Are day-active small mammals rare and small birds abundant in Australian desert environments because small mammals are inferior thermoregulators?

2004 ◽  
Vol 26 (2) ◽  
pp. 117 ◽  
Author(s):  
PC Withers ◽  
CE Cooper ◽  
WA Buttemer
Keyword(s):  
Life History ◽  
Small Mammals ◽  
Life History Traits ◽  
Activity Patterns ◽  
Direct Result ◽  
Desert Environment ◽  
Geographic Scale ◽  
Terrestrial Mammals ◽  
Physiological Capacity ◽  
Physiological Adjustments

Small desert birds are typically diurnal and highly mobile (hence conspicuous) whereas small non-volant mammals are generally nocturnal and less mobile (hence inconspicuous). Birds are more mobile than terrestrial mammals on a local and geographic scale, and most desert birds are not endemic but simply move to avoid the extremes of desert conditions. Many small desert mammals are relatively sedentary and regularly use physiological adjustments to cope with their desert environment (e.g., aestivation or hibernation). It seems likely that prey activity patterns and reduced conspicuousness to predators have reinforced nocturnality in small desert mammals. Differences such as nocturnality and mobility simply reflect differing life-history traits of birds and mammals rather than being a direct result of their differences in physiological capacity for tolerating daytime desert conditions.

Sexual dimorphism and age structure of the Montseny newt (Calotriton arnoldi)

2015 ◽  
Vol 36 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Fèlix Amat ◽  
Neus Oromí ◽  
Delfí Sanuy ◽  
Salvador Carranza
Keyword(s):  
Life History ◽  
Sexual Dimorphism ◽  
Age Structure ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Geographic Scale ◽  
Total Body ◽  
Similar Body ◽  
Two Populations ◽  
Small Geographic Scale

Patterns of sexual dimorphism and age structure were investigated in two populations of the newtCalotriton arnoldi, endemic of the Montseny Massif (NE of the Iberian Peninsula). In contrast to the Pyrenean newt (Calotriton asper) sexual dimorphism in the Montseny brook newt is characterized by slightly larger females (60.3 ± 0.3 mm; maximum: 68 mm) than males (59.5 ± 0.2 mm; maximum: 64 mm) and more similar body shape between sexes. Both populations and sexes mature at the same age (3 years), show the same age structure and achieve similar longevity (8-9 years). Comparing our results with the framework of the variation of life-history traits inCalotriton, the Montseny newts exhibit fast sexual maturity and short longevity. Curiously, we have found a lack of covariation between age at sexual maturity, longevity and total body size in the populations ofCalotritonspecies. Only in males, age at sexual maturity seems to be affected by altitude, but in an unexpected way: sexual maturation is delayed in populations at low altitudes. Moreover, the age at sexual maturity does not differs between the populations where immatures are terrestrial vs. those where they remain aquatic. Our results suggest that life-history traits inCalotritonnewts could be determined by selective factors that play their role at small geographic scale.

Short-Term Effects of Fuel Reduction Burning on Populations of Small Terrestrial Mammals

1989 ◽  
Vol 16 (2) ◽  
pp. 117 ◽  
Author(s):  
MB Thompson ◽  
G Medlin ◽  
R Hutchinson ◽  
N West
Keyword(s):  
Population Dynamics ◽  
Small Mammals ◽  
Direct Result ◽  
Fuel Reduction ◽  
Short Term ◽  
Terrestrial Mammals ◽  
Low Intensity ◽  
Sclerophyll Forest ◽  
Rattus Fuscipes ◽  
Low Levels

Small mammals (Rattus fuscipes, Mus musculus, Antechinus flavipes, Isoodon obesulus) were livetrapped for 18 months prior to fuel reduction burning (FRB) in dry sclerophyll forest dominated by Eucalyptus obliqua south of Adelaide. Although the fire prescription was hotter than that normally conducted for a FRB in this habitat, the fire was of low intensity, removing most of the litter and understorey but only singeing the canopy in a few places. Trapping continued for 16 months after the burn, when the study site was destroyed by a wildfire (Ash Wednesday, 16 February 1983). No animals were known to have died as a direct result of the FRB and little effect was observed on the population dynamics of A. flavipes. However, numbers of R. fuscipes declined precipitously in the 3 months following the FRB and remained at low levels with no summer recruitment of juveniles over the following 16 months (2 summers) as there had been in the summer prior to the FRB. No movements to unburned areas were recorded in either species after the FRB. There was no influx of M, musculus after the fire and there was no marked affect on the population of I. obesulus.

Prey tell: what quillback rockfish early life history traits reveal about their survival in encounters with juvenile coho salmon

2020 ◽  
Vol 650 ◽  
pp. 7-18 ◽  
Author(s):  
HW Fennie ◽  
S Sponaugle ◽  
EA Daly ◽  
RD Brodeur
Keyword(s):  
Life History ◽  
Early Life ◽  
Life History Traits ◽  
Direct Evidence ◽  
Coho Salmon ◽  
Larval Fish ◽  
Early Life History ◽  
In The Wild ◽  
Otolith Microstructure Analysis ◽  
Pelagic Juvenile

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.

Life History Traits in a Population of Pelobates syriacus (Boettger, 1889) from Turkey

2020 ◽  
Vol 27 (4) ◽  
pp. 195-200
Author(s):  
Ufuk Bülbül ◽  
Halime Koç ◽  
Yasemin Odabaş ◽  
Ali İhsan Eroğlu ◽  
Muammer Kurnaz ◽  
...  
Keyword(s):  
Life History ◽  
Age Structure ◽  
Life History Traits ◽  
Spadefoot Toad ◽  
Males And Females

Age structure of the eastern spadefoot toad, Pelobates syriacus from the Kızılırmak Delta (Turkey) were assessed using phalangeal skeletochronology. Snout-vent length (SVL) ranged from 42.05 to 86.63 mm in males and 34.03 to 53.27 mm in females. Age of adults ranged from 2 to 8 years in males and 3 to 5 years in females. For both sexes, SVL was significantly correlated with age. Males and females of the toads reached maturity at 2 years of age.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

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