by Dr. Molly Darr | May 25, 2022 | 2021-Present Publications, Southern Pine Beetle
Abstract
Several species of aggressive bark beetle in the genus Dendroctonus (Coleoptera: Curculionidae) undergo large fluctuations in population density with distinct outbreak and non-outbreak phases. We investigated attributes we hypothesized as subject to density-dependent variation (in particular, those likely to express phenotypic plasticity) in the southern pine beetle (SPB), Dendroctonus frontalis, as possible indicators of population fluctuations. These traits were morphology (body size and hindwing shape) and the sex ratio of trap-captured, dispersing SPB populations. We compared attributes of beetles from locations that ranged from having zero to high numbers (>1500) of SPB infestations (spots) at the county level for two summers. Southern pine beetle were obtained from six states in the southeastern USA and had been collected during a springtime, region-wide trapping survey used for forecasting outbreaks annually. Although we detected an expected but weak sexual dimorphism in both size and shape-related traits, no morphological differences were found between SPB collected from traps in counties with low or high densities of spots (≤10 or >10 per county, respectively). We found no relationship between numbers of SPB spots per county and trapped sex ratios in 2016, but we observed a strong trend in 2017, with about three times higher proportions of females trapped in counties with low compared with high numbers of spots. This implies that one or more known or possible factors influencing trapped sex ratios (e.g., disparities between the sexes in their responses to semiochemicals or in their propensity to disperse) can be density dependent. Including trap-captured sex ratios in prediction models may improve current forecasting of SPB outbreaks in the southeastern USA, informing more timely and effective management of one of the most economically and ecologically important beetle species of this region.
Keywords
bark beetles; density dependence; forest pests; geometric morphometrics; hindwing morphology; phenotypic plasticity; sex ratio; sexual dimorphism; southern pine beetle.
To read the full article please visit the link below:
McNichol, Bailey H., Brian T. Sullivan, Holly L. Munro, Cristian R. Montes, John T. Nowak, Caterina Villari, and Kamal J. K. Gandhi. 2021. “Density-Dependent Variability in an Eruptive Bark Beetle and Its Value in Predicting Outbreaks.” Ecosphere 12 (1): e03336. https://doi.org/10.1002/ecs2.3336.
by Dr. Molly Darr | May 25, 2022 | 2021-Present Publications, Southern Pine Beetle
Abstract
Several species of aggressive bark beetle in the genus Dendroctonus (Coleoptera: Curculionidae) undergo large fluctuations in population density with distinct outbreak and non-outbreak phases. We investigated attributes we hypothesized as subject to density-dependent variation (in particular, those likely to express phenotypic plasticity) in the southern pine beetle (SPB), Dendroctonus frontalis, as possible indicators of population fluctuations. These traits were morphology (body size and hindwing shape) and the sex ratio of trap-captured, dispersing SPB populations. We compared attributes of beetles from locations that ranged from having zero to high numbers (>1500) of SPB infestations (spots) at the county level for two summers. Southern pine beetle were obtained from six states in the southeastern USA and had been collected during a springtime, region-wide trapping survey used for forecasting outbreaks annually. Although we detected an expected but weak sexual dimorphism in both size and shape-related traits, no morphological differences were found between SPB collected from traps in counties with low or high densities of spots (≤10 or >10 per county, respectively). We found no relationship between numbers of SPB spots per county and trapped sex ratios in 2016, but we observed a strong trend in 2017, with about three times higher proportions of females trapped in counties with low compared with high numbers of spots. This implies that one or more known or possible factors influencing trapped sex ratios (e.g., disparities between the sexes in their responses to semioc hemicals or in their propensity to disperse) can be density dependent. Including trap-captured sex ratios in prediction models may improve current forecasting of SPB outbreaks in the southeastern USA, informing more timely and effective management of one of the most economically and ecologically important beetle species of this region.
Keywords
bark beetles; density dependence; forest pests; geometric morphometrics; hindwing morphology; phenotypic plasticity; sex ratio; sexual dimorphism; southern pine beetle
To read the full article please visit the link below:
McNichol, Bailey H., Brian T. Sullivan, Holly L. Munro, Cristian R. Montes, John T. Nowak, Caterina Villari, and Kamal J. K. Gandhi. 2021. “Density-Dependent Variability in an Eruptive Bark Beetle and Its Value in Predicting Outbreaks.” Ecosphere 12 (1): e03336. https://doi.org/10.1002/ecs2.3336.
by Dr. Molly Darr | May 25, 2022 | 2011-2020 Publications
Abstract
First, by changing or manipulating the environment, man has created conditions that permit certain species to increase their population densities.
To read the full article please visit the link below:
Maser, Chris. 2013. Changes in Insect Abundance and Distribution. Insects and Sustainability of Ecosystem Services.
by Dr. Molly Darr | May 24, 2022 | 2011-2020 Publications, Southern Pine Beetle
Abstract
Blue-stained wood cut from bark beetle-attacked southern pine has a lower economic value than unstained wood. Wood composite products containing blue-stained wood may offer an opportunity to recover some lost timber value. This study investigated the surface-free energy of blue-stained wood. Southern pine sapwood samples with and without blue stain from both green and kiln-dried sources were obtained. Dynamic contact angle analyses were performed using three probe liquids: ethylene glycol, formamide, and deionized water. Surface-free energy was determined by applying the geometric mean model using two-liquid pairs with deionized water. The polar forces were higher across all wood types and in water–ethylene glycol vs water formamide. Surface-free energy of air-dried blue-stained sapwood was lower than all other wood types. However, kiln-dried blue-stained sapwood had a higher surface-free energy than all other wood types. These results were indicative of a tree’s wound response to bark beetle attack, the volatilization of naturally occurring hydrocarbons in southern pine sapwood, and the resulting increase in wood permeability caused by blue-stained fungal colonization across the sapwood. However, improvements in wetting observed for kiln-dried blue-stained sapwood may lead to cost and quality issues in wood composite manufacturing associated with over drying and overpenetration of an adhesive.
Keywords
Blue-stain, bark beetle, dynamic contact angle, southern pine, surface-free energy, wood composite.
To read the full article please visit the link below:
Little, Nathan S., T. Eric McConnell, Nathan E. Irby, Sheldon Q. Shi, and John J. Riggins. 2013. “SURFACE FREE ENERGY OF BLUE-STAINED SOUTHERN PINE SAPWOOD FROM BARK BEETLE-ATTACKED TREES.” Wood and Fiber Science 45 (2): 206–14.
by Dr. Molly Darr | May 24, 2022 | 2011-2020 Publications, Southern Pine Beetle
Abstract
In coming decades, warmer winters are likely to ease range constraints on many cold-limited forest insects. Recent unprecedented expansion of the southern pine beetle (SPB, Dendroctonus frontalis) into New Jersey, New York, and Connecticut in concert with warming annual temperature minima highlights the risk that this insect pest poses to the pine forests of the northern United States and Canada under continued climate change. Here we present projections of northward expansion in SPB-suitable climates using a statistical bioclimatic range modeling approach and current-generation general circulation model (GCM) output under the Representative Concentration Pathway (RCP) 4.5 and 8.5 emissions scenarios. Our results show that by the middle of the 21st century, the climate is likely to be suitable for SPB expansion into vast areas of previously unaffected forests throughout the northeastern United States and into southeastern Canada. This scenario would pose a significant economic and ecological risk to the affected regions, including disruption of local ecosystem services, shifts in forest structure, and threats to native biodiversity.
SPB is a major forest pest in the southeastern United States responsible for 14 million m3 of timber losses worth an estimated US$1.7 billion over 1990–2004. SPB has historically been most damaging in southeastern states, with limited activity in the northern portion of its range including Ohio, Pennsylvania, and Maryland. However, SPB outbreaks have become increasingly problematic and extensive in southern New Jersey since 2001, and populations have been detected for the first time on Long Island, New York, in 2014 and in Connecticut in 2015.
To read the full article please visit the link below:
Lesk, Corey, Ethan Coffel, Anthony W. D’Amato, Kevin Dodds, and Radley Horton. 2017. “Threats to North American Forests from Southern Pine Beetle with Warming Winters.” Nature Climate Change 7 (10): 713-+. https://doi.org/10.1038/NCLIMATE3375.
