Southern pine beetle (SPB), Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), is a serious native pest of pines (Pinus spp.) that ranges from the eastern USA to Nicaragua. Chemical signals, including pheromones and host tree odors, mediate mass attacks necessary for host tree colonization. Responses by SPB to the pine oleoresin volatile, 4-allylanisole, have been highly variable in past experiments, but factors governing this variation are unknown. In three experiments, we investigated how trapping methods and lure composition may influence 4-allylanisole's effects on the behavior of SPB and the clerid predator, Thanasimus dubius (F.) (Coleoptera: Cleridae) in Georgia, USA. Multiple, simultaneous alterations to trapping methods (including trap type, isomers of pheromone component brevicomin in lures, and positioning of release devices) caused significant changes in attraction enhancement by 4-allylanisole for SPB but not T. dubius. 4-Allylanisole increased attraction of SPB only when both components of the SPB aggregation pheromone, frontalin and endo-brevicomin, were present, whereas 4-allylanisole increased T. dubius catches with frontalin alone. The enhancement of SPB catches by 4-allylanisole's was greater when host odor alpha-pinene (a synergist), but not beta-pinene, was present. These three compounds were redundant in enhancing attraction of T. dubius. Our data suggest that multiple, interacting factors influence the attractive effects of 4-allylanisole for SPB. This semiochemical has the potential to substantially improve detection of cryptic populations of SPB, and thus it may enhance monitoring in the newly invaded, northeastern USA where the species may be difficult to detect.

The eastern larch beetle, Dendroctonus simplex LeConte, colonizes tamarack, Larix laricina (Du Roi) K. Koch, and has become a major tree killer in parts of its temperate North American range. To fill existing gaps in knowledge of this insect’s pheromone system, we used gas chromatography-mass spectrometry to perform quantitative studies of pheromone production by unfed beetles of both sexes, founding females excised from newly established galleries in a tamarack log, and both sexes excised post-pairing. To identify olfactory stimulants and thereby possible, additional pheromone components, we performed gas chromatography-electroantennographic detection analyses with antennae of both sexes exposed to volatiles collections from the beetles. We also exposed unfed male and female beetles to juvenile hormone III (JH III) to identify pheromone components regulated through this mechanism. Both female and male beetles exhibited antennal responses to 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane (frontalin), 3-methylcyclohex-2-en-1-ol (seudenol), and 3-methylcyclohex-2-en-1-one (MCH) in volatiles of solitary mining females. Within approximately 24 h of joining a male, female production of seudenol and MCH largely ceased while production of frontalin continued. Unfed females produced no more than minute amounts of pheromone, and application of JH III induced production of frontalin from some females but not seudenol or MCH. Unfed males and males exposed to JH III produced almost no volatiles, whereas paired males produced minute amounts of frontalin (possibly an artifact), no seudenol or MCH, and some oxygenated monoterpenes. We found that timing of production of certain pheromone components was inconsistent with their known activity.

The eastern 5-spined ips, Ips grandicollis (Eichhoff), is native to the eastern USA and is an invasive pest of exotic pines (Pinus spp.) in Australia. It can kill stressed trees and transmit ophiostomoid fungi that cause blue staining of wood and reduce the commercial value of timber. Ips grandicollis uses semiochemicals produced by conspecifics to locate mates, while semiochemicals from competitors and nonhosts may reduce the reaction to attractants. To investigate methods to exploit these behaviors in a management strategy, we evaluated the impact of 12 potential semiochemical inhibitors of I. grandicollis attraction using traps baited with aggregation pheromone (ipsenol and cis-verbenol) in the beetle's native (northeast Georgia and central Louisiana, USA) and invasive (southeast Queensland, Australia) ranges over 2 yr. In the first trapping experiment (2022 to 2023), 2 semiochemicals (2-phenylethanol and methyl eugenol) significantly decreased attraction to the lure by 35% to 39% in the native range and 55% to 56% in the invasive range. Camphor reduced trap catches in Louisiana (26%) and Queensland (41%) but not in Georgia. In the second experiment (2023 to 2024), the inhibitory effects of methyl eugenol, 2-phenylethanol, and camphor were tested alone and in binary and ternary combinations. The binary combination of methyl eugenol and 2-phenylethanol reduced attraction by 66% in Georgia. However, such differences were not observed in Louisiana. The ternary combination of these compounds reduced attraction by 76% in the invasive range. Further research on these inhibitors could lead to a sustainable push-pull management strategy for protecting pine trees and log stacks from I. grandicollis attacks.

The 19 species of Dendroctonus bark beetles native to North America include several of the most significant biotic mortality agents of conifers in this region, and they have impacted millions of hectares of forest in recent decades. Semiochemical attractants play several vital roles in the biology of these insects including host finding, host assessment, and mate finding. They are key to the virulence of these insects, since they mediate the mass attacks that enable killing and reproduction within healthy trees. These attractants consist of combinations of thirteen identified pheromone components in three primary chemical classes and at least ten host-associated compounds dominated by monoterpene hydrocarbons in host defensive resin. Due to their potential for use in pest management technologies, semiochemical attractants for Dendroctonus have received extensive research into their chemical compositions and effects on insect behavior. This paper is intended as a synthesis of this research over the past 60 years as well as a critical examination of approaches to investigation of this topic and interpretation of experimental results. Its purpose is to assist practitioners in formulating suitable attractive lures for use in applications and identify gaps in knowledge of the semiochemistry of Dendroctonus that should be addressed if the practical potential of attractants is to be fully realized.

Monoterpenes in the resin of host trees are important host-location and -selection signals for conifer-infesting bark beetles and can increase or reduce responses to aggregation pheromones. Research on this interaction has been largely limited to collocated release points of the semiochemicals; however, sources are often separated in nature. I performed a trapping experiment to investigate whether distance between semiochemical release points influences how host monoterpene alpha-pinene affects Ips avulsus (Eichhoff) (Coleoptera: Curculionidae) response to its aggregation pheromone (ipsdienol and lanierone). High release (8 g/day) of alpha-pinene from a pheromone-baited trap caused a reduction in catches, but the same release of alpha-pinene from 4 m away significantly increased catches relative to pheromone alone. A low release (0.06 g/day) of alpha-pinene with either arrangement had no effect. Hence, a host odour released at rates sufficient to deter I. avulsus responses to its pheromone may nevertheless enhance attraction if the release point is sufficiently displaced from the pheromone source. The result suggests that, for I. avulsus, the semiochemical alpha-pinene may influence host finding and close-range assessment of host suitability in different ways. Operational lure formulations for some species of bark beetle might be improved by separating pheromone and host odour components or by adding a displaced host odour device.

The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), is a major pine tree killer in North and Central America. In the southeastern USA, responses by D. frontalis to its aggregation pheromone can be substantially increased by at least three host odours: the monoterpenes alpha ‐ and beta ‐pinene, and the phenylpropanoid 4‐allylanisole. We executed three trapping experiments to assess the influence of 4‐allylanisole release rate on aggregation behaviour of D. frontalis and to evaluate the compound as an adjuvant for the operational monitoring lure for D. frontalis . Addition of devices releasing 4‐allylanisole at any of three rates (4.8, 48, and 500 mg/day measured at mean 21°C) increased D. frontalis attraction to a pheromone lure, both in the presence and in the absence of an alpha ‐pinene lure. The increase was 5‐ to 50‐fold with a positive dose response up to the highest tested release rate of 4‐allylanisole. Attraction of an associate, the black turpentine beetle, Dendroctonus terebrans (Olivier), and a major D. frontalis predator, Thanasimus dubius (F.) (Coleoptera: Cleridae), was also significantly increased by 4‐allylanisole. A device releasing 4‐allylanisole at 0.05 g/day (at mean 23°C) increased attraction of D. frontalis to the current operational monitoring lure (which uses alpha ‐ and beta ‐pinene as the host odour component) approximately 4‐fold, but it did not increase attraction to a lure with turpentine as the host odour component (used in a former operational monitoring lure). Additionally, we observed none of the attraction‐inhibiting effects that were previously reported for 4‐allylanisole with D. frontalis . It is possible that the addition of 4‐allylanisole to the D. frontalis lure might allow detection of beetles at lower population densities and, if so, aid in earlier detection of populations invading the northeastern USA in response to climate change. This possibility should receive further investigation.

Aggressive bark beetles colonize and kill healthy conifers through pheromone-mediated mass aggregation. In several species, the focal point of aggregation moves progressively from mass-attacked 'focus trees' to adjacent, unattacked 'recipient trees', resulting in infestation growth. This process, termed 'switching', is hypothesized to be mediated in whole or in part by antiaggregation pheromones released by beetles as colonization intensifies on a focus tree. We tested this hypothesis with the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), by using a windvane apparatus that maintained an unbaited, black, cylindrical trap (surrogate for a recipient tree) continuously 4 m downwind from an identical trap baited with synthetic aggregation attractant (surrogate for a focus tree). In two of three replicated trials, addition of pheromone components with antiaggregation activity, endo-brevicomin or verbenone, to the upwind trap caused a significant but small (<15%) increase in the proportion of beetles caught in the downwind trap. In one of two trials with endo-brevicomin, this shift was associated with a significant reduction in catches in the downwind trap and an overall reduction in catches of beetles by the trap pair. This suggests that an inhibitor-induced increase in landings on the recipient relative to the focus tree may be countered by the radial effects of the inhibitor, which at sufficiently high release may reduce responses to both the focus and recipient tree. We discuss spatial factors that might govern the role of antiaggregation pheromones in stimulating infestation growth as well as additional factors that likely govern switching behavior.

Climate change is altering the geographic distribution of many species, including numerous forest insect pests, with the potential for severe impacts to forest ecosystems. The southern pine beetle (Dendroctonus frontalis), one of the world's most persistently destructive forest pests, has extended its distribution towards the north, while impacts within its historic range in the southeastern United States have diminished, indicating that a range shift may be occurring. This pattern could be explained by the hypothesis of climatic envelopes if summers in the southern part of the range are warming about as much as winters in the northern part of their range. Here, we tested whether the southeastern United States is becoming too hot for D. frontalis even as the northeastern United States has become climatically permissive. We measured effects of heat on insect survival, and characterized the thermal environment of D. frontalis, including estimating the frequency of potentially lethal heat waves and testing whether the intensity or duration of heat waves has increased over the past 80 years. We found that temperatures warm enough to kill D. frontalis larvae, pupae, or callow adults have been rare or absent and that there has been no change in the duration or severity of heat waves in the southern pine forest region over the last 80 years. Therefore, alternative explanations for the reduced activity of D. frontalis within its historic range must be considered. The broad conclusions are not restricted to D. frontalis because they flow from an asymmetry in climate change: at least for now in eastern North America, the coldest winter temperatures have been becoming less extreme without summer heat becoming more extreme. This creates broad potential for northward range expansions without expectation of corresponding contractions in southern distribution limits.

We investigated geographic variation in the semiochemistry of major disturbance agents of western North American pine forests, Dendroctonus brevicomis Le Conte and Dendroctonus barberi Hopkins (Coleoptera: Curculionidae: Scolytinae), species separated by the Great Basin in the USA that until recently were synonymous. At 15 sites in the western USA and northern Mexico, beetle populations were examined to determine (1) pheromone production by solitary, mining females, (2) male electroantennogram amplitudes in response to known semiochemicals for the genus, or (3) relative attractiveness of two female-produced pheromone components (endo- and exo-brevicomin) and two host odors (alpha-pinene and myrcene) to beetles in the field. Compared to female beetles collected east of the Great Basin (D. barberi), western females (D. brevicomis) produced a consistently higher proportion of, and male antenna were correspondingly more sensitive to, the exo- than the endo-isomer of brevicomin. With the exception of one sampling location (where no preference was observed), beetles west of the Great Basin were more attracted to exo- than endo- brevicomin trap lures, whereas eastern beetles displayed the reverse preference. In contrast, there was not a consistent difference between these populations regarding relative attraction or olfactory response to myrcene or alpha-pinene, although some geographic variability was evident. These data show that the semiochemical systems of D. brevicomis and D. barberi have diverged and corroborate genetic and morphological evidence that they are distinct, allopatric species.

The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), is among the most destructive bark beetle pests of pines (Pinaceae) of the southeast and mid-Atlantic United States of America, Mexico, and Central America. Numerous volatile compounds can stimulate or reduce attraction of the beetle, but efforts to incorporate these into effective, practical technologies for pest management have yielded mixed results. Attractants have been incorporated into lures used in monitoring traps that are employed operationally to forecast outbreaks and detect emerging populations. The attraction inhibitor, verbenone, shows efficacy for suppressing southern pine beetle infestations but has not yet been adopted operationally. No effective semiochemical tree protectant has been developed for the beetle. We discuss complexities in the chemical ecology of the beetle that likely have impeded research and development of semiochemical management tools, and we describe basic science gaps that may hinder further progress if not addressed. We also report some supporting, original experimental data indicating (1) that a verbenone device can inhibit the beetle's response to sources of attractant in a radius of at least several metres, (2) similar olfactory responses by the beetle to both enantiomers of verbenone, and (3) that pheromone background can cause conflicting results in semiochemical field tests.

Abstract Sirex noctilio F. (Hymenoptera: Siricidae) is a major exotic pest of pines (Pinus spp.) in the Southern Hemisphere and has become established in northeastern North America. We investigated the suitability of bolts of six economically and ecologically important U.S. pine species grown in the southeastern United States, including eastern white (P. strobus L.), loblolly (P. taeda L.), longleaf (P. palustris Miller), shortleaf (P. echinata Miller), slash (P. elliottii Engelmann), and Virginia (P. virginiana Miller) pines and its native Eurasian host, Scots pine (P. sylvestris L.), for S. noctilio reproduction. The properties of wood and resin of different pine species were also analyzed for possible correlates to S. noctilio's colonization and reproductive success on bolts. Sirex noctilio completed development on bolts within 4 mo of oviposition activities. Among the seven pine species, S. noctilio completed development in eastern white, Scots, and Virginia pines. Females tended to drill less on bolts with higher area and density of resin canals, as well as higher first 10-ring and radial stripspecific gravity. The resin of eastern white and Virginia pines had distinct extractive profiles, and eastern white pine may have two 3-carene chemotypes in the southeastern region.

The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) utilizes a multi-component aggregation pheromone to mediate mass-attacks and thereby colonize otherwise unsusceptible trees. Females produce the attractant frontalin and a synergist, trans-verbenol. We investigated trans-verbenol to determine whether enantiomeric composition, airborne concentration, and possibly other factors might affect its biological activity. Newly-emerged females from Mississippi populations produced 54-87% of the (-)-enantiomer; females initiating galleries in logs produced lower amounts and a wider range of enantiomeric ratios [12-92% (-)]. Coupled gas chromatography-electroantennographic detection (GC-EAD) studies did not suggest large differences in the concentration threshold of olfaction for the two enantiomers. We examined the effect of adding trans-verbenol to traps located outside infested areas and baited with components of the aggregation attractant. Male attraction was similarly increased by lures with 3, 81, or 98% of the (-)-enantiomer of trans-verbenol, whereas females preferred 81 over 3%. When release rate of 81% (-)-trans-verbenol in traps was varied across three orders of magnitude (0.3, 3, and 30 mg/d), the data suggested a positive dose-response trend. A high release (i.e., 2-5 g/d) device of host-odor alpha-pinene had a much stronger enhancing effect on trap catches than a trans-verbenol device (~30 mg/d), and trans-verbenol did not further enhance attraction when alpha-pinene was present. Our results suggest that the weak attraction-enhancing activity of trans-verbenol reported previously cannot be improved by adjusting the enantiomeric composition or release rate of lures, and furthermore there are no anticipated benefits of adding trans-verbenol to the D. frontalis monitoring lure.

Phenological synchrony can promote population growth in species with positive density dependence. Variation among life stages in the thermal thresholds for development can foster phenological synchrony under thermal regimes that include frequent occurrence of temperatures between developmental thresholds. The southern pine beetle is an insect with positive density dependence that has recently undergone important shifts in population abundance at the northern extremes of their distribution. We evaluated the hypothesis that cooler winter temperatures in their northern range cause a convergence of the population life stage structure that leads to synchrony in spring flight phenology. We used a combination of approaches. First, in situ laboratory experiments demonstrated a threshold temperature for pupation that was greater than was required for larval development; rearing larvae at lower temperatures increased the pooling of individuals at the end stage of larval development and synchrony in adult emergence. Second, a development rate model showed a similar convergence of the majority of the population at the end stage of larval development when brood experienced the cooler temperatures of the northern region, but not with temperatures from the southern region, or as a null model. Finally, field trapping of wild beetles showed greater synchrony in the pine forests of New Jersey than in the warmer, historically occupied forests of Georgia and Mississippi. Given these results, pine-dominated forests in the northern edge of the southern pine beetle’s range may experience more frequent occurrence of outbreaks, due to the positive feedbacks associated with a synchronous spring emergence of this insect.

This paper presents the design, manufacture and characterization results of two optical interference filters to be used in the Lightning Imager (LI) optical head on the Meteosat Third Generation (MTG) mission. The first optical filter is a Solar Rejection Window (SRW) to limit the solar thermal radiation absorbed by the optical head while the second optical filter is a Narrow Band Filter (NBF) intended to only pass the lightning discharge emission wavelengths. Each filter has its own distinctive design considerations and manufacturing challenges. The SRW must pass wavelengths from the 760 to 780 nm spectral range and reject (block) wavelengths from the ultraviolet (UV) to the mid-wave infrared (MWIR) and up to 16.3° angle of incidence (AOI) and over a large temperature range (as when exposed to direct sunlight). The NBF is designed to pass only the oxygen emission triplet, centered around the 777.6 nm (vacuum) wavelength and rejecting other wavelengths. Considering the AOI of the light and the temperature excursion, the center wavelength (CWL) uniformity has to be better than 0.04% peak-to-valley (PV) over the 114 mm diameter clear aperture, which is a formidable challenge. We achieved a coating thickness uniformity less than ±0.01% PV, exceeding the prescribed specification. Post-deposition annealing was carried out to tune the bandpass to within pico-meters (pm) of the target CWL value while maintaining the desired CWL uniformity. To ensure that both the SRW and NBF filter meet the desired optical and physical specifications, a comprehensive series of optical and physical characterization tests, along with durability tests, were carried out on each deposition batch.

In the Central American region, the aggressive, sibling bark beetles Dendroctonus frontalisZimmermann (Coleoptera: Curculionidae: Scolytinae) and Dendroctonus mesoamericanus Armendariz-Toledano & Sullivan (Coleoptera: Curculionidae: Scolytinae) commonly colonize pines concurrently, and in nature they avoid heterospecific pairing, although it can be produced in the lab. We performed walking arrestment bioassays in the lab to examine the capacity of both sexes of both species to discriminate odors from frass expelled from gallery entrances of either solitary females or conspecific pairs of either species. Males of both species strongly preferred odors of frass from solitary, conspecific females over those of heterospecific females or pairs of either species. Female D. frontalis did not discriminate among these frass categories, whereas female D. mesoamericanus preferred frass of conspecific females. In gas chromatography-electroantennographic detection and gas chromatography-mass spectrometry analyses, we determined that males of both species could sense a nearly identical spectrum of approximately 16 host- and beetle-produced compounds present in frass of females of one or both species. Only two of these compounds, endo-brevicomin and ipsdienol, which were present in frass of female D. mesoamericanus and pairs of either species but absent in frass of solitary D. frontalis females, qualitatively distinguished these categories. Several known attractants and synergists for either species declined in concentration postpairing. Our results complement earlier research and indicate how semiochemical composition and concentration in frass might mediate male discrimination of attack sites of conspecific, unpaired females. Furthermore, our data indicate that semiochemical responses for walking females differ from those of males and between species.

Successful information literacy programs require collaboration between multiple constituencies, including faculty, staff, administrators, and librarians. The purpose of this article is to share some of the lessons we’ve learned in our faculty-librarian partnership, in the hope that it might inform and guide others seeking to build successful collaborations as they strive to promote information literacy on their campuses. Our collaboration began somewhat modestly in 2008 with a traditional oneshot session, overoptimistically designed to teach a class of first year sociology students everything they might need to know about library research. Over the next six years, we shaped, customized, tweaked, and adjusted our approach until we arrived at a fully embedded librarian model. The First Year Experience (FYE) Introduction to Sociology course now includes five hands-on information literacy sessions that use active learning, several additional appearances by the librarian in the classroom, and mandatory one-on-one meetings between each student and the librarian. The librarian and subject faculty member also worked together to create the syllabus and other course materials, including a handbook for student e-portfolios that are a required component of Alfred University’s FYE program. Although the initial impetus for change came from a restructuring of the FYE program, which requires each course to be either writing or information literacy intensive, we have taken our collaboration well beyond the required parameters. Along the way we have seen significant improvement in student research papers. We hope to provide a more comprehensive analysis of our assessment data in a future publication. Fully embedded team teaching is the gold standard The ideal to strive for is a situation in which librarians and teaching faculty are complete equals working together on the content and coverage of the information literacy components of the course. Although this ideal cannot always be reached due to various local constraints, interdisciplinary teams often make for a richer educational experience. By endeavoring to move beyond the traditional one-shot model towards full embeddedness, we demonstrate that information literacy is fundamental to generating and consuming knowledge across all disciplines.

The southern pine beetle, Dendroctonus frontalis Zimmermann is generally considered to be one of the most significant biotic mortality agents of pines within North America, with a range stretching from New England to eastern Texas and from Arizona south to Nicaragua. As with other aggressive pine beetles, it relies on semiochemicals for coordinating the mass attacks necessary for colonization of healthy pines. Over the past 50 years its chemical ecology has received extensive study aimed at development of effective and practical semiochemical-based management strategies which might replace the destructive and costly techniques in practice. I review the literature on the chemical ecology of this insect with particular attention to the functional categorizations assigned to different semiochemicals and the data underlying these assignments. Additionally, I attempt to identify conflicts and knowledge gaps within current understanding of the chemical ecology of this insect that might represent a significant hindrance to progress in development of effective semiochemical-based management strategies.

The male-produced bicyclic acetal endo-brevicomin is a component of the pheromone blend that mediates colonization of host pines by the bark beetle Dendroctonus frontalis Zimmermann. Efforts to identify its behavioral function have been complicated by contrasting reports that it either enhances or reduces attraction of flying beetles. Our studies failed to support the hypothesis that this published variability is due to differences in release rate and/or the enantiomeric composition [i.e., the beetle-produced (+)-enantiomer vs. the racemate] of the endo-brevicomin used in the experiments. In trapping trials within active D. frontalis infestations, racemic and (+)-endo-brevicomin did not differ from each other in behavioral effects when tested at seven different release rates ranging from 0.005 to 3 mg/d. At the highest release rates, racemic and (+)-endo-brevicomin similarly reduced catches in traps baited with an attractant (frontalin and turpentine), but neither enhanced catches at any release rate. Furthermore, the activity of racemic endo-brevicomin baits depended on trap proximity to D. frontalis infestations. Addition of these baits to attractant-baited traps located inside active infestations reduced catches, but they enhanced catches at traps located either 100 or 200 m outside these infestations. The contrasting responses may reflect differences in host-seeking strategies by either aggregated or dispersing D. frontalis, and may be elicited by differing abundance of natural sources of semiochemicals or differing responsiveness of beetles inside vs. outside of infestations. We suspect that much of the published variability in D. frontalis responses to endo-brevicomin is attributable to differing proximity of experimental field sites to infestations.

Optical monitoring is a critical factor in ensuring that thin film optical filters can be grown to the desired specification. This paper describes some of the different types of optical monitoring techniques that are employed for different types of filters and outlines some of the difficulties and advantages associated with each method.