In this overview we compare the significance and evolutionary history of two interacting biological systems, the conifer-feeding bark beetles (Coleoptera: Scolytidae) and their host conifers (Gymnospermae: Coniferales and Taxales). Isoprenoid natural products play key roles in the aggregation of the bark beetles and in the defence of the conifers. Our approach is to couple the most recent advances in the biochemical and molecular literature on these systems with ecological and behavioral data to compare monoterpenoid pheromone biosynthesis in scolytids with monoterpene biosynthesis in conifers. This synthesis reveals and evaluates the evolutionary redundancy occurring in the biochemical systems of the insect and host. Although host monoterpenes may be utilized directly or as derivatives in aggregation by scolytids, oxygenated monoterpenes that are behaviorally active for scolytids have been rarely identified from their coniferous hosts. De novo monoterpenoid biosynthesis in the Scolytidae, a process that is likely to be rare among metazoans, is substantially different from monoterpene biosynthesis in the conifers. The pathways appear to be shared only at the late-stage reactions that follow the formation of isopentenyl diphosphate. Little is known of the regulation of monoterpene biosynthesis in conifers, but scolytids positively regulate monoterpenoid biosynthesis using a sesquiterpenoid hormone, juvenile hormone, which does not occur in conifers. Little is known of the subcellular site of synthesis of monoterpenoids in scolytids, but conifer monoterpene biosynthesis is compartmentalized in the plastids, which do not occur in scolytid cells. In addition to bark beetles and conifers, the vertebrate model presents one of the few systems in which isoprenoid synthesis has been studied enough to provide a meaningful comparison. Possible unique features of monoterpenoid pheromone biosynthesis in scolytids relative to isoprenoid biosynthesis in vertebrates include the following: (1) a monoterpenoid end product; (2) a hypothetically scolytid-specific prenyl transferase (= geranyl diphosphate synthase) that catalyzes the condensation of two five-carbon (C5) units, but does not catalyze additional condensation reactions with the C5 monomelic unit; (3) a scolytid-specific monoterpene (myrcene) synthase; and (4) a scolytid-specific, transcriptional-level sesquiterpenoid isoprenoid regulatory mechanism. Features 2 and 3 may be shared with conifers. This review also updates the 1985 landmark scientific paper by John Borden by listing the references and species of coniferophagous Scolytidae for which aggregation pheromones have been identified since 1985.

Platypus bordenisp.nov. and Platypus namosianussp.nov. are described from the island of Viti Levu, Fiji, breeding in Syzygium ?curvistylum (Gillespie) Merr. and Perry (Myrtaceae). A key is provided to nine species of Platypodidae from the South Pacific islands. A review of the economic importance of Platypodidae in the region and possible management strategies is provided.

Seven species of mites (Acari: Tarsenomidae) were associated with two local outbreaks of the southern pine beetle, Dendroctonus frontalis Zimmerman, in Chiapas, Mexico; three of these species were new records for Mexico and Central America. The morphology and phoretic behavior of these mites differed little between the western and southern populations from the United States. One major difference was that the hyperphoretic ascospores of the southern pine beetle mycangial fungus, Ceratocystiopsis sp. (Ophiostomataceae), were common in sporothecae of Tarsonemus krantzi Smiley and Moser (Acari: Tarsonemidae) and Tarsonemus ips Lindquist in Chiapas, Mexico, whereas the ascospores of the blue stain fungus, Ophiostoma minus (Hedgcock) H. and P. Sydow (Ophiostomataceae), were rare; this situation in the southern United States is reversed. The paucity of behavioral and morphological differences between the two southern pine beetle populations and the relevant historical climatology suggest that the appearance of D. frontalis in the southern United States may be a recent event.

Pissodes terminalis Hopping attacks the current year's leader growth of lodgepole pine, Pinus contorta var. latifolia Engelmann (Pinaceae), causing its death or defects such as crooks, forks, and multiple leaders (Maher 1982). In southern British Columbia, the duration of the growing season can vary greatly among ecosystems as evidenced by the presence of several biogeoclimatic zones and subzones (Lloyd et al. 1990). In most of these zones, P. terminalis overwinters as fourth instar larva and adult emergence occurs the following season, thus requiring more than 1 year to complete its life cycle. However, in warmer ecosystems and in some silviculturally manipulated stands, its life cycle can be univoltine (Maclauchlan 1992; Cameron and Stark 1989). Knowledge of laboratory temperature requirements for P. terminalis development would enable future comparisons with field temperature accumulations and insect development.

The female-produced sex pheromone blend of the pandora moth, Coloradia pandora pandora Blake, a pest responsible for periodic defoliation of pine forests in the western United States, has been identified. The pheromone consisted of a mixture of E10,Z12-hexadecadienal, E10,Z12-hexadecadienyl acetate, and E10,E12-hexadecadienyl acetate. All three components were essential for optimal attraction. E10,Z12-Hexadecadienol, tentatively identified in trace amounts in pheromone gland extracts, elicited strong responses from male antennae in coupled gas chromatography – electroantennogram analyses but had no apparent effect as a pheromone component at physiologically relevant levels. Hexadecanal, octadecanal, and hexadecyl acetate also were identified in extracts of female pheromone glands but elicited no responses from male antennae, nor did they appear to be components of the attractant blend. In field trials, each trap baited with the optimized three-component blend of E10,Z12-hexadecadienal, E10,Z12-hexadecadienyl acetate, and E10,E12-hexadecadienyl acetate captured an average of more than 40 male moths per night.

The effect of semiochemical interruptants was examined for Ips latidens (LeConte) and Ips pini (Say) using artificial trees (tall-traps) consisting of an array of seven Lindgren multiple-funnel traps suspended vertically on a rope ladder. S-(+)-Ipsdienol reduced the numbers of I. latidens captured in (±)-ipsenol-baited funnel traps relative to funnel traps immediately above them and to control tall-traps. The combination of (±)-exo-brevicomin and cis- and trans-verbenol reduced the numbers of I. pini captured in (±)-ipsdienol-baited funnel traps relative to funnel traps immediately above them and to control tall-traps. These results provide support for semiochemical-based pest-management tactics that utilize a point source of interruptant at the base of a tree while noting limitations in behavioural effects and efficacy.

Bark beetles were trapped for two summers in a mature stand of lodgepole pine, Pinus contorta var. latifolia Engelmann (Pinaceae), infested by mountain pine beetle, Dendroctonus ponderosae Hopkins, near Princeton, British Columbia. Columns of flight-barrier traps were suspended next to uninfested live trees and from dead brood trees containing new adult beetles. The brood trees had been treated in the previous year with mountain pine beetle pheromone bait alone or in combination with Ips pini Say (Coleoptera: Scolytidae) pheromone bait and subsequently killed by mountain pine beetles. A total of 3376 individuals from 30 species of Scolytidae were captured in the traps. Most of the species for which lodgepole pine is a nonhost or occasional host were captured in low numbers (one or two specimens). The most abundant species (> 30 individuals) were D. ponderosae, I. pini, Hylurgops porosus LeConte, Pityogenes knechteli Swaine, and Trypodendron lineatum Olivier. The treatments affected captures of mountain pine beetles and I. pini but only in the year when trees were either unbaited or baited simultaneously for mountain pine beetle and I. pini. There were significant differences among the five most abundant species in the mean heights and mean Julian dates of capture. In addition to host condition requirements, these differences reflected partitioning of the food and habitat resource and competitive interactions among species. There was no interaction between treatment and trap height, indicating that treatment did not affect the height distribution of flying beetles.

Host specificity of Pissodes strobi (Peck) from different geographic regions and genetic divergence of local host-associated weevil populations were studied in a series of experiments. Pacific coast P. strobi reared from Sitka spruce, Picea sitchensis (Bong.) Carr (Pinaceae), were unable to successfully colonize either eastern white pine, Pinus strobus L. (Pinaceae), or western white pine, Pinus monticola Dougl. ex D. Don., in a forced-infestation study on interplanted trees in New York. Reproductively mature field-collected P. strobi from British Columbia did not oviposit on eastern white pine in New York, but field-collected New York weevils successfully reproduced in Sitka spruce leaders in British Columbia. Unacceptability of eastern white pine for western P. strobi was shown to be under genetic control, rather than influenced by prior host experience on Sitka spruce. Pissodes strobi originating from Sitka spruce but reared one generation in the laboratory on the exotic Norway spruce, Picea abies (L.) Karst., were also unable to utilize eastern white pine as a host in a forced-infestation experiment in the field. Population genetic studies using allozyme electrophoresis found that P. strobi populations occurring on different host species within 2 km of each other had significant differences in allele frequencies in three out of four cases. These results suggest that P. strobi can exist as small breeding populations that can facilitate host specialization. Applied research on host resistance against P. strobi could target mechanisms that prevent western P. strobi from utilizing nonhosts such as eastern and western white pines.

We investigated the factors responsible for changes in abundance of the spruce bud moth, Zeiraphera canadensis Mut. and Free. (Lepidoptera: Tortricidae) in one unmanaged and several managed (i.e., planted) young white spruce, Picea glauca (Moench.) Voss (Pinaceae), stands in northern New Brunswick, Canada. Spruce bud moth densities declined when one stand closed (branches from neighbouring trees overlapped) and had already declined in another similarly aged closed stand, but remained high on 8- to 22-year-old open-grown white spruce. Both the intrageneration survival rate and the egg-to-moth ratios increased when population densities increased, and generally decreased, although the egg-to-moth ratio fluctuated, during the population decline in a managed stand. Increases in intrageneration survival rates of spruce bud moth on 5- to 10-year-old trees were due to increased larval or pupal survival. Crown closure explained 76 and 81% of the variability in larval and intrageneration survival, respectively, in four managed stands. The strong inverse relationship between larval survival and degree of crown closure resulted in statistically significant but spurious relationships between larval survival and larval density and between larval survival and tree age. A reduction in larval survival occurring as degree of crown closure increased was the most important factor influencing decreases in intrageneration survival at the beginning of population decline. Increases in the egg-to-moth ratio during the population increase, and decrease during population decline, suggested that dispersal behaviour and (or) realized fecundity of females also contributed to annual changes in population.

Field studies were conducted in the United States and Canada to determine the response of the white pine cone beetle, Conophthorus coniperda (Schwarz), and the red pine cone beetle, Conophthorus resinosae Hopkins, to two potential inhibitors, conophthorin and verbenone, of pheromone communication. Trap catches of male C. coniperda and C. resinosae were significantly reduced and generally declined with increasing concentrations of conophthorin in traps baited with the pityol, a female-produced pheromone. Verbenone did not significantly reduce trap catches of C. coniperda. Conophthorin, but not verbenone, significantly reduced cone attacks by C. coniperda when placed near cone clusters. The twig beetles, Pityophthorus cariniceps LeConte and Pityophthorus puberulus (LeConte), responded to traps with pityol and α-pinene baits alone or with conophthorin. Thanasimus dubius (F) (Coleoptera: Cleridae) was attracted to the pityol and α-pinene, but conophthorin had no effect on attraction of this generalist bark beetle predator. Verbenone significantly reduced trap catches of T. dubius in pityol-baited traps.

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that is regulated by federal quarantines in the United States and Canada. Mark–release–recapture experiments were performed with infested logs coated with fluorescent powder to determine if overwintering beetles in logs would leave a mill yard if infested logs were transported to sawmills in uninfested areas. Overwintering T. piniperda adults were marked with powder as they emerged in spring. Dispersal studies were conducted in four simulated mill yards and five operational sawmills to determine whether T. piniperda would colonize only the log pile in which they overwintered, fly to nearby log piles, or disperse beyond the mill yard. Each simulated mill yard was composed of 36 uninfested red pine logs, Pinus resinosa Ait. (Pinaceae), and 12 α-pinene-baited funnel traps set up to 100 m from a central release pile of six uninfested red pine and nine infested logs of Scotch pine, Pinus sylvestris L. At the five operational sawmills, baited funnel traps were set up to 400 m outside of each mill yard. Overall, 482 T. piniperda galleries were found on the experimental logs recovered from the four simulated mill yards combined. Tomicus piniperda adults dispersed and attacked the most distant logs at 100 m from the release point in the simulated mill yards. Likewise, adults were captured in baited funnel traps at distances up to 230 m in simulated mill yards and 250 m around operational sawmills. Although numbers of recaptured T. piniperda were generally low, in all cases some adults dispersed outside the mill yards despite the presence of abundant suitable breeding material. Therefore, logs containing overwintering adults pose a risk of spreading T. piniperda if not processed prior to initiation of spring flight.

Our objective was to test the hypothesis that late-instar nymph, male, and (or) female German cockroaches, Blattella germanica (L.), use sonic signals for intraspecific communication. A digital-recording system was assembled that consisted of a computer equipped with data-acquisition hardware and software, microphones sensitive to sonic and ultrasonic frequencies, and speakers capable of emitting sonic and ultrasonic sound. Sound was repeatedly recorded from groups of five nymphs, five virgin males, or five virgin females. Click-type sounds were commonly present in recordings from nymphs, and consisted of sound pulses of about 10-ms duration and peak frequencies of 7, 9, 11, and 14 kHz. Similar "clicks" were found in recordings from females. In replicated binary choice arena bioassays with individual laboratory-reared insects, played-back "clicks" from nymphs or females or computer-generated artificial clicks attracted nymphs but not males or females. These results provide the first evidence that sonic signals are part of the complex B. germanica communication system.

The effects of lineatin enantiomer ratios, lineatin release rate, and trap length on catches and the flight periods of three sympatric species of Trypodendron Stephens were investigated in field bioassays using multiple-funnel traps. The ambrosia beetle, Trypodendron betulae Swaine, was caught in similar numbers in baited traps and blank control traps, showing that this species does not respond to lineatin. Our results confirmed that Trypodendron lineatum (Olivier) is attracted only to (+)-lineatin. Trypodendron rufitarsus (Kirby) and Trypodendron retusum (LeConte) were shown to utilize lineatin and like T. lineatum were caught only when (+)-lineatin was present. These results indicate that lineatin does not govern reproductive isolation among these three species. There was no effect by (+)-lineatin release rate within the range tested. The flight of T. rufitarsus commenced earlier and ceased before the peak of the T. lineatum flight, suggesting that temporal separation may be an important component of reproductive isolation between these two species. The flight period of T. retusum was similar to that of T. lineatum. Host odours may aid in reproductive isolation of these two species. Enantiomer blend did not significantly affect sex ratio in any species; however, sex ratio differed among species, indicating that different species responded differently to the traps or that natural sex ratios differ. Catches of T. rufitarsus and T. retusum increased with trap length when pheromone release per trap was held constant and when release was held constant relative to trap length. Trap length and release rate did not affect sex ratio.

Analyses of pentane extracts of frass, whole beetles, and volatiles trapped on Porapak-Q from Pityophthorus Eichhoff spp. fed on Pinus radiata D. Don demonstrated that (E)-pityol [2-(1-hydroxy-1-methylethyl)-5-methyltetrahydrofuran] was produced by male Pityophthorus carmeli Swaine, female Pityophthorus nitidulus (Mannerheim), and female Pityophthorus setosus Blackman. (E)-(−)-Conophthorin) [(5S,7S)-(−)-7-methyl-1,6-dioxaspiro[4.5]decane] was produced by male P. carmeli and male P. nitidulus. Only the (2R,5S)-(+) stereoisomer of (E)-pityol was produced by male P. carmeli and female P. setosus. In field bioassays in central coastal California, P. setosus was attracted to (E)-(+)-pityol, whereas P. carmeli responded only to a combination of (E)-(−)-conophthorin and (E)-(+)-pityol. Male P. setosus and female P. carmeli responded to these treatments with larger numbers than opposite-sex conspecifics. (E)-(−)-Conophthorin alone did not attract species of Pityophthorus but significantly reduced catches of P. setosus to (E)-(+)-pityol. Lasconotus pertenuis Casey (Coleoptera: Colydiidae) and Ips mexicanus (Hopkins) (Coleoptera: Scolytidae) were attracted to a combination of (E)-(−)-conophthorin and (E)-(+)-pityol, and showed a trend for attraction to all (E)-(−)-conophthorin-containing treatments. (E)-(−)-Pityol was neither attractive nor interruptive for any taxon. (E)-(+)-Pityol is shown to be an aggregation pheromone component for P. carmeli and P. setosus. (E)-(−)-Conophthorin functions as a pheromone component for P. carmeli and may also function as a synomone that decreases competition of P. carmeli and P. nitidulus with P. setosus and as a kairomone for L. pertenuis. These semiochemicals have been useful in studying relationships among twig insects and the pathogen Fusarium circinatum (Nirenberg and O’Donnell), causal agent of pitch canker disease in P. radiata.

Among the three species of potential hosts for Phoracantha semipunctata (F.) (Eucalyptus propinqua Deane and Maiden, Eucalyptus maculata Hook., and Angophora costata (Gaertner) Britten (all Myrtaceae)) tested in southeast Queensland, there were no differences in number of beetle galleries initiated by neonate larvae, larval mortality, larval survivorship, or parasitism rates. The larvae that survived to pupation in E. maculata produced significantly larger galleries, indicating larger larval size, than did larvae in either of the other two host species tested. There were no differences in the size of parasitized larvae among the three species of potential hosts. The results suggest that there were differences among species in host suitability for larval development but that females were either not able to distinguish those differences during oviposition or the selection for discrimination was not strong relative to the associated potential ecological costs.

Females of Alydus eurinus (Say) release an attractant pheromone from their metathoracic scent gland. Conspecific males and, to a lesser extent, females and nymphs were attracted to blends containing the female-specific essential pheromone components 2-methylbutyl butyrate and (E)-2-methyl-2-butenyl butyrate, whereas individuals of Alydus pilosulus Herrick-Schaeffer were not attracted. When attacked, however, alydid adults emit chemicals for defense—butyric and hexanoic acids in A. eurinus—from the metathoracic scent glands. Mimicry is actually the first line of defense for most broad-headed bugs, including the common North American species studied here, whose nymphs are remarkable ant mimics and whose adults strongly resemble spider wasps (Hymenoptera: Pompilidae). The possibility that disparate heteropterans (Hemiptera) produce sexual pheromones in their metathoracic scent glands must be considered in future pheromone research on heteropterans, especially for species with the specialized lines of defense indicated by aposematism or mimicry.

We tested six behavioral chemicals, pityol, conophthorin, 4-allylanisole, verbenone, 2-hexenol, and α-pinene, in a series of field trials directed at six combinations of Conophthorus Hopkins – Pinus L. spp. (Pinaceae) in sites distributed across North America. Beetle – host tree combinations included Conophthorus ponderosae Hopkins on Pinus ponderosa Laws., C. ponderosae on Pinus monticola Dougl., Conophthorus conicolens Wood on Pinus pseudostrobus Lindl., Conophthorus teocotum Wood on Pinus teocote Schl. & Cham., Conophthorus coniperda (Schwarz) on Pinus strobus L., and Conophthorus resinosae Hopkins on Pinus resinosa Ait. trans-Verbenol was tested only on C. resinosae on P. resinosa. Traps baited with pityol caught more beetles than unbaited traps in nearly all of the assays, and conophthorin consistently inhibited male beetle response to pityol for all species tested. Behavioral responses of species of Conophthorus to α-pinene appeared to parallel host phylogeny, inasmuch as beetles using Haploxylon pines as hosts utilized α-pinene as a synergist for the beetle-produced pityol, whereas beetles using Diploxylon pines as hosts did not. α-Pinene was a synergist for pityol in C. ponderosae on P. monticola and C. coniperda on P. strobus, but not for species of Conophthorus on any other pines tested. Conophthorus ponderosae on P. ponderosa was the only beetle–host combination tested where verbenone was a synergist for pityol, but this effect was not consistent in all years of testing. It was also the only beetle–host combination in which 4-allylanisole was a repellent. For all other beetle–host combinations, verbenone was neutral to slightly repellent and 4-allylanisole was either synergistic or neutral in pityol-baited traps. Promising synergists and interruptants/repellents were identified for implementation in pest-management regimes, including conophthorin as an interruptant for all species of Conophthorus tested, 4-allylanisole as an interruptant for C. ponderosae on P. ponderosa, α-pinene as a synergist for pityol in all species tested on Haploxylon pines, and 4-allylanisole as a synergist for pityol in C. conicolens and C. coniperda.

Brood production and shoot feeding by the pine shoot beetle, Tomicus piniperda (L.), were studied over 3 years in naturally infested plantations of Scots pine, Pinus sylvestris L. (Pinaceae), near Guelph and Waterloo, Ontario, using trap-logs. Adult beetles produced a single brood in 1996 and 1997 and two broods in 1999. Galleries for the first brood were all initiated under the bark over a 2- to 3-week period from mid-April to early May. The lone second brood occurred in early June. In all years, eggs were present by late April, larvae by mid-May, pupae by late June, and new adults by mid-July. Complete development (egg–pupa) required 12–13 weeks for the first brood and 8 weeks for the second brood. First-brood adults emerged over a 2- to 3-week period from early to mid-July in all years, with second-brood adults emerging in late July. The effective heat sums (degree-days (°d) > developmental-threshold temperature) were 77–79 °d for eggs, 267–293 °d for the larval stage, 139–152 °d for the pupal stage, and 43.2 °d for the pre-emergence stage, depending on the developmental-threshold temperature used. The total heat sums for the first brood (1249.8 ± 73.3 °d > 0 °C) were larger that those required for the second brood (856.4 ± 124 °d > 0 °C). Overall, values for first-brood development were similar to those calculated for European and Asian populations. Pine shoots in the upper tree crowns were used by adult beetles for maturation feeding between late July and late September in both 1995 and 1996. The re-emerging parental adults fed upon 1-year-old shoots, whereas newly emerging adults fed primarily upon current-year shoots. The beetles appeared to move to overwintering sites in late October to November, and no adults were found overwintering in shoots on the trees or the ground. Our results parallel those obtained by others under similar climatic conditions in Europe, and can be used to improve the management and regulation of this species as it becomes established in our native pine forests.

The aggregation pheromone of Pityogenes hopkinsi Swaine was identified; it is a three-component mixture, comprising chalcogran, cis-verbenol, and ethyl dodecanoate. Ethyl dodecanoate is new as a bark beetle pheromone component. Chemical analyses (GC–MS) were made on hindgut extracts from unmated and mated males and mated females collected in the field during colonization of Pinus strobus L. (Pinaceae). Aerations from the naturally colonized logs were also analyzed to quantify the released amounts of the pheromone components, a necessary preliminary step to making up biologically relevant doses for field bioassay. Beetles reared from infested host material in the laboratory were introduced into logs of P. strobus, and the production and release of pheromone components in relation to attack phase and "mating status" were described. In general, unmated males increased their production of chalcogran and ethyl dodecanoate until females were admitted, after which production ceased. A field subtractive bioassay showed that chalcogran was the key pheromone component, synergized by different compounds for the two sexes. Females exhibited their strongest response to a mixture of chalcogran and ethyl dodecanoate, whereas cis-verbenol was the synergist for male response. Male-produced 1-hexanol had an inhibitory effect on male attraction to the aggregation-pheromone blend.

Leaf and bark volatiles from non-host birches, Betula pendula Roth. and Betula pubescens Ehrh. (Betulaceae), and aspen, Populus tremula L. (Salicaceae), were tested on spring-dispersing Tomicus piniperda (L.) and Tomicus minor (Hart.) by gas chromatographic – electroantennographic detection (GC–EAD) and by attractant-baited traps in southern Sweden. GC–EAD analysis of the head-space volatiles from fresh bark chips of B. pendula revealed two green leaf alcohols, 1-hexanol and (Z)-3-hexen-1-ol, that consistently elicited antennal responses by T. piniperda and T. minor. Further analyses with synthetic mixtures showed that the antennae of these two Tomicus species also responded to other green leaf alcohols, such as (E)-2-hexen-1-ol found from the non-host leaves, and C8-alcohols, 3-octanol and 1-octen-3-ol, from bark of non-host birches and aspen. No antennal responses of the Tomicus species were observed to green leaf C6-aldehydes and C6-acetate or to non-host bark volatiles like trans-conophthorin, benzaldehyde, salicylaldehyde, and benzyl alcohol. In field trapping experiments, blends of electrophysiologically active green leaf alcohols or C8-alcohols resulted in reductions (> 60%) in the number of T. piniperda captured compared with that for the kairomone-baited trap. When these two blends were combined, trap catch was further reduced (90%), which was not significantly different from that for the blank control. Neither the blend of two green leaf aldehydes plus the acetate nor the bark compounds trans-conophthorin or benzyl alcohol reduced trap catches. Tomicus minor had a response pattern similar to that of T. piniperda. Hylurgops palliatus (Gyll.) (Coleoptera: Scolytidae) was attracted to the combination of kairomone and verbenone but not to kairomone and was not affected by the blends of green leaf volatiles. Our results suggest that selected leaf–bark C6-alcohols and the bark C8-alcohols may have potential in developing semiochemical-based management programs against both pine shoot beetles by repelling them from suitable breeding and feeding sites.