ABSTRACT Little (abstract + little)

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Life Sciences80%

Selected Abstracts

Birds and army ants in a fragment of the Atlantic Forest of Brazil

JOURNAL OF FIELD ORNITHOLOGY, Issue 4 2009
Christiana M. A. Faria
ABSTRACT Little is known about the birds associated with army-ant swarms in the Brazilian Atlantic forest. Our objectives were to locate and monitor army-ant swarms in the Atlantic rainforest of Brazil and to identify the species of birds that attended the swarms and exhibited bivouac-checking behavior. From July 2004 to August 2005, we located 49 swarms of army ants, including 28 Eciton burchelli, 19 Labidus praedator, and 2 Eciton vagans swarms. No birds were present at 17 (35%) swarms. At 32 swarms where birds were present, 22 (69%) were E. burchelli swarms and 10 (31%) were L. praedator swarms. No birds were observed at the two E. vagans swarms. We identified 66 species of birds attending the swarms, but only 43 species were observed foraging on prey flushed by the ants. Eighteen of these species had not been previously reported to forage in association with army-ant swarms. Most birds observed during our study attended army-ant swarms opportunistically, with White-shouldered Fire-eyes (Pyriglena leucoptera) the only obligate ant follower. Our observations suggest that the arthropods and other organisms flushed by army ants represent an important food resource for several species of birds in the Atlantic forest ecosystem. RESUMEN Se conoce poco sobre las aves asociadas con los enjambres de las hormigas soldado en el bosque Atlántico de Brasil. Nuestros objetivos fueron de localizar y monitorear los enjambres de las hormigas soldado en el bosque húmedo del Atlántico en Brasil e identificar las especies de aves que se encontraban junto con los enjambres y que chequeaban a los vivaques de las hormigas. Desde Julio 2004 hasta Agosto 2005, localizamos 49 enjambres de hormigas soldado, incluyendo a 28 enjambres de Eciton burchelli, 19 de Labidus praedator, y dos de Eciton vagans. No detectamos aves en 17 (35%) de los enjambres. En 32 enjambres donde encontramos aves, 22 (69%) eran enjambres de E. burchelli y 10 (31%) eran enjambres de L. praedator. No observamos aves en los dos enjambres de E. vagans. Identificamos 66 especies de aves junto con los enjambres, pero solo 43 especies fueron observadas comiendo las presas ahuyentadas por las hormigas. Dieciocho de estas especies no habían sido anteriormente reportadas forrajeando en conjunto con los enjambres de las hormigas soldado. La mayoría de las aves observadas durante nuestro estudio forrajeaban junto con las hormigas de manera oportunística, con Pyriglena leucoptera siendo la única especie que forrajeaba obligatoriamente con las hormigas soldado. Nuestras observaciones sugieren que los artrópodos y otros organismos que son ahuyentados por las hormigas soldado representan un recurso de comida para una variedad de especies de aves en el ecosistema del bosque Atlántico. [source]

Seasonal diets of insectivorous birds using canopy gaps in a bottomland forest

JOURNAL OF FIELD ORNITHOLOGY, Issue 1 2007
Christopher E. Moorman
ABSTRACT Little is known about how insectivorous bird diets are influenced by arthropod availability and about how these relationships vary seasonally. We captured birds in forest-canopy gaps and adjacent mature forest during 2001 and 2002 at the Savannah River Site in Barnwell County, South Carolina, and flushed their crops to gather information about arthropods eaten during four periods: spring migration, breeding, postbreeding, and fall migration. Arthropod availability for foliage- and ground-gleaning birds was examined by leaf clipping and pitfall trapping. Coleopterans and Hemipterans were used by foliage- and ground-gleaners more than expected during all periods, whereas arthropods in the orders Araneae and Hymenoptera were used as, or less than, expected based on availability during all periods. Ground-gleaning birds used Homopterans and Lepidopterans in proportions higher than availability during all periods. Arthropod use by birds was consistent from spring through fall migration, with no apparent seasonal shift in diet. Based on concurrent studies, heavily used orders of arthropods were equally abundant or slightly less abundant in canopy gaps than in the surrounding mature forest, but bird species were most frequently detected in gaps. Such results suggest that preferential feeding on arthropods by foliage-gleaning birds in gap habitats reduced arthropod densities or, alternatively, that bird use of gap and forest habitat was not determined by food resources. The abundance of arthropods across the stand may have allowed birds to remain in the densely vegetated gaps where thick cover provides protection from predators. SINOPSIS Se conoce poco de como la dieta de insectívoros está influenciada por la disponibilidad de artrópodos y de como estas interacciones varían estacionalmente. Capturamos aves en huecos o aberturas del docel de un bosque, adyacente a un bosque maduro durante el 2001 y el 2002 en Savannah River Site, Condado Garnwell, Carolina del Sur. A las aves le lavamos el buche para obtener información sobre los artrópodos utilizados como alimento durante la migración primaveral, durante la época reproductiva, post-reproductiva y durante la migración otoñal. Para determinar la disponibilidad de artrópodos en el follaje y en el suelo, usamos la técnica de cortar hojas con artrópodos y la de trampas de envases en el suelo. Los coleópteros y los hemípteros fueron utilizados como fuente de alimento, más de lo esperado tanto por aves que se alimentaron en el follaje como en los suelos, durante todos los periodos. Por su parte, los arácnidos y los himenópteros, fueron utilizados menos de lo esperado, basándose en la disponibilidad de estos durante todos los periodos de estudio. Las aves que se alimentaron en los suelos utilizaron homópteros y lepidópteros en mayor proporción que lo esperado, dada su disponibilidad, durante todos los periodos. Los artrópodos utilizados por las aves fueron consistentes desde la primavera hasta la migración otoñal, sin que hubiera desplazamiento o cambios estacionales en la dieta. Basado en estudios concurrentes, los ordenes de artrópodos más utilizados como alimento, estuvieron en similar o un poco más bajo en abundancia en los huecos del docel que en los alrededores de bosque maduro, pero las especies de aves se detectaron con mayor frecuencia en los huecos. Estos resultados sugieren que la alimentación preferencial de artrópodos por aves que se alimentan buscando insectos entre el follaje en habitats con huecos, reducen la densidad de artrópodos, o que el uso de los huecos o de bosque maduro no esta determinado por los recursos alimentarios. La abundancia de artrópodos a lo largo del rodal puede haber permitido que la aves permanecieran en los huecos o aperturas con alta densidad de plantas, en donde el follaje provee de protección contra los depredadores. [source]

INTRUDER IN THE NIGHT: CANCER AND THE ,I' WITHIN

BRITISH JOURNAL OF PSYCHOTHERAPY, Issue 4 2003
Judy Parkinson
ABSTRACT Little has been written about psychoanalytic psychotherapy with people who suffer from medical conditions such as cancer and as distinct from the well-established literature describing psychoanalytic theories and clinical work with those who have medical conditions which may be considered to have a psychologically-influenced causal basis. In this paper, I will explore the nature and experience of cancer, its psychological impact upon the patient and also the therapist, and the patient's relation to the disease inside. I think about cancer as an unboundaried invader within the body which may temporarily dislocate the patient's ego, resulting in the ,I' of the patient feeling overwhelmed or threatened. The subject of this paper is the ,I' which perceives and relates to the cancer within. The aim of the paper is to work towards describing the principles and practice of a model of ego-supportive psychotherapy with cancer patients, its goal being to help the patient to strengthen, relocate or reinstate his/her vulnerable ego. [source]

MINIMAL SELFING, FEW CLONES, AND NO AMONG-HOST GENETIC STRUCTURE IN A HERMAPHRODITIC PARASITE WITH ASEXUAL LARVAL PROPAGATION

EVOLUTION, Issue 3 2006
Charles D. Criscione
Abstract Little is known about actual mating systems in natural populations of parasites or about what constitutes the limits of a parasite deme. These parameters are interesting because they affect levels of genetic diversity, opportunities for local adaptation, and other evolutionary processes. We expect that transmission dynamics and the distribution of parasites among hosts should have a large effect on mating systems and demic structure, but currently we have mostly speculation and very few data. For example, infrapopulations (all the parasites in a single host) should behave as demes if parasite offspring are transmitted as a clump from host to host over several generations. However, if offspring are well mixed, then the parasite component population (all the parasites among a host population) would function as the deme. Similarly, low mean intensities or a high proportion of worms in single infections should increase the selfing rate. For species having an asexual amplification stage, transmission between intermediate and definitive (final) hosts will control the variance in clonal reproductive success, which in turn could have a large influence on effective sizes and rates of inbreeding. We examined demic structure, selfing rates, and the variance in clonal reproductive success in natural populations of Plagioporus shawi, a hermaphroditic trematode that parasitizes salmon. Overall levels of genetic diversity were very high. An a posteriori inference of population structure overwhelmingly supports the component population as the deme, rather than individual infrapopulations. Only a single pair of 597 adult individuals was identified as clones. Thus, the variance in clonal reproductive success was almost zero. Despite being hermaphroditic, P. shawi appears to be almost entirely outcrossing. Genetic estimates of selfing (<5%) were in accordance with the proportion of parasites from single infections. Thus, it appears that individual flukes outcross whenever possible and only resort to selfing when alone. Finally, our data support the hypothesis that aquatic transmission and the use of several intermediate hosts promotes high genetic diversity and well-mixed infrapopulations. [source]

Roost preferences and foraging ranges of the eastern forest bat Vespadelus pumilus under two disturbance histories in northern New South Wales., Australia

AUSTRAL ECOLOGY, Issue 4 2000
BRADLEY S. LAW
Abstract Little is known about the habitat requirements of Australian bats; however, this information is needed to make better-informed decisions when systems are disturbed. This study contrasts the roosting and foraging ecology of the eastern forest bat Vespadelus pumilus (Vespertilionidae), one of Australia's smallest bats, between two sites of differing disturbance history on the mid-north coast of New South Wales. Lome Flora Reserve (182 ha) is primarily old-growth forest surrounded by regrowth forest and eucalypt plantations, while Swans Crossing is dominated by regrowth and eucalypt plantations established on part of an old dairy farm. A total of 38 bats were tracked during the maternity and mating seasons at the two sites. Roost preferences were determined by comparing trees used as roosts with those randomly available, while foraging bats were triangulated from fixed stations at night. Bats tracked at Lome Flora Reserve typically roosted in hollows within large, mature trees and showed a strong preference for roosting and foraging (females only) within the Reserve. Lactating females at Swans Crossing roosted in hollows of remnant rainforest trees within a gully and dead eucalypts, while males often roosted in understorey trees (such as Acacia). Dead trees were frequently used as roosts at both sites. Under both disturbance histories, the mean distance of female maternity roosts from creeks was 20m, indicating that riparian zones provide important roosting habitat for V. pumilus. However, roosts shifted to the mid-slope prior to winter when bats mate. Retention of mature trees in a variety of topographic locations may allow behavioural adjustments with the seasons. Bats caught in the regrowth forest also foraged there, with foraging ranges averaging just 5.3 ha (n = 10), indicating that regrowth is used by this bat for both foraging and roosting. [source]