Development of Reproductive Maturity in Adélie Penguins

1975 ◽  
pp. 139-157 ◽  
Author(s):  
David G. Ainley
Keyword(s):  
Reproductive Maturity ◽  
Adélie Penguins

Inter-individual differences in the foraging behavior of breeding Adélie penguins are driven by individual quality and sex

2020 ◽  
Vol 636 ◽  
pp. 189-205
Author(s):  
A Lescroël ◽  
PO’B Lyver ◽  
D Jongsomjit ◽  
S Veloz ◽  
KM Dugger ◽  
...  
Keyword(s):  
Individual Differences ◽  
Foraging Behavior ◽  
Ross Sea ◽  
Individual Quality ◽  
High Quality ◽  
Breeding Experience ◽  
Age Related ◽  
Demographic Traits ◽  
Iteroparous Species ◽  
Adélie Penguins

Inter-individual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in individual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an individual can allocate to reproduction and self-maintenance, foraging behavior is a key trait to study to better understand the mechanisms underlying these differences. So far, most seabird studies have focused on the effect of maturation and learning processes on foraging performance, while only a few have included measures of individual quality. Here, we investigated the effects of age, breeding experience, sex, and individual breeding quality on the foraging behavior and location of 83 known-age Adélie penguins at Cape Bird, Ross Sea, Antarctica. Over a 2 yr period, we showed that (1) high-quality birds dived deeper than lower quality ones, apparently catching a higher number of prey per dive and targeting different foraging locations; (2) females performed longer foraging trips and a higher number of dives compared to males; (3) there were no significant age-related differences in foraging behavior; and (4) breeding experience had a weak influence on foraging behavior. We suggest that high-quality individuals have higher physiological ability, enabling them to dive deeper and forage more effectively. Further inquiry should focus on determining the physiological differences among penguins of different quality.

Maintenance of nest quality in Adélie penguins Pygoscelis adeliae: an additional benefit to life in the center

Polar Biology ◽  
2021 ◽  
Author(s):  
Virginia Morandini ◽  
Katie M. Dugger ◽  
Amélie Lescroël ◽  
Annie E. Schmidt ◽  
Grant Ballard
Keyword(s):  
Additional Benefit ◽  
Pygoscelis Adeliae ◽  
Nest Quality ◽  
Adélie Penguins

Effect of management factors on tiller dynamics in tall fescue: Numbers of tillers reaching reproductive maturity

1996 ◽  
Vol 13 (2) ◽  
pp. 63-66
Author(s):  
R.L. Phillips ◽  
N.M. Tainton ◽  
J.D.H. Reusch ◽  
D.E.A. Cumming
Keyword(s):  
Tall Fescue ◽  
Reproductive Maturity ◽  
Management Factors ◽  
Tiller Dynamics

Rates of Evolution in Ancient DNA from Adelie Penguins

Science ◽  
2002 ◽  
Vol 295 (5563) ◽  
pp. 2270-2273 ◽  
Author(s):  
D. M. Lambert
Keyword(s):  
Ancient Dna ◽  
Rates Of Evolution ◽  
Adélie Penguins

Twinning in Susceptible Mothers—An Exploratory Study of International Data by Payami's Models Suggests “Reproductive Maturity” as a Risk Factor

1991 ◽  
Vol 40 (3-4) ◽  
pp. 269-289 ◽  
Author(s):  
P. Philippe
Keyword(s):  
Maternal Age ◽  
Comparison Group ◽  
Linear Increase ◽  
Reproductive Maturity ◽  
Secondary Exposure ◽  
Twin Birth ◽  
Age Dependent ◽  
Common Etiology ◽  
International Data ◽  
The Common

AbstractAn attempt has been made to apply Payami's models to maternal age-specific twin birth prevalences in several countries. The models disclose the heterogeneity of a cohort and spell out the risks to susceptible members (who will actually get the disease) according to age (or time). Payami's method specifies that the typical cohort of susceptibles is ascribed to two exposures: a potent and generalised exposure and a very low or no risk secondary exposure. The models have been adjusted to international data from current as well as old populations, of Occidental and Japanese origin. Results show that cohorts of twin-prone mothers aged 25 to 45 are homogeneous. A single dominant etiology is suggested which applies to both MZ and DZ twins. Heterogeneity, from 10% to 25%, is present in all countries whenever the 20-24 age group is involved. A separate study of illegitimate twin births from Denmark reduces the heterogeneity and shows that MZ illegitimate twin births are due to a secondary exposure responsible for a distinct twinning etiology. The age-specific risks of a MZ illegitimate twin birth are much higher than those of any comparison group, and are constant until age 35 years. This suggests a single-hit exposure akin to a neuroendocrine stimulus which short-cuts the usual age-dependent etiologic pathway. MZ and DZ twins both experience the same maternal age specific risks, an observation which underscores the common etiology of both types of twins. Risks increase with age from age 20 to 45 years. The pattern according to age varies among countries and time periods. Occidental populations have a pattern varying from an exponential to a more linear increase in old and recent populations, respectively. Only present-day Japan displays a logarithmic-like growth curve. The concept of “reproductive maturity” is introduced, and related to the secular trend of the DZ twin birth risk and to its variation across countries. Two new conclusions are drawn: a) The higher the rate of reproductive maturity, the less the DZ twin birth risk and, b) Reproductive maturity determines the maternal age-specific gonadotropin levels.

Historical and phenological observations on the spread of Chaenorrhinum minus across North America

1983 ◽  
Vol 61 (1) ◽  
pp. 179-187 ◽  
Author(s):  
Mark P. Widrlechner
Keyword(s):  
North America ◽  
Rapid Onset ◽  
Herbarium Specimens ◽  
Reproductive Maturity ◽  
Phenological Data ◽  
Dispersal Mechanism ◽  
Rapid Spread ◽  
The Relationship

Through a review of floristic and taxonomic literature and an examination of over 1500 herbarium specimens, this report documents the rapid spread of Chaenorrhinum minus (L.) Lange along railroads across North America. The relationship between C. minus and railroads is described and phenological data on flowering and fruiting are presented. The combination of an effective dispersal mechanism and the rapid onset of reproductive maturity contributes to the species' adaptive success.

scholarly journals Cephalopods in the diets of Emperor and Adelie penguins in Adelie Land, Antarctica

1985 ◽  
Vol 86 (2) ◽  
pp. 199-202 ◽  
Author(s):  
C. Offredo ◽  
V. Ridoux ◽  
M. R. Clarke
Keyword(s):  
Adélie Penguins

scholarly journals The influence of subcolony-scale nesting habitat on the reproductive success of Adélie penguins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Annie E. Schmidt ◽  
Grant Ballard ◽  
Amélie Lescroël ◽  
Katie M. Dugger ◽  
Dennis Jongsomjit ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Colony Size ◽  
Nest Predation ◽  
Size Variation ◽  
Area Ratio ◽  
Slope Aspect ◽  
Nesting Habitat ◽  
Terrain Attributes ◽  
Small Colony ◽  
Adélie Penguins

AbstractGroup-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic parameter that can impact colony size, and it varies in association with a number of factors, including nesting habitat quality. Within colonies, seabirds often aggregate into distinct groups or subcolonies that may vary in quality. We used data from two colonies of Adélie penguins 73 km apart on Ross Island, Antarctica, one large and one small to investigate (1) How subcolony habitat characteristics influence reproductive success and (2) How these relationships differ at a small (Cape Royds) and large (Cape Crozier) colony with different terrain characteristics. Subcolonies were characterized using terrain attributes (elevation, slope aspect, slope steepness, wind shelter, flow accumulation), as well group characteristics (area/size, perimeter-to-area ratio, and proximity to nest predators). Reproductive success was higher and less variable at the larger colony while subcolony characteristics explained more of the variance in reproductive success at the small colony. The most important variable influencing subcolony quality at both colonies was perimeter-to-area ratio, likely reflecting the importance of nest predation by south polar skuas along subcolony edges. The small colony contained a higher proportion of edge nests thus higher potential impact from skua nest predation. Stochastic environmental events may facilitate smaller colonies becoming “trapped” by nest predation: a rapid decline in the number of breeding individuals may increase the proportion of edge nests, leading to higher relative nest predation and hindering population recovery. Several terrain covariates were retained in the final models but which variables, the shapes of the relationships, and importance varied between colonies.

Sea-ice and density-dependent factors affecting foraging habitat and behaviour of Adélie penguins throughout the breeding season

2021 ◽  
Vol 168 (7) ◽  
Author(s):  
Nobuo Kokubun ◽  
Louise Emmerson ◽  
Julie McInnes ◽  
Barbara Wienecke ◽  
Colin Southwell
Keyword(s):  
Sea Ice ◽  
Breeding Season ◽  
Foraging Habitat ◽  
Factors Affecting ◽  
Density Dependent ◽  
Adélie Penguins

scholarly journals Early and late fawn mortality in a remnant population of Arabian gazelles (Gazella arabica)

2021 ◽  
Author(s):  
Benny Shalmon ◽  
Ping Sun ◽  
Torsten Wronski
Keyword(s):  
Developmental Stages ◽  
Cox Regression ◽  
Mortality Rates ◽  
Female Offspring ◽  
Maximum Temperature ◽  
Reproductive Maturity ◽  
Fawn Survival ◽  
Conservation History ◽  
Offspring Sex ◽  
Weaning Age

AbstractThe Arabian gazelle (Gazella arabica) population in Israel has experienced a turbulent conservation history and repeatedly faced local extinction. Low fawn survival was considered the main cause for the constant decline. In our study, we analyzed instantaneous fawn mortality rates, using a binomial coding at three different developmental stages, i.e., mortality rates to 3 months after parturition (weaning age), to 5 months after parturition (male fawns leave their mothers), and to the age of reproductive maturity, i.e., recruitment (12 months). We used a dataset obtained from 20 individually discernible mothers and their fawns (49 females and 48 males) born between June 2006 and September 2019. To explore causes for the fawn mortality rates, parental- (age of the mother at parturition) and offspring-related attributes (offspring sex), year of birth, together with one weather variable (mean monthly maximum temperature) were included as independent variables into three independent mixed effects cox regression models. Out of 97 fawns, 92 survived to weaning age, 73 to the age of 5 months and only 7 to the age of reproductive maturity. Temperature had significant effects on instantaneous fawn mortality rates, suggesting that low temperatures were detrimental to the survival of fawns after weaning (4–5 months) and male dispersal age (6–12 months). Male offspring encountered a higher instantaneous mortality rate than female offspring at the age of 6–12 months. Moreover, fawns from less experienced mother (young age at parturition) experienced higher mortality. Our results were in line with previous studies on fawn mortality observed in other desert dwelling ungulates.

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