Egg Size, Clutch Size, and Reproductive Effort of the Australian Broad-Shelled River Turtle, Chelodina expansa

1998 ◽  
Vol 32 (4) ◽  
pp. 592 ◽  
Author(s):  
David T. Booth
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Effort

Intra- and inter-individual variation in reproductive effort in captive-breeding zebra finches (Taeniopygia guttata)

1996 ◽  
Vol 74 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Tony D. Williams
Keyword(s):  
Mass Loss ◽  
Clutch Size ◽  
Intraspecific Variation ◽  
Body Condition ◽  
Individual Variation ◽  
Egg Size ◽  
Reproductive Effort ◽  
Captive Breeding ◽  
Taeniopygia Guttata ◽  
Zebra Finches

Intraspecific variation in egg size, clutch size, and timing of laying was studied in captive-breeding zebra finches (Taeniopygia guttata) maintained under conditions of constant temperature, humidity, photoperiod (14 h light: 10 h dark), and ad libitum food supply. Individual variation was marked in the experimental population: egg size 0.915–1.342 g, clutch size 2–7 eggs, and laying interval 4–13 days; however, within individual females egg size (r = 0.742) and clutch size (r = 0.588) were highly repeatable between first and second clutches. Body condition explained only 8% of egg size variation, and clutch size and laying interval were independent of body condition. Clutch size was negatively related to laying interval: females laying later relative to pairing laid smaller clutches (b = −0.175 eggs/day). Body mass of breeding females decreased by 1.57 g (9% of initial mass) during laying of first clutches; mass loss was positively related to initial body condition (R2 = 27.8%) and total clutch mass (R2 = 7.6%). Mass loss was lower (0.47 g) during laying of second or replacement clutches than during laying of first clutches. Individual variation in reproductive effort in captive-breeding zebra finches is very similar to that in free-living avian populations. Laboratory studies on captive-breeding species can provide a valuable approach for the study of proximate physiological mechanisms underlying intraspecific variation in reproduction.

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.

Parental Investment in Clutch Size and Egg Size in the Ural Owl Strix uralensis

1986 ◽  
Vol 17 (4) ◽  
pp. 309 ◽  
Author(s):  
Hannu Pietiainen ◽  
Pertti Saurola ◽  
Risto A. Vaisanen
Keyword(s):  
Clutch Size ◽  
Parental Investment ◽  
Egg Size ◽  
Ural Owl

scholarly journals Male harassment leads to fitness costs for females by disrupting oviposition site preferences

2020 ◽  
Vol 31 (3) ◽  
pp. 611-617
Author(s):  
Elisabeth Bacon ◽  
Flavia Barbosa
Keyword(s):  
Clutch Size ◽  
Sexual Conflict ◽  
Egg Size ◽  
Callosobruchus Maculatus ◽  
Optimal Number ◽  
Oviposition Site ◽  
Fitness Costs ◽  
Male Harassment ◽  
Oviposition Substrate ◽  
Pinto Beans

Abstract In many species, a difference in the optimal number of copulations for males and females leads to sexual conflict. This is well documented in the bean beetle Callosobruchus maculatus, where both sexes mate multiply and females incur fitness costs from injuries caused by the male genitalia. Here, we demonstrate that sexual conflict also decreases female fitness due to male harassment. We hypothesized that harassment costs would come as 1) decreased clutch size, egg size, or both and by 2) disruption of female preference for higher-quality oviposition substrate. Mated females were housed with two bean types—cowpeas, their preferred natal hosts, and toxic pinto beans. They were then submitted to either no, moderate, or high male harassment in the oviposition site. Females under harassment produced smaller clutch sizes but not smaller eggs, resulting in the absence of an egg-size/clutch-size trade-off. Additionally, females did not exhibit a preference for their natal cowpeas hosts over toxic pinto beans when males were present at the oviposition site, although they do so when harassing males are not present. Harassment disrupted female responses to variation in oviposition substrate quality, resulting in considerable fitness consequences in the form of lower offspring production and survival.

scholarly journals How Many Baskets? Clutch Sizes That Maximize Annual Fecundity of Multiple-Brooded Birds

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 973-982 ◽  
Author(s):  
George L. Farnsworth ◽  
Theodore R. Simons ◽  
J. Brawn
Keyword(s):  
Clutch Size ◽  
Breeding Season ◽  
Nest Predation ◽  
Reproductive Effort ◽  
Nest Survival ◽  
Survival Rates ◽  
Season Length ◽  
Deterministic Models ◽  
Cavity Nesting ◽  
Theoretical Issues

Abstract We developed deterministic models on the basis of nest survival rates and renesting behavior capable of predicting annual fecundity in birds. The models calculate probabilities of fledging from one to four nests within a discrete breeding season. We used those models to address theoretical issues related to clutch size. In general, birds require at least one day to lay an egg, and many species delay incubation until their entire clutch is laid. Because it takes longer to complete a larger clutch, and fewer such clutches can fit into a limited breeding season, there exists a clutch size for which annual fecundity is maximized. We asked, for a given amount of reproductive effort (i.e. a set number of eggs), does the age-old maxim “don't put all your eggs in one basket” apply? If so, in how many “baskets” should a nesting bird place its eggs? The answer depends on both likelihood of nest predation and length of the breeding season. Those results are consistent with the observed increase in clutch size with latitude (shorter breeding season length) and larger clutch sizes characteristic of cavity-nesting species (with higher nest survival rates). The models also predict that the size of replacement clutches should decrease as the breeding season progresses, and that intraseasonal decline in clutch size should be more pronounced when the breeding season is short.

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.

Annual variation in common eider egg size: effects of temperature, clutch size, laying date, and laying sequence

1995 ◽  
Vol 73 (9) ◽  
pp. 1579-1587 ◽  
Author(s):  
Gregory J. Robertson
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Annual Variation ◽  
Size Variation ◽  
Egg Laying ◽  
Laying Date ◽  
Somateria Mollissima ◽  
Ambient Temperatures ◽  
Common Eiders ◽  
N 93

Annual variation in volumes of eggs laid by common eiders (Somateria mollissima sedentaria) nesting at La Pérouse Bay, Manitoba (58°43′N, 93°27′W), was studied over 3 years (1991–1993). Temperatures during the egg-laying period were higher in 1991 than in 1992 and 1993. However, the eiders began nesting in 1993 at the same time as in 1991, whereas in 1992 the eiders began laying approximately 2 weeks later. Eiders laid significantly smaller clutches in 1992 than in the other 2 years. Egg size did not correlate with clutch size or laying date in any year. However, eiders laid smaller eggs in 1992 and 1993 than in 1991. In five egg clutches, the pattern of intraclutch egg-size variation was different among years. The last laid eggs of five egg clutches were disproportionately smaller in 1992 and 1993 (cold years) than those laid in 1991. Minimum daily temperatures before the egg-laying period (during rapid yolk development) were positively correlated with egg size. However, this effect was not significant when year and egg sequence were controlled for. Egg-size variation was correlated with the overall ambient temperatures during the laying period, whereas annual clutch-size variation was correlated with laying date, suggesting that the proximate mechanisms affecting clutch and egg size are different.

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.

Egg size and clutch size in three species of Nihonotrypaea (Decapoda: Thalassinidea: Callianassidae) from western Kyushu, Japan

2006 ◽  
Vol 86 (1) ◽  
pp. 103-111 ◽  
Author(s):  
K. Kubo ◽  
K. Shimoda ◽  
A. Tamaki
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Relative Size ◽  
Size Variation ◽  
Middle Part ◽  
Reproductive Period ◽  
Late Winter ◽  
Estuarine System ◽  
Ariake Sound ◽  
Interspecific Comparisons

Three species of the callianassid genus Nihonotrypaea occur in the Ariake Sound estuarine system, southern Japan; they consist of two tidal-flat species (N. harmandi; N. japonica) and one boulder-beach species (N. petalura), with maximum population densities of 1440, 343, and 12 ind m−2, respectively. Nihonotrypaea harmandi and N. petalura are distributed along the coastline from the outermost part of the sound to the open sea, while N. japonica occurs in the middle part of the sound. Nihonotrypaea japonica has an extended reproductive period from late winter to autumn, while those of the other species are from late spring or summer to autumn. Interspecific comparisons were made for recently laid egg size (as volume) and clutch size (as number of eggs per female). Only in N. japonica was a seasonal egg size variation observed, being significantly larger in winter to spring (mean=0.106 mm3) than in summer (0.080 mm3). By contrast, clutch size was significantly smaller in winter to spring, resulting in nearly the same clutch volume per female (product of the mean egg volume and clutch size) between the seasons. Among the three species, the egg size was ordered as N. japonica (overall mean volume through the seasons=0.092 mm3)>>N. petalura (0.057 mm3)>N. harmandi (0.054 mm3). The clutch size was ordered as N. harmandi>N. petalura≈N. japonica. The clutch volume was ordered as N. japonica≈N. harmandi>N. petalura. The smallest clutch volume value for N. petalura female showed an opposite trend to the relative size of the major cheliped found in a previous study.

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