Patrick C. Tobin's research while affiliated with Trinity Washington University and other places

Publications (184)

Chapter
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The study of the spatial dynamics of forest insects has a long history, and many forest insect species have served as model systems for studying conceptual processes of population biology and ecology. Because forest insect population data were often collected from georeferenced locations, even prior to the development of geodatabases and spatial st...
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Purpose Old-growth forests in the Pacific Northwest host a variety of epiphytes on their branches and stem. Given the common and often large epiphytic biomass associated with Acer macrophyllum (Pursh) in this region, we evaluated how seasonal weather changes and urbanization (metal and nitrogen deposition), affect canopy epiphytic N2 fixation in th...
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Over the past several decades, forests worldwide have experienced increases in biotic disturbances caused by insects and plant pathogens-a trend that is expected to continue with climate warming. Whereas the causes and effects of individual biotic disturbances are well studied, spatiotemporal interactions among multiple biotic disturbances are less...
Article
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Spring-emerging bees depend upon the synchronized bloom times of angiosperms that provide pollen and nectar for offspring. The emergence of such bees and bloom times are linked to weather but can be phenologically mismatched, which could limit bee developmental success. However, it remains unclear how such phenologically asynchrony could affect spr...
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Among insects, symbionts such as bacteria and fungi can be linked to their physiology and immature development, and in some cases are part of a defense system against parasites and diseases. Current bacterial and fungal symbiont associations in solitary bees are understudied, especially in the Pacific Northwest region of the USA. We collected polle...
Preprint
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Purpose : Old-growth forests in the Pacific Northwest host a variety of epiphytes on their branches and stem. Given the common and often large epiphytic biomass associated with Acer macrophyllum (Pursh ) in this region, we evaluated how seasonal weather changes and urbanization (metal and nitrogen deposition), affect canopy epiphytic N2 fixation in...
Article
Some introduced species cause severe damage, though the majority have little impact. Robust predictions of which species are most likely to cause substantial impacts could focus efforts to mitigate those impacts or prevent certain invasions entirely. Introduced herbivorous insects can reduce crop yield, fundamentally alter natural and managed fores...
Article
The invasive azalea lace bug, Stephanitis pyrioides (Scott), is one of the most damaging insect pests of the genus Rhododendron, especially azaleas. Feeding by nymphs and adults reduces the aesthetic value of infested plants. Rhododendron spp. (L.) and cultivars are a major component of public and private landscapes in the Pacific Northwest, as wel...
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Understanding and predicting the spread of invading insects is a critical challenge in management programs that aim to minimize ecological and economic harm to native ecosystems. Although efforts to quantify spread rates have been well studied over the past several decades, opportunities to improve our ability to estimate rates of spread, and ident...
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Botanical gardens have extensive spatial databases of their plant specimens; however, the fungi occurring in them are generally unstudied. Botanical gardens, with their great plant diversity, undoubtedly harbor a wide range of symbiotic fungi, including those that are plant-pathogenic. One such group of fungi is powdery mildews (Erysiphaceae). The...
Article
Biological invasions by insects entail several processes including spread and outbreaks that can cause widespread tree mortality. These processes are commonly viewed as a linear sequence because we often lack the mechanistic understanding needed to partition them. We explored an invasion that occurred over a large enough spatial scale and time fram...
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Lymantria dispar (L.), formerly known in the U.S.A. as the gypsy moth, has been a major pest species in North American forests for > 100 years. Due to the economic and ecological consequences of L. dispar outbreaks, many aspects of its population biology and ecology have been studied. However, as L. dispar continues to spread into new areas, it rem...
Article
This datasheet on Lymantria dispar covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Natural Enemies, Impacts, Prevention/Control, Further Information.
Article
The invasive azalea lace bug, Stephanitis pyrioides (Scott) (Tingidae: Hemiptera), is an important pest of Rhododendron (L.) (Ericales: Ericaceae). Feeding by nymphs and adults removes chlorophyll, reduces rates of photosynthesis and transpiration, and causes leaf stippling, which reduces the aesthetic value of infested plants. Rhododendron spp. ar...
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Geographical variation in the likelihood of biological invasions can be affected by propagule pressure and habitat suitability, which are driven by ecological and social processes. Past studies have empirically quantified the role of drivers by comparing geographical variation in numbers of invading species with variation in candidate factors; howe...
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Acer macrophyllum is a prominent component of the western Washington landscape where it performs ecological, economic, and cultural functions. Reports of its decline and increased mortality in the Pacific Northwest were documented beginning in 2011. Symptoms of this decline include a systemic loss of vigor, loss of transpiration, and reduced photos...
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Non-native organisms have invaded novel ecosystems for centuries, yet we have only a limited understanding of why their impacts vary widely from minor to severe. Predicting the impact of non-established or newly detected species could help focus biosecurity measures on species with the highest potential to cause widespread damage. However, predicti...
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Protein and amino acids in pollen are important nutritional components for larval development in several insect species, especially in Apoidea. The Bradford assay is a widely used method to measure relative protein content of pollen, which can shed light on pollen quality and consequences to fitness. Prior to using the Bradford assay, protein must...
Article
Management responses to invasive forest insects are facilitated by the use of detection traps ideally baited with species-specific semiochemicals. Emerald ash borer, Agrilus planipennis Fairmaire, is currently invading North American forests, and since its detection in 2002, development of monitoring tools has been a primary research objective. We...
Article
The introduction, spread, and impact of fungal plant pathogens is a critical concern in ecological systems. In this study, we were motivated by the rather sudden appearance of Acer macrophyllum heavily infected with powdery mildew. We used morphological and genetic analyses to confirm the pathogen causing the epidemic was Sawadaea bicornis. In subs...
Article
Erysiphe species (powdery mildews) on Corylus and Ostrya hosts (Betulaceae subfam. Coryloideae) in Asia and North America are widespread pathogens on these economically and ecologically valuable nut crops. An improved understanding of their phylogeny and taxonomy is of ecological and applied importance. Phylogenetic analyses and morphological reexa...
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Lysimachia vulgaris L., garden loosestrife, is an invasive wetland plant that is subject to management in King County, Washington, USA. Large scale management efforts are generally conducted using herbicides. In this case study, we analyzed 17 yr of monitoring and treatment data in four riparian areas in King County to estimate the rate of spread o...
Article
The host range and severity of pathogens are dependent on interactions with their hosts and are hypothesized to have evolved as products of a coevolutionary arms race. An understanding of the factors that affect host range and pathogen severity is especially crucial in introduced pathogens that infect evolutionarily-naïve hosts and cause substantia...
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• The size of adult gypsy moths, (Lymantria dispar L.), a capitalbreeder, is correlated with environmental conditions experienced as larvae. Proxies for adult size such as wing length may provide information about habitat quality and population density. • We used male gypsy moths collected from pheromone traps at intervals through the flight season...
Thesis
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Coppicing is a silvicultural practice that involves regeneration of new stems from a stump after harvesting is performed. Coppice techniques provide several benefits including a repeatable source of harvest of fuelwood, construction materials, and other products without the cost of replanting. It also offers stability to the landscape and resilienc...
Article
Powdery mildew (Erysiphaceae) is a detrimental plant disease that occurs on a variety of economically important crops. Powdery mildew consists of over 873 species of fungal pathogens that affect over 10,000 plant species. Genetic identification of powdery mildew is accomplished using the internal transcribed spacer (ITS) and large subunit (LSU) reg...
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The phylogeny and taxonomy of powdery mildew on Viburnum species is evaluated and discussed. Morphological and phylogenetic analyses revealed two new species and demonstrated that Erysiphe hedwigii and E. viburni should be reduced to synonymy and are referred to herein as E. viburni. The two new species, E. viburniphila and E. pseudoviburni, previo...
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Assessing the ecological and economic impacts of non-native species is crucial to providing managers and policymakers with the information necessary to respond effectively. Most non-native species have minimal impacts on the environment in which they are introduced, but a small fraction are highly deleterious. The definition of ‘damaging’ or ‘high-...
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In the city of Seattle and the surrounding Puget Sound region, increased human population and the resulting increased domestic and commercial transportation has led to higher inputs of heavy metal pollutants in the region, many of which have been shown to increase in toxicity for various organisms at higher temperatures. One pollutant of concern in...
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The Allee threshold, the critical population density separating growth from decline in populations experiencing strong Allee effects, can vary over space and time but few empirical studies have examined this variation. A lack of geographically extensive, long-term studies on low density population dynamics makes studying variability in Allee effect...
Article
Douglas-fir dominated forests are an integral part of the Pacific Northwest. In the Cedar River Municipal Watershed, Washington, these forests provide erosion control and ecosystem buffering for the Cedar River system that supplies high-quality drinking water to the Seattle area. Mortality of Douglas-fir in the watershed has been increasing in rece...
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A long‐standing goal of invasion biology is to identify factors driving highly variable impacts of non‐native species. Although hypotheses exist that emphasize the role of evolutionary history (e.g., enemy release hypothesis & defense‐free space hypothesis), predicting the impact of non‐native herbivorous insects has eluded scientists for over a ce...
Article
The gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is a non‐native defoliating insect that continues to expand its range in North America and undergo periodic outbreaks. In management efforts to suppress outbreaks, slow its spread and eradicate populations that arrive outside of the invaded range, aerial deployments of mating disruption...
Article
Major and trace element deposition across western Washington, USA was assessed in 2016 and 2017 by analyzing tissue metal concentrations in the epiphytic mosses Isothecium stoloniferum (Bridel) and Kindbergia praelonga (Hedw.) Ochyra. We used an intensive, vertically stratified sampling approach in Acer macrophyllum canopies in the Hoh Rainforest o...
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Temperature provides important physiological constraints that can influence the distribution of an invasive species. Gypsy moth (Lymantria dispar L.) is a generalist defoliator in North America and supraoptimal temperatures (above the optimal for developmental rate) have been implicated in range dynamics at the southern invasion front in West Virgi...
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Aim The European gypsy moth, Lymantria dispar dispar (L.), (Lepidoptera: Erebidae) is an invasive defoliator that has been expanding its range in North America following its introduction in 1869. Here, we investigate recent range expansion into a region previously predicted to be climatically unsuitable. We examine whether winter severity is correl...
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Invasive species pose considerable harm to native ecosystems and biodiversity and frustrate and at times fascinate the invasive species management and scientific communities. Of the numerous non-native species established around the world, only a minority of them are invasive and noxious, whereas the majority are either benign or in fact beneficial...
Conference Paper
Mating disruption is the dominant tactic used against expanding gypsy moth populations in the United States, it has been proven to be safer, more economical and more effective than any other control method. Historically, mating disruption has been assumed to be most effective against low-density gypsy moth populations (≤30 males/trap/season). Howev...
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The ability to predict key phenological stages of insect pests is of prime importance in sampling and management programs. Hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae), is a non-native invasive pest of eastern and Carolina hemlock that is currently expanding its range westward through the central Appalachian region. We con...
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Oak wilt is a lethal disease caused by the invasive fungus Bretziella fagacearum, which is transmitted belowground via root grafts and aboveground by sap beetles (Nitidulidae). Attempts to limit spread and impact of B. fagacearum emphasize limiting harvesting and pruning to periods of vector inactivity. However, there is limited information on sap...
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Mating disruption tactics involve the deployment of pheromones to interfere with mate finding behaviors in insect populations. This management strategy is the dominant one used against expanding gypsy moth populations in the United States, and historically it has been assumed to be most effective against low-density populations. Operationally, mati...
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Higher temperatures projected under current climate change models are generally predicted to exert an overall positive effect on the success of invasive insects through increased survivability, developmental rates and fecundity, and by facilitating geographic range expansion. However, these effects have primarily focused on the shifts in winter tem...
Article
Globalization leads to the introduction of invasive species that are often accompanied by associated microorganisms, and this can lead to homogenization of both introduced hosts and microbes with the native biota. One such example is the invasive Eurasian woodwasp Sirex noctilio , which inoculates pines with an obligate nutritional mutualist, the w...
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The ability to survive winter temperatures is a key determinant of insect distributional ranges and population dynamics in temperate ecosystems. Although many insects overwinter in a state of diapause, the hemlock woolly adelgid [Adelges tsugae (Annand)] is an exception and instead develops during winter. We studied a low density population of A. t...
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Variation in thermal performance within and between populations provides the potential for adaptive responses to increasing temperatures associated with climate change. Organisms experiencing temperatures above their optimum on a thermal performance curve exhibit rapid declines in function and these supraoptimal temperatures can be a critical physi...
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From a regulatory perspective, Asian gypsy moth is a species complex consisting of three species of Lymantria and two subspecies of Lymantria dispar (L.), differing from the European subspecies, L. dispar dispar (L.), by having consistently flight-capable females. As such, the invasion potential in North America is thought to exceed that of Europea...
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Following establishment in a new environment, invasive species expand their range through stratified diffusion, the coupling of local growth and spatial spread with long-distance movement of propagules that found new colonies. Consequently, the stages of arrival and establishment serially repeat until the entire habitat susceptible to invasion is o...
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Many insect species undergo multiple generations each year. They are found across biomes that vary in their strength of seasonality and, depending on location and species, can display a wide range of population dynamics. Some species exhibit cycles with distinct generations (developmental synchrony/generation separation), some exhibit overlapping g...
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Range expansions are a function of population growth and dispersal, and nascent populations often must overcome demographic Allee effects (positive density dependence at low population densities) driven by factors such as mate-finding failure. Given the importance of individual movement to mate finding, links between landscape structure and movemen...
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Eradication is the deliberate elimination of a species from an area. Given that international quarantine measures can never be 100% effective, surveillance for newly arrived populations of nonnative species coupled with their eradication represents an important strategy for excluding potentially damaging insect species. Historically, eradication ef...
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Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) was brought to the United States from China as a potential biological control agent for hemlock woolly adelgid (Adelges tsugae Annand) (Hemiptera: Adelgidae). Scymnus camptodromus phenology is closely synchronized with that of A. tsugae and has several characteristics of a prom...
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Background With the loss of species worldwide due to anthropogenic factors, especially in forested ecosystems, it has become more urgent than ever to understand the biodiversity–ecosystem functioning relationship (BEFR). BEFR research in forested ecosystems is very limited and thus studies that incorporate greater geographic coverage and structural...
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The effects of long-term mass rearing of laboratory insects on ecologically relevant traits is an important consideration when applying research conclusions to wild populations or developing management strategies. Laboratory strains of the gypsy moth, Lymantria dispar (L.), an invasive forest pest in North America, have been continuously reared sin...
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Significance International society has made a commitment to mainstreaming biodiversity conservation into broader socioeconomic development, but an incomplete theoretical basis translates into a lack of practical applications, especially regarding how individual plant productivity changes in response to the overall species loss. In this study, we de...
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Classical theories of biological invasions predict constant rates of spread that can be estimated from measurable life history parameters, but such outcomes depend strongly on assumptions that are often unmet in nature. Subsequent advances have demonstrated how relaxing assumptions of these foundational models results in other spread patterns seen...
Article
The emerald ash borer (EAB), first discovered in North America in Michigan in 2002, continues to expand its distributional range. Early detection of EAB remains a major caveat in efforts to implement proactive management strategies. Past reports have shown that ash trees infested with EAB have an increased risk of branch failure and other symptoms...
Article
The introduction and successful establishment of nonnative species poses a significant threat to the function and structure of native ecosystems and biodiversity. Forest ecosystems are especially threatened due to the worldwide importance of wood packaging material universally used in global trade, the importation of lumber and wood products, and t...
Chapter
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The International Pest Risk Mapping Workgroup acknowledges that advanced training and a 'tool kit' of software packages are needed to produce pest risk maps that are fully fit for purpose. This book is an initial attempt to address those needs. Invited chapters emphasize specific steps and data requirements to guide users through the development of...
Article
Since its introduction in the 1860s, gypsy moth, Lymantria dispar (L.), has periodically defoliated large swaths of forest in the eastern United States. Prior research has suggested that the greatest costs and losses from these outbreaks accrue in residential areas, but these impacts have not been well quantified. We addressed this lacuna with a ca...
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Mating disruption is the primary control tactic used against the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae) under the gypsy moth Slow the Spread (STS) program. In this paper, we present the results of the multiyear study designed to evaluate a new liquid SPLAT GM™ (ISCA Tech, Riverside, CA, USA) Organic formulation, which is appr...
Article
Natural enemies and environmental factors likely both influence the population cycles of many forest-defoliating insect species. Previous work suggests precipitation influences the spatiotemporal patterns of gypsy moth outbreaks in North America, and it has been hypothesized that precipitation could act indirectly through effects on pathogens. We i...
Conference Paper
The gypsy moth was introduced into the United States in 1869, and has been expanding its range ever since. This invasive species is univoltine with an obligate overwintering in the egg phase. Lack of sufficiently cold winter temperatures may limit range expansion southward in the United States, whereas lethal winter temperatures may present a clima...
Article
Reproductive asynchrony, a temporal mismatch in reproductive maturation between an individual and potential mates, may contribute to mate‐finding failure and A llee effects that influence the establishment and spread of invasive species. Variation in elevation is likely to promote variability in maturation times for species with temperature‐depende...
Article
Insects that reproduce sexually must locate a suitable mate, and many species have evolved efficient communication mechanisms to find each other. The number of reproductively viable individuals in a population can be an important constraint in the growth of populations. One factor that can affect insect fecundity is the age of mating adults, as fec...
Article
AimTo examine the relationship between the range dynamics of the non-native species Lymantria dispar (L.) and supraoptimal temperatures during its larval and pupal period.LocationWest Virginia and Virginia, United States, North America.Methods We linked the annual frequency of supraoptimal temperatures during the larval and pupal period of L. dispa...
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Despite substantial increases in public awareness and biosecurity systems, introductions of non-native arthropods remain an unwelcomed consequence of escalating rates of international trade and travel. Detection of an established but unwanted non-native organism can elicit a range of responses, including implementation of an eradication program. Pr...
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Xylosandrus germanus (Blandford), a spe-cies native to Asia but currently invading North American and European forests, exploits living, but weakened trees. In response to many sources of stress, trees emit ethanol, which represents an important host-location cue for X. germanus. Because stressed trees can be spatially and temporally variable over...
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The ability to ascertain abundance and spatial extent of a nascent population of a non-native species can inform management decisions. Following initial detection, delimiting surveys, which involve the use of a finer network of samples around the focal point of a newly detected colony, are often used to quantify colony size, spatial extent, and the...