Social organization of snowshoe hares

1985 ◽  
Vol 63 (3) ◽  
pp. 468-474 ◽  
Author(s):  
R. P. Graf
Keyword(s):  
Social Organization ◽  
Breeding Season ◽  
Population Regulation ◽  
Lepus Americanus ◽  
Wild Populations ◽  
Dominance Hierarchies ◽  
Snowshoe Hares ◽  
In The Wild ◽  
Natural Situation

Snowshoe hares, Lepus americanus, showed various stereotyped agonistic behaviours in both penned and wild populations. Male hares were involved more frequently and in more intense interactions than females. Hares displayed dominance hierarchies in pens, at feeding stations in the wild, and in a completely natural situation. Males were most dominant in the winter, but females were most dominant during the summer breeding season. It is suggested that the switch in dominance occurred because of changes in the approach behaviour of males towards females. In view of the aggression exhibited by this species, further investigation of behavioural population regulation hypotheses is warranted.

Observations on the behaviour of the smoky mouse Pseudomys fumeus (Rodentia: Muridae).

2000 ◽  
Vol 22 (1) ◽  
pp. 35 ◽  
Author(s):  
RE Woods ◽  
FD Ford
Keyword(s):  
Social Interactions ◽  
Breeding Season ◽  
Wild Population ◽  
New South ◽  
Post Partum ◽  
Small Sample ◽  
Wild Populations ◽  
South Wales ◽  
In Captivity ◽  
In The Wild

This study examined aspects of behaviour in a captive colony of smoky mice, Pseudomys fumeus, over a two year period. Wherever possible behaviours observed in the captive population are compared to data collected in a study of a wild population in south-eastern New South Wales. This paper provides the first recorded observations of behavior in this species. Both captive and wild populations of P. fumeus display strictly nocturnal circadian activity rhythms. In the captive study, P. fumeus were found to exhibit social interactions similar to some previously studied Pseudomys species. However, in the wild, the species was found to communally nest during the breeding season, behaviour not observed in other Pseudomys from similar habitats. P. fumeus in captivity can have more than two litters in one breeding season which suggests that their reproductive parameters are more flexible than previous studies of wild populations have shown. Field data indicate that post-partum oestrus can occur in this species, and that gestation lasts for approximately 30 days, although these observations are based on a small sample.

scholarly journals Phenotypic plasticity of labile traits in the wild

2013 ◽  
Vol 59 (4) ◽  
pp. 485-505 ◽  
Author(s):  
Jon E. Brommer
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Statistical Approach ◽  
Scale Up ◽  
Population Level ◽  
Wild Populations ◽  
Quantitative Genetic ◽  
In The Wild ◽  
The Individual ◽  
Quantitative Genetic Parameters

Abstract Individual-based studies allow quantification of phenotypic plasticity in behavioural, life-history and other labile traits. The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically significant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild populations, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that ‘scale up’ to population level processes and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated.

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

scholarly journals A fencing experiment on a high-density population of Microtus townsendii

1977 ◽  
Vol 55 (7) ◽  
pp. 1166-1175 ◽  
Author(s):  
Rudy Boonstra ◽  
Charles J. Krebs
Keyword(s):  
Survival Rate ◽  
Breeding Season ◽  
Population Regulation ◽  
Control Area ◽  
High Density ◽  
Low Density ◽  
Vole Population ◽  
Sharp Decline ◽  
Density Population ◽  
Microtus Townsendii

If dispersal is prevented, a low-density vole population will increase to unusually high densities. A mouse-proof fence was constructed around a vole population that had already reached high density and both this population and one on a control area were live-trapped from January 1975 to November 1975. The population on the control remained at peak densities. The enclosed population increased to even higher density once the breeding season had started and had a higher survival rate than the control population. By midsummer the enclosed population had severely overgrazed the vegetation and went into a sharp decline. Dispersal losses from the control were estimated at 32% for males and 31% for females in these high-density populations. Microtus townsendii populations thus responded to a fence in a manner similar to that of other species that have been studied. This experiment indicates the importance of dispersal to population regulation in voles even at peak densities.

scholarly journals Telomere heritability and parental age at conception effects in a wild avian population

2020 ◽  
Author(s):  
Alexandra Sparks ◽  
Lewis G. Spurgin ◽  
Marco van der Velde ◽  
Eleanor A. Fairfield ◽  
Jan Komdeur ◽  
...  
Keyword(s):  
Animal Models ◽  
Telomere Length ◽  
Paternal Age ◽  
Parental Age ◽  
Wild Populations ◽  
Evolutionary Potential ◽  
Confounding Variables ◽  
In The Wild ◽  
Seychelles Warbler ◽  
Heritability Estimates

Individual variation in telomere length is predictive of health and mortality risk across a range of species. However, the relative influence of environmental and genetic variation on individual telomere length in wild populations remains poorly understood. In previous studies, heritability of telomere length has primarily been calculated using parent-offspring regression, but shared environments can confound such estimates. Furthermore, associations with age and parental age at conception effects are typically not accounted for but can also bias heritability estimates. To control for these confounding variables, quantitative genetic ‘animal models’ can be used. However, the few studies on wild populations using this approach have been restricted by power. Here, we investigated the heritability of telomere length and parental age at conception effects in the Seychelles warbler using 2664 telomere length measures from 1318 birds over 20 years and a multi-generational pedigree. We found a weak negative within-paternal age at conception effect (as fathers aged, their offspring had shorter telomeres) and a weak positive between-maternal age at conception effect (females that survived to older ages had offspring with longer telomeres). While parent–offspring regressions did not detect heritability, animal models provided evidence that heritability of telomere length was low in this population. Environmental and technical variation largely influenced telomere length and would have biased heritability estimates if unaccounted for. Estimating the heritability of telomere length is complex, requiring large sample sizes and accounting for confounding effects in order to improve our understanding of the evolutionary potential of telomere length in the wild.

Dynamics of a snow shoe hare population in fragmented habitat

1993 ◽  
Vol 71 (7) ◽  
pp. 1385-1392 ◽  
Author(s):  
Lloyd B. Keith ◽  
Sara E. M. Bloomer ◽  
Tomas Willebrand
Keyword(s):  
Patch Size ◽  
Canis Latrans ◽  
Lepus Americanus ◽  
Fragmented Habitat ◽  
Proximate Cause ◽  
Lower Survival ◽  
The Third ◽  
Snowshoe Hares ◽  
Poorly Drained Soils ◽  
Hare Population

During November 1988 – December 1991 we livetrapped, radio-collared, and monitored the survival, reproduction, and movements of snowshoe hares (Lepus americanus) in highly fragmented habitat near the species' geographic limit in central Wisconsin. Our 7 study areas centered on 5- to 28-ha patches of prime habitat: dense stands of willow (Salix), alder (Alnus), and regenerating aspen (Populus) on poorly drained soils. Maximum hare densities averaged 1.6 – 0.8/ha, and were unrelated to patch size. Rapid declines to extinction occurred on 3 of the 5 smallest study areas; on another, where extinction seemed imminent, juvenile ingress restored the population. On the 2 largest areas (23 – 28 ha of prime habitat) hare populations were stationary during the first 2 years, but declined by 50 – 70% in the third as mean annual (September – August) survival of radio-collared hares fell from 0.27 (1988 – 1990) to 0.07 (1990 – 1991). Annual survival on the 3 extinction sites averaged just 0.015 compared with 0.179 elsewhere. Reproduction did not differ between small (5 – 7 ha) vs. larger (23 – 28 ha) patches nor between years. Estimated dispersal of adult and juvenile hares from the 5 small study areas was twice as high as from the 2 larger, viz. 16 vs. 35% annually. Dispersers appeared to have markedly lower survival. Predation, chiefly by coyotes (Canis latrans), was the proximate cause of 96% (117 of 122) of natural deaths among radio-collared hares, and was therefore the overwhelming determinant of survival and thus population trend. Results of this study suggest that probabilities of extinction in such fragmented habitat depend importantly on patch size and attendant hare numbers; i.e., fall populations of < 10 hares frequenting patches of prime habitat ≤ 5 ha are not likely to persist long without ingress.

A preliminary study of regeneration in wild populations of threatened endemic Hawaiian palms (Pritchardia; Arecaceae)

2007 ◽  
Vol 13 (1) ◽  
pp. 20 ◽  
Author(s):  
Melany H. Chapin ◽  
Mike Maunder ◽  
Katherine E. Horak
Keyword(s):  
Seed Predation ◽  
Conservation Management ◽  
Management Strategies ◽  
Ecological Change ◽  
Wild Populations ◽  
In The Wild ◽  
Human Colonization ◽  
Preliminary Study ◽  
Term Management

Island floras have been subject to catastrophic changes since human colonization; the Hawaiian Islands exemplify this pattern of species decline and ecological change. Archaeological and historic findings support the former existence of coastal, lowland and interior Pritchardia dominated forests. Wild Pritchardia populations are highly fragmented and exhibit poor or absent regeneration in the wild. This study records seed predation, goat grazing, pig damage, and human harvesting on six wild populations of three species and outlines requirements for the long-term management of wild populations. Only one population of the six studied was found to contain seedlings. Recommended conservation management strategies are outlined.

Reproductive isolation between two closely related species of the Queensland fruit fly Dracus tryoni (Frogg) and D. neohumeralis Hardy (Diptera : Tephritidae) I. Variation in humeral callus pattern and the occurrence of intermediate colour forms in the wild

1967 ◽  
Vol 15 (3) ◽  
pp. 501 ◽  
Author(s):  
H Wolda
Keyword(s):  
Reproductive Isolation ◽  
Related Species ◽  
Fruit Fly ◽  
Abundant Species ◽  
Colour Pattern ◽  
Wild Populations ◽  
Closely Related Species ◽  
Similar Variation ◽  
In The Wild

A number of samples from wild populations of the Queensland fruit fly, Dacus tryoni and D. neohumeralis, were studied. There is a considerable variation in the colour pattern on the humeral callus. This variation is continuous so that any criterion for distinguishing between "intermediates" and "good species" is purely arbitrary. It was found in areas where D. neohumeralis does not occur as well as in localities where it is very abundant. By whatever criterion one defines intermediates, there appears to be no relation between the frequency of such forms and the presence or absence of D. neohumeralis or with the relative proportions of the two species in the population. However, flies with only a very small yellow area on an otherwise brown humeral callus were found only in Cairns where D. neohumeralis is usually the most abundant species. A similar variation in humeral callus pattern was found in other related species, such as D. kraussi and D. halfordiae. It is concluded that the intermediate colour forms may not be hybrids between D. tryoni and D. neohumeralis but variants of D. tryoni and, possibly the darker forms from Cairns, of D. neohumeralis.

scholarly journals Are model organisms representative for climate change research? Testing thermal tolerance in wild and laboratory zebrafish populations

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Rachael Morgan ◽  
Josefin Sundin ◽  
Mette H Finnøen ◽  
Gunnar Dresler ◽  
Marc Martínez Vendrell ◽  
...  
Keyword(s):  
Climate Change ◽  
Thermal Tolerance ◽  
Thermal Environment ◽  
Model Organisms ◽  
Acclimation Temperature ◽  
Wild Populations ◽  
Climate Change Research ◽  
Genetic Traits ◽  
In The Wild ◽  
Laboratory Acclimation

Abstract Model organisms can be useful for studying climate change impacts, but it is unclear whether domestication to laboratory conditions has altered their thermal tolerance and therefore how representative of wild populations they are. Zebrafish in the wild live in fluctuating thermal environments that potentially reach harmful temperatures. In the laboratory, zebrafish have gone through four decades of domestication and adaptation to stable optimal temperatures with few thermal extremes. If maintaining thermal tolerance is costly or if genetic traits promoting laboratory fitness at optimal temperature differ from genetic traits for high thermal tolerance, the thermal tolerance of laboratory zebrafish could be hypothesized to be lower than that of wild zebrafish. Furthermore, very little is known about the thermal environment of wild zebrafish and how close to their thermal limits they live. Here, we compared the acute upper thermal tolerance (critical thermal maxima; CTmax) of wild zebrafish measured on-site in West Bengal, India, to zebrafish at three laboratory acclimation/domestication levels: wild-caught, F1 generation wild-caught and domesticated laboratory AB-WT line. We found that in the wild, CTmax increased with increasing site temperature. Yet at the warmest site, zebrafish lived very close to their thermal limit, suggesting that they may currently encounter lethal temperatures. In the laboratory, acclimation temperature appeared to have a stronger effect on CTmax than it did in the wild. The fish in the wild also had a 0.85–1.01°C lower CTmax compared to all laboratory populations. This difference between laboratory-held and wild populations shows that environmental conditions can affect zebrafish’s thermal tolerance. However, there was no difference in CTmax between the laboratory-held populations regardless of the domestication duration. This suggests that thermal tolerance is maintained during domestication and highlights that experiments using domesticated laboratory-reared model species can be appropriate for addressing certain questions on thermal tolerance and global warming impacts.

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