Foraging Strategies among Male and Female Marmosets and Tamarins (Callitrichidae): New Perspectives in an Underexplored Area

1997 ◽  
Vol 68 (3-5) ◽  
pp. 296-306 ◽  
Author(s):  
Hilary O. Box
Keyword(s):  
Foraging Strategies ◽  
Male And Female

Group structure in wood bison: nutritional and reproductive determinants

1993 ◽  
Vol 71 (7) ◽  
pp. 1367-1371 ◽  
Author(s):  
Petr E. Komers ◽  
François Messier ◽  
Cormack C. Gates
Keyword(s):  
Habitat Selection ◽  
Group Structure ◽  
Dilution Effect ◽  
Foraging Strategies ◽  
Female Ratio ◽  
Male And Female ◽  
Wood Bison ◽  
Males And Females ◽  
Mixed Groups ◽  
Male To Female

Sexual segregation in ungulates has been documented for many species including bison. However, male and female bison do not differ in their pattern of habitat selection. In the present study we observed that a fraction of bison groups did not have young (<2 years) despite the presence of males and females. The male to female ratio in these groups was 2.4. We call them adult groups, in contrast to mixed groups, where young were present and the male to female ratio was 0.4. The proportion of cows with young (mothers) in a group was negatively correlated with the male to female ratio, suggesting that mothers associated more often with other cows than with bulls. Before the rut, cows without young (non-mothers) spent less time feeding than either mothers or bulls. However, mothers and non-mothers did not differ in the number of steps per minute they took while grazing, and both types of cows stepped faster than bulls. We suggest that cows feed more selectively than bulls and that the differing foraging strategies result in temporal but not spatial segregation of the sexes. Possibly as a result of similar nutritional demands, mothers tended to aggregate, forming nursery groups. We suggest that the formation of nursery groups can also serve to protect calves through a dilution effect of predation. Whether mothers actually prefer to associate with other mothers remains to be investigated.

Parasite populations in the brown ratRattus norvegicusfrom Doha, Qatar between years: the effect of host age, sex and density

2005 ◽  
Vol 79 (2) ◽  
pp. 105-111 ◽  
Author(s):  
M.A. Abu-Madi ◽  
J.M. Behnke ◽  
M. Mikhail ◽  
J.W. Lewis ◽  
M.L. Al-Kaabi
Keyword(s):  
Parasite Species ◽  
Hymenolepis Diminuta ◽  
Female Rats ◽  
Foraging Strategies ◽  
Host Age ◽  
Adult Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Parasite Populations ◽  
Age And Sex

AbstractA total of 179 urban rats were sampled in the city of Doha in Qatar across the winter seasons (February–April) of 2002 and 2003. Only two parasites were identified, with overall prevalences of 35.8% and 41.3% for the cestodeHymenolepis diminutaand the fleaXenopsylla astiarespectively. The prevalence ofH. diminutawas markedly influenced by both year of study and host age, being higher in 2003 and amongst older rats. The abundance of infection ofH. diminutawas influenced by the year of study, host age and sex. Worm burdens in adult rats were almost twice as heavy in males compared with females and adults of both sexes harboured heavier infections than juveniles. The prevalence ofX. astiawas influenced by both year and host age, being higher in juvenile rats in 2002 and in adults in 2003. The abundance ofX. astiawas significantly higher in 2003 and both male and female rats showed similar abundances, but in 2003 females were more heavily infested. Reasons for this are discussed in relation to the differing foraging strategies shown by male and female rats. The prevalence and abundance profiles for bothH. diminutaandX. astiawere higher overall in 2003 due to a significant increase in the rat population density, although this did not reflect in any increase in parasite species richness. Rats that were infected withH. diminutawere almost twice as likely to be infected withX. astiathan those without the cestode, but when controlled for the effects of year, host age and sex, no quantitative interactions were detected between the two parasite species.

ALTERNATIVE FORAGING STRATEGIES AND RESOURCE ALLOCATION BY MALE AND FEMALE WANDERING ALBATROSSES

Ecology ◽  
1997 ◽  
Vol 78 (7) ◽  
pp. 2051-2063 ◽  
Author(s):  
Henri Weimerskirch ◽  
Yves Cherel ◽  
Franck Cuenot-Chaillet ◽  
Vincent Ridoux
Keyword(s):  
Resource Allocation ◽  
Foraging Strategies ◽  
Male And Female

scholarly journals The Sun, Moon, Wind, and Biological Imperative–Shaping Contrasting Wintertime Migration and Foraging Strategies of Adult Male and Female Northern Fur Seals (Callorhinus ursinus)

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e93068 ◽  
Author(s):  
Jeremy T Sterling ◽  
Alan M. Springer ◽  
Sara J. Iverson ◽  
Shawn P. Johnson ◽  
Noel A. Pelland ◽  
...  
Keyword(s):  
Adult Male ◽  
Foraging Strategies ◽  
Callorhinus Ursinus ◽  
The Sun ◽  
Male And Female ◽  
Fur Seals ◽  
Northern Fur Seals

Postfledging parental care in the White-throated Sparrow (Zonotrichia albicollis)

1993 ◽  
Vol 71 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Jeffrey G. Kopachena ◽  
J. Bruce Falls
Keyword(s):  
Parental Care ◽  
Foraging Strategies ◽  
Zonotrichia Albicollis ◽  
Male And Female ◽  
Nestling Period

We studied parental care in White-throated Sparrows (Zonotrichia albicollis) during the last 4 days of the nestling period and the first 4 days of the fledgling period. Both parents made more provisioning trips and delivered more food to fledglings than to nestlings. Though male and female parents provided nestlings with equal amounts of food, female parents provided fledglings with more food than did male parents. Fledglings received fewer items per trip than did nestlings. This suggests that fledging was associated with a change in parental foraging strategies. Postfledging parental care did not differ between broods from late nests and broods that were to be followed by a second nesting attempt.

The Clinical, Roentgenological and Morphological Effects of an Acute Exposure of Phosgene on the Lungs of Dogs

1971 ◽  
Vol 29 ◽  
pp. 236-237
Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth
Keyword(s):  
Latent Period ◽  
Chemical Industry ◽  
Toxic Substance ◽  
Lung Edema ◽  
X Rays ◽  
Beagle Dogs ◽  
Male And Female ◽  
Morphological Alterations ◽  
Before And After ◽  
Electron Microscopes

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.

Ultrastructural investigation of spontaneous pituitary gonadotroph cell adenomas in aging Sprague-Dawley rats

1983 ◽  
Vol 41 ◽  
pp. 702-703
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Epoxy Resin ◽  
Immunoelectron Microscopy ◽  
Tumor Type ◽  
Gonadal Function ◽  
Sprague Dawley ◽  
Male And Female ◽  
Reticulin Fibers ◽  
Sprague Dawley Rats

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.

Quantitative ultrastructural reconstruction of small regions within large volumes by correlative light and high voltage electron microscopy of serial 0.25-0.50 μm sections

1987 ◽  
Vol 45 ◽  
pp. 578-581
Author(s):  
Conly L. Rieder ◽  
Frederick J. Miller ◽  
Edwin Davison ◽  
Samuel S. Bowser ◽  
Kirsten Lewis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Mitotic Spindle ◽  
Meiotic Spindle ◽  
High Voltage Electron Microscopy ◽  
Male And Female ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Differential Stability ◽  
Sperm Aster

In this abstract we Illustrate how same-section correlative light and high voltage electron microscopy (HVEM) of serial 0.25-0.50-μm sections can answer questions which are difficult to approach by EM of 60-100 nm sections.Starfish (Pisaster and Asterlas) eggs are fertilized at meiosis I when the oocyte contains two maternal centrosomes (e.g., asters) which form the poles of the first meiotic spindle. Immediately after fertilization a sperm aster is assembled in the vicinity of the male pronucleus and persists throughout meiosis. At syngamy the sperm aster splits to form the poles of the first mitotic spindle. During this time the functional and replicative properties of the maternal centrosome, inherited from the last meiotic division, are lost. The basis for this differential stability, of male and female centrosomes in the same cytoplasm, is a mystery.

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