The contribution of genetics and genomics to understanding the ecology of the mountain pine beetle system

Abstract

Environmental change is altering forest insect dynamics worldwide. As these systems change, they pose significant ecological, social, and economic risk through, for example, the loss of valuable habitat, green space, and timber. Our understanding of such systems is often limited by the complexity of multiple interacting taxa. As a consequence, studies assessing the ecology, physiology, and genomics of each key organism in such systems are increasingly important for developing appropriate management strategies. Here we summarize the genetic and genomic contributions made by the TRIA project — a long-term study of the mountain pine beetle (Dendroctonus ponderosae Hopkins) system encompassing beetle, fungi, and pine. Contributions include genetic and genomic resources for species identification, sex determination, detection of selection, functional genetic analysis, mating system confirmation, hybrid stability tests, and integrated genetic studies of multiple taxa. These resources and subsequent findings have accelerated our understanding of the mountain pine beetle system, facilitating improved management strategies (e.g., enhancements to stand susceptibility indices and predictive models) and highlighting mechanisms for promoting resilient forests. Further, work from the TRIA project serves as a model for the increasing number and severity of invasive and native forest insect outbreaks globally (e.g., Dutch elm disease and thousand cankers disease).

Moving On from the Insect Apocalypse Narrative: Engaging with Evidence-Based Insect Conservation

“…Where possible, better integration of genetic approaches with traditional surveys could greatly advance our knowledge of insect biodiversity and biology (e.g. (Cullingham et al 2018)). Integration of these methods is becoming increasingly time-and cost-effective because: (i) material for DNA-based work can often be collected during planned surveys or opportunistic site visits by non-specialists; (ii) improved specimen preservation methods are increasing the longevity of samples for research (Matos-Maraví et al 2019); (iii) commercial DNA extraction kits are decreasing the amount of starting material (e.g.…”

Factors influencing dispersal by flight in bark beetles (Coleoptera: Curculionidae: Scolytinae): from genes to landscapes

“…There is a lack of research on the genetics of flight in bark beetles; however, hints at important flight genes can be gained from bark beetle population structure and gene flow using population and landscape genetics tools. The genetics associated with range expansion in D. ponderosae reveal several informative patterns and isolation by distance (reviewed by Cullingham et al 2019). More research is needed on the landscape genetics of other bark beetle species undergoing range expansion to determine if the patterns discovered for D. ponderosae are common in other species.…”

“…Several studies have used population genetics to understand population structure and gene flow in D. ponderosae (Cullingham et al 2019). Other studies have identified potentially adaptive loci that contribute to our understanding of the spread of D. ponderosae across the landscape (Janes et al 2014;Batista et al 2016); however, the specific genes relating to flight in bark beetles and any associated physiological mechanisms remain unknown.…”

How to put forest and conservation genomics into motion for and with Indigenous communities?

“…Genomics can also provide an overview of the genetic diversity that exists within a species and the degree of connectivity between populations (Borrell et al 2019;Godbout et al 2019;Ingvarsson et al 2019). It can give us information on a forest species, namely its vulnerability to climate change and its ability to adapt (genetic and phenological diversity) to new environments (Cullingham et al 2018;Godbout et al 2019). The genomics information and indicators developed can thus be used to measure the impact of infrastructure development and implementation on populations by measuring and comparing their genetic diversity (Balkenhol et al 2009;Fauvelot et al 2009;Jackson and Fahrig 2011;Torterotot et al 2014).…”