5,352 research outputs found
Oviposition and Development of Emerald Ash Borer \u3ci\u3e(Agrilus Planipennis)\u3c/i\u3e (Coleoptera: Buprestidae) on Hosts and Potential Hosts in No-Choice Bioassays
Emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Bupres- tidae) is an invasive phloem-feeding pest native to Asia. It was first identified in North America in 2002 and has killed millions of ash (Fraxinus spp.) trees in southeast Michigan and Essex County, Ontario. Since then, additional populations have been discovered across Michigan and in areas of Ohio, Indiana, Illinois, Maryland, Pennsylvania and West Virginia. In Asia, A. planipennis reportedly colonizes other genera, including species of Juglans, Pterocarya and Ulmus. In North America, attacks on non-ash species have not been observed but there is concern about host switching as ash mortality progresses. From 2003 to 2005, we evaluated A. planipennis oviposition and larval development on 4 North American ash species: green ash (F. pennsylvanica Marshall), white ash (F. americana L.), black ash (F. nigra Marshall), blue ash (F. quadrangulata Michaux), and 6 potential alternate hosts including privet (Ligustrum and Forestiera spp.), Japanese tree lilac (Syringa reticulate (Blumb) Hara), American elm (Ulmus americana L.), black walnut (Juglans nigra L.), hickory (Carya ovata (Miller) K. Koch) and hackberry (Celtis occidentalis L.). In no- choice tests using cut branches in cages, female A. planipennis oviposited on all species tested. Larvae on green ash, white ash, black ash, blue ash and privet developed to the second instar before branches desiccated. Larvae attempted to feed on some black walnut, Japanese tree lilac, American elm and hackberry branches but died as first instars. There were no feeding attempts on hickory branches. We also conducted no-choice tests by placing adult A. planipennis in cages that encircled the lower 1 m of the trunk of live green ash, white ash, black walnut and Japanese tree lilac nursery trees. High densities of larvae developed on green ash and white ash nursery trees but there was no evidence of any larval survival, feeding, or development on the Japanese tree lilac or black walnut nursery trees
Effects of Nitrogen Fertilization on Monoterpenes of Jack Pine Seedlings and Weight Gain of Jack Pine Budworm (Lepidoptera: Tortricidae)
Nine-month old jack pine (Pinus banksiana) seedlings were grown in a greenhouse under four nitrogen fertilization regimes. Levels of total nitrogen and five monoterpenes in new foliage were measured. Fertilization resulted in four significantly different levels of foliar nitrogen; means ranged from 1.8-4.5 percent dry weight. Contrary to predictions of resource availability theory, seedlings grown under the highest fertilization regime had higher foliar monoterpene levels than seedlings in the other treatments. Newly molted, sixth-instar female jack pine budworm (Choristoneura pinus pinus [Lepidoptera: Tortricidae]) larvae were allowed to feed for four days on new foliage of the seedlings. Larvae that fed on low-nitrogen seedling gained less weight and process more vegetation than did larvae on high- nitrogen seedlings. Larval weight gain was positively related to foliar nitrogen
Phase Space Reconstruction and Nonlinear Equilibrium Dynamics in the United States Beef Market
This paper investigates dynamic interactions in the US beef market using phase space reconstruction, which has been developed to analyze nonlinear dynamical systems. This approach provides important and unique empirical insights into consumers behavior in the beef market. Our results from a phase space reconstruction analysis demonstrate distinct differences between intertemporal short run impacts from food safety outbreaks (e.g., E. Coli) and longer run health effects (e.g., cholesterol). Adjustments due to factors such as cholesterol are permanent changes and do not affect the manner by which people consume, while consumers react to food safety scares by adjusting consumption for a short period of time and then returning to their normal steady state cycle of consumption.nonlinear time series, phase space reconstruction, food safety, health effects, Livestock Production/Industries, Marketing,
Management regime and habitat response influence abundance of regal fritillary (Speyeria idalia) in tallgrass prairie
The \u3e2,570,000-ha Flint Hills ecoregion of Kansas, USA, harbors the largest remaining contiguous tract of tallgrass prairie in North America, a unique system, as the remainder of North America’s tallgrass prairie has succumbed to development and conversion. Consequently, the loss and degradation of tallgrass prairie has reduced populations of many North American prairie-obligate species including the regal fritillary (Speyeria idalia) butterfly. Population abundance and occupied range of regal fritillary have declined \u3e99%, restricting many populations to isolated, remnant patches of tallgrass prairie. Such extensive decline has resulted in consideration of the regal fritillary for protection under the Endangered Species Act. Although it is widely accepted that management practices such as fire, grazing, and haying are necessary to maintain prairie ecosystems, reported responses by regal fritillary to these management regimes have been ambiguous.We tested effects of prescribed fire across short, moderate, and long fire-return intervals as well as grazing and haying management treatments on regal fritillary density. We also tested the relative influence of habitat characteristics created by these management regimes by measuring density of an obligate host plant (Viola spp.) and canopy cover of woody vegetation, grasses, forbs/ferns, bare ground, and litter. We found density was at least 1.6 times greater in sites burned with a moderate fire-return interval vs. sites burned with short and long fire-return intervals. Overall management regardless of fire-return interval did not have an effect on density. Percent cover of grass had the strongest positive association, while percent cover of woody vegetation had the greatest negative effect on density. Our results indicate that patch-burning is a viable and perhaps even ideal management strategy for regal fritillary in tallgrass prairie landscapes. Additionally, these results elucidate the importance of fire, particularly when applied at moderate-return intervals to regal fritillary, and corroborate a growing suite of studies that suggest fire is perhaps not as detrimental to populations of regal fritillary as previously believed
For Whom the Court Tolls: Equitable Tolling of the AEDPA Statute of Limitations in Capital Habeas Cases
Recommended from our members
Searching for Prosociality in Qualitative Data: Comparing Manual, Closed-Vocabulary, and Open-Vocabulary Methods
Although most people present themselves as possessing prosocial traits, people differ in the extent to which they actually act prosocially in everyday life. Qualitative data that were not ostensibly collected to measure prosociality might contain information about prosocial dispositions that is not distorted by self–presentation concerns. This paper seeks to characterise charitable donors from qualitative data. We compared a manual approach of extracting predictors from participants’ self–described personal strivings to two automated approaches: A summation of words predefined as prosocial and a support vector machine classifier. Although variables extracted by the support vector machine predicted donation behaviour well in the training sample ( N = 984), virtually, no variables from any method significantly predicted donations in a holdout sample ( N = 496). Raters’ attempts to predict donations to charity based on reading participants’ personal strivings were also unsuccessful. However, raters’ predictions were associated with past charitable involvement. In sum, predictors derived from personal strivings did not robustly explain variation in charitable behaviour, but personal strivings may nevertheless contain some information about trait prosociality. The sparseness of personal strivings data, rather than the irrelevance of open–ended text or individual differences in goal pursuit, likely explains their limited value in predicting prosocial behaviour. © 2020 European Association of Personality Psycholog
Laboratory Rearing of \u3ci\u3eLycaeides Melissa Samuelis\u3c/i\u3e (Lepidoptera: Lycaenidae), An Endangered Butterfly in Michigan
The Karner blue butterfly (Lycaeides melissa samuelis) is listed as a federally endangered species in the United States. It occurs in oak savanna and pine barren habitats from eastern Minnesota to New Hampshire. In 1994, we successfully reared Karner blue larvae under controlled laboratory conditions for experimental purposes, and report on those rearing methods here. We collected 20 female Karner blue adults of the spring generation from two areas in Michigan, and housed them in cages in an environmental chamber at 240 -26°C for 5 days. The female butterflies produced 154 eggs, of which 72 hatched in an average of 4.5 days, and 68 first instars survived. Eggs, larvae and pupae were kept in a growth chamber at 24°C. Developmental time from egg to adult averaged 26 days; the average duration of each instar ranged from 3 to 4 days, and the average pupal duration was 8 days. Thirty three lab- oratory-reared Karner blue larvae successfully completed the 4 instars, and were released as adults into maternal collection sites. Laboratory rearing may be a viable means of providing Karner blue individuals for reintroduction into areas where the species is extirpated, for supplementation of small populations, or for research. Ultimately, such methods may become an integral part in the recovery of this and other rare invertebrate species
The role of data & program code archives in the future of economic research
This essay examines the role of data and program-code archives in making economic research "replicable." Replication of published results is recognized as an essential part of the scientific method. Yet, historically, both the "demand for" and "supply of" replicable results in economics has been minimal. "Respect for the scientific method" is not sufficient to motivate either economists or editors of professional journals to ensure the replicability of published results. We enumerate the costs and benefits of mandatory data and code archives, and argue that the benefits far exceed the costs. Progress has been made since the gloomy assessment of Dewald, Thursby and Anderson some twenty years ago in the American Economic Review, but much remains to be done before empirical economics ceases to be a "dismal science" when judged by the replicability of its published results.Econometrics ; Research
- …