scholarly journals Experimental manipulation of female reproduction reveals an intraspecific egg size clutch size trade-off

2001 ◽  
Vol 268 (1465) ◽  
pp. 423-428 ◽  
Author(s):  
T. D. Williams
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Experimental Manipulation ◽  
Female Reproduction ◽  
Trade Off

Environmental, ontogenetic, and genetic variation in egg size of Pied Flycatchers

1993 ◽  
Vol 71 (8) ◽  
pp. 1534-1542 ◽  
Author(s):  
Jaime Potti
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Relative Volume ◽  
Laying Date ◽  
Territory Quality ◽  
Trade Off ◽  
Nest Boxes ◽  
Female Condition ◽  
Almost All ◽  
Breeding Seasons

Ontogenetic, genetic, and environmental variation in egg length, breadth, and volume were investigated in the Pied Flycatcher across four breeding seasons in central Spain. Egg length and breadth were poorly correlated and did not vary with laying date. There was an indication of decreasing egg breadth with increasing clutch size that may indicate a trade-off between both variables. Egg size increased with female condition and, independently, with territory quality. Mean egg size decreased with advancing female age, which is perhaps related to the increase of clutch size with age in this species. There were high, significant repeatabilities of almost all egg dimensions, including relative volumes of first and last eggs, among females, both within and between years. Also, nest boxes were repeatable in the relative volume of the last eggs of (different) females laying in them, suggesting an influence of territory quality on relative egg size. Territory quality also had positive influences on some egg measurements that were independent of female condition. Heritability, estimated by mother–daughter regression, was significant only for egg length. These results are discussed in relation to proximate constraints on egg formation, predictions from the brood-survival hypothesis, and a possible trade-off between clutch and egg sizes.

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.

Inter and Intraspecific Relationships between Egg Size and Clutch Size in Waterfowl

The Auk ◽  
1988 ◽  
Vol 105 (1) ◽  
pp. 161-176 ◽  
Author(s):  
Frank C. Rohwer
Keyword(s):  
Clutch Size ◽  
Egg Production ◽  
Egg Size ◽  
Inverse Relationship ◽  
Oceanic Islands ◽  
Trade Off ◽  
Anas Discors ◽  
Intraspecific Relationships ◽  
Strong Inverse Relationship

Abstract Lack (1967, 1968a) proposed that clutch size of waterfowl and other birds with self-feeding young was limited by females' ability to produce eggs. Lack supported this egg-production hypothesis by showing a strong inverse relationship between egg size and clutch size within and among species of waterfowl. A reanalysis using updated data and more appropriate statistics failed to confirm Lack's results. Grouping all the waterfowl produced a weak (r2 = 0.13 inverse relationship between relative egg size and relative clutch size. This relationship was due mainly to a handful of ducks that nest on oceanic islands. Analyses by tribes showed that relative egg size and relative clutch size were inversely related in only 2 of the 8 major tribes of waterfowl. Finally, intraspecific analyses failed to reveal a trade-off between egg size and clutch size in Blue-winged Teal (Anas discors) and Northern Shovelers (A. clypeata). Similar intraspecific analyses for 12 other waterfowl have failed to show the predicted inverse relationship between egg size and clutch size. These results suggest that the widely accepted egg-production hypothesis may be considerably overemphasized.

scholarly journals Nesting Effort of Northern Pintails in Alberta

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 619-628 ◽  
Author(s):  
Karla L. Guyn ◽  
Robert G. Clark
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Trade Off ◽  
Variable Environments ◽  
Southern Alberta ◽  
First Clutch ◽  
Northern Pintails ◽  
One Year

Abstract We studied nesting effort and success of Northern Pintails (Anas acuta) in southern Alberta. Annual nesting success estimates ranged from 6–18%. Clutch size averaged 7.2, and declined in a simple curvilinear fashion with nest initiation date. We found no relationship between egg size and clutch size or evidence from one year to the next of a trade-off between current and future investment in eggs. Within-year renesting rate ranged from 55%, based on a sample of 20 decoy-trapped females that lost their first nests to predators, to 85% based on a sample of 13 nest-trapped females forced to renest when we removed their clutches. Greater investment in initial clutches led to longer delays in laying replacement clutches. Because delays in renesting are costly (late-nesting females produce fewer offspring), females must contend with a trade-off between maximizing reproductive output in initial clutches versus the risk of delayed renesting if the first clutch should fail. We suggest that pintail reproductive traits have evolved primarily in response to short nesting seasons and variable environments.

scholarly journals Terrestrial reproduction and parental care drive rapid evolution in the trade-off between offspring size and number across amphibians

PLoS Biology ◽  
2022 ◽  
Vol 20 (1) ◽  
pp. e3001495
Author(s):  
Andrew I. Furness ◽  
Chris Venditti ◽  
Isabella Capellini
Keyword(s):  
Parental Care ◽  
Clutch Size ◽  
Egg Size ◽  
Direct Development ◽  
Life History Strategies ◽  
Offspring Size ◽  
Trade Off ◽  
Offspring Development ◽  
Egg Brooding ◽  
Tadpole Transport

The trade-off between offspring size and number is central to life history strategies. Both the evolutionary gain of parental care or more favorable habitats for offspring development are predicted to result in fewer, larger offspring. However, despite much research, it remains unclear whether and how different forms of care and habitats drive the evolution of the trade-off. Using data for over 800 amphibian species, we demonstrate that, after controlling for allometry, amphibians with direct development and those that lay eggs in terrestrial environments have larger eggs and smaller clutches, while different care behaviors and adaptations vary in their effects on the trade-off. Specifically, among the 11 care forms we considered at the egg, tadpole and juvenile stage, egg brooding, male egg attendance, and female egg attendance increase egg size; female tadpole attendance and tadpole feeding decrease egg size, while egg brooding, tadpole feeding, male tadpole attendance, and male tadpole transport decrease clutch size. Unlike egg size that shows exceptionally high rates of phenotypic change in just 19 branches of the amphibian phylogeny, clutch size has evolved at exceptionally high rates in 135 branches, indicating episodes of strong selection; egg and tadpole environment, direct development, egg brooding, tadpole feeding, male tadpole attendance, and tadpole transport explain 80% of these events. By explicitly considering diversity in parental care and offspring habitat by stage of offspring development, this study demonstrates that more favorable conditions for offspring development promote the evolution of larger offspring in smaller broods and reveals that the diversity of parental care forms influences the trade-off in more nuanced ways than previously appreciated.

scholarly journals Reproductive trade-offs of the estuarine copepod Eurytemora affinis under different thermal and haline regimes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anissa Souissi ◽  
Jiang-Shiou Hwang ◽  
Sami Souissi
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Cold Temperature ◽  
Female Size ◽  
Eurytemora Affinis ◽  
Trade Off ◽  
Trade Offs ◽  
Higher Temperature

AbstractCopepod females invest a quantity of resources in their reproduction. Depending on several biotic and abiotic factors and their evolutionary history a trade-off can be commonly observed between producing a large number of smaller offspring or a small number of larger offspring. In this study, a multi-generational approach was applied to determine whether a trade-off between clutch size and egg size existed in the copepod Eurytemora affinis under different controlled conditions of temperature and salinity. This protocol was based on the follow-up of reproductive (Clutch Size ‘CS’, Egg Diameter ‘ED’) and morphological (Prosome Length ‘PL’) traits during several generations. Copepods were acclimated to cold (7 °C) and warm (20 °C) temperatures, and then their reproductive output was tested at the higher temperature of 24 °C. CS and ED were positively correlated to PL, so as a first step linear regressions between each reproductive trait and female PL were performed. The residuals from the regression lines of CS and ED with PL were calculated to remove the effect of female size. When the normalized data (residuals) of CS and ED plotted together a negative relationship between egg size and egg number revealed the existence of a trade-off. Copepod populations initially acclimated to cold temperature are commonly characterized by relatively smaller CS and larger ED. Conversely, warm temperature adapted females produced relatively larger CS and smaller ED. After transfer to a temperature of 24 °C, the ED did not change but the CS showed high variability indicating stressful conditions and no trade-off was observed. These observations suggest that E. affinis is able to modulate its reproduction depending on the encountered temperature. It seems that this copepod species can shift between a K- and an r-strategy in response to colder or warmer conditions. In a late winter-early spring like cold temperature, copepod females seem to invest more on offspring quality by producing relatively larger eggs. This ecological strategy ensures a high recruitment of the spring generation that is responsible for the strength of the maximum population size usually observed in late spring-early summer (May–June). To the contrary, at summer-like temperature, where the population density decreases significantly in the Seine estuary, copepod females seem to switch from K to r strategy by favoring offspring number compared to offspring size. Finally, the use of a higher temperature of 24 °C seems to disrupt the observed reproductive trade-off even after several generations. These results suggest that a switching between K- or r-strategy of E. affinis depends highly on temperature effects. The effect of salinity increase during a summer-like temperature of 20 °C as well as after transfer to 24 °C decreased PL and CS but the ED did not change significantly.

Egg size and shape, clutch dynamics, and reproductive effort in European tortoises

1988 ◽  
Vol 66 (7) ◽  
pp. 1527-1536 ◽  
Author(s):  
A. Hailey ◽  
N. S. Loumbourdis
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Egg Production ◽  
Egg Size ◽  
Reproductive Effort ◽  
Energy Content ◽  
The Body ◽  
Female Reproduction ◽  
Northern Greece ◽  
Clutch Mass

Energetic aspects of female reproduction are described for the tortoises Testudo graeca, Testudo marginata, and Testudo hermanni (three populations of different body size) from northern Greece. Egg width increased with body size in some populations, but smaller individuals produced more elongate eggs, and egg weight was not related to body size. This method for overcoming the constraint of the width of the pelvic canal means that egg width is a poor measure of egg size. Clutch size, clutch mass, and annual egg production varied with body size between populations. Mean relative clutch mass ranged from 4 to 7%, and was highest in the three populations of T. hermanni. All populations laid two or three clutches per year, based on the total number of eggs and large follicles divided by clutch size. Multiple clutches reflect the morphological constraint of packing shelled eggs within the body, rather than energy accumulation during the nesting period. Material for reproduction was stored in growing follicles rather than fat bodies; follicles reached half of their final weight before the animals entered hibernation. Annual reproductive effort as a proportion of body energy content was about 15% in all populations. This is lower than in other reptiles, partly because the carapace accounts for over half of the total ash-free dry weight of the tortoise body.

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

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