Spider Community Composition and Structure In A Shrub-Steppe Ecosystem: The Effects of Prey Availability and Shrub Architecture

Habitat structure is an important driver of many ecological patterns and processes, but few studies investigate whether habitat structure interacts with other environmental variables to affect community dynamics. The main objective of this study was to disentangle the relative importance of prey availability and shrub architecture on the distribution, abundance, and biodiversity of spiders of northern Utah, USA. We conducted field experiments which focused on: (1) describing the importance of these factors on spider community organization, (2) specifically evaluating whether prey availability mediates the relationship between shrub architecture and spider abundance and biodiversity, and (3) investigating spider and prey responses to manipulations of surrounding vegetation structures. For the first two experiments, big sagebrush shrubs were randomly assigned to six experimental treatments: two levels of prey attractant (shrubs were either baited or not baited) and three levels of foliage density (low, natural/control, or high). The purpose of manipulating both prey availability and shrub architecture was to delineate their significance to spiders. For the last experiment, changes in these factors were investigated at two different levels of spatial context (a single manipulated shrub surrounded by untreated shrubs vs. a manipulated shrub surrounded by a patch of similarly treated shrubs). We found both prey availability and shrub architecture directly influenced patterns of spider abundance and species richness and that spider species diversity and community composition varied in response to shrub architecture alone. Preferences of some spiders for certain shrub types likely reflect differences in foraging strategies or the substrate required to support different types of webs. We also demonstrate that spider response to shrub architecture is the result of multiple processes (i.e., a combination of direct and indirect effects via prey availability) and that surrounding vegetation structures affect spider abundances on shrubs. In addition, prey composition varied among different shrub foliage density treatments, but only when surrounding vegetation structures were also manipulated. More generally, this study suggests that ecological responses to habitat structure are in part mediated by associated variables and the significance of shrub architecture varies depending on the organisms examined and the spatial scale to which they respond most strongly

NH3 in IRC plus 10216

Ammonia was detected in the circumstellar envelope of IRC +10216 by means of three infrared absorption lines in the nu sup 2 band around 950/cm. The lines are fully resolved at a resolution of 0.22 km/sec and indicate that most of the circumstellar gas is accelerated to expansion velocities around 14 km/sec within a few stellar radii. The NH3 profiles indicate a rotational temperature between 400 and 700 K, and H2 density between 10 to the 8th power/cu cm and 10 to the 10th power/cu cm, and NH3 column density of 10 to the 17th power/sq cm. The H2 density indicates that the mass of the circumstellar envelope within a 1 arcsec radius is approximately 0.1 solar masses

Data acquisition system for NASA LaRC impact dynamics research facility

A data system is designed to permit the simultaneous recording of 90 data channels on one 28 track magnetic tape recorder using a constant bandwidth FM multiplexing technique. Dynamic signals from transducers located in the test aircraft are amplified and fed to voltage controlled oscillators where they are converted to discrete FM signals. The signals from each group of five VCO's are fed to a mixer/distribution amplifier where they are combined into one composite signal and recorded, using direct recording techniques, on one magnetic tape recorder track. Millivolt signals from the recorders reproduce heads are amplified to one volt and then electronically switched to an FM demultiplexing system where appropriate frequency discrimination and signal filtering recover the original analog information

Quagga Mussel and Zebra Mussel

Quagga mussel and zebra mussel can cause significant ecological, economical, and recreational impacts. This fact sheet describes these two-sided mollusks and reviews impacts, monitoring, and management of these invasive species

Spotted Lanternfly [Lycorma delicatula (White)]

This fact sheet describes spotted lanternfly, an invasive planthopper that is native to China and first detected in the U.S. in 2014. It includes information on plant hosts, damage symptoms, life history, monitoring, and management

Spongy Moth (Lymantria dispar dispar Linnaeus)

Spongy moths (Lepidoptera: Erebidae) are invasive leaf-eating (defoliating) pests that threaten trees and shrubs in urban, suburban, and rural landscapes. The spongy moth was accidentally introduced to the U.S. in 1869 by an amateur French entomologist in Massachusetts who sought to establish a hardier American silkworm industry. These moths now commonly occur in the northeastern U.S. and are also found in parts of Illinois, Indiana, Michigan, Minnesota, North Carolina, Ohio, Virginia, West Virginia, Wisconsin, California, Oregon, and Washington. In Utah, according to the Utah Department of Agriculture and Food (2021), the spongy moth is anticipated to survive and multiply rapidly if populations become established. This pest was first detected in Utah in1988 in monitoring traps and was quickly eradicated via extensive trapping and spray applications of Bacillus thuringiensis kurstaki (Btk), a naturally occurring bacterium. Since that time, additional specimens have been detected and eradicated, most recently in 2016 (1 moth) and 2020 (1 moth). This fact sheet describes this pest, its hosts, life stages and history, damage symptoms, and management

Asian Longhorned Beetle

Asian longhorned beetle (ALB) is a large wood-boring pest that threatens maple and other North American hardwood tree species. This fact sheet describes its life stages, plant hosts, damage symptoms, and monitoring, prevention, and management

Lily Leaf Beetle

The lily leaf beetle (LLB) (Coleoptera: Chrysomelidae) is an important pest from Eurasia that threatens native and cultivated true lilies (Lilium spp.) and fritillaries (Fritillaria spp.). It is also known as the red lily leaf beetle or scarlet lily beetle. LLB was first reported in North America in Montréal, Canada, in 1945 and in the U.S. in 1992 in Massachusetts, likely arriving via European shipments of lily bulbs. LLB has been detected in nine of the 10 Canadian provinces and 14 U.S. states, including the New England states, Pennsylvania, Wisconsin, Minnesota, and Washington (EDDMapS, 2021). Based on LLB’s native distribution and habitat suitability, it is likely capable of establishing throughout most of the U.S. where plants in the Liliaceae family occur (Freeman et al., 2020), which includes Utah. In its native range, LLB outbreaks are rare, but significant losses to lily crops are currently occurring where LLB has been introduced, including the Netherlands and Great Britain. This fact sheet includes a description of LLB and provides reliable information on plant hosts, damage symptoms, life cycle, monitoring, and management

Communicating expectancies about others

Contains fulltext : 56812.pdf (publisher's version ) (Closed access)The linguistic expectancy bias hypothesis predicts that, in general, person impressions are shared with others via subtle differences in the level of linguistic abstraction that is used to communicate expected and unexpected information about an individual. In a two-part communication experiment, we examined this hypothesis. In the first part of the experiment communicators were asked to provide a description of an event where a good friend had behaved in an expected or unexpected way. In the second part, recipients of these stories who were blind to the conditions under which the description was generated judged whether the story target's behavior was due to dispositional or situational factors. Behaviors in expected events were judged to be more dispositional relative to behaviors in unexpected events. As predicted, the level of linguistic abstraction mediated this effect. It is concluded that person impressions may be transmitted and formed at an interpersonal level via differential language use.10 p