scholarly journals Variation in Size, Composition, and Quality of Ruddy Duck Eggs and Ducklings

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Jeffrey T. Pelayo ◽  
Robert G. Clark
Keyword(s):  
Body Size ◽  
Egg Size ◽  
Size Composition ◽  
Egg Mass ◽  
Direct Proportion ◽  
Female Body Size ◽  
Ruddy Duck ◽  
Better Than ◽  
Oxyura Jamaicensis

AbstractTo evaluate why ducklings hatching from large eggs generally survive better than ducklings from small eggs, we quantified egg-size-related variation in composition and quality of eggs and ducklings of wild Ruddy Ducks (Oxyura jamaicensis). Fresh egg mass averaged 74.1 ± 4.3 g (SD), but ranged from 60.5 to 83.8 g. Despite remarkably large egg size relative to adult female body size, and a 1.4-fold difference in mass between the smallest and largest eggs, most egg constituents increased in direct proportion to fresh egg mass, with bigger eggs producing heavier and larger ducklings. However, large ducklings had proportionately larger yolk sac stores than did small ducklings. Thus, large ducklings also had greater total lipid reserves, an advantage that could enable them to survive better than small ducklings during the first few days after hatching.Variación en el Tamaño, Composición y Calidad de los Huevos y Polluelos de Oxyura jamaicensisResumen. Para evaluar por qué los polluelos que eclosionan de huevos grandes sobreviven mejor que polluelos provenientes de huevos pequeños, cuantificamos la variación en la composición y calidad de huevos y polluelos en relación al tamaño del huevo en Oxyura jamaicensis. La masa fresca de los huevos promedió 74.1 ± 4.3 g (DE), pero varió entre 60.5 y 83.8 g. A pesar del gran tamaño de los huevos en relación al tamaño corporal de la hembra, y de una diferencia de 1.4 veces en la masa entre el huevo más pequeño y él más grande, la mayoría de los componentes del huevo aumentaron en proporción directa con la masa fresca del huevo. Huevos más grandes produjeron polluelos más grandes y pesados. Sin embargo, polluelos grandes presentaron relativamente mayores reservas en el saco vitelino que polluelos pequeños. Por lo tanto, los polluelos grandes también presentaron una mayor reserva total de lípidos, ventaja que podría permitirles sobrevivir mejor que a los polluelos más pequeños durante los primeros días luego de la eclosión.

scholarly journals Juvenile exposure to predator cues induces a larger egg size in fish

2011 ◽  
Vol 279 (1731) ◽  
pp. 1241-1248 ◽  
Author(s):  
Francisca H. I. D. Segers ◽  
Barbara Taborsky
Keyword(s):  
Body Size ◽  
Predation Risk ◽  
Egg Size ◽  
Growth Trajectories ◽  
Egg Mass ◽  
Offspring Survival ◽  
Predator Cues ◽  
Female Body Size ◽  
Natural Predator ◽  
Perceived Predation Risk

When females anticipate a hazardous environment for their offspring, they can increase offspring survival by producing larger young. Early environmental experience determines egg size in different animal taxa. We predicted that a higher perceived predation risk by juveniles would cause an increase in the sizes of eggs that they produce as adults. To test this, we exposed juveniles of the mouthbrooding cichlid Eretmodus cyanostictus in a split-brood experiment either to cues of a natural predator or to a control situation. After maturation, females that had been confronted with predators produced heavier eggs, whereas clutch size itself was not affected by the treatment. This effect cannot be explained by a differential female body size because the predator treatment did not influence growth trajectories. The observed increase of egg mass is likely to be adaptive, as heavier eggs gave rise to larger young and in fish, juvenile predation risk drops sharply with increasing body size. This study provides the first evidence that predator cues perceived by females early in life positively affect egg mass, suggesting that these cues allow her to predict the predation risk for her offspring.

Annual variations in reproductive characteristics of painted turtles (Chrysemys picta)

1986 ◽  
Vol 64 (5) ◽  
pp. 1148-1151 ◽  
Author(s):  
Lin Schwarzkopf ◽  
Ronald J. Brooks
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Repeated Measures ◽  
Egg Size ◽  
Annual Variation ◽  
Egg Mass ◽  
Annual Variations ◽  
Painted Turtles ◽  
Sources Of Variation ◽  
Clutch Mass

In Algonquin Park, Ontario, body size and clutch characteristics were recorded for 51 female painted turtles (Chrysemyspicta) in 1983, 61 in 1984, and 24 in 1985. Clutch size, clutch mass, and egg width correlated significantly with body size (carapace length) in all 3 years. Egg length and egg mass were significantly related to body size in 1984 and 1985, but not in 1983. There were no significant correlations of egg width or egg mass to clutch size. For a group of the same individuals compared by repeated-measures ANOVA, mean clutch mass and mean egg size, but not mean clutch size, varied significantly among years. Correlation of egg size with body size, lack of correlation between egg size and clutch size, and annual variation in egg size, but not clutch size, all fail to support current versions of optimal egg size theory. Twenty-six females nested in both 1983 and 1984 and 11 females nested in both 1984 and 1985. Fourteen females nested twice in 1 year: six in 1983 and eight in 1984. Between 43 and 73% of adult females nested in a given year and 12–13% nested twice in a single season. These estimates are similar to those reported for other populations of this species. It appears that variations in both clutch size (frequency) and egg size are important sources of variation in reproductive output.

Clutch and egg size of the tropical lizard Tropidurus torquatus (Tropiduridae) along its geographic range in coastal eastern Brazil

2008 ◽  
Vol 86 (12) ◽  
pp. 1376-1388 ◽  
Author(s):  
M. C. Kiefer ◽  
M. Van Sluys ◽  
C. F.D. Rocha
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Female Body ◽  
Egg Size ◽  
Reproductive Investment ◽  
Geographic Range ◽  
Minimum Size ◽  
Brazilian Coast ◽  
Female Body Size ◽  
Almost All

The tropidurid lizard Tropidurus torquatus (Wied, 1820) has a set of populations inhabiting coastal sand dune habitats (“restinga”) along the eastern Brazilian coast. Despite its wide geographic range, there is no information about geographic variation in reproductive features among its populations. In the present study we compared some reproductive aspects of females in 10 coastal populations of T. torquatus, aiming to evaluate to what extension they vary geographically. The minimum size at maturity was relatively similar to most populations, but mean female body size had a considerable variation. Clutch size of almost all coastal populations of T. torquatus had little variation and was composed predominantly of two eggs. Interpopulational variation in the mean egg volume was relatively wide and strongly influenced by the variation in mean female body size. The data of the present study indicated that females of almost all coastal populations of T. torquatus produce, predominantly, clutches with two eggs and invest more energy in egg size instead of clutch size, probably as a consequence of morphological and environmental factors. The increased reproductive investment in egg size was confirmed by the values obtained for the relative clutch mass, which remained relatively constant along the coastal geographic distribution of T. torquatus.

Within-clutch egg-size variation in a subsocial bug: the positional effect hypothesis

2006 ◽  
Vol 84 (11) ◽  
pp. 1540-1544 ◽  
Author(s):  
Shin-ichi Kudo
Keyword(s):  
Predation Risk ◽  
Clutch Size ◽  
Egg Size ◽  
Size Variation ◽  
Instar Nymph ◽  
Offspring Size ◽  
Egg Mass ◽  
Female Body Size ◽  
Positional Effect ◽  
Effect Hypothesis

If there are differences in predation risk among the offspring within a clutch, parents should allocate less resources to the offspring facing higher risk. Predation risk, and thus offspring size, may depend on the spatial position of individual offspring within a clutch. To test this positional effect hypothesis, I examined egg-size (egg-mass) variation in the subsocial bug Elasmucha signoreti Scott, 1874 (Hemiptera: Acanthosomatidae). In subsocial insects, including Elasmucha , in which females guard their clutches against predators by covering the clutch with their bodies, there are large differences in survival between offspring at the centre and at the periphery of the clutch. There was considerable variation in reproductive output among females; female body size was positively correlated with egg mass but not with clutch size. Females laid significantly lighter eggs in the peripheral, and thus more vulnerable, part of the clutch. No phenotypic trade-off between egg mass and clutch size was detected. Egg mass was positively correlated with hatched first-instar nymph mass. Thus, E. signoreti females seem to allocate their resources according to the different predation risks faced by the offspring within a clutch. I suggest that the positional effect hypothesis can generally be applicable to species whose females lay eggs in clutches and that the eggs suffer different mortality rates which depend on their spatial positions within the clutch.

Female reproductive characteristics of the Balkan wall lizard (Podarcis taurica) in the northwestern periphery of its range

2010 ◽  
Vol 5 (3) ◽  
pp. 391-395 ◽  
Author(s):  
Katarina Ljubisavljević ◽  
Georg Džukić ◽  
Miloš Kalezić
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Breeding Season ◽  
Egg Size ◽  
Reproductive Traits ◽  
Species Range ◽  
Trade Off ◽  
Female Body Size ◽  
Female Reproductive Traits ◽  
Gravid Females

AbstractWe present data on the female reproductive traits of the Balkan wall lizard in the Deliblato Sand, a large continental sandland in the Pannonian area in the northwestern periphery of the species range. The clutch and egg characteristics of the population were investigated on the basis of clutches laid in laboratory conditions by gravid females captured in one locality. Balkan wall lizards produced at least two clutches in a breeding season. Individual females laid clutches of commonly two (range 1–4) eggs. The female body size had no effect on clutch and egg size. There was no trade-off between egg size and clutch size.

scholarly journals ISOMETRY OF EGG SIZE IN A TEXAS POPULATION OF THE TURTLE STERNOTHERUS ODORATUS THAT EXHIBITS A NEARLY FIXED CLUTCH SIZE

2020 ◽  
pp. 13-17
Author(s):  
Peter V. Lindeman
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Egg Size ◽  
Female Body Size ◽  
Competing Demands ◽  
Sternotherus Odoratus ◽  
Central Texas ◽  
Relationship Of ◽  
The Relationship ◽  
Anatomical Constraints

In evaluating optimal egg-size theory and the effects of anatomical constraints on egg size in turtles, pivotal questions concern the significance of the relationship of egg size to female body size and whether the relationship is isometric or hypoallometric. In a central Texas population of the kinosternid turtle Sternotherus odoratus in which clutch size of a sample of turtles was nearly fixed (seven of eight females had two eggs while the largest female had three eggs), there was an isometric increase in egg width with body size among the females with two-egg clutches and significantly reduced egg width in the largest female’s three-egg clutch. Allometric analyses of populations that exhibit little variation in clutch size, as well as analysis of modal clutch sizes in populations with more variable clutch sizes, both have the potential to further illuminate the competing demands of increasing egg size vs. increasing clutch size as females grow larger, enabling them to optimize their reproductive output as it increases with body size.

scholarly journals Variations in the reproductive strategies of three populations of Phrynocephalus helioscopus in China

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5705
Author(s):  
Tao Liang ◽  
Lu Zhou ◽  
Wenfeng He ◽  
Lirong Xiao ◽  
Lei Shi
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Reproductive Strategies ◽  
Female Body ◽  
Egg Size ◽  
Reproductive Traits ◽  
Breeding Period ◽  
Female Body Size ◽  
Trade Offs ◽  
Morphological Constraint

Background Egg size and clutch size are key life history traits. During the breeding period, it is possible for females to increase their reproductive output either by increasing the number of eggs if the optimal egg size (OES) is maintained, or by increasing the allocation of energy to each egg. However, the strategies adopted are often influenced by animals’ morphology and environment. Methods Here, we examined variation in female morphological and reproductive traits, tested for trade-offs between egg size and clutch size, and evaluated the relationship between egg size and female morphology in three populations of Phrynocephalus helioscopus. Results Female body size, egg size, and clutch size were larger in the Yi Ning (YN) and Fu Yun (FY) populations than in the Bei Tun (BT) population (the FY and YN populations laid more, and rounder eggs). Egg size was independent of female body size in two populations (BT and FY), even though both populations had an egg-size/clutch size trade-off. In the YN population, egg size and clutch size were independent, but egg size was correlated with female body size, consistent with the hypothesis of morphological constraint. Conclusions Our study found geographical variation in body size and reproductive strategies of P. helioscopus. Egg size was correlated with morphology in the larger-bodied females of the YN population, but not in the smaller-bodied females of the BT population, illustrating that constraints on female body size and egg size are not consistent between populations.

scholarly journals Egg Size, Body Size, Locomotion, and Feeding Performance in Captive King Eider Ducklings

The Condor ◽  
2001 ◽  
Vol 103 (1) ◽  
pp. 195-199 ◽  
Author(s):  
Vanessa R. Anderson ◽  
Ray T. Alisauskas
Keyword(s):  
Body Size ◽  
Egg Size ◽  
Feeding Rate ◽  
Canadian Arctic ◽  
Feeding Rates ◽  
Egg Volume ◽  
King Eider ◽  
Somateria Spectabilis ◽  
Predator Evasion ◽  
Better Than

Abstract We studied the effect of egg volume and body size on swimming speed, endurance, and feeding rate in captive King Eider (Somateria spectabilis) ducklings in the Canadian arctic. Sprint speed, endurance, and feeding rate were positively related to egg size and body size. Large ducklings from large eggs performed better than small ducklings from small eggs. Ducklings that are more capable swimmers and have higher feeding rates may grow more quickly and be more effective at predator evasion. Thus, ducklings from large eggs may have a survival advantage over those from small eggs under conditions where predation and nutrition may constrain survival.

VARIATION IN SIZE, COMPOSITION, AND QUALITY OF RUDDY DUCK EGGS AND DUCKLINGS

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 457 ◽  
Author(s):  
Jeffrey T. Pelayo ◽  
Robert G. Clark
Keyword(s):  
Size Composition ◽  
Ruddy Duck
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