scholarly journals Robert B. Weladji; Climatic Influences on the Life History and Population Dynamics of a Northern Ungulate, Rangifer tarandus

Rangifer ◽  
2003 ◽  
Vol 23 (2) ◽  
pp. 87
Author(s):  
Editor Editor
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Rangifer Tarandus

Life-history strategies and population dynamics of abomasal nematodes in Svalbard reindeer (Rangifer tarandus platyrhynchus)

Parasitology ◽  
2000 ◽  
Vol 120 (3) ◽  
pp. 297-311 ◽  
Author(s):  
R. J. IRVINE ◽  
A. STIEN ◽  
O. HALVORSEN ◽  
R. LANGVATN ◽  
S. D. ALBON
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Life Histories ◽  
Rangifer Tarandus ◽  
Host Population ◽  
The Arctic ◽  
Life History Strategies ◽  
Late Winter ◽  
Svalbard Reindeer ◽  
Marshallagia Marshalli

The observation that the total abundance of adult nematodes in the abomasum of Svalbard reindeer increases between October and April suggests adaptation to cope with the Arctic winter. Here we investigate the extent to which selection has led to similar life-history strategies in the 3 most numerous trichostrongyle species. The life-histories are found to differ markedly. We use flexible statistical models for the abundance and dispersion of parasites in the host population. One of the taxa, Marshallagia marshalli, was most abundant and had its highest egg output in the winter. In contrast, the abundance of the most common taxa, Ostertagia gruehneri, m. gruehneri was stable or declined from autumn to late winter, and the closely related taxa, O. gruehneri, m. arcticus, showed a similar over winter drop. The faecal egg output of these 2 taxa was highest in summer, as found in temperate trichostrongyle species. Despite the apparent contamination of summer pastures with O. gruehneri, calves showed negligible burdens until their second summer and the abundance of infection reached an asymptote within their third year. In contrast, the abundance of M. marshalli in calves showed a rapid increase over the first summer and by late winter was similar to peak levels found in adults (8000 worms). This increase could not be accounted for by the developing abomasum larvae population and is therefore evidence for transmission over the winter for this taxa. While M. marshalli showed little between-year variation, O. gruehneri showed 2-fold fluctuation in the abundance of infection. O. gruehneri may therefore play a role in the fluctuating population dynamics of the host. Since there was no apparent decline in abundance with host age in any of the 3 taxa there was no evidence of reindeer mounting an immune response.

Population dynamics of Stenothoe valida Dana, 1852 (Amphipoda, Stenothoidae) at Cheongsapo beach of Busan, Republic of Korea

Crustaceana ◽  
2021 ◽  
Vol 94 (4) ◽  
pp. 413-429
Author(s):  
Ye Ji Lee ◽  
Won Gyu Park
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Sex Ratio ◽  
Brood Size ◽  
Ovigerous Female ◽  
Seasonal Pattern ◽  
Recruitment Rate ◽  
Republic Of Korea ◽  
Female Size ◽  
History Of

Abstract The population dynamics of Stenothoe valida Dana, 1852 were studied at Cheongsapo beach of Busan, Republic of Korea, from March 2019 to March 2020. Sampling was conducted once a month at low tide during spring tides. Specimens were grouped by the cephalic length at 0.025 mm intervals, and classified into four categories: females, ovigerous females, males and juveniles. The sex ratio, defined as females : total males + females, exceeded 0.5 during most of the study period. Brood size was significantly coupled with ovigerous female size. Two to four cohorts appeared at each study period. New cohorts occurred at almost every sampling except in the samples Jun-2, and Nov-2. Life span was estimated at 1-2 months. The juvenile ratio, the ratio of ovigerous females, and the recruitment rate estimated by FiSAT were commonly high in summer and winter. The life history of S. valida was not coupled with water temperature, but had a strong seasonal pattern.

Size-specific sensitivity of cladocerans to freshwater salinization: Evidences from the changes in life history and population dynamics

2022 ◽  
Vol 296 ◽  
pp. 118770
Author(s):  
Jing Huang ◽  
Yurou Li ◽  
Yunfei Sun ◽  
Lu Zhang ◽  
Kai Lyu ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Specific Sensitivity ◽  
Freshwater Salinization

scholarly journals Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)

2006 ◽  
Vol 58 (4) ◽  
pp. 562-566 ◽  
Author(s):  
C. Reigada ◽  
W.A.C. Godoy
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Body Size ◽  
Larval Density ◽  
Chrysomya Megacephala ◽  
Life History Characteristics ◽  
Two Temperatures ◽  
Biological Aspects ◽  
Experimental Populations ◽  
Simultaneous Influence

The effect of larval density on the survival, fecundity and body size at two temperatures in experimental populations of C. megacephala was studied. No effect from simultaneous influence of density and temperature on life history characteristics of C. megacephala was found. Significant effects of density and temperature on survival, fecundity and body size were observed. The importance of these results for the population dynamics of C. megacephala is discussed.

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