Developmental Parameters of a Southern Mountain Pine Beetle (Coleoptera: Curculionidae) Population Reveal Potential Source of Latitudinal Differences in Generation Time

Mountain pine beetle (Dendroctonus ponderosae, Hopkins) is a major disturbance agent in pine ecosystems of western North America. Adaptation to local climates has resulted in primarily univoltine generation time across a thermally diverse latitudinal gradient. We hypothesized that voltinism patterns have been shaped by selection for slower developmental rates in southern populations inhabiting warmer climates. To investigate traits responsible for latitudinal differences we measured lifestage-specific development of southern mountain pine beetle eggs, larvae and pupae across a range of temperatures. Developmental rate curves were fit using maximum posterior likelihood estimation with a Bayesian prior to improve fit stability. When compared to previously published data for a northern population (Régnière et al. 2012), optimal development of southern individuals occurred at higher temperatures, with higher development thresholds, as compared with northern individuals. Observed developmental rates of the southern and northern populations were similar across studied lifestages at 20 °C, and southern lifestages were generally faster at temperature extremes (10, 27 °C). At 25 °C southern fourth instars were significantly slower than northern fourth instars. Our results suggest that evolved traits in the fourth instar and remaining unstudied lifestage, teneral (i.e., pre-emergent) adult, likely influence latitudinal differences in mountain pine beetle generation time

6.3 DOUGLAS-FIR BEETLE ATTACK AND TREE MORTALITY FOLLOWING WILDFIRE

ABSTRACT A major concern after wildfires is the buildup of bark beetle populations in fire injured trees, and subsequent attack and population buildup in adjacent unburned areas. To examine this concern, we documented fire injury and insect attacks in Douglas-fir (Pseudotsuga menziesii) on the 2001 Green Knoll Fire, Wyoming to determine attack preferences, brood production, and emergence densities in different levels of fireinjured trees. Tree injuries of crown scorch, ground char, bole char, and basal girdling were recorded in mixed-severity burn areas. Douglas fir beetle (Dendroctonus pseudotsugae) attack densities and brood production were sampled on two sides of infested trees in the fall of 2002. Sampled trees were organized into different combinations of crown scorch and basal girdling. Cages (1x2 ft) were installed on a subsample of trees in each category in spring of 2003 to sample beetle emergence densities. Crown scorch, prefire vigor, dbh, and the interaction of crown scorch and basal girdling were significant variables in explaining whether a tree was attacked by Douglas fir beetle. The number of brood sampled in fall was significantly affected by the percent crown scorch but not the percent basal girdling; however, the emergence the following spring was not significantly correlated with either crown scorch or basal girdling. Further analyses of attack and tree injury correlations are planned

Individual-Based Modeling: Mountain Pine Beetle Seasonal Biology in Response to Climate

Over the past decades, as significant advances were made in the availability and accessibility of computing power, individual-based models (IBM) have become increasingly appealing to ecologists (Grimm 1999). The individual-based modeling approachprovides a convenient framework to incorporate detailed knowledge of individuals and of their interactions within populations (Lomnicki 1999). Variability among individuals is essential to the success of populations that are exposed to changing environments, and because natural selection acts on this variability, it is an essential component of population performance. © Springer International Publishing Switzerland 2015

Response to responsible research assessment I and II from the perspective of the DGPs working group on open science in clinical psychology

We comment on the papers by Schönbrodt et al. (2022) and Gärtner et al. (2022) on responsible research assessment from the perspective of clinical psychology and psychotherapy research. Schönbrodt et al. (2022) propose four principles to guide hiring and promotion in psychology: (1) In addition to publications in scientific journals, data sets and the development of research software should be considered. (2) Quantitative metrics can be useful, but they should be valid and applied responsibly. (3) Methodological rigor, research impact, and work quantity should be considered as three separate dimensions for evaluating research contributions. (4) The quality of work should be prioritized over the number of citations or the quantity of research output. From the perspective of clinical psychology, we endorse the initiative to update current practice by establishing a matrix for comprehensive, transparent and fair evaluation criteria. In the following, we will both comment on and complement these criteria from a clinical-psychological perspective

The Fire and Tree Mortality Database, for Empirical Modeling of Individual Tree Mortality After Fire

Wildland fires have a multitude of ecological effects in forests, woodlands, and savannas across the globe. A major focus of past research has been on tree mortality from fire, as trees provide a vast range of biological services. We assembled a database of individual-tree records from prescribed fires and wildfires in the United States. The Fire and Tree Mortality (FTM) database includes records from 164,293 individual trees with records of fire injury (crown scorch, bole char, etc.), tree diameter, and either mortality or top-kill up to ten years post-fire. Data span 142 species and 62 genera, from 409 fires occurring from 1981-2016. Additional variables such as insect attack are included when available. The FTM database can be used to evaluate individual fire-caused mortality models for pre-fire planning and post-fire decision support, to develop improved models, and to explore general patterns of individual fire-induced tree death. The database can also be used to identify knowledge gaps that could be addressed in future research

Mountain Pine Beetle

The biology, evidence of infestation and control of the scolytid Dendroctonus ponderosae, a pest of pine trees (Pinus spp.) is described. Natural enemies of D. ponderosae include a dolichopodid fly, 2 coleopterans, one of which is the clerid Enoclerus sphegeus, parasitic hymenopterans, nematodes and woodpeckers. Silvicultural control measures are the most efficient

Climate change and forest disturbance: The case of the mountain pine beetle

Forecasts of climate change raise concerns about future modifications to forest ecosystem composition, structure and dynamics. Distributions of some tree species are also predicted to change with alterations in abiotic conditions and possible repercussions to biotic interactions. Native bark beetles in the genus Dendroctonus have historically played important roles in forest ecosystem dynamics through their influence on patterns of tree mortality. Climate change is predicted to influence Dendroctonus populations, thereby affecting community dynamics and succession pathways of forest ecosystems. In susceptible forests, climatic changes influence bark beetle populations directly through effects on beetle physiology, and indirectly through effects on host trees. The direct and indirect influences of temperature and precipitation on population outbreak dynamics is complex, however, and can result in both positive and negative feedbacks to beetle population success. To predict spatial and temporal patterns of future tree mortality, and evaluate future forest resiliency capacity, it is necessary to understand the climate-driven processes that influence beetle population success. I will discuss field, laboratory, and model-derived data that describe physiological processes driving potential response of Dendroctonus ponderosae, the mountain pine beetle, in a changing climate. Connecting models of thermally-driven bark beetle population dynamics and forest ecosystems will also be discussed

Direct and indirect parametrization of a localized model for the mountain pine beetle — lodgepole pine system

The dynamic interaction between mountain pine beetles (MPB) and one of its hosts is reviewed briefly. The ‘local’ projection of a partial differential equation model describing this interaction is employed in model parameter estimation. Methods and assumptions for estimating non-fitted parameter values are given. Assigning values to non-fitted parameters, direct and indirect parametrization techniques are employed to estimate remaining parameter values. The indirect method is quickly and easily applied to many data sets but requires some assumptions and model simplifications. The direct method requires fewer assumptions but is computationally intensive. The results of these two techniques are compared and evaluated