Pheromone Biology Research Articles

Biology of a putative male aggregation-sex pheromone in Sirex noctilio (Hymenoptera: Siricidae).

A putative male-produced pheromone has recently been described for the global pest of pines, Sirex noctilio, but field-activity has not been demonstrated. This study aimed to investigate the pheromone biology of S. noctilio in more detail. Specifically, we i) analysed effluvia and extracts for additional compounds by gas chromatography coupled with electro-antennographic detection (GC-EAD), mass spectrometry (GC-MS) and two dimensional time of flight mass spectrometry (GC X GC TOF MS), ii) conducted dose-response experiments for putative pheromone components, iii) determined the site of synthesis/ storage of the putative pheromone and iv) determined the release rate of the putative pheromone from males and three types of lures. A blend of four compounds was identified, including the previously described (Z)-3-decenol and (Z)-4-decenol, and two new compounds (Z)-3-octenol and (Z)-3-dodecenol. All compounds elicited a response from both male and female antennae, but the strength of the response varied according to sex, compound and dose tested. (Z)-3-Decenol and (Z)-3-octenol at lower and higher doses, respectively, elicited larger responses in males and females than the other two compounds. (Z)-3-Octenol and (Z)-4-decenol generally elicited larger female than male antennal responses. The site of synthesis and/or storage in males was determined to be the hind legs, likely in the leg-tendon gland. The relative release rate of the major compound by male wasps was shown to be 90 ± 12.4 ng/min, which is between 4 and 15 times greater than that observed from typical lures used previously. These observations are consistent with the hypothesis that these compounds may mediate lek formation in S. noctilio males and lek location in females.

The Pheromone Frontalin and its Dual Function in the Invasive Bark Beetle Dendroctonus valens

The red turpentine beetle, Dendroctonus valens LeConte, is one of the most destructive invasive forest pests in China, having killed more than 6 million pines since its first outbreak in 1999. Little is known about D. valens pheromone biology and no aggregation pheromone has yet been identified. Analysis by gas chromatograph/mass spectrometer of volatiles collected from live beetles in China showed that female beetles produce frontalin and males do not. Olfactory assays in the laboratory showed that males were attracted to frontalin at a wide range of concentrations, whereas females were attracted to it at a narrow range of concentrations. In field trials, 3-carene, a monoterpene kairomone from a pine tree selected to host the beetles attracted both sexes, and when frontalin was added, the total number of beetles captured increased by almost 200%. However, increasing concentrations of frontalin significantly decreased the percentage of female beetles trapped. These results suggest a new role of frontalin as an aggregation pheromone in addition to a female-produced sex pheromone, which was previously shown in a North American population. The dual functions of the pheromone frontalin produced by D. valens females, as well as its ecological significance for overcoming host resistance, are discussed.

Research output in pheromone biology: a case study of India

Analyses the growth and development of pheromone biology research productivity in India in terms of publication output as reflected in Science Citation Index (SCI) for the period 1978---2008. It includes 330 publications from India, including 285 articles, 22 notes, 18 reviews, 4 letters and 1 conference paper, from 200 institutions. About 9.4 % of publications is contributed by Indian Institute of Technology, Kanpur followed by Bhabha Atomic Research Centre, Bombay (7.27 %). All the papers published by Indian researchers have appeared in journals with impact factors between 0.20 and 4.14. About 24.24 % of authors contributed single articles. The growth rate of publications varied from 0.30 to 9.09 % per year. The annual growth rate was highest in the year 2006 at 9.09 %. The study reveals that the output of pheromone biology research in India has gradually increased over the years.

Insect pheromone research in South America

Insect pheromone research has a long and rich history built up primarily by studies conducted in the Northern hemisphere. Not surprisingly, these studies have largely targeted species relevant to these regions of the world, for the most part agricultural and forest pests. Pheromone research in South American countries came a few decades behind, albeit their strong dependence in agriculture and therefore in pest management. In the last 20 years, a combination of economic, environmental and technical factors have come together to generate a small but rising number of chemical ecologists working in pheromone chemistry and biology in South America. In this article we summarize the results of this trend. We review pheromone studies in which South American scientists have participated in collaboration with foreign scientists, mostly chemistry groups, as well as the ever-growing number of studies carried out completely within the region. We have focused mainly in research involving the characterization of pheromones from native species, which involve the most important insect orders, namely Lepidoptera, Coleoptera, Heteroptera and Hymenoptera. We also present a simple meta-analysis including geographical distribution, trends in collaborative or independent work, and a 20-year evolution of published articles in the field. Finally, we emphasize the importance of a coordinated effort to further promote the growth of this field in Latin America, through the endorsement of international collaborations within the region. Such goal would be facilitated by a regional academic organization, which would in turn initiate the occurrence of regular scientific meetings.

Re-analysis of pheromone-mediated aggregation behaviour of European earwigs

AbstractAggregation of the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), is known to be, in part, a response to aggregation pheromone. However, many aspects of pheromone biology remain unknown or controversial. In two-choice experiments with field-collected specimens in a still-air olfactometer, we determined that female, male, and juvenile F. auricularia all produce and respond to aggregation pheromone and that the pheromone is perceived by means of olfaction. Various sources (or extracts thereof) reportedly containing or emitting pheromone (including the insects’ integument, tibiae, or fecal excreta) did not induce significant responses. Our data suggest that none of these sources contains all or any of the essential pheromone components. These controversial results may be due to differences in (i) experimental procedures, such as single- or grouped-insect bioassays, or (ii) developmental stages of the bioassay insects. It is conceivable that juveniles and adults produce and respond to different components of aggregation pheromone.

Early-summer pheromone biology of Galerucella calmariensis and relationship to dispersal and colonization

Galerucella calmariensis (Coleoptera: Chrysomelidae) has become an effective biological control agent for purple loosestrife ( Lythrum salicaria). A male-produced aggregation pheromone was recently identified in this mostly univoltine beetle, and attractiveness to both sexes was demonstrated in the spring, when overwintered adults reproduce. Nothing was known about whether the pheromone functioned for the summer generation, when some of the beetles may undergo a brief reproductive period before entering diapause. Our results showed that both sexes of the beetles responded strongly to synthetic pheromone during summer, and males collected in the field during early summer and held under the prevailing photoperiod were able to emit pheromone. These males mated readily with field-collected females, and fertile eggs were laid, indicating a reproductive role for the pheromone during early summer. Males emitted pheromone well only when fed L. salicaria. Adult beetles were able to persist on marginal hosts such Salix interior and Rosa spp., but almost no pheromone was detected. Emission ceased and resumed as host access changed, even after a long interruption. Attractiveness of L. salicaria foliage was investigated. Six “green-leaf” volatiles were identified that were readily sensed by beetle antennae, but a preliminary synthetic blend of these was not attractive in the field. A model is presented for pheromone-mediated host colonization after dispersal, and relationships among pheromone biology, diapause, photoperiod, and host quality are discussed. Practical uses for the pheromone are noted, and new information is given about longevity of pheromone lures.

Electrophysiological and Behavioral Responses of <I>Dendroctonus valens</I> (Coleoptera: Curculionidae: Scolytinae) to Candidate Pheromone Components Identified in Hindgut Extracts

Abstract The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is a serious, exotic pest of pines in China that was introduced from North America during the 1980s. Relatively little is known of its pheromone biology. In our studies, gas chromatographic and mass spectral (GC-MS) analysis of hindgut volatiles revealed the presence of trans-verbenol, cis-verbenol, myrtenol, myrtenal, and verbenone, which are frequently reported pheromone compenents of Dendroctonus spp. Subsequently, bioactivity trials were conducted in the laboratory and field for three oxygenated monoterpenes: trans-verbenol, myrtenol, and myrtenal. Electroantennogram tests indicated that D. valens possess olfactory sensitivity for these three compounds. Additionally, walking D. valens displayed anemotaxis toward all three compounds in a Y-tube olfactometer. In field tests, both trans-verbenol and myrtenol significantly increased catches of beetles in traps baited with host kairomone [a blend of thr...

Electrophysiological and Behavioral Responses ofDendroctonus valens(Coleoptera: Curculionidae: Scolytinae) to Candidate Pheromone Components Identified in Hindgut Extracts

The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is a serious, exotic pest of pines in China that was introduced from North America during the 1980s. Relatively little is known of its pheromone biology. In our studies, gas chromatographic and mass spectral (GC-MS) analysis of hindgut volatiles revealed the presence of trans-verbenol, cis-verbenol, myrtenol, myrtenal, and verbenone, which are frequently reported pheromone compenents of Dendroctonus spp. Subsequently, bioactivity trials were conducted in the laboratory and field for three oxygenated monoterpenes: trans-verbenol, myrtenol, and myrtenal. Electroantennogram tests indicated that D. valens possess olfactory sensitivity for these three compounds. Additionally, walking D. valens displayed anemotaxis toward all three compounds in a Y-tube olfactometer. In field tests, both trans-verbenol and myrtenol significantly increased catches of beetles in traps baited with host kairomone [a blend of three host monoterpenes: (+)--pinene, (−)-&bgr;-pinene and (+)-3-carene]. These conspecific-produced attractants may have a role in D. valens chemical communication. Although the appropriateness of classifying these compounds as pheromones is still uncertain, these compounds clearly have potential for use in management of this serious pest.

Wake up and smell the conspecific!

Mammals regulate their behavior using odor cues called pheromones. These compounds are detected and recognized by neurons in the accessory olfactory system. New electrophysiological recordings in behaving mice by Luo, Fee and Katz reveal aspects of pheromone biology and how these stimuli are represented by single neurons.

Does pheromone biology of Lambdina athasaria and L. pellucidaria contribute to their reproductive isolation?

Recently, 7-methylheptadecane and 7,11-dimethylheptadecane have been reported as sex pheromone components of both spring hemlock looper (SHL), Lambdina athasaria, and pitch pine looper (PPL), Lambdina pellucidaria. Our objective was to test the hypothesis that SHL and PPL are reproductively isolated, in part, through species specificity in: (1) absolute configuration of pheromone components, (2) diel periodicity of pheromonal communication, and/or (3) seasonal flight period. In coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized (7S)- and (7R)-7-methylheptadecane [7S; 7R] as well as (7S,11S)-, (7R,11R)-, and (meso-7,11)-7,11-dimethylheptadecane [7S,11S; 7R,11R; meso-7,11], only 7S and meso-7,11 elicited responses by male SHL and PPL antennae. In field experiments, male SHL and PPL were attracted only to lures containing 7S plus meso-7,11. In hourly recordings of trap-captured males, SHL and PPL in their respective habitats were trapped between 24:00 and 03:00 hr. Capture of both SHL and PPL in pheromone-baited traps throughout June indicated overlapping seasonal flight periods. These findings of identical absolute configuration of pheromoal components, diel periodicity of pheromonal communication, and overlap of seasonal flight periods support synonymy of SHL and PPL. Finite taxonomic classification of PPL and SHL must await careful assessment of further criteria, such as morphometrics, molecular comparisons and ecological analyses.

Sex Pheromone Components of Nettle Caterpillar, Setora nitens

Gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts of female nettle caterpillars, Setora nitens, revealed four compounds that consistently elicited responses from male moth antennae. Retention indices on three fused silia columns (DB-5, DB-23, and DB-210) of two EAD-active compounds were almost identical to those of (E)-9-dodecenal (E9–12 : Ald) and (E)-9,11-dodecadienal (E9,11–12 : Ald), two pheromone components previously identified in congeneric Setothosea asigna. However, comparative GC, GC-EAD, and GC-mass spectrometry of extracted S. nitens compounds and authentic standards revealed that the candidate pheromone components were (Z)-9-dodecenal (Z9–12 : Ald) and (Z)-9,11-dodecadienal (Z9,11–12 : Ald). The two other EAD-active compounds in pheromone gland extracts proved to be the corresponding alcohols to these aldehydes. In field-trapping experiments in Tawau, Malaysia, synthetic Z9–12 : Ald and Z9,11–12 : Ald at a 1 : 1 ratio, but not singly, attracted male S. nitens. Attractiveness of these two aldehydes could not be enhanced through the addition of their corresponding alcohols. Whether these differences in pheromone biology and chemistry between S. nitens and S. asigna are sufficient to prevent cross-attraction of heterospecific males or whether nonpheromonal mechanisms are required to maintain reproductive isolation is currently being studied.

Intra- and Interspecific Aggregation Responses of Locusta migratoria migratorioides and Schistocerca gregaria and a Comparison of Their Pheromone Emissions

Gregarious nymphs of Schistocerca gregaria and Locusta migratoria migratorioides are often seen to march together in common bands in the field. In the present study, the intraspecific aggregation responses of nymphal and older stages of the two insects were compared with their interspecific responses. Unlike S. gregaria, L. m. migratorioides shows a lesser pattern of stage and sex differentiation in its aggregation pheromone biology. Thus, although fifth-instar nymphs did not respond significantly to the adult pheromone, adults responded significantly to the nymph pheromone. No cross-stage aggregative responses occur in S. gregaria. In the adults of S. gregaria, production of the pheromone is male-specific; in L. m. migratorioides both sexes induced a significant level of aggregation from conspecifics. Aggregation assays between corresponding stages of the two species showed stronger interaction between the nymphal stages than between the adults and account for the frequent occurrence of mixed hopper bands in the field. GC-EAD studies of volatiles of nymphal and adult stages by using antennal preparations from both species also showed significant interspecies reactivities. GC-MS analyses showed that of S. gregaria nymphal pheromone components (C6 and C8 to C10 straight-chained aldehydes and acids and the fecal phenols, guaiacol and phenol), the acids and phenols constitute the common components of nymphal stages. Phenylacetonitrile, the major component of S. gregaria adult aggregation pheromone, is present in L. m. migratorioides nymphal volatiles, albeit at a lower level. Unlike S. gregaria adult pheromone blend, which is made up wholly of benzene derivatives, the volatile emissions of L. m. migratorioides adults is dominated by aliphatic aldehydes and alcohols. The possible role of cross-aggregation effects in mutually facilitating phase transformation of the two species is discussed.

Sex pheromone production in Callosobruchus maculatus (Coleoptera: Bruchidae): Electroantennographic and behavioral responses

Behavioral and electroantennogram (EAG) assays were used to determine rhythmicity and dynamics of the sex pheromone biology of the bruchid beetle, Callosobruchus maculatus (F.). Beetles were sexually active throughout the photophase. Virgin females entrained to a 16:8 L:D light cycle emitted more sex pheromone during the first half of photophase than during the second half of photophase or during scotophase. Sex pheromone production increased from day 0 to day 3 of adult life, and then decreased as females grew older. Availability of garbonzo beans, one of the larval food and adult oviposition hosts, to females did not stimulate sex pheromone production. Mating resulted in a reduction in post-coital sex pheromone production. Mated females, however, regained attractiveness to males and this attractiveness increased from day 1 to day 3 after first mating when females had been mated at day 0 after emergence. ( Z)-3-Methyl-2-heptenoic acid (Z32A) and ( Z)-3-methyl-3-heptenoic acid (Z33A), two compounds implicated as sex pheromone components for C. maculatus, both elicited male EAG and behavioral responses in the beetles; however, Z33A elicited larger responses than Z32A. Binary mixtures of the two compounds were more effective than either compound alone.

Effect of male and female age on the mating success of the obliquebanded leafrollerChoristoneura rosaceana (Lepidoptera: Tortricidae) under different ecological conditions

The present study was undertaken to test the hypothesis that male and female age, as well as temperature, can affect the mating success ofChoristoneura rosaceana, given the role that these two factors play in the pheromone biology of this species. In the laboratory, the mating success of females generally declined linearly with age, whereas in males, it increased during the first 3 days and then decreased. The decline in female mating success was more pronounced under warm than cool thermocycles, while the changes observed in males were greater under fluctuating than constant temperature regimes. The onset time of mating was unaffected by male age, however, older females always mated earlier than younger ones, with the advance being more pronounced at cool than warm temperatures. Similar results were also obtained under field conditions. When a single 3-day-old male was provided with 0-, 3-, and 5-day-old females simultaneously, older females obtained mates significantly more often than younger individuals at all temperatures, indicating that calling earlier may afford a reproductive advantage to older females. At both constant temperatures, the time spent mating was longer in older than in younger females, but not under fluctuating thermocycles. Very young and very old males generally spent more time in copula than middle-aged individuals both at constant temperatures and under the warm thermocycle. Under the cool thermocycle, the duration of mating was considerably prolonged at all ages, which could increase the risk of predation.

E-MYRCENOL: A NEW PHEROMONE FOR THE PINE ENGRAVER, IPS PINI (SAY) (COLEOPTERA: SCOLYTIDAE)

AbstractE-Myrcenol reduced catches of the pine engraver, Ips pini (Say), to ipsdienol-baited, multiple-funnel traps in a dose-dependent fashion. The sex ratio was unaffected by E-myrcenol treatments. Lures containing E-myrcenol in ethanol solution failed to protect freshly cut logs of lodgepole pine from attack by I. pini. Rather, I. pini preferentially attacked logs treated with devices releasing E-myrcenol and ethanol, over nontreated, control logs. Our results demonstrate that E-myrcenol is a new pheromone for I. pini, and emphasize the importance of understanding basic pheromone biology before utilisation of a semiochemical in forest pest management.

Sex pheromone released as an aerosol by the moth Pyrrharctia isabella

In most moth species the female sex pheromone evaporates from the surface of a gland that is everted and exposed to the air1–3. Considerable attention has been directed towards the pheromone biology of arctiid moths because (1) the female pheromone gland is atypical, consisting of a branched tube or pair of tubes that is invaginated into the haemocoel and opens dorsally between the eight and ninth abdominal segments4–5, and (2) pheromone release behaviour ('calling') is also atypical, involving rhythmic protrusion and retraction of the abdominal tip4. This pulsing action, which alternately exposes and occludes the orifice of the pheromone gland, is thought to result in the expulsion of discrete puffs of pheromone in the vapour phase4. We now report that calling females of the arctiid species, Pyrrharctia isabella, emit a visible stream of liquid droplets. This emission consists solely of the sex pheromone, with no incidental material or inert carrier material present in the aerosol. The quantities of pheromone released in this way are the largest known for a female moth. Also this is the first report of an airborne sex-attractant released as a liquid.

Pheromone biology of the Mediterranean fruit fly (Ceratitis capitata Wied.) with emphasis on the functional anatomy of the pheromone glands and antennae as well as mating behaviour

AbstractIn calling males of Ceratitis capitata Wied. (Dipt., Trypetidae), the sex pheromone is released from the anal glands through ducts to the surface of the expanded anal ampulla. The epithelium of the anal glands of sexually mature males comprises ramified as well as columnar cells, of which the former are likely to secrete the pheromone. The anal gland cells of newly emerged males are undifferentiated and fail to produce pheromone. Within the first week of adult life the pheromone level increases steeply, whereupon it remains relatively high until senescence.The sex pheromone is perceived by sensilla trichodea which abundantly occur on the apical region of the funiculus (third antennal segment) of the female's antenna and which are ˜ 103 times more sensitive to male odour than to female odour. In addition to numerous cuticular spines, the female's funiculus also comprises sensilla basiconica, sensilla clavata, sensilla styloconica and an olfactory pit. The funiculi of female and male antennae are provided by the same types of sensilla.Unlike pheromone perception, the sight of a calling male fails to induce sexual attraction, while combination of both stimuli is synergistic and elicits the complete sequence of the courtship behaviour in females. The origin of the genus and species names of the Mediterranean fruit fly is also discussed.ZusammenfassungPheromonbiologie der Mittelmeerfruchtfliege (Ceratitis capitata Wied., Dipt., Trypetidae) nebst einem Beitrag zur Kenntnis der Pheromondrüsen und Füblersensillen sowie des BalzverhaltensDas Sexualpheromon männlicher Ceratitis capitata wird während der Lockstellung (Abb. 1) von den Analdrüsen ausgeschieden (Abb. 3, 4), der ausgestülpten Analampulle (Abb. 1, 3) zugeführt und von deren Oberfläche abgegeben. Das Analdrüsenepithel geschlechtsreifer Männchen besteht aus Verbänden zylindrischer sowie verästelter Zellen (Abb. 5, 6a), und diese sind höchstwahrscheinlich der Sekretionsort des Sexualpheromons. Das Analdrüsenepithel frisch geschlüpfter Männchen ist noch undifferenziert (Abb. 6b) und gibt auch kein Sexualpheromon ab. Während der ersten Woche nach dem Schlupf steigt der Pheromongehalt der Männchen verhältnismäßig steil an, um dann bis zu einem Alter von ~4 Wochen relativ hoch zu bleiben (Abb. 14).Die Antenne der Mittelmeerfruchtfliege (Abb. 7) besteht aus einem relativ kleinen Scapus, einem sockelartigen Pedicellus, einem ~320 μm langen Funiculus (3. Fühlersegment) sowie einer fadenförmigen, dreigliedrigen Arista (~720 μm lang). Die Funiculi beider Geschlechter sind an der Oberfläche mit zahlreichen, abgebogenen Dornen sowie mit Sensilla trichodea (Abb. 9), Sensilla basiconica, Sensilla clavata (Abb. 11), Sensilla styloconica (Abb. 12a, b) und je einer Riechgrube (Abb. 7) besetzt. Unterhalb der Cuticula der Funiculi befindet sich eine 30 bis 60 μm dicke Schicht primärer Sinneszellen, deren Axone im Fühlernerv vereinigt sind (Abb. 8). Die ‐ mit zahlreichen Poren ausgestatteten ‐ Sensilla trichodea (Abb. 10) reagieren auf Männchenduft mindestens 103fach empfindlicher als auf Weibchenduft (Abb. 13). Die Pheromonwahrnehmung erfolgt an den ‐ besonders am oberen Teil des Weibchenfuniculus zahlreich vorhandenen ‐ Sensilla trichodea (Abb. 9).Der Anblick eines Männchens in Lockstellung rief bei weiblichen, ungepaarten C. capitata keine Paarung hervor (Abb. 15), wogegen Erblicken eines lockenden Männchens und gleichzeitige Wahrnehmung dessen Pheromons auf die Weibchen synergistisch wirkte und die ‐ zur Paarung führende ‐ Verhaltenssequenz auslöste (Abb. 16). Ursprung der Gattungs‐ und Artnamen der Mittelmeerfruchtfiiege sowie deren Schadwirkung an Zitrusfrüchten wurden diskutiert.

Pheromone biology of the tobacco beetle (Lasioderma serricorne F., Anobiidae) with notes on the pheromone antagonism between 4S,6S,7S‐ and 4S,6S,7R‐serricornin

Pheromone biology of the tobacco beetle (<i>Lasioderma serricorne</i> F., Anobiidae) with notes on the pheromone antagonism between 4S,6S,7S‐ and 4S,6S,7R‐serricornin

IPS pini: The basis for interpopulational differences in pheromone biology

Ips pini from Idaho (ID) produce (−)-ipsdienol and respond to it in the laboratory.I. pini from New York (NY) produce (+) and (−)-ipsdienol in a 65∶35 ratio and respond much more strongly to the (+) than to the (−) enantiomer. Response byI. pini-ID to (−)-ipsdienol in the laboratory was inhibited by (+)-ipsdienol, while the field response byI. pini-NY was optimal to a 50:50 mixture of (+) and (−)-ipsdienol. This differential production and response to enantiomers of ipsdienol is sufficient to account for populational specificity observed in earlier experiments and confirmed by our current work. Reciprocal hybrids of the NY and IDI. pini populations did not differ in their patterns of attraction and response; those of both types of F1 were similar to NY beetles. Thus, it appears that (+)-ipsdienol is produced by the hybrids and is necessary for their maximum response, but this supposition was not tested. The genes controlling the pheromone biology ofI. pini are not sex linked. Since previous whole-antenna and single-cell electrophysiological data show that the receptor systems of the two populations are virtually identical, response behavior seems to be governed by the central nervous system rather than by the characteristics of the olfactory receptors.