Regulatory Mechanisms in House-Mouse Populations: The Effect of Limited Food Supply on an Unconfined Population

Ecology ◽  
1954 ◽  
Vol 35 (2) ◽  
pp. 249-253 ◽  
Author(s):  
Robert L. Strecker
Author(s):  
Elena Dmitrievna Tverdyukova

The hierarchy of food supply in besieged Leningrad is one of the most polemical questions in historiography. The subject of this research is the measures taken by the city administration during the first winter of blockade (1941-1942) aimed at maintenance of vitality of Leningraders who were highly valued for economy of the city or regarded as creative elite of the city. The goal consists in clarification of facts on the work of medical and nutritional inpatient facilities intended for persons suffering from dystrophy, including municipal inpatient facility for emaciated workers of science, technology, art and executive personnel, located the Hotel Astoria. The work of medical and nutritional inpatient facilities in the period from January to April of 1942 had not previously become the subject of separate research for national or foreign historians. The conducted research demonstrate that the establishment of such healthcare facilities was the first attempt to organize food supply for citizens suffering from dystrophy. In the conditions of severe shortage of food resources, the city administration was able to help only a limited circle of people. Working in the extreme conditions with no electricity, water, shortage of qualified medical personnel, limited food funds, medical and nutritional inpatient facilities were could not fully solve the tasks imposed on them.


1984 ◽  
Vol 41 (11) ◽  
pp. 1552-1564 ◽  
Author(s):  
Timothy C. Lambert

Complexities of herring (Clupea harengus) stocks previously alluded to are here explored in detail. Analysis of polymodal larval populations of both herring and capelin (Mallotus villosus) from a number of localities reveals the presence of a succession of larval cohorts over time. Separation of these cohorts in time and space is quantified and similarities and differences between species are indicated. The concept of "feeding range" can be applied in explanation of this cohort phenomenon. I suggest that this reproductive strategy serves to limit intraspecific competition and divides a limited food supply more equitably among the total larval population.


1975 ◽  
Vol 26 (3) ◽  
pp. 317 ◽  
Author(s):  
RG Chittleborough ◽  
BF Phillips

Settlement of puerulus larvae on collectors composed of artificial seaweed and measurements of density of young juveniles on 'nursery' reefs show wide fluctuations in year-class strength, recent settlement from the spawning crop of 1973-74 being particularly high. Owing to restricted holding capacity of the shallow 'nursery' reefs (mainly due to limited food supply), density-dependent mortality reduces most year-class strengths to similar levels by the time juveniles reach 5 years of age. Particularly weak year-classes have been shown to be associated with poor catches from the coastal 'white' fishery at the opening of a fishing season. The applications of these findings to the management of the fishery are discussed. In theory, part of the wastage resulting from excess settlement of larvae in certain areas might be saved by transplanting to less crowded reefs or by mass-rearing in ponds, without diminishing recruitment from those left on the now overstocked reefs.


Behaviour ◽  
1980 ◽  
Vol 74 (1-2) ◽  
pp. 92-100 ◽  
Author(s):  
Jiro Kikkawa

Abstract1. A flock of ten silvereyes kept under regular food deprivation of one hour per day exhibited a dominance hierarchy resulting from aggressive encounters. The weight gain of these birds in six weeks of winter was significantly less than that of the control flock of ten birds kept with uninterrupted food supply. 2. In the experimental flock the omega bird lost weight whereas the two most aggressive birds gained considerably less weight than the others. This was interpreted to mean that both agonistic behaviour and the resultant social organisation have biological significance in the survival of individuals. 3. It is proposed that winter flocking serves a conservation function in exploiting limited food sources and that agonistic behaviour is an integrating factor in the organisation of the flock.


2021 ◽  
Vol 41 ◽  
Author(s):  
Emanoelly M.S. Silva ◽  
Rafael B. Rosa ◽  
Franciéli A. Molossi ◽  
Paula R. Ribeiro ◽  
Kevin G.S. Almeida ◽  
...  

ABSTRACT: This study describes an outbreak of acute necrotic hepatopathy associated with spontaneous poisoning by Lantana camara L. in dairy cattle. A herd of 15 cows and heifers was introduced into a native pasture with limited food supply, and, sixteen days later, eight animals had spontaneous nasal hemorrhage, fever, lethargy, jaundice, and dry, dark stools with mucus and blood. The clinical course varied from two to five days. In the pasture where the cattle were kept, abundant adult specimens of L. camara L. with evident signs of consumption were observed. In total, seven cattle died and necropsy was performed in three of them. All animals had moderate jaundice, hemorrhage in the subcutaneous tissue and on the surface of different organs. The liver was slightly enlarged, with orange discoloration and enhanced lobular pattern. Histologically, multifocal areas of coagulative necrosis of hepatocytes in the centrilobular area, occasionally extending to the midzonal area, were observed, as well as marked hepatocellular degeneration and prominent cholestasis. The current study suggests that L. camara L. poisoning should be considered a differential diagnosis of acute and necrotic hepatotoxicity in cattle, despite the absence of photosensitization.


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