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.

scholarly journals Development and application of a delayed-release anthelmintic intra-ruminal bolus system for experimental manipulation of nematode worm burdens

Parasitology ◽  
2012 ◽  
Vol 139 (8) ◽  
pp. 1086-1092 ◽  
Author(s):  
ANJA M. CARLSSON ◽  
KENNETH WILSON ◽  
R. JUSTIN IRVINE
Keyword(s):  
Experimental Manipulation ◽  
Host Population ◽  
The Arctic ◽  
Repeated Treatment ◽  
Host Fitness ◽  
Delayed Release ◽  
Svalbard Reindeer ◽  
Marshallagia Marshalli ◽  
Host Parasite ◽  
The Impact

SUMMARYIn order to quantify the impact of parasites on host population dynamics, experimental manipulations that perturb the parasite-host relationship are needed but, logistically, this is difficult for wild hosts. Here, we describe the use of a delayed-release anthelmintic delivery system that can be administered when the hosts can be captured and its activity delayed until a more appropriate period in the host-parasite cycle. Our model system is Svalbard reindeer infected with a nematode parasite, Marshallagia marshalli, which appears to accumulate during the Arctic winter. To determine the extent to which this occurs and the effect on host fitness, reindeer need to be treated with anthelmintics in late autumn but they can only be caught and handled in April. To solve this problem, we devised an intra-ruminal capsule that releases the anthelmintic from up to 6 months after being administered. The capsule was trialed in cannulated sheep and red deer to determine optimum capsule orifice size and release rates. Capsules were estimated to release placebo for 100–153 days followed by abamectin for 22–34 days. To test the efficacy of treatment in reindeer, capsules were administered in April and retrieved in October. All capsules had fully released the anthelmintic and treated reindeer had significantly lower worm burdens than controls. Thus, success of this system allows repeated treatment over several years to test the effect of winter parasitism on host fitness.

Synchrony in Svalbard reindeer population dynamics

2003 ◽  
Vol 81 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Ronny Aanes ◽  
Bernt-Erik Sæther ◽  
Erling J Solberg ◽  
Sondre Aanes ◽  
Olav Strand ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Rangifer Tarandus ◽  
Regional Climate ◽  
The Arctic ◽  
Climate Index ◽  
Local Climate ◽  
Svalbard Reindeer ◽  
Reindeer Population ◽  
The Arctic Oscillation

We examined potential synchrony in the growth rates of three Svalbard reindeer (Rangifer tarandus platyrhynchus) populations and tested whether this pattern may result from correlated environmental variation. Two neighbouring populations had synchronized dynamics during the study period, while a more distant population showed different temporal variation. Climatic forcing (the Moran effect) was a likely synchronizing mechanism in combination with contrasting density-dependence patterns between the synchronous and asynchronous populations. Local climate was a more important synchronizing agent than a regional climate index (the Arctic Oscillation). Nevertheless, our results also suggest that variation in climate at a large scale may be important. Based on indirect measurements of dispersal/migration, our findings indicate that this factor does not play a key role in the spatial synchrony of Svalbard reindeer population dynamics.

scholarly journals Contrasting effects of climate change on seasonal survival of a hibernating mammal

2020 ◽  
Vol 117 (30) ◽  
pp. 18119-18126 ◽  
Author(s):  
Line S. Cordes ◽  
Daniel T. Blumstein ◽  
Kenneth B. Armitage ◽  
Paul J. CaraDonna ◽  
Dylan Z. Childs ◽  
...  
Keyword(s):  
Climate Change ◽  
Population Dynamics ◽  
Life History ◽  
Environmental Conditions ◽  
Temporal Trends ◽  
Life History Strategies ◽  
Environmental Drivers ◽  
Age Classes ◽  
History Of ◽  
Colorado Rocky Mountains

Seasonal environmental conditions shape the behavior and life history of virtually all organisms. Climate change is modifying these seasonal environmental conditions, which threatens to disrupt population dynamics. It is conceivable that climatic changes may be beneficial in one season but result in detrimental conditions in another because life-history strategies vary between these time periods. We analyzed the temporal trends in seasonal survival of yellow-bellied marmots (Marmota flaviventer) and explored the environmental drivers using a 40-y dataset from the Colorado Rocky Mountains (USA). Trends in survival revealed divergent seasonal patterns, which were similar across age-classes. Marmot survival declined during winter but generally increased during summer. Interestingly, different environmental factors appeared to drive survival trends across age-classes. Winter survival was largely driven by conditions during the preceding summer and the effect of continued climate change was likely to be mainly negative, whereas the likely outcome of continued climate change on summer survival was generally positive. This study illustrates that seasonal demographic responses need disentangling to accurately forecast the impacts of climate change on animal population dynamics.

scholarly journals Evolution of Divergent Life History Strategies in Marine Alphaproteobacteria

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Haiwei Luo ◽  
Miklós Csűros ◽  
Austin L. Hughes ◽  
Mary Ann Moran
Keyword(s):  
Life History ◽  
Life Histories ◽  
Scale Up ◽  
Carbon Mineralization ◽  
Life History Strategies ◽  
Free Living ◽  
Heterotrophic Bacterioplankton ◽  
Evolutionary Origins ◽  
Eukaryotic Phytoplankton ◽  
Microbial Groups

ABSTRACT Marine bacteria in the Roseobacter and SAR11 lineages successfully exploit the ocean habitat, together accounting for ~40% of bacteria in surface waters, yet have divergent life histories that exemplify patch-adapted versus free-living ecological roles. Here, we use a phylogenetic birth-and-death model to understand how genome content supporting different life history strategies evolved in these related alphaproteobacterial taxa, showing that the streamlined genomes of free-living SAR11 were gradually downsized from a common ancestral genome only slightly larger than the extant members (~2,000 genes), while the larger and variably sized genomes of roseobacters evolved along dynamic pathways from a sizeable common ancestor (~8,000 genes). Genome changes in the SAR11 lineage occurred gradually over ~800 million years, whereas Roseobacter genomes underwent more substantial modifications, including major periods of expansion, over ~260 million years. The timing of the first Roseobacter genome expansion was coincident with the predicted radiation of modern marine eukaryotic phytoplankton of sufficient size to create nutrient-enriched microzones and is consistent with present-day ecological associations between these microbial groups. We suggest that diversification of red-lineage phytoplankton is an important driver of divergent life history strategies among the heterotrophic bacterioplankton taxa that dominate the present-day ocean. IMPORTANCE One-half of global primary production occurs in the oceans, and more than half of this is processed by heterotrophic bacterioplankton through the marine microbial food web. The diversity of life history strategies that characterize different bacterioplankton taxa is an important subject, since the locations and mechanisms whereby bacteria interact with seawater organic matter has effects on microbial growth rates, metabolic pathways, and growth efficiencies, and these in turn affect rates of carbon mineralization to the atmosphere and sequestration into the deep sea. Understanding the evolutionary origins of the ecological strategies that underlie biochemical interactions of bacteria with the ocean system, and which scale up to affect globally important biogeochemical processes, will improve understanding of how microbial diversity is maintained and enable useful predictions about microbial response in the future ocean.

scholarly journals Evidence of breeding activity of subadult Turdus thrushes in Argentina

2019 ◽  
Vol 27 (3) ◽  
pp. 149-152
Author(s):  
Exequiel Barboza ◽  
Patricia Capllonch ◽  
Fernando Diego Ortiz ◽  
Alex E. Jahn
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Bird Species ◽  
Life History Strategies ◽  
Brood Patch ◽  
Breeding Condition ◽  
Different Populations ◽  
Males And Females ◽  
Breeding Seasons ◽  
Subadult Female

AbstractLittle is known about the age at which many Neotropical bird species first attempt to breed. We evaluated the breeding condition of 515 adult and subadult males and females among four species of Turdus thrushes (T. nigriceps, T. chiguanco, T. amaurochalinus and T. rufiventris) in Tucumán, Argentina during three breeding seasons (2015 to 2018). We registered a total of 126 individuals with brood patches and cloacal protuberances, which accounted for 24.5% of thrushes in breeding condition that we sampled. Forty thrushes had a brood patch (31.7% of those in breeding condition), of which 11 were subadults (8.7%). Eighty-six thrushes (68.3%) had a swollen cloacal protuberance, 18 of which were subadults (14.3%). Only a few of the subadults in breeding condition built nests, incubated eggs or raised nestlings. Of 130 nests we found, only 3 belonged to a subadult thrush (in all cases, a subadult female with an adult social mate), one of which was successful. Further research on these patterns among various Neotropical bird species could lead to important insights into the life history strategies that characterize different populations, and how these ultimately affect their population dynamics.

scholarly journals Patterns of Life-History Diversification in North American Fishes: implications for Population Regulation

1992 ◽  
Vol 49 (10) ◽  
pp. 2196-2218 ◽  
Author(s):  
Kirk O. Winemiller ◽  
Kenneth A. Rose
Keyword(s):  
Life History ◽  
Parental Care ◽  
North American ◽  
Life Histories ◽  
Egg Size ◽  
Life History Strategies ◽  
Large Species ◽  
High Fecundity ◽  
Adult Growth ◽  
Trade Offs

Interspecific patterns of fish life histories were evaluated in relation to several theoretical models of life-history evolution. Data were gathered for 216 North American fish species (57 families) to explore relationships among variables and to ordinate species. Multivariate tests, performed on freshwater, marine, and combined data matrices, repeatedly identified a gradient associating later-maturing fishes with higher fecundity, small eggs, and few bouts of reproduction during a short spawning season and the opposite suite of traits with small fishes. A second strong gradient indicated positive associations between parental care, egg size, and extended breeding seasons. Phylogeny affected each variable, and some higher taxonomic groupings were associated with particular life-history strategies. High-fecundity characteristics tended to be associated with large species ranges in the marine environment. Age at maturation, adult growth rate, life span, and egg size positively correlated with anadromy. Parental care was inversely correlated with median latitude. A trilateral continuum based on essential trade-offs among three demographic variables predicts many of the correlations among life-history traits. This framework has implications for predicting population responses to diverse natural and anthropogenic disturbances and provides a basis for comparing responses of different species to the same disturbance.

scholarly journals The influence of weather conditions during gestation on life histories in a wild Arctic ungulate

2016 ◽  
Vol 283 (1841) ◽  
pp. 20161760 ◽  
Author(s):  
Mathieu Douhard ◽  
Leif Egil Loe ◽  
Audun Stien ◽  
Christophe Bonenfant ◽  
R. Justin Irvine ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
Early Life ◽  
Life Histories ◽  
Weather Conditions ◽  
Later Life ◽  
Svalbard Reindeer ◽  
Long Term Study ◽  
Age Related

The internal predictive adaptive response (internal PAR) hypothesis predicts that individuals born in poor conditions should start to reproduce earlier if they are likely to have reduced performance in later life. However, whether this is the case remains unexplored in wild populations. Here, we use longitudinal data from a long-term study of Svalbard reindeer to examine age-related changes in adult female life-history responses to environmental conditions experienced in utero as indexed by rain-on-snow (ROS utero ). We show that females experiencing high ROS utero had reduced reproductive success only from 7 years of age, independent of early reproduction. These individuals were able to maintain the same annual reproductive success between 2 and 6 years as phenotypically superior conspecifics that experienced low ROS utero . Young females born after high ROS utero engage in reproductive events at lower body mass (about 2.5 kg less) than those born after low ROS utero . The mean fitness of females that experienced poor environmental conditions in early life was comparable with that of females exposed to good environmental conditions in early life. These results are consistent with the idea of internal PAR and suggest that the life-history responses to early-life conditions can buffer the delayed effects of weather on population dynamics.

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