: Scarabaeidae) were attracted with female-produced pheromone, anthranilic acid (2-aminobenzoic acid), in the field. Male chafers were observed to apparently directly locate cotton balls impregnated with 1 to 10 mg of pheromone. In contrast, females never directly oriented to the treated balls but landed 0.2-1.5 m away and exposed their abdominal glands in a calling posture, which occasionally resulted in aggregation of both females and males. This suggested the mating aggregation of this species could be primarily induced by pheromone released by females. A hypothesis for adaptability of female aggregation is proposed and discussed.     

Main nutrient compounds in food bodies of Mexican <Emphasis Type="Italic">Acacia</Emphasis> ant-plants

Summary. Myrmecophytic plants use obligate ant mutualists as a constitutive indirect defence mechanism. These plants often produce cellular food bodies (FBs) to nourish their resident ants. Lipids, proteins, and even highly specialised compounds such as glycogen have been reported from FBs, but detailed chemical analyses of FB composition have so far been presented only for Southeast Asian Macaranga and Central American Piper myrmecophytes. Here we report the chemical composition of FBs of five myrmecophytic Acacia (Fabaceae) species from Mexico using HPLC (carbohydrates and proteins) and GC-MS (lipids). Feeding experiments revealed no hints on any use of external food sources by the inhabiting Pseudomyrmex ants. These ants obviously rely completely on FBs and extrafloral nectar provided by their hosts. The total content of nutrients in Acacia FBs was 15-25% of FB dry mass, being much lower than in Macaranga or Piper FBs. Proteins were dominating (8-14 % dm) in Acacia FBs and thus were present in higher amounts than in Macaranga FBs, yet in lower amounts than in Piper. Lipids contributed 1-9 % of dry mass, showing a lower proportion than in FBs of Macaranga or Piper. Carbohydrates made up 3-11 % dm, reaching in most Acacia species the same range as observed in Macaranga and in Piper FBs. Water content was 18-24 % of FB fresh mass, and structural tissue obviously made up a much higher proportion in Acacia FBs than in Macaranga or Piper FBs. Both characters might represent an adaptation to producing FBs unprotected at the leaf tips under dry conditions. Acacia FBs contain all amino acids and all fatty acids that are considered essential for insects, and their contents of lipids and proteins are higher than in the leaves from which they are ontogenetically derived. This indicates a putatively adaptive enrichment of nutritionally valuable compounds in structures functioning as ant-food.     

Sex pheromone components of male <Emphasis Type="Italic">Tirathaba mundella</Emphasis> (Lepidoptera: Pyralidae)

Summary. During peak calling activity by male oil palm bunch moths, Tirathaba mundella Walker (Lepidoptera: Pyralidae), their hairpencils, wings or entire body were extracted in hexane. Gas chromatographic-electroantennographic detection (GC-EAD) analyses of hair pencil extracts revealed four compounds that consistently elicited responses from female antennae. The NMR spectrum of isolated compound 1, and mass spectra and retention indices of compounds 1–4 suggested that they were (3S,6S)-2,2,6-trimethyl-6-vinyl-tetrahydro-pyran-3-ol (1), 4-hydroxy-3-methoxy-benzaldehyde (2, vanillin), 6,10,14-trimethyl-2-pentadecanone (3), and 6,10,14-trimethyl-2-pentadecanol (4). Comparative GC and GC-MS analyses of hair pencils extract and synthetic standards confirmed these structural assignments. Moreover, comparative chromatography of synthetic and hairpencil-isolated 1 on a Cyclodex-B column (which separated the four stereoisomers with baseline resolution) revealed that male T. mundella produce the SS-stereoisomer (SS-1). In field cage bioassay experiments in Palembang, Indonesia, synthetic SS-1 and vanillin in combination, but not singly, attracted female T. mundella. SS-1 plus vanillin were as effective as male T. mundella in attracting females. Compounds 3 and 4 did not enhance the blend's attractiveness. Received October 11 2002; accepted March 14, 2003. R1D=" Correspondence to: Gerhard Gries, email: gries@sfu.ca     

Multiple feeding stimulants in <Emphasis Type="Italic">Sinapis alba</Emphasis> for the oligophagous leaf beetle <Emphasis Type="Italic">Phaedon cochleariae</Emphasis>

Summary. In earlier investigations on host plant discrimination of leaf beetles glucosinolates were described as feeding stimulants for the Brassicaceae specialist Phaedon cochleariae F. (Coleoptera: Chrysomelidae). However, since these findings could not be confirmed in later studies offering 2-propenylglucosinolate in concentrations corresponding to those detected in host plant leaf material, the identification of feeding stimulants of this leaf beetle species remained unclear. In order to investigate which compounds of the host plant Sinapis alba (Brassicaceae) are involved in feeding stimulation, leaf extracts of different polarities were tested in bioassays with adults of P. cochleariae. Number of feeding beetles and net consumption rates were highest on pea leaves painted with methanol extracts of S. alba, whereas weak feeding responses were also detectable for hexane extracts. In subsequent bioassay-guided fractionations of methanol extracts with semi-preparative high performance liquid chromatography, two distinct fractions, one containing glucosinolates and another containing flavonoids, were found to stimulate beetles to feed to variable degrees. Other collected fractions had zero activity. The combination of both active fractions evoked significantly higher consumption rates and stimulated more beetles to feed than fractions tested individually. At least one compound of each fraction, among these the main glucosinolate of S. alba, 4-hydroxybenzylglucosinolate, act additively. Effects of two different naturally-occurring ratios of glucosinolates and flavonoids on the strength of feeding responses were investigated by use of extracts of two sets of host plants differently exposed to radiation. One set was outdoors-exposed, whereas the second set was kept in the greenhouse. However, the feeding behaviour of P. cochleariae was not affected by the significantly different relative compositions of both compound classes in the host material. In conclusion, mustard leaf beetles need a combination of distinct plant metabolites acting in concert for feeding stimulation, whereby the mere presence of these stimulants, but probably not the ratio of involved compounds, determines their feeding response.     

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.     

Genetic analysis of tuna populations,<Emphasis Type="Italic"> Thunnus thynnus thynnus</Emphasis> and<Emphasis Type="Italic"> T</Emphasis>.<Emphasis Type="Italic"> alalunga</Emphasis>

The genetic population structures of Atlantic northern bluefin tuna ( Thunnus thynnus thynnus) and albacore ( T. alalunga) were examined using allozyme analysis. A total of 822 Atlantic northern bluefin tuna from 18 different samples (16 Mediterranean, 1 East Atlantic, 1 West Atlantic) and 188 albacore from 5 samples (4 Mediterranean, 1 East Atlantic) were surveyed for genetic variation in 37 loci. Polymorphism and heterozygosity reveal a moderate level of genetic variability, with only two highly polymorphic loci in both Atlantic northern bluefin tuna ( FH* and SOD- 1*) and albacore ( GPI- 3* and XDH*). The level of population differentiation found for Atlantic northern bluefin tuna and albacore fits the pattern that has generally been observed in tunas, with genetic differences on a broad rather than a more local scale. For Atlantic northern bluefin tuna, no spatial or temporal genetic heterogeneity was observed within the Mediterranean Sea or between the East Atlantic and Mediterranean, indicating the existence of a single genetic grouping on the eastern side of the Atlantic Ocean. Very limited genetic differentiation was found between West Atlantic and East Atlantic/Mediterranean northern bluefin tuna, mainly due to an inversion of SOD- 1* allele frequencies. Regarding albacore, no genetic heterogeneity was observed within the Mediterranean Sea or between Mediterranean and Azores samples, suggesting the existence of a single gene pool in this area.     

Trail pheromones and Dufour gland contents in three <Emphasis Type="Italic">Camponotus</Emphasis> species (<Emphasis Type="Italic">C. castaneus,C. balzani,C. sericeiventris</Emphasis>: Formicidae,Hymenoptera)

Summary. By means of gas chromatography, gas chromatographic coupled mass spectrometry and behavioral analysis the major trail pheromone components from the hindgut of the formicine species Camponotus castaneus, C. balzani and C. sericeiventris were identified. The trail pheromone of C. castaneus is 3,5-dimethyl-6-(1-methylpropyl)- tetrahydro-2H-pyran- 2-one, and that of the other two species is 3,4-dihydro-8-hydroxy-3,5,7-trimethylisocoumarin. Although both compounds release precise trail following behavior in the respective species, the major recruitment signal in the three Camponotus species appears to be formic acid discharged from the poison gland. The composition of the Dufour gland secretions of C. castaneus and C. sericeiventris is similar, but that of the hypertrophied Dufour gland of C. balzani is very different from any other Camponotus Dufour gland content described up to date: it contains large amounts of esters, the major compound of which is octyl hexanoate, which makes up 97% a/a of the total volatiles.     

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.