Open research questions in Forest Insect Ecology and Management

What the literature leaves open

• Future monitoring of these same trees in our study will pro- vide valuable insight into the changes in beetle communities over time and may shed light on more specific questions such as if or when obligate old-oak cavity specialists estab- lish and if they reproduce, as the artificial cavities age and decay develops. Future comparative studies repeating the use of flight interception traps and emergence traps could help clarify the link between attraction and reproduction. It would also be interesting to study if trees with artificial cavities can develop decay at higher rates if they have also been inoculated with fungi (Wainhouse and Boddy 2022). It would also be interesting to know at what age the artificial cavities host similar species richness and diversity to natural cavities.

  Veteranised oak cavities attract saproxylic beetles within two years · 2026 · DOI

• Beech forests, on the other hand, are naturally limited to the more southern, less continental areas of the region and have also been replaced in many cases by other forest types or converted to cultivated land (ProVincia autonoma di bolzano-alto adiGe 2010).

  Monitoring of three Saproxylic Beetles (Cerambyx cerdo, Osmoderma eremita, Rosalia alpina) in South Tyrol: Population Status and Habitat Management. · 2026 · DOI

• 1 3Journal of Chemical Ecology (2026) 52:78 Some aspects of the pheromone system remain to be resolved. Thus, although the synthetic lure was strongly attractive in the field, the absolute con- figuration of the naturally produced pheromone and the rela- tive behavioral activity of its enantiomers remain unknown. Finally, the precise source of p-mentha-1,8-dien-4-ol, whether direct male emission, metabolism of host precursors, frass, or male-induced microbial activity, remains to be determined.

  A Male-Associated Aggregation Pheromone of Cyrtogenius luteus, An Invasive Bark Beetle in Southern South America · 2026 · DOI

• Forest (last European Union: Regulation (EU) 2023/839, EUR-Lex, https: //eur-lex.europa.eu/eli/reg/2023/839/oj/eng (last access: 8 July 2025), 2023.

  Natural disturbances from bark beetle outbreaks and windthrow increasingly affect Europe's most mature and carbon-rich forests · 2026 · DOI

• Several species, including Northern House Wren, White-crowned Sparrow, Song Sparrow, and House Finch are primarily ground feeders, but these species varied widely in the effect of SHB on their abundance.

  Non-native invasive beetle alters structure of a riparian bird community in a biodiversity hotspot · 2026 · DOI

• Forest ecosystems face a number of threats globally. The most serious threats include fragmentation, invasive species and climate change, which not only releases insects from cold limitation to northward spread, but also increases the frequency and severity of disturbances, such as storms, fire and drought. Fragmentation is an immediate threat to forests. Conversion of natural forests to plantation monocultures eliminates a large proportion of species, especially in the tropics, and increases forest vulnerability to outbreaks of species adapted to the selected tree species (Brown and Ewel, 1987; Jactel and Brockerhoff, 2007; Pollierer et al., 2023; Schowalter and Turchin, 1993). Loss of habitat connectivity in fragmented forests hinders dispersal by species unable to cross inhospitable landscape patches, thereby restricting gene flow and re-colonization of available habitats (Várkonyi et al., 2003). Adapted insects are able to avoid or detoxify phytochemicals of the plantation species, and every tree is a host, eliminating costs of searching for suitable hosts. This raises the likelihood of frequent and severe outbreaks in the future. Invasive species represent serious threats to native flora and fauna. Invasive species typically are not regulated by either host chemistry or natural enemies in their invaded habitats and are capable of devastating and sustained outbreaks (Boyd et al., 2013). Schulz et al. (2025) found that analysis of diet breadth of invasive species indicated an inflection point in a model of impact assess- ment and improved prediction of which exotic species are likely to become invasive. Disturbances (especially storms and droughts) and environ- mental changes (such as global warming) are recognized as impor- tant triggers for insect outbreaks (Mattson and Haack, 1987; Schowalter et al., 2021). Disturbances have dramatic immediate effects on forest structure, e.g., burning or blowing trees down, but also create contrasting post-disturbance conditions that eliminate some (intolerant) species and favor other (pioneer) species (see Schowalter, 2022 for a review of disturbance and successional processes). The landscape mosaic of patches affected by different types, intensities or scales of disturbance affect the sizes of resulting species pools and their ability to recolonize and utilize recovering sites (Schowalter, 2012b). Global warming is expected to increase the frequency and severity of extreme weather events and other disturbances (Cunningham et al., 2025; Pandey and Schowalter, 2022; Vosper et al., 2020) that may induce outbreaks of some insect species and cause disappearance of others (Pandey and Schowalter, 2022), with consequences for ecosystem and landscape structure and processes (Harvey et al., 2020). Global warming is occurring over a longer period of time but will affect forests as some species are able to shift geographic ranges northward faster than others. Some forest insect species already are showing significant shifts northward as climate warms, including the southern pine beetle and spruce budworm in North America (e.g., FIGURE 4 Biomass production (left of break in horizontal axis) and nitrogen accumulation (right of break in horizontal axis) of birch, Betula pendula, seedlings. Bars above the horizontal axis are stems (orange) and leaves (yellow); bars below the horizontal axis are roots in humus (blue) and roots in mineral soil (yellow). C, fauna removed; F, refaunated. Vertical lines represent 1 standard deviation for all data (except nitrogen at week 45, where vertical lines represent minimum and maximum values). For C vs. F, *P < 0.05; ***P < 0.001). Stem nitrogen was not measured week 10. From Setälä and Huhta (1991) with permission from John Wiley & Sons.

  Contributions of forest insect ecology to understanding of forest ecosystem structure, processes and services · 2026 · DOI

• While the current framework provides a robust and scalable foundation for automated beetle identification, future research will focus on key strategies to address current data constraints.

  MVBeetle: an interpretable multi-view deep learning model for fine-grained classification of Galerucinae and Alticinae (Coleoptera: Chrysomelidae) · 2026 · DOI

• In particular, the magnitude and ecological relevance of changes in bark permeability, subcortical gas and vapor exchange, microbial microenvironmental heterogeneity, and sensory cues guid- ing beetle behavior remain poorly quantified.

  From Colonization to Collapse: a Mechanistic Perspective on Tree Mortality by Bark Beetles · 2026 · DOI

• While our study successfully demonstrates the applicability of mark-recapture methodologies and mass trapping effectiveness at low population densities, several areas warrant further investigation.

  Operational use of mass-trapping to study and suppress Monochamus galloprovincialis (Col.: Cerambycidae) populations: a field case · 2026 · DOI

• Given the small percentage of species which have been studied to date, additional novel structures and structural motifs undoubtedly remain to be discovered.

  Variations on a Theme: Cerambycid Beetles Use Lactone Stereoisomers to Optimize Use of Pheromone Chemical Space · 2026 · DOI

• Future research is needed to explore potential geographical and host plant-specific differences in the S.

  The almond bark beetle mycobiome: fungal associates of Scolytus amygdali within southern Mediterranean almond orchards · 2026 · DOI

• Experimental studies of dead-wood biodiversity — a review identifying global gaps in knowledge.

  Trap tales: The influence of red alder stand conditions and forest fragmentation on family-level beetle bycatch diversity · 2026 · DOI

• However, these factors alone were insufficient to explain patterns of species diversity.

  Elevational Gradients as Natural Filters: Assemblage Structure and Diversity of Ambrosia beetles (Curculionidae: Scolytinae) on the Tacaná Volcano, Chiapas, Mexico · 2026 · DOI

• However, there is a lack of evidence regarding how these diversity patterns in Scolytinae change in response to environmental changes associated with elevation.

  Elevational Gradients as Natural Filters: Assemblage Structure and Diversity of Ambrosia beetles (Curculionidae: Scolytinae) on the Tacaná Volcano, Chiapas, Mexico · 2026 · DOI

• Microbial symbiosis underpins host adaptation, yet mechanisms of metabolic integration in holobionts remain unclear.

  Cross-domain cooperation drives nutrient acquisition and metabolism in the bark beetle holobiont · 2026 · DOI

• Despite the pervasiveness of this pathogen, its impact on forests’ capacity to mitigate global change and the factors influencing symptom severity and mortality of infected trees are poorly understood.

  Risk factors of ash dieback disease and consequences for carbon storage in natural ash populations · 2026 · DOI

• Semiochemical “push–and–pull” systems, combining anti-attractants with pheromone-baited traps, are widely promoted, yet their performance under outbreak pressure and operational constraints remains understudied.

  The paradox of attraction: Why push-and-pull doesn’t always work for spruce protection against bark beetles · 2026 · DOI

• However, field-based comparisons of sanitation timing remain scarce in the European hemiboreal region.

  Sanitation timing matters: Winter and spring felling effectiveness against Ips typographus in hemiboreal Norway spruce forests · 2026 · DOI

• Bark beetle outbreaks are an increasingly important disturbance in boreal forests, yet empirical evidence is limited on how management systems influence stand- and tree-level susceptibility to bark beetle infestation.

  Drivers of primary bark beetle (Coleoptera: Curculionidae, Scolytinae) infestations in even-aged, uneven-aged, and unmanaged Norway spruce forests in central Sweden · 2026 · DOI

• There was limited evidence that the understory flora beneath ash was functionally unique.

  The loss of canopy ash trees (Fraxinus spp.) from North American forests may result in homogenization of understory flora · 2026 · DOI

• Introduction Phoretic mites associated with bark beetles play important ecological roles in forest ecosystems, yet their diversity and ecological relationships remain insufficiently documented in Turkey.

  A comprehensive study of phoretic mites (Acari: Mesostigmata) associated with bark beetles in northern Turkey: new records and ecological insights · 2026 · DOI

• However, satellite-based warning methods that rely solely on machine learning and driving factors remain limited by the complex mechanisms of FID and the poor quality of driver data.

  Integrating spatiotemporal prior knowledge from co-segmented time-series into factor-driven modeling for forest insect damage warning · 2026 · DOI

• However, the effects of agroforestry on the seasonal and spatial distribution of arthropods providing regulative ecosystem services remain understudied.

  Agroforestry enhances functional trait diversity and promotes early season pest control potential of carabid beetles · 2026 · DOI

• The recent detection of EAB in Oregon puts the future of these 2 hosts into question, as little is known about EAB's development in these species or how introduced biocontrol agents will respond.

  Larval development and parasitism of emerald ash borer (Agrilus planipennis) in Oregon ash (Fraxinus latifolia) and European olive (Olea europaea): implications for the West Coast invasion · 2025 · DOI

• ]) in an ornamental container nursery in Georgia (United States); however, its potential impact on other ornamental plants remains unknown.

  Emerging threat: Lysathia ludoviciana (Coleoptera: Chrysomelidae) as a pest of container-grown roses in ornamental nurseries · 2025 · DOI

Most-cited papers in Forest Insect Ecology and Management

• High and rising economic costs of biological invasions worldwide · Nature · 2021 · 1,289 citations
• Climate Change and Bark Beetles of the Western United States and Canada: Direct and Indirect Effects · BioScience · 2010 · 1,091 citations
• Bark Beetle Outbreaks in Europe: State of Knowledge and Ways Forward for Management · Current Forestry Reports · 2021 · 408 citations
• Historical Accumulation of Nonindigenous Forest Pests in the Continental United States · BioScience · 2010 · 397 citations
• Unwelcome exchange: International trade as a direct and indirect driver of biological invasions worldwide · One Earth · 2021 · 385 citations
• The Relationship Between Trees and Human Health · American Journal of Preventive Medicine · 2013 · 364 citations
• Forest Ecosystem Responses to Exotic Pests and Pathogens in Eastern North America · BioScience · 2006 · 323 citations
• Devastating outbreak of bark beetles in the Czech Republic: Drivers, impacts, and management implications · Forest Ecology and Management · 2021 · 274 citations
• Biological invasion costs reveal insufficient proactive management worldwide · The Science of The Total Environment · 2022 · 221 citations
• Is an Unprecedented Dothistroma Needle Blight Epidemic Related to Climate Change? · BioScience · 2005 · 215 citations

Most recent work

• Quantitative analysis of the spread pattern of pine wilt disease from the Yangtze River Basin in China · Pest Management Science · 2026
• Impact of resin-tapping on growth, defences and reproduction of 40 yr-old maritime pines in NW-Spain · Forest Ecology and Management · 2026
• Three-dimensional gallery system reconstruction reveals more frequent intraspecific than interspecific interactions in ambrosia beetles · Proceedings of the Royal Society B Biological Sciences · 2026
• Quantifying the probability of bark beetle induced damage in central German Norway spruce forests · Forest Ecology and Management · 2026
• Spatial and temporal dynamics of a bark beetle outbreak in the Eastern European Alps · Ecosphere · 2026
• Resin-based response of Pinus pinaster and P. radiata during infection by Fusarium circinatum · Journal of Experimental Botany · 2026
• Effects of the Stress of Beauveria bassiana on the Reproductive Success of an Idiobiont Parasitoid, Sclerodermus guani · Insects · 2026
• Warming temperatures and shifting precipitation patterns may exacerbate pest damage in North American forests · Nature Ecology & Evolution · 2026
• Satellite data show trees delay budburst across landscapes to escape herbivores · Nature Ecology & Evolution · 2026
• Spatial patterns of bark beetle–induced pine mortality on a Mediterranean island: Implications for forest impact assessment · Environmental Impact Assessment Review · 2026

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