Justin B Runyon

US Forest Service | FS · Maintaining Resilient Dryland Ecosystems

The importance of plant volatiles in mediating interactions between plant species is much debated. Here, we demonstrate that the parasitic plant Cuscuta pentagona (dodder) uses volatile cues for host location. Cuscuta pentagona seedlings exhibit directed growth toward nearby tomato plants (Lycopersicon esculentum) and toward extracted tomato-plant...

A previously unknown group of flies is described whose males exhibit directional asymmetry, in that the left wing is larger than, and of a different shape from, the right wing. To our knowledge, wing asymmetry of this degree has not previously been reported in an animal capable of flight. Such consistent asymmetry must result from a left-right axis...

High-elevation five-needle pine trees are a group of Pinus species in the subgenus Strobus that occur at the edges of plant growth near the alpine tree line. These species are ecologically very important and are also threatened by climate-driven insect outbreaks and an exotic pathogen. Volatile organic compounds (VOCs) play central roles in the env...

1.While the importance of floral odors for pollinator attraction relative to visual cues is increasingly appreciated, how they structure community‐level plant‐pollinator interactions is poorly understood. Elucidating the functional roles of flowering plant species with respect to their floral volatile organic compounds (VOCs) and how those roles va...

Study of all flies (Diptera) collected for one year from a four-hectare (150 x 266 meter) patch of cloud forest at 1,600 meters above sea level at Zurquí de Moravia, San José Province, Costa Rica (hereafter referred to as Zurquí), revealed an astounding 4,332 species. This amounts to more than half the number of named species of flies for all of Ce...

Background Orchid bees are abundant and widespread in the Neotropics, where males are important pollinators of orchids they visit to collect fragrant chemicals later used to court females. Assemblages of orchid bees have been intensively surveyed in parts of Central America, but less so in Belize, where we studied them during the late-wet and early...

Individual plant species play valuable roles in meeting restoration goals for pollinators. However, the selection of plant species for pollinator restoration is rarely informed using empirical evidence and is usually developed in agroecosystems, which experience frequent human interventions to ensure plant success as compared to seminatural ecosyst...

A new long-legged fly species, Chrysotus soya sp. nov. (Diptera: Dolichopodidae), is described and illustrated from specimens collected in soybean fields near Brookings, South Dakota, USA. The abundance of this species in soybeans suggests it plays an important role as a beneficial predator.

Plants resist herbivores and pathogens by using constitutive (baseline) and inducible (change in defense after an attack) defenses. Inducibility has long been predicted to trade off with constitutive defense, reflecting the economic use of resources. However, empirical evidence for such tradeoffs is variable, and we still lack understanding about w...

Purpose of Review: Fire and insects are major disturbances in North American forests. We reviewed literature on the effects of fire on bark beetles, defoliators, and pollinators, as well as on the effects of bark beetle and defoliator epidemics on fuels and wildfires. Recent Findings: Fire has direct and indirect effects on insects, but our unders...

Trade‐offs between plant defense investment and fitness traits, including growth, are often invoked to explain evolutionary strategies targeted at resisting herbivores. Many Pinus species have specialized herbivores, including the mountain pine beetle (MPB), Dendroctonus ponderosae, and have historically been a focus of defense investigations. We c...

Crops emit a variety of volatile organic compounds (VOCs) that serve as attractants or repellents for pests and their natural enemies. Crop rotations, off-farm chemical inputs, and mechanical and cultural tactics-collectively called cropping systems-alter soil nutrients, moisture content, and microbial communities, all of which have the potential t...

Public lands face growing demands to provide ecosystem services, while protecting species of conservation concern, like insect pollinators. Insect pollinators are critical for the maintenance of biodiversity and ecosystem function, but it is unclear how management of public lands influence pollinator conservation. We found 63 studies investigating...

The worldwide decline in bee populations is threatening the delivery of pollination services, thus leading to the development of pollinator restoration strategies. In the United States, one way to protect and restore bee populations is to use seed mixes composed of pollinator-friendly native plants to revegetate federal lands following disturbance....

Demasculinization, the reduction of male sexual characters due to parasitic nematode infection, is described in Nearctic Dolichopodidae. Five species are confirmed to be demasculinized (3 species of Dolichopus Latreille and 1 species each of Rhaphium Meigen and Tachytrechus Haliday) by nematodes in two families (apparent Mermithidae and Parasitylen...

A tylenchid nematode parasite of a male long-legged fly, Tachytrechus sanus Osten Sacken (Diptera: Dolichopodidae) from Montana, USA is described as Parasitylenchus myiophagus n. sp. (Nematoda: Parasitylenchidae). The new species is characterized by the presence of an extremely long first generation female and numerous short and wide second generat...

Ecological Consequences of Mountain Pine Beetle Outbreaks in the Intermountain West

Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (DFB), is the most damaging insect pest of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, in western North America. Individual high-value trees and stands can be protected during DFB outbreaks using the beetle's anti-aggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), which is availabl...

Welcome to the 13th annual issue of the Rocky Mountain Research Station's (RMRS) Invasive Species Science Update. This newsletter is designed to keep managers and other users up to date with recently completed and ongoing research by RMRS scientists, as well as to highlight breaking news related to invasive species issues. The newsletter is produce...

Long-term management strategies are invoked once an invasive species has become established and spread beyond feasible limits for eradication or containment. Although an invasive species may be well-established in small to large geographical areas, prevention of its spread to non-affected areas (e.g., sites, regions, and cross-continent) through ea...

Mean surface temperatures have increased globally by ~0.7 °C per century since 1900 and 0.16 °C per decade since 1970 (Levinson and Fettig 2014). Most of this warming is believed to result from increases in atmospheric concentrations of greenhouse gases produced by human activity. Temperature increases have been greater in winter than in summer, an...

Snags (standing dead trees) are important components of forest ecosystems that, among other benefits, provide critical habitat for many species of wildlife, but also represent important safety concerns to firefighters, forest workers, and the public. We identified factors that influence the fall rates of lodgepole pines, Pinus contorta Dougl. ex Lo...

The article is targeted to a general audience and provides a brief review of how wildland fires and bark beetles interact in forests of the western United States.

Bark beetle outbreaks alter forests in many ways including stand structure, fuels and fire behavior, wildlife habitat, and aesthetic value. Less understood are the effects outbreaks have on understory vegetation, despite the importance for overstory succession, nutrient cycling, water quality, soil erosion, and wildlife. Beetle outbreaks also chang...

Mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), is the most important forest insect in western North America. We determined causes and rates of tree mortality and changes in forest structure and composition associated with D. ponderosae outbreaks in the Intermountain West, U.S. during 2004–2019 based on a network...

The status of wild bees has received increased interest following recent estimates of large-scale declines in their abundances across the United States. However, basic information is limited regarding the factors affecting wild bee communities in temperate coniferous forest ecosystems. To assess the early responses of bees to bark beetle disturbanc...

Aims (main purpose and research question)Soil properties, including microbial composition and nutrient availability, can influence the emissions of plant volatile organic compounds (VOCs) that serve as host-location cues for insect pests and their natural enemies. Agricultural practices have profound effects on soil properties, but how these influe...

Bark beetles are keystone species that can alter the structure and function of forested ecosystems, yet the mechanisms underlying host selection and successful colonization remain poorly understood for most species. Comparison of closely related tree species that vary in their susceptibility to bark beetles could provide insights into such mechanis...

The long-legged flies (Dolichopodidae) of the island of Montserrat in the Lesser Antilles have been surveyed and include 63 species in 27 genera. The following eleven new species are described and illustrated: Amblypsilopus marskeae sp. nov., Medetera iviei sp. nov., Medetera montserratensis sp. nov., Systenus ladonnae sp. nov., Thrypticus mediofus...

Floral volatile organic compounds (VOCs) are traits that influence plant interactions with pollinators and other species. Interspecific and intraspecific variation in traits can strongly influence community and ecosystem processes. Yet, we lack an understanding of patterns of variation in floral VOCs among individuals of a species and across specie...

The Great Plains of North America encompass approximately 1,300,000 km² of land from Texas to Saskatchewan. The integrity of these lands is under continual assault by long-established and newly-arrived invasive plant species, which can threaten native species and diminish land values and ecological goods and services by degrading desired grassland...

Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, trees and stands can be protected from Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (DFB)-caused mortality by application of synthetic formulations of the beetle's antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH). A biodegradable formulation of MCH, SPLAT MCH, was developed and...

This newsletter is designed to keep managers and other users up to date with recently completed and ongoing research by RMRS scientists, as well as to highlight breaking news related to invasive species issues. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), a core group of scientists who volunteer to disseminate RMRS...

In 2017, we found 17 dead females of Megachile frigida Smith in clear plastic bags of composted bark mulch in a residential yard in Bozeman, Montana, USA. Females apparently entered bags via small ventilation holes, then became trapped and died. To investigate whether this is a common source of mortality, we deployed unmodified bags of mulch and th...

Four new species of Enlinia Aldrich are described from Chile: Enlinia biobio n. sp., Enlinia chilensis n. sp., Enlinia enormis n. sp., and Enlinia isoloba n. sp. These specimens were collected during a 2013 invertebrate survey in sclerophyll and Valdivian temperate rain forest habitats of the central and southern Chilean Andes. The only other speci...

This newsletter is designed to keep managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, as well as to highlight breaking news related to invasive species issues. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), a core group of scientists who volunteer to disseminate RMRS...

Alpine treeline species, like Great Basin bristlecone pine (GBBP) (Pinus longaeva Bailey), have received attention for their potential as indicators of climate change. Most studies have focused on climate-induced changes to treeline position, but climate effects on the physiology and stress of treeline plants remain poorly understood. Volatile orga...

Two new species of the long-legged fly genus Hurleyella Runyon & Robinson, 2010 are described and illustrated: Hurleyella belizensis sp. nov. from Belize and Hurleyella salina sp. nov. from alkali areas of the Northern Rockies of the USA (Idaho, Montana, Wyoming). The discovery of these new species greatly extends the known distribution of Hurleyel...

The genus Enlinia Aldrich, 1933 is recorded from French Guiana for the first time and six new species are described: E. loboptera n. sp., E. bova n. sp., E. colossicornis n. sp., E. mitarakensis n. sp., E. touroulti n. sp., and E. dalensi n. sp. A seventh unnamed species belonging to the E. armata Robinson, 1969 species group, and represented by a...

Runyon, Justin, ed. 2018. Invasive Species Science Update (No. 10). Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 12 p.

Linked Article: https://doi.org/10.1002/ece3.3964

Estimations of tropical insect diversity generally suffer from lack of known groups or faunas against which extrapolations can be made, and have seriously underestimated the diversity of some taxa. Here we report the intensive inventory of a four-hectare tropical cloud forest in Costa Rica for one year, which yielded 4332 species of Diptera, provid...

Climate change can alter species interactions essential for maintaining biodiversity and ecosystem function, such as pollination. Understanding the interactive effects of multiple abiotic conditions on floral traits and pollinator visitation are important to anticipate the implications of climate change on pollinator services. Floral visual and olf...

Four new Nearctic species belonging to the Chrysotus longipalpus species group are described: Chrysotus keyensis sp. nov. (Florida), Chrysotus mccreadiei sp. nov. (Alabama), Chrysotus mystax sp. nov. (Alabama), and Chrysotus plumarista sp. nov. (Alabama). This brings the number of known species in this group to twelve. A key to species of males of...

As diverse environmental changes continue to influence the structure and function of plant–pollinator interactions across spatial and temporal scales, we will need to enlist numerous approaches to understand these changes. Quantitative examination of floral volatile organic compounds (VOCs) is one approach that is gaining popularity, and recent wor...

This newsletter is designed to keep managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, as well as to highlight breaking news related to invasive species issues. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), a core group of scientists who volunteer to disseminate RMRS...

Inducible plant defenses—those produced in response to herbivore feeding—are thought to have evolved as a cost-saving tactic that allows plants to enact defenses only when needed. The costs of defense can be significant, and loss of plant fitness due to commitment of resources to induced defenses could affect plant populations and play a role in de...

As an international group of taxonomists who study a range of taxa, we consider that you misconstrued the case of a new insect species that was described on the basis of photographs (see Nature 535, 323–324; 2016). The species was described without a preserved type specimen, the individuals having escaped before preservation (S. A. Marshall and N....

Mass attack by tree-killing bark beetles (Curculionidae: Scolytinae) brings about large chemical changes in host trees that can have important ecological consequences. For example, mountain pine beetle (Dendroctonus ponderosae Hopkins) attack increases emission of terpenes by lodgepole pine (Pinus contorta Dougl. ex Loud.), affecting foliage flamma...

Exotic plant invasions present a global threat to natural ecosystems, yet the efficacy of management efforts in mitigating invader impacts remains unclear. A rapidly emerging problem is that of secondary invasion — an increase in abundance of non-target exotics following treatment of targeted invasive plants. Here, we present a global literature re...

The effects of climate change on species interactions are poorly understood. Investigating the mechanisms by which species interactions may shift under altered environmental conditions will help form a more predictive understanding of such shifts. In particular, components of climate change have the potential to strongly influence floral volatile o...

Volatile organic compounds (VOCs) play important roles in the environmental adaptation and fitness of plants. Comparison of the qualitative and quantitative differences in VOCs among closely related taxa and assessing the effects of environment on their emissions are important steps to deducing VOC function and evolutionary importance. Headspace VO...

To convey the full importance of drought impacts on rangelands in both natural and managed settings, our goals in this chapter are to describe: (1) the ecological history of rangeland drought, (2) the ecological consequences of drought to native rangeland species and ecosystems, (3) the effects of drought on natural disturbances, (4) the effects of...

Introduction: Bark beetle outbreaks have increased in severity and extent in recent years and have affected millions of hectares of trees in western North America. These epidemics can alter forest fuels with consequences for the frequency and intensity of wildfires. Methods: We measured changes to tree chemistry, moisture, and flammability induced...

Many pest and beneficial insects overwinter as larvae in a state of diapause, with development resuming in the spring. In these cases, rates of post-diapause development of parasitoids must be synchronised with the vulnerable life stages of their hosts. Phenological asynchrony between introduced parasitoids and their targeted hosts has limited the...

The tree-killing mountain pine beetle (Dendroctonus ponderosae Hopkins) is an important disturbance agent of western North American forests and recent outbreaks have affected tens of millions of hectares of trees. Most western North American pines (Pinus spp.) are hosts and are successfully attacked by mountain pine beetles whereas a handful of pin...

In the western US, Greater Sage-Grouse (Centrocercus urophasianus Bonaparte [Phasianidae]) have become an indicator species of the overall health of the sagebrush (Artemisia L. [Asteraceae]) dominated communities that support a rich diversity of flora and fauna. This species has an integral association with sagebrush, its understory forbs and grass...

The new micro-dolichopodid genus Haromyia gen. nov. and the type species H. iviei sp. nov. are described from the island of Dominica in the Lesser Antilles. Males and females of Haromyia are distinguished by the large setae on a bulging clypeus, minute size, and wing veins that are nearly straight and evenly diverging from wing base. Haromyia does...

The new micro-dolichopodid genus Haromyia gen. nov. and the type species H. iviei sp. nov. are described from the island of Dominica in the Lesser Antilles. Males and females of Haromyia are distinguished by the large setae on a bulging clypeus, minute size, and wing veins that are nearly straight and evenly diverging from wing base. Haromyia does...

The purpose of this application, under Article 81.1 of the Code, is to conserve the genus-group names Liancalus Loew, 1857 and Scellus Loew, 1857 (Diptera, DOLICHOPODIDAE), widely distributed and well-established genera of doli-chopodid flies whose names have been used consistently for more than one-and-a-half centuries. They are threatened by a ch...