Data set for diet specific differential gene expression analysis in three Spodoptera moths.

Examination of closely related species pairs is suggested for evolutionary comparisons of different degrees of polyphagy, which we did here with three taxa of lepidopteran herbivores, Spodoptera spp (S. littoralis, S. frugiperda maize (C) and rice (R) strains) for a RNAseq analysis of the midguts from the 3rd instar insect larvae for differential metabolic responses after feeding on pinto bean based artificial diet vs maize leaves. Paired-end (2×100 bp) Illumina HiSeq2500 sequencing resulted in a total of 24, 23, 24, and 21 million reads for the SF-C-Maize, SF-C-Pinto, SF-R-Maize, SF-R Pinto, and a total of 35 and 36 million reads for the SL-Maize and SL-Pinto samples, respectively. After quality control measures, a total of 62.2 million reads from SL and 71.7 million reads from SF were used for transcriptome assembly (TA). The resulting final de novo reference TA (backbone) for the SF taxa contained 37,985 contigs with a N50 contig size of 1030 bp and a maximum contig length of 17,093 bp, while for SL, 28,329 contigs were generated with a N50 contig size of 1980 bp and a maximum contig length of 18,267 bp. The data presented herein contains supporting information related to our research article Roy et al. (2016) http://dx.doi.org/10.1016/j.ibmb.2016.02.006[1].

Diet dependent metabolic responses in three generalist insect herbivores Spodoptera spp.

Adaption to dietary changes is critical in the evolution of host plant ranges in polyphagous insects. We compared three taxa of lepidopteran herbivores from the predominantly generalist genus Spodoptera showing different degrees of polyphagy: Spodoptera littoralis, with a broad host range including both mono- and dicotyledonous plants, and two Spodoptera frugiperda strains [Corn (i.e. maize) (C) and Rice (R)] adapted primarily to different grass species. When feeding on maize we show a lower performance in the broad generalist taxon compared to the grass adapted taxa. Among these taxa, the maize adapted S. frugiperda C-strain generally performed better than the R-strain on maize leaves. On artificial pinto diet, all taxa performed well. Our RNA-Seq analysis of midgut transcriptomes from 3rd instar larvae feeding on maize showed broader transcriptional readjustments in the generalist S. littoralis compared to grass adapted S. frugiperda strains. Substantial alteration in the expression levels of midgut physiological function related transcripts, such as digestive and detoxifying enzymes, transporters, immunity, and peritrophic membrane associated transcripts, existed in all taxa. We found high background expression of UDP-glucosyl transferases, which are known to neutralize maize leaf toxins, in the maize adapted S. frugiperda C-strain, contributing to its fitness on maize compared to the R-strain. Our findings provide evidence for divergent diet specific response of digestive physiology within these Spodoptera taxa. Unexpectedly, the C- and R-strains of S. frugiperda fed on the same diet showed large differences in expression patterns between these two closely related taxa.

Associations between polysubstance use and psychiatric problems in a criminal justice population in Sweden.

BACKGROUND: Polysubstance use is common in substance users, and may complicate their clinical course. This study, in a criminal justice setting in Sweden, examines the association between the number of concurrently used substance types and psychiatric symptoms during 30 days before incarceration, while controlling for background variables such as family history (drug and alcohol problems, psychiatric problems, criminality), demographic data and history of emotional, physical or sexual abuse. METHODS: The data material comprised 5659 criminal justice clients reporting a substance use problem, examined with the Addiction Severity Index. Variables were compared in a multinomial regression analysis, comparing clients reporting one (n=1877), two (n=1408), three (n=956), four (n=443) and five or more (n=167) substance types. RESULTS: The 30-day prevalence of most psychiatric symptoms included in the study (depression, anxiety, cognitive problems, hallucinations, difficulty controlling violent behaviour, suicidal ideation, suicide attempts) was higher in individuals with a higher number of concurrent substance types used. In multinomial regression analysis, while controlling for background variables, these associations remained for concurrent suicidal ideation, cognitive problems, hallucinations and violent behaviour, with the latter two being associated with the higher numbers of substance types. Binge alcohol drinking, tranquilizers, opioids and the number of substance types reported were associated with several of the psychiatric symptoms. CONCLUSIONS: In the present criminal justice setting in Sweden, the use of multiple substance types and concurrent psychiatric symptoms appear to be associated, and a sub-group reporting particularly high numbers of concurrent substance types are particularly likely to report potentially severe psychiatric problems.

Non-host volatiles mediate associational resistance to the pine processionary moth.

An increasing body of evidence indicates that the association between different plant species may lead to a reduction in insect herbivory, i.e. associational resistance. This might be due to a top-down regulation of herbivores by increased numbers of natural enemies or to a disruptive bottom-up influence of lower host plant accessibility. In particular, the richer plant communities release more diverse plant odours that may disturb olfactory-guided host choice and mating behaviour of insect herbivores, i.e. the "semiochemical diversity hypothesis". However, this hypothesis has been rarely tested experimentally in natural habitats, notably forest ecosystems. We tested the effects of non-host volatiles (NHV) on mate and host location by the pine processionary moth (PPM) at the scale of individual pine trees with branches of non-host tree (birch) at their base. Pheromone trap catches and the numbers of larval nests were both reduced by non-host presence under treated pine trees, confirming an associational resistance mediated by NHV. In both males and females, the antenna could detect several birch volatiles, including methyl salicylate (MeSa). MeSa inhibited the attraction of the PPM male to pheromone traps, as did bark and leaf chips from birch trees. Our test of three doses of MeSa at the habitat scale (50 m forest edges) showed that the reduction in the numbers of male PPM captured in traps and in larval nests was MeSa dose-dependent. These results show that odours released by deciduous non-host trees can reduce herbivory by a forest defoliator in conifers, providing support to the "semiochemical diversity hypothesis" as a mechanism of associational resistance.

Suppression of leopard moth (Lepidoptera: Cossidae) populations in olive trees in Egypt through mating disruption.

The leopard moth, Zeuzera pyrina (L.) (Lepidoptera: Cossidae), is a damaging pest for many fruit trees (e.g., apple [Malus spp.], pear [Pyrus spp.] peach [Prunus spp.], and olive [Olea]). Recently, it caused serious yield losses in newly established olive orchards in Egypt, including the death of young trees. Chemical and biological control have shown limited efficiency against this pest. Field tests were conducted in 2005 and 2006 to evaluate mating disruption (MD) for the control of the leopard moth, on heavily infested, densely planted olive plots (336 trees per ha). The binary blend of the pheromone components (E,Z)-2,13-octadecenyl acetate and (E,Z)-3,13-octadecenyl acetate (95:5) was dispensed from polyethylene vials. Efficacy was measured considering reduction of catches in pheromone traps, reduction of active galleries of leopard moth per tree and fruit yield in the pheromone-treated plots (MD) compared with control plots (CO). Male captures in MD plots were reduced by 89.3% in 2005 and 82.9% in 2006, during a trapping period of 14 and 13 wk, respectively. Application of MD over two consecutive years progressively reduced the number of active galleries per tree in the third year where no sex pheromone was applied. In all years, larval galleries outnumbered moth captures. Fruit yield from trees where sex pheromone had been applied in 2005 and 2006 increased significantly in 2006 (98.8 +/- 2.9 kg per tree) and 2007 (23 +/- 1.3 kg per tree) compared with control ones (61.0 +/- 3.9 and 10.0 +/- 0.6 kg per tree, respectively). Mating disruption shows promising for suppressing leopard moth infestation in olives.

Factors associated with the history of attempted suicide.

BACKGROUND: The present study examines a population of criminal justice clients for suspected substance-related problems. AIMS: It aims to identify variables associated with a history of suicide attempt (SA). METHOD: 6,836 clients were interviewed with the Addiction Severity Index (ASI). Attempters were compared to nonattempters regarding substance use, medical/psychiatric status, family history, and social relationships in a stepwise forward logistic regression. RESULTS: Attempters (21%) were more likely to report binge drinking, intake of illicit drugs, injection of drugs, physical and mental illness, problematic family history, and history of being abused. After logistic regression, SA was independently associated with older age, female gender, binge drinking, delirium tremens, injection, overdose, medical problems, psychiatric symptoms, family history of alcohol or psychiatric problems, and sexual, physical, and emotional abuse. The psychiatric and family/social domains (including being abused) most strongly separated attempters from nonattempters. CONCLUSIONS: Family background factors, psychiatric symptoms, severity of substance use, and sexual, physical, and emotional abuse appear to be factors associated with SA among criminal justice clients.

Characteristics of primary amphetamine users in Sweden: a criminal justice population examined with the Addiction Severity Index.

BACKGROUND/AIMS: Characteristics of primary amphetamine, heroin and cocaine users were compared in a criminal justice population. METHODS: 7,085 clients with suspected or reported substance use were studied using the Addiction Severity Index. Variables separating amphetamine, heroin and cocaine users were analyzed in stepwise logistic regression. RESULTS: There were considerably more primary amphetamine users (n = 1,396) than heroin (n = 392) and cocaine (n = 119) users. Amphetamine users were older, a more rural population, and less likely to be non-Nordic immigrants. Compared with heroin, amphetamine use was associated with older age, Nordic origin, nonurban residence, memory/concentration problems, parental alcohol problems, and less history of other opioid use, overdose and detoxification. Compared with cocaine, amphetamine use was associated with older age, Nordic origin, nonurban residence, injecting, tobacco and institution treatment. Overlap of drug use between groups was relatively uncommon. CONCLUSION: This pattern of amphetamine use, common among Swedish criminals, has relatively distinct boundaries from heroin and cocaine use, commonly involves injecting, and differs from other countries. Psychiatric problems and alcohol heredity were common, and evidence-based treatment for amphetamine users is needed. The connection between amphetamine use and criminal behavior is insufficiently understood and should be further addressed.

Factors associated with history of non-fatal overdose among opioid users in the Swedish criminal justice system.

BACKGROUND: Overdose (OD) is a common cause of death in opioid users. Also, many current opioid users report a history of non-fatal OD. The present study aimed to identify factors associated with a history of non-fatal OD. METHODS: A sample of 7085 Swedish criminal justice clients with alcohol or drug misuse was assessed, using the Addiction Severity Index. Subjects reporting use of opioids during the 30 days prior to incarceration were included (n=1113). Relevant variables of misuse pattern, heredity, psychiatric symptoms and previous criminal charges were analysed in a logistic regression model. RESULTS: A history of non-fatal OD was reported by 55% (n=604). The estimated contribution to the variance in OD history was 25% for variables describing misuse pattern, compared to 10% for psychiatric symptoms, 8% for heredity, and 8% for previous criminal charges. The final model included the following variables: history of injection drug use (OR 3.28), history of heroin use (OR 2.87), history of suicide attempt (OR 1.92), history of tranquilliser use (OR 1.91), being born in Sweden or other Nordic countries (OR 1.74), difficulty in controlling violent behaviour (OR 1.68), and paternal alcohol problems (OR 1.57). CONCLUSIONS: Suicide attempts and difficulty in controlling violent behaviour were associated with history of non-fatal OD, independent of variables of misuse pattern. This may indicate a possible association with impulse control disturbances, and may have clinical applications. Country of birth and heredity of alcohol problems also had some influence. As expected, severity of misuse most strongly contributed to history of non-fatal OD.

A model for peak and width of signaling windows: Ips duplicatus and Chilo partellus pheromone component proportions--does response have a wider window than production?

Pheromone communication systems have a reliable signal with a restricted window of amounts and ratios released and perceived. We propose a model based on a Gaussian response profile that allows a quantification of the response peak (location of optimum) and a measure of the peak width (response window). Interpreting the Gaussian curve, fitted by nonlinear regression (NLR), as a standard normal distribution, the peak location equals the mean (it) and the window width equals 2 x the standard deviation (2sigma). The NLR procedure can provide an objective measure for both peak location and width for a wide range of data sets. Four empirical data sets as well as 10 literature data sets were analyzed. The double-spined spruce engraver, Ips duplicatus, was field tested in four populations to find the optimum proportion for attraction to the two male aggregation pheromone components, ipsdienol (Id) and (E)-myrcenol(EM), ranging from 0 to 100% of Id. Tests in Norway and the Czech Republic confirmed the preference of western populations for a blend between 50 and 90% Id. A population in Inner Mongolia showed a preference for traps with the 10 and 50% Id baits. The NLR fitted values for response peak and width (mu; 2sigma) were: Norway 0.64, 0.73; Czech Republic 0.53, 0.73; NE China 0.77, 0.29; and Inner Mongolia 0.33, 0.50. The signal produced by Norwegian field-collected males had a narrower window width (2sigma = 0.12). Males of the maize stem borer, Chilo partellus, were tested in a flight tunnel for their response to variation in the two major female sex pheromone gland components, (Z)- l1-hexadecenal and the corresponding alcohol (OH). Variation of the alcohol in seven levels from 2 to 29% OH showed the highest male response for 17% OH. For all behavioral steps, the peak of male response was near mu = 0.14, while the window width fell from 2sigma = 0.5 to 0.2 for eight sequential behavioral steps from take-off to copulation. Female production had a similar peak location (mu = 0.13) but a narrower width, 2sigma = 0.14. Literature data from other moth species showed similar patterns, with a wider male response relative to the female production windows. Literature data on response to enantiomer ratios in a hymenopteran and to pheromone amounts in a dipteran were also described by our model. In a bark beetle population (Ips pini), with two hybridizing enantiomeric strains, the production peaks were narrower (0.1) than the response peaks (0.5). Thus, it in general, seems that in the pheromone systems analyzed, the width of the response window (2sigma = 0.1 to 0.8) is larger than that of the production window (2sigma = 0.03 to 0.14), irrespective of the sex of the sender.

[Psychosocial survey of drunken drivers within the KAPUBRA project. A new interview technique suitable for matching the right treatment with the right client]. / Psykosocial kartläggning av rattfyllerister inom KAPUBRA-projektet. Ny intervjumetod lämplig för att para ihop rätt behandling med rätt klient.

Three different programs for individuals convicted of drunken driving are being evaluated in a randomized design in collaboration between researchers at the Karolinska Institute and the Prison and Probation Service in Sweden. In the years 1996-1998, 912 clients were interviewed by means of a structured interview, the Addiction Severity Index (ASI), which covers seven problem areas (medical status, alcohol use, employment status, drug use, legal status, family/social and psychiatric status). So far about half of the subjects have been re-investigated two years after leave. Initially, the group being investigated had problems particularly in the areas of criminality and alcohol use. Two years later a positive trend in most of the problem areas could be observed for clients in follow-up.

Olfactory responses of Ips duplicatus from inner Mongolia, China to nonhost leaf and bark volatiles.

Leaf and bark volatiles from nonhost angiosperm trees were tested on Ips duplicatus by gas chromatographic-electroantennographic detection (GC-EAD) and by pheromone-baited traps in Sweden and Inner Mongolia, China, respectively. GC-EAD analysis of the headspace volatiles from fresh bark chips of Betula pubescens revealed trans-conophthorin, two green leaf volatiles (GLVs): 1-hexanol and (Z)-3-hexen-1-ol, and two C8 alcohols: 3-octanol and 1-octen-3-ol, that consistently elicited antennal responses by I. duplicatus. The identification of these EAD-active compounds was confirmed in further GC-EAD recordings with synthetic mixtures. Antennal responses were also found to synthetic (E)-2-hexen-1-ol and linalool, which have been identified from the leaves of nonhost birch and aspen species. No antennal responses of I. duplicatus were found to hexanal, (E)-2-hexenal, and (Z)-3-hexyl acetates. In field trapping experiments, blends of EAD-active green leaf alcohols or C8 alcohols, or transconophthorin alone resulted in significant reductions (27-60%) in the number of I. duplicatus captured compared with pheromone-baited traps. The unsuitable host compound, verbenone (Vn), also significantly reduced trap catches by up to 60% in both experiments. The strongest disruptive effect resulted from the addition of the combination of green leaf alcohols, C8 alcohols, and verbenone to the pheromone trap, which caused an 84% reduction in trap catch. The blend of two green leaf aldehydes plus the acetate increased the trap catches in 1998 and had no negative or positive effects in 1999. Our results suggest that these nonhost volatiles (NHVs) are important olfactory signals used by I. duplicatus in host selection. They may have great significance in developing semiochemical-based management programs for I. duplicatus by reducing or stopping attacks on suitable hosts.

High recaptures and long sampling range of pheromone traps for fall web worm mothHyphantria cunea (Lepidoptera: Arctiidae) males.

Newly emerged males ofHyphantria cunea (Drury) (Lepidoptera: Arctiidae), marked with different fluorescent colors, were recaptured by pheromone trapping. Three Uni-traps, baited with (3Z,6Z)9,10-epoxyheneicosadiene, (9Z,12Z,15Z)octadecatrienal, and (3Z,6Z)9,10-epoxyheneicosa-triene in a 1:10:1 ratio, total 6 mg/dispenser, were placed in a line 15 m apart, perpendicular to the dominant wind direction, and checked after 12, 36, and 60 hr. At dusk, releases of 10-25 males were made over distances from 30 to 250 m, during 4 periods over a soybean field (nonhost plant). Recapture rates were high; of a total of 176 males released, 115 were recaptured with 88% of these within 12 hours. Between 40 and 100% of males were recovered over shorter distances (30-150 m), and between 10-24% at longer distances (200 and 250 m). No other species or unmarked males were captured. The trapping period showed little effect on recaptures. The central trap of the three traps had somewhat higher catches, but the slope of the regression of recapture over distance did not differ among traps. There was a significant decline of recapture over distance (r=-0.56) for catches of individual traps but a large scatter. Summed recaptures per distance gave less scatter and hadr=-0.86, allowing calculation of the maximum sampling range (R s ) after 60 hr as 340 m with a 95% confidence interval of 190-710 m (regression of arcsin √p and √R). The area of sampling, found by integrating the probability function of recapture over distance, from the source to maximumR, was 7 ha. The high recapture rates and the longR,. compared to those in the literature for other taxa, indicate that pheromone traps are highly efficient sampling devices in this species.

Variation of enantiomeric composition of α-pinene in norway spruce,Picea abies, and its influence on production of verbenol isomers byIps typographus in the field.

The enantiomeric composition of α-pinene in individual Norway spruce trees [Picea abies (L.) Karst.] was determined on a chiral GC column after stereoselective hydroboration-oxidation followed by a reaction with isopropyl isocyanate to form the carbamate derivative. The enantiomeric composition varied considerably between trees of different genetic origin. There was a strong correlation between the chirality of α-pinene in host spruce trees and thecis/trans ratio of verbenols found in the hindguts of the bark beetleIps typographus (L.) infesting the trees.

Inhibition of attraction to aggregation pheromone by verbenone and ipsenol : Density regulation mechanisms in bark beetleIps typographus.

The semiochemicals verbenone (Vn), ipsenol (Ie), and ipsdienol (Id), present in late phases of host colonization, have been implicated as qualitative "shut-off" signals regulating attack density. Combinations of the three chemicals were released in pipe traps together with the aggregation pheromone components 2-methyl-3-buten-2-ol (MB) andcis-verbenol (cV) at different levels and in different ratios to MB + cV, and with two spacings of traps to test for possible effects on reducing catch at traps baited with aggregation pheromone. When they were released with the attractants Vn and Ie (alone or together) decreased the mean catch significantly at the higher release rates used (1 mg/day). Id alone or together with Vn at low release rates (0.1 mg/day), with the attractants, increased catch somewhat. A dose-response test of Vn, with the attractants held constant, showed a decline in catches, down to about < 10% of the control, at ratios of Vn to cV between 1∶1 and 150∶ 1. A larger spacing (25 m) of traps gave a stronger response to change in doses of Vn and MB + cV than a smaller (6 m) spacing. The sex ratio was more skewed towards females when two or three inhibitors were present and at higher doses of Vn. It is suggested that Vn could be the most important density-regulating signal in the natural system, as release of Vn from galleries is larger and starts earlier than that of Id and Ie.

Individual variation in aggregation pheromone content of the bark beetle,Ips typographus.

The total amounts of, and proportions among, components of the aggregation pheromone produced byIps typographus were found to vary considerably among individuals excised from attacks on standing spruce trees. Chemical analyses of 392 individual male beetles were made by GC-MS. Both unmated and mated males had log-normal frequency distributions in their content of the pheromone components 2-methyl-3-buten-2-ol (MB) andcis-verbenol (cV), since a large fraction of males had a low content. The amount of MB in male hindguts varied independently of cV and the other oxygenated monoterpenes, while the amount of cV covaried with the other pinene alcohols and showed a variation between beetles from different spruce trees. Mated males had, on average, lower amounts of MB than unmated, while the average content of cV in mated males varied with the resin content of their host trees. Ipsdienol and ipsenol were only found in mated males, but in less than 40% and 10%, respectively, of these mated males. Even-aged males exposed to α-pinene in the laboratory showed slightly less variation in the amounts of verbenols, and the variations in ratio between cV and tV were similar to those among males attacking the same spruce tree.

Field response of spruce bark beetle,Ips typographus, to aggregation pheromone candidates.

Six compounds previously identified from hindguts of unmated maleIps typographus (L.) during host colonization: 2-methyl-3-buten-2-ol (MB),cis-verbenol (cV),trans-verbenol (tV), myrtenol (Mt),trans-myrtanol (tM), and 2-phenylethanol (PE), were tested for their attractivity in the field with a subtractive method. The amounts of MB and cV released from a pipe trap were similar to those given off from the commercial bait Ipslure as well as that from a Norway spruce tree,Picea abies (L.) Karst., under mass attack. The blend of the compounds became nonattractive when either MB or cV was subtracted, while subtraction of any of the other four compounds had no effect. Addition of ipsdienol (Id) to the blend did not significantly increase the attraction. In a second comparative test, the addition of three compounds as a group (tV + Mt + PE) to MB + cV again had no effect on the attraction, but the addition of Id increased the catch somewhat. Addition of host logs to a bait releasing MB + cV at a rate lower than in previous experiments did not influence the attraction to pipe traps. Sticky traps containing natural pheromone sources (50 males in a log), which released 1-5 mg/day of MB as determined by aerations with deuterated MB as internal standard, were less attractive than a synthetic source releasing similar amounts of MB.

Differences in attraction to semiochemicals present in sympatric pine shoot beetles,Tomicus minor andT. piniperda.

The chemical ecology of host- and mate-finding in the pine shoot beetles,Tomicus minor andT. piniperda, was studied in southern Sweden. Beetles were collected in the field from defined attack phases on Scots pine. Using gas chromatography-mass spectroscopy, a number of oxygen-containing monoterpenes, e.g., 3-carene-10-ol, myrtenol,trans-verbenol, and verbenone, were identified from hindgut extracts of both sexes of both species. Compared toT. minor,T. piniperda contained additional compounds and in larger amounts. The amounts were highest in both species at the time when the beetles had bored into contact with the resin-producing xylem-phloem tissue. The synthesis of (1S,6R)-3-carene-10-ol by photooxidatipn of (+)-(1S,6R)-3-carene is described. In comparative electroantennogram (EAG) measurements on males and females of both species, the most active of the tested compounds wastrans-verbenol. Laboratory bioassays of walking beetles showed thatT. piniperda was attracted to uninfestèd pine logs.T. minor was more strongly attracted to pine logs infested with females than to uninfested pine logs, indicating a female-produced aggregation pheromone. Field tests confirmed thatT. piniperda was strongly attracted to pine logs. The attraction ofT. minor to logs was significant only when logs were combined with racemictrans-verbenol and (1S,6R)-3-carene-10-ol.T. minor was also attracted to a combination of these monoterpene alcohols alone. We suggest that host and mate location inT. piniperda is achieved by means of a kairomone composed of host monoterpenes, whileT. minor utilizes a primitive pheromone synergized by host odors. Evolution of host colonization strategies of the two beetles are discussed.

Attraction to pheromone sources of different quantity, quality, and spacing: Density-regulation mechanisms in bark beetleIps typographus.

The density of bark-beetle colonization of a tree could be regulated by a quantitative effect of the pheromone signal from beetles in the tree (cessation of release of attractive pheromone) or by a qualitative effect (production of pheromone components inhibiting attraction). The quantitative hypothesis was tested onIps typographus by varying the release rate of the two known attractive compounds, 2-methyl-3-buten-2-ol (MB) and (4S)-cis-verbenol (cV). The highest number of beetles were captured at traps with the highest release rates. The catch was nearly proportional to the release of MB and cV at a distance between traps of 12 m or more. At 6-, 3-, and 1.5-m distances between traps deployed in a triangular arrangement there was still a good discrimination between release rates, but relatively more beetles, especially males, were caught on the blank. The lower release rates caught an equal sex ratio while the highest release rate caught only about 30% males. The qualitative hypothesis was tested by releasing the suspected inhibitors ipsdienol (Id) and ipsenol (Ie), from traps in the same amounts as cV. Only small effects were noted forI. typographus. However, the competitorI. duplicatus was attracted to Id and inhibited by Ie, while the predatorThanasimus formicarius was attracted to both compounds. On the other hand, when the ratio of Id or Ie to cV was 10∶1 or 0.1∶1 rather than 1∶1, they affected the numbers ofI. typographus attracted. A small amount of Id combined with the attractants increased trap catch, while large amounts of Id or Ie decreased attraction, especially when combined. Attack density regulation is modeled as an effect of both quantitative and qualitative mechanisms acting in sequence.

Quantitative variation of pheromone components in the spruce bark beetleIps typographus from different attack phases.

Ips typographus beetles were collected in the field, separated into eight attack phases (from beetles walking on the trunk of a tree under attack to those excavating gallery systems with a mother gallery longer than 4 cm), and immediately frozen in liquid nitrogen. 2-Methyl-3-buten-2-ol,cis- andtrans-verbenol, verbenone, myrtenol, trans-myrtanol, ipsenol, ipsdienol, and 2-phenylethanol were quantified from excised hindguts against an internal standard, heptyl acetate, in the extraction solvent. Methylbutenol, the pinene alcohols, and 2-phenylethanol showed the same pattern of variation between attack phases in males, with the largest amounts present before accepting females and then a fast decline. Ipsenol and ipsdienol were not detected in males before the females were accepted, and the amounts increased when the females start their egg laying. Verbenone occurred only in trace amounts. The beetles were sampled from five Norway spruce trees (Picea abies) of differing resin flow. The correlations between the nine pheromone components and five major host monoterpenes in the gut showed that the variation in the amount of methyl-butenol, ipsenol, and ipsdienol could not be explained by the variation in the amounts of host monoterpenes. In contrast over 80% of the quantitative variation ofcis-verbenol,trans-verbenol, and myrtenol was explained by the amount of α-pinene. The nine pheromone components from 36 individual males were also quantified. Both methylbutenol andcis-verbenol showed a large variation in both amounts and proportions. Females containedtrans-verbenol and traces of most other components found in males. When accepted by the male, they also contained a female-specific compound, ß-isophorone. Behavioral and biosynthetic implications of the results are discussed.