Evolution of sexual segregation in mammalian herbivores: kangaroos as marsupial models

2006 ◽  
Vol 54 (3) ◽  
pp. 217 ◽  
Author(s):  
G. Coulson ◽  
A. M. MacFarlane ◽  
S. E. Parsons ◽  
J. Cutter
Keyword(s):  
Sexual Segregation ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Single Sex ◽  
Two Factors ◽  
Body Sizes ◽  
Preliminary Study ◽  
Western Victoria ◽  
Initial Results ◽  
North Western

Sexual segregation is best known in sexually dimorphic ungulates. Many hypotheses have been proposed to explain the evolution of sexual segregation in ungulates, but all are reducible to the influence of two factors: body size and sex-specific reproductive strategy. Definitive tests of these hypotheses are lacking in ungulates because these factors are confounded, all males being somewhat larger than females. Kangaroos represent a parallel radiation of terrestrial herbivores, but their populations are composed of a spectrum of adult body sizes, ranging from small males the same size as females to large males more than twice the size. We exploited this heteromorphism to assess the independent influences of size and sex in these ungulate analogues. We conducted a preliminary study of western grey kangaroos (Macropus fuliginosus) in north-western Victoria, Australia. Adult males predominately occupied grassland habitat, whereas females occurred mostly in lakebed, woodland and shrubland. Single-sex groups occurred more often than expected during the non-mating season. The diet of large males had the highest proportion of grass, and females had the least. These initial results indicate that both size and sex influence segregation in this species, confirming the worth of kangaroos as marsupial models for research into the evolution of sexual segregation.

Sexual segregation in bison: a test of multiple hypotheses

Behaviour ◽  
2005 ◽  
Vol 142 (7) ◽  
pp. 897-927 ◽  
Author(s):  
Eric W. Schaad ◽  
David S. Wiseman ◽  
Royce R. Huber ◽  
Michael S. Mooring ◽  
Dominic D. Reisig ◽  
...  
Keyword(s):  
Body Size ◽  
Predation Risk ◽  
Sexual Segregation ◽  
Bison Bison ◽  
Sexually Dimorphic ◽  
Activity Budgets ◽  
Single Sex ◽  
Multiple Hypotheses ◽  
Mixed Groups ◽  
Large Groups

AbstractSexual segregation, in which males and females form separate groups for most of the year, is common in sexually dimorphic ungulates. We tested multiple hypotheses to explain sexual segregation in bison (Bison bison) at National Bison Range, Montana and Fort Niobrara National Wildlife Refuge, Nebraska during June-August of 2002-2003. Fieldwork involved use of GPS to record space use by segregated groups, vegetation transects to measure forage availability, fecal analyses to document diet composition and quality, and behavioural observations to characterize activity budgets. During sexual segregation, males in bull groups used areas with greater per capita abundance of forage, higher proportion of weeds, and less nutritious grasses (as indicated by lower % fecal nitrogen) compared with females in cow or mixed groups. However, there was no difference between the sexes in activity budgets, predation risk factors, or distance to water. Single-sex bull groups were no more synchronized in activity than mixed groups. These results support the 'sexual dimorphism-body size hypothesis', which proposes that males segregate from females because their larger body size requires more abundant forage, while longer ruminal retention permits efficient use of lower-quality forage. The gastrocentric model, based on the digestive physiology and foraging requirements of dimorphic ungulates, supplies the most likely proximate mechanism for bison sexual segregation. Our results would also partly support the 'reproductive strategy-predation risk hypothesis' if females form large groups to reduce predation risk. The predictions of the 'activity budget hypothesis' were not supported for bison.

Translation and Validation of the Brazilian Portuguese Version of the Broad Conceptualization of Beauty Scale With Brazilian Women

2021 ◽  
pp. 036168432110134
Author(s):  
Alessandra Costa Pereira Junqueira ◽  
Tracy L. Tylka ◽  
Sebastião de Sousa Almeida ◽  
Telma Maria Braga Costa ◽  
Maria Fernanda Laus
Keyword(s):  
Factor Structure ◽  
Reliability And Validity ◽  
Well Being ◽  
The United States ◽  
Brazilian Portuguese ◽  
Incremental Validity ◽  
Body Appreciation ◽  
Two Factors ◽  
Body Sizes ◽  
Definition Of

In many countries, women are socialized to adopt a narrow definition of beauty. Research has revealed that, in the United States and China, the ability to broadly conceptualize beauty (perceive beauty in diverse body sizes, shapes, and appearances) is linked to women’s lower anti-fat attitudes, higher body appreciation, and higher well-being. In this study, we translated an existing measure of this construct, the Broad Conceptualization of Beauty Scale (BCBS), into Brazilian Portuguese and evaluated the factor structure and reliability and validity of its scores with a diverse sample of 563 Portuguese women. Findings revealed that the Brazilian Portuguese BCBS contains two factors—external/appearance features of beauty (BCBS-E) and internal features of beauty (BCBS-I)—contrary to the unidimensional factor structure found in previous studies. Support for internal consistency and 3-week test–retest reliability was garnered. Total BCBS and BCBS-E scores evidenced convergent, discriminant, and incremental validity, whereas the BCBS-I did not accrue substantial convergent or incremental validity support beyond its inverse bivariate association with anti-fat attitudes. We recommend the use of the Brazilian Portuguese BCBS in body image research programs as well as clinical practice and prevention programs with Brazilian women seeking support for body dissatisfaction and disordered eating.

Spacing, movements, and habitat selection of the river otter in boreal Alberta

1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero
Keyword(s):  
Lontra Canadensis ◽  
Home Ranges ◽  
Adult Males ◽  
Movement Rates ◽  
River Otters ◽  
Aquatic Mammal ◽  
Adult Females ◽  
Two Factors ◽  
Bog Lakes ◽  
Selection Of

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.

Leaf spot and dry rot of lettuce caused by Xanthomonas vitians (Brown) Dowson

1963 ◽  
Vol 14 (6) ◽  
pp. 778 ◽  
Author(s):  
DE Harrison
Keyword(s):  
Leaf Spot ◽  
Early Spring ◽  
Late Winter ◽  
Laboratory Studies ◽  
Dry Rot ◽  
Complete Destruction ◽  
Western Victoria ◽  
Valley Area ◽  
North Western

During the late winter and early spring of 1960, and again to a lesser extent in 1961 and 1962, many lettuce crops in the Murray Valley area of north-western Victoria were seriously affected by a disease characterized by blackening, dry rotting, and collapse of the affected leaves. The incidence of disease varied from about 10% up to practically complete destruction of some plantings. A yellow bacterium was consistently isolated from affected plants and proved to be pathogenic to lettuce. Laboratory studies have shown that the organism agrees closely with the recorded description of Xanthomonas vitians (Brown) Dowson, which has not, apparently, been previously studied in Australia.

The Relationships Between Data, Information and Knowledge Based on a Preliminary Study of Engineering Designers

1999 ◽  
Author(s):  
Saeema Ahmed ◽  
Luciënne Blessing ◽  
Ken Wallace
Keyword(s):  
Aerospace Industry ◽  
Initial Study ◽  
Knowledge Based ◽  
Different Types ◽  
Preliminary Study ◽  
Initial Results

Abstract The aerospace industry, along with other industries, has acknowledged the need to bridge the experience gap between novice and experienced designers [Moore, 1997]. The research aims to identify the support a novice designer requires to gain experience faster. The focus of this paper is to present some initial results of a study of novice and experienced designers. This initial study highlighted the difficulty in establishing consistent and precise usage for the terms data, information and knowledge. It is concluded that data, information and knowledge are relative concepts that cannot be defined in absolute terms. As relative concepts, these help differentiate experts and novices, and different types of novices. The relationships between data, information and knowledge are examined with the aim of prompting a discussion.

Dominance Structuring of a Red-Winged Blackbird Roost

The Auk ◽  
1984 ◽  
Vol 101 (3) ◽  
pp. 551-555 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Drew J. Hoysak
Keyword(s):  
Deep Water ◽  
Agelaius Phoeniceus ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Sparse Vegetation ◽  
Dense Vegetation ◽  
Dimorphic Species ◽  
Older Males

Abstract Observations of the behavior of roosting male Red-winged Blackbirds (Agelaius phoeniceus) indicated that after hatching year (AHY) males were dominant over hatching year (HY) males. This dominance resulted in AHY males occupying central roost positions in dense vegetation and HY males occupying edge positions in sparse vegetation. Overall, the birds preferred positions over deep water, although the edge positions of HY males were over deeper water than were the positions of AHY males. These results are consistent with the two-strategies roosting hypothesis (Weatherhead 1983), in that the dominance of older males allows them access to roost positions with relatively low vulnerability to predation. In this study, these positions also appeared to be microclimatically superior. These results also suggest that the bright plumage of adult males of sexually dimorphic species may be advantageous in some nonbreeding situations in addition to their more commonly recognized role in reproduction.

Spatial variability in the social organisation of the yellow-bellied glider (Petaurus australis) near Ravenshoe, north Queensland

2001 ◽  
Vol 49 (4) ◽  
pp. 397 ◽  
Author(s):  
Ross L. Goldingay ◽  
Darren G. Quin ◽  
Sue Churchill
Keyword(s):  
Adult Female ◽  
Social System ◽  
Dominant Male ◽  
Female Group ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Adult Females ◽  
The Social ◽  
Natal Home ◽  
Petaurus Australis

A detailed study was conducted over a 12-month period of 10 yellow-bellied glider groups at Nitchaga Creek in north Queensland. Adult gliders were sexually dimorphic in body size and were characterised by yellow ventral fur, which is consistent with southern populations. Gliders lived in groups of 3–6 individuals that occupied exclusive areas of about 50 ha. The structure of glider groups varied enormously: five contained one adult pair, three contained one adult male and 2–3 adult females, and two initially contained 2–3 adult males and one adult female but then persisted as bachelor groups after the death or disappearance of the adult female. Group size changed during the year as offspring matured and as individuals died. One male glider dispersed about 1 km from its natal home-range and became the dominant male in a nearby group. Young were born throughout the year, with a peak in the number of pouch-young in June. This study has confirmed the highly variable social system of the yellow-bellied glider, which appears to be mediated by local resource abundance.

Control of Amsinckia spp. by the pastures of north-western Victoria

1965 ◽  
Vol 5 (19) ◽  
pp. 500
Author(s):  
DJ Connor
Keyword(s):  
Seed Production ◽  
Subterranean Clover ◽  
Barrel Medic ◽  
Limited Application ◽  
One Year ◽  
The One ◽  
Western Victoria ◽  
Establishment Phase ◽  
North Western ◽  
Very High

Amsinckia is a serious weed in the wheat growing areas of north-western Victoria. It is successful in the inter-crop pastures, based upon barrel medic, because it grows faster than barrel medic in the cooler months of May to August. In addition, the rapid growth in height associated with the change from rosette to elongating phases ensures a height advantage over the pasture species when the flush of pasture growth does commence. Seed production by each Amsinckia plant is very high, and for this reason any competitive restriction obtained in one year is not necessarily reflected in the establishment phase of the next. Subterranean clover c.v. Clare is more competitive than barrel medic and was able to eliminate Amsinckia from the sward in two years. However it has only limited application in the pastures of north-western Victoria. A mowing treatment was carried out at the commencement of Amsinckia flowering, for this coincides with the beginning of rapid pasture growth. Regrowth produced a reversal of height relationships within the pasture and enabled barrel medic to shade Amsinckia BJ this treatment growth and seed production of Amsinckia were reduced by 99 per cent within the one season.

A Bird-Lover in the Mallee of North-western Victoria

1927 ◽  
Vol 27 (2) ◽  
pp. 69-75
Author(s):  
Charles Sullivan
Keyword(s):  
Western Victoria ◽  
North Western
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