Plant structural complexity and mechanical defenses mediate predator-prey interactions in an odonate-bird system.

Habitat-forming species provide refuges for a variety of associating species; these refuges may mediate interactions between species differently depending on the functional traits of the habitat-forming species. We investigated refuge provisioning by plants with different functional traits for dragonfly and damselfly (Odonata: Anisoptera and Zygoptera) nymphs emerging from water bodies to molt into their adult stage. During this period, nymphs experience high levels of predation by birds. On the shores of a small pond, plants with mechanical defenses (e.g., thorns and prickles) and high structural complexity had higher abundances of odonate exuviae than nearby plants which lacked mechanical defenses and exhibited low structural complexity. To disentangle the relative effects of these two potentially important functional traits on nymph emergence-site preference and survival, we conducted two fully crossed factorial field experiments using artificial plants. Nymphs showed a strong preference for artificial plants with high structural complexity and to a lesser extent, mechanical defenses. Both functional traits increased nymph survival but through different mechanisms. We suggest that future investigations attempt to experimentally separate the elements contributing to structural complexity to elucidate the mechanistic underpinnings of refuge provisioning

Chemicals on plant surfaces as a heretofore unrecognized, but ecologically informative, class for investigations into plant defence

ABSTRACT Plants produce and utilize a great diversity of chemicals for a variety of physiological and ecological purposes. Many of these chemicals defend plants against herbivores, pathogens and competitors. The location of these chemicals varies within the plant, some are located entirely within plant tissues, others exist in the air-(or water-) space around plants, and still others are secreted onto plant surfaces as exudates. I argue herein that the location of a given defensive chemical has profound implications for its ecological function; specifically, I focus on the characteristics of chemical defences secreted onto plant surfaces. Drawing from a broad literature encompassing ecology, evolution, taxonomy and physiology, I found that these external chemical defences (ECDs) are common and widespread in plants and algae; hundreds of examples have been detailed, yet they are not delineated as a separate class from internal chemical defences (ICDs). I propose a novel typology for ECDs and, using existing literature, explore the ecological consequences of the hypothesized unique characteristics of ECDs. The axis of total or proportional investment in ECDs versus ICDs should be considered as one axis of investment by a plant, in the same way as quantitative versus qualitative chemical defences or induced versus constitutive defences is considered. The ease of manipulating ECDs in many plant systems presents a powerful tool to help test plant defence theory (e.g. optimal defence). The framework outlined here integrates various disciplines of botany and ecology and suggests a need for further examinations of exudates in a variety of contexts, as well as recognition of the effects of within-plant localization of defences

Induction of the sticky plant defense syndrome in wild tobacco.

Many plants engage in protective mutualisms, offering resources such as extrafloral nectar and shelters to predatory arthropods in exchange for protection against herbivores. Recent work indicates that sticky plants catch small insects and provide this carrion to predators who defend the plants against herbivores. In this study, we investigated whether wild tobacco, Nicotiana attenuata, fits this sticky plant defense syndrome that has been described for other sticky plants. We developed a bioassay for stickiness involving the number of flies that adhered to flowers, the stickiest tissues. In surveys conducted over three field seasons at four sites, we found that the number of carrion that adhered to a plant was positively correlated with the number of predators that we observed foraging over its surfaces. The number of predators was positively correlated with the number of seed capsules that the plant produced, a measure of lifetime female reproductive success. Structural equation modeling indicated strong support for the causal path linking carrion numbers to predator numbers to capsule production. We investigated whether stickiness was an inducible trait and examined two potential cues. We found that experimental clipping of rosette leaves induced greater stickiness, although clipping of neighboring sagebrush leaves did not. Damage to leaf tissue is likely to be a more reliable predictor of risk than is damage to a neighboring plant. The sticky plant defense syndrome is a widespread protective mutualism; its strength and ecological relevance can adjust as risk of herbivory changes

Post-mortem correlates of in vivo PiB-PET amyloid imaging in a typical case of Alzheimer's disease

The positron emission tomography (PET) radiotracer Pittsburgh Compound-B (PiB) binds with high affinity to β-pleated sheet aggregates of the amyloid-β (Aβ) peptide in vitro. The in vivo retention of PiB in brains of people with Alzheimer's disease shows a regional distribution that is very similar to distribution of Aβ deposits observed post-mortem. However, the basis for regional variations in PiB binding in vivo, and the extent to which it binds to different types of Aβ-containing plaques and tau-containing neurofibrillary tangles (NFT), has not been thoroughly investigated. The present study examined 28 clinically diagnosed and autopsy-confirmed Alzheimer's disease subjects, including one Alzheimer's disease subject who had undergone PiB-PET imaging 10 months prior to death, to evaluate region- and substrate-specific binding of the highly fluorescent PiB derivative 6-CN-PiB. These data were then correlated with region-matched Aβ plaque load and peptide levels, [3H]PiB binding in vitro, and in vivo PET retention levels. We found that in Alzheimer's disease brain tissue sections, the preponderance of 6-CN-PiB binding is in plaques immunoreactive to either Aβ42 or Aβ40, and to vascular Aβ deposits. 6-CN-PiB labelling was most robust in compact/cored plaques in the prefrontal and temporal cortices. While diffuse plaques, including those in caudate nucleus and presubiculum, were less prominently labelled, amorphous Aβ plaques in the cerebellum were not detectable with 6-CN-PiB. Only a small subset of NFT were 6-CN-PiB positive; these resembled extracellular ‘ghost’ NFT. In Alzheimer's disease brain tissue homogenates, there was a direct correlation between [3H]PiB binding and insoluble Aβ peptide levels. In the Alzheimer's disease subject who underwent PiB-PET prior to death, in vivo PiB retention levels correlated directly with region-matched post-mortem measures of [3H]PiB binding, insoluble Aβ peptide levels, 6-CN-PiB- and Aβ plaque load, but not with measures of NFT. These results demonstrate, in a typical Alzheimer's disease brain, that PiB binding is highly selective for insoluble (fibrillar) Aβ deposits, and not for neurofibrillary pathology. The strong direct correlation of in vivo PiB retention with region-matched quantitative analyses of Aβ plaques in the same subject supports the validity of PiB-PET imaging as a method for in vivo evaluation of Aβ plaque burden

New bird distribution records for Lambayeque, Peru: Nomonyx dominicus (Linneaus, 1766) (Anatidae) and Incaspiza pulchra (Sclater, 1886) (Emberizidae)

New records of the Great Inca-finch (Incaspiza pulchra) and the Masked Duck (Nomonyx dominicus) from 2011 and 2012 in the department of Lambayeque, Peru are presented and discussed. Several Masked Ducks were discovered in seasonal wetlands near the town of La Viña. Single individuals (possibly the same) of the inca-finch were found in both 2011 and 2012 on Cerro Chalpón, near the city of Motupe, and frequent handouts offered by pilgrims to a shrine on the hill. Both these records represent significant range expansions or previously unrecorded populations

New bird distribution records for Lambayeque, Peru: Nomonyx dominicus (Linneaus, 1766) (Anatidae) and Incaspiza pulchra (Sclater, 1886) (Emberizidae)

New records of the Great Inca-finch (Incaspiza pulchra) and the Masked Duck (Nomonyx dominicus) from 2011 and 2012 in the department of Lambayeque, Peru are presented and discussed. Several Masked Ducks were discovered in seasonal wetlands near the town of La Viña. Single individuals (possibly the same) of the inca-finch were found in both 2011 and 2012 on Cerro Chalpón, near the city of Motupe, and frequent handouts offered by pilgrims to a shrine on the hill. Both these records represent significant range expansions or previously unrecorded populations

New bird distribution records for Lambayeque, Peru: Nomonyx dominicus (Linneaus, 1766) (Anatidae) and Incaspiza pulchra (Sclater, 1886) (Emberizidae)

New records of the Great Inca-finch (Incaspiza pulchra) and the Masked Duck (Nomonyx dominicus) from 2011 and 2012 in the department of Lambayeque, Peru are presented and discussed. Several Masked Ducks were discovered in seasonal wetlands near the town of La Viña. Single individuals (possibly the same) of the inca-finch were found in both 2011 and 2012 on Cerro Chalpón, near the city of Motupe, and frequent handouts offered by pilgrims to a shrine on the hill. Both these records represent significant range expansions or previously unrecorded populations

loudSPIRE, an auditory display schema for the SPIRE system

Presented at 3rd International Conference on Auditory Display (ICAD), Palo Alto, California, November 4-6, 1996.SPIRE is a system for visualizing large amounts of document-based information. Auditory display was identified as a way to supplement SPIRE's existing visual interface; however, the diversity of data did not lend itself to a single sonification method. Researchers at the Pacific Northwest National Laboratory developed a schema that organizes the auditory display into layers so that multiple sonification methods can be used without sacrificing intuitiveness and usability. This paper describes the design motivations underlying the schema, gives examples of constituent data-to-sound mappings, and describes a prototype implementation named "loudSPIRE." Keywords: auditory display, information visualization, document analysis, sonification, multimedi