Clutch size and egg size of spruce grouse in relation to spring diet, food supply, and endogenous reserves

1989 ◽  
Vol 67 (4) ◽  
pp. 969-980 ◽  
Author(s):  
Brian J. Naylor ◽  
James F. Bendell
Keyword(s):  
Body Weight ◽  
Clutch Size ◽  
Food Supply ◽  
Crude Protein ◽  
Egg Size ◽  
Follicular Development ◽  
Egg Laying ◽  
High Rate ◽  
Large Clutch ◽  
Endogenous Reserves

We examined the hypothesis that female spruce grouse (Dendragapus canadensis) rely entirely on their spring diet or endogenous reserves for the nutrients required for clutch formation. Spring food habits of 40 radio-tagged hens were documented by direct observation (21 262 min) during the period encompassing oviducal recrudescence, follicular development, and egg laying (late April – late May 1984 – 1986) and compared with clutch size and mean egg weight. Hens consumed conifer foliage, flowers, fruits, and foliage of ground plants, grit, and arthropods. Compared with their prebreeding diet, foods preferred in spring were rich in protein and P, but not necessarily Ca. Large clutch size was associated with a high rate of intake of the two most preferred foods, flowers of trailing arbutus (Epigaea repens) and spore capsules of Polytrichum mosses, and crude protein, P, and Ca, but was not related to the size of hens (body weight) or the size of endogenous reserves (scaled body weight). Egg size was not associated with spring diet or the size of endogenous reserves, but appeared to be related to the size of hens. Rate of intake of arbutus flowers and moss capsules was correlated with their availability on territories, suggesting that clutch size might have been proximately limited by food supply. However, rough estimates of nutrient intake suggested that the spring diet provided only about 60% of the protein and 45% of the Ca needed for clutch formation. Consequently, hens appeared to rely on both their spring diet and stored reserves for the nutrients required for clutch formation.

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.

Spawning Mode and Reproductive Output of the Tropical Cephalopod Idiosepius pygmaeus

1993 ◽  
Vol 50 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Andrew R. Lewis ◽  
J. Howard Choat
Keyword(s):  
Body Weight ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Potential ◽  
Adult Life ◽  
Somatic Growth ◽  
Egg Laying ◽  
Adult Life Span ◽  
Adult Weight ◽  
Food Stress

Reproductive biology of the tropical sepioid cephalopod Idiosepius pygmaeus was investigated in wild specimens and in individuals maintained in aquaria through the adult life span. This species produced multiple egg batches over 80% of the observable adult weight range, indicating a coordination of reproductive and somatic growth. Reproductive output was consistent within, but variable between, individuals. Oocyte synthesis and maturation occur continuously after sexual maturation has been reached. Senescence and death are not related to an exhaustion of reproductive potential. On average, captive female I. pygmaeus with access to unlimited food produced 640 eggs in 11 batches over 18 d. When reproductive output was expressed as a ratio of dry female body weight, on average, specimens had incorporated five times their body weight into eggs and egg coatings. Under food stress, captive specimens laid fewer eggs but maintained egg size and periodicity of egg laying. Food stress had no effect on either laying duration or weight at death. This study provides further evidence that terminal spawning modes are not ubiquitous amongst cephalopods.

scholarly journals Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

2012 ◽  
Vol 58 (6) ◽  
pp. 820-827 ◽  
Author(s):  
Long-Hui Lin ◽  
Fei Mao ◽  
Ce Chen ◽  
Xiang Ji
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Egg Laying ◽  
Laying Date ◽  
Egg Mass ◽  
Size Number ◽  
Female Reproductive Traits ◽  
Clutch Mass

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou (CZ), Jiangshan (JS) and Dinghai (DH), to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern lati-tutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity (clutch size), greater reproductive output (clutch mass) and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.

Seasonal and annual variations in egg mass and clutch size for Loggerhead Sea Turtles (Caretta caretta): experienced females lay heavier eggs

2019 ◽  
Vol 97 (7) ◽  
pp. 644-649
Author(s):  
Hideo Hatase ◽  
Kazuyoshi Omuta
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Annual Variation ◽  
Sea Turtles ◽  
Follicular Development ◽  
Reproductive Traits ◽  
Caretta Caretta ◽  
Egg Mass ◽  
Loggerhead Sea Turtles ◽  
Yakushima Island

Organisms modify reproductive traits adaptively or non-adaptively in response to temporal environmental variation. Long-lived iteroparous sea turtles are ideal animals to examine such temporal shifts in resource allocation. We analyzed seasonal shifts in egg mass and clutch size for Loggerhead Sea Turtles (Caretta caretta (Linnaeus, 1758)) nesting at a temperate rookery (Yakushima Island, Japan) over a 2-year period, as well as annual variation in egg mass and clutch size over a 5-year period. Egg mass and clutch size, adjusted for female body size, did not vary seasonally at both the population and individual levels. Adjusted egg mass showed significant annual variation, despite a lack of annual variation in adjusted clutch size. Thus, Loggerhead Sea Turtles are unlikely to exhibit adaptive seasonal variation in reproductive traits, whereas they vary egg size non-adaptively in response to annual environmental conditions. Although experienced Loggerhead Sea Turtles laid heavier eggs, the annual variation in egg mass was not attributable either to breeding experience of the sampled females or to ambient temperature during follicular development, implying that other factors are involved, such as resource availability. Our data show that egg size is a more plastic reproductive trait than clutch size for Loggerhead Sea Turtles inhabiting the North Pacific.

Effects of temperature and food on the fecundity and egg development rates of Boeckella symmetrica Sars (Copepoda : Calanoida)

1981 ◽  
Vol 32 (6) ◽  
pp. 997 ◽  
Author(s):  
IO Woodward ◽  
RWG White
Keyword(s):  
Lower Limit ◽  
Clutch Size ◽  
Food Availability ◽  
Food Supply ◽  
Egg Size ◽  
Food Regime ◽  
Egg Development ◽  
Thermal Range ◽  
Effects Of Temperature ◽  
Increasing Temperature

The effects of temperature and food regime on the fecundity and egg development of B. symmetrica are presented. Clutch size decreases with increasing temperature and decreased food availability. At low food levels; there is increased variability in clutch size; this increase is less marked at lower temperatures. Duration of egg development decreases hyperbolically with increasing temperature; there may be a slight increase with increased food availability. Egg size decreases linearly with increasing temperature: food supply may have some effect. Variability of egg size decreases with decreasing temperature. Egg mortality is highest towards the lower limit of the natural thermal range of B. symmetrica and lowest near the middle.

Relationships between egg size, body weight and pelvic dimensions in turkeys

1993 ◽  
Vol 56 (1) ◽  
pp. 145-150 ◽  
Author(s):  
P. M. Hocking
Keyword(s):  
Body Weight ◽  
Egg Size ◽  
Large Strain ◽  
Strain Differences ◽  
Abdominal Fat ◽  
The Body ◽  
High Rate ◽  
Egg Weight ◽  
Species Relationship ◽  
Ad Libitum

AbstractFemales of four strains of commercial turkeys, including one large strain with a characteristically high rate of oviducal prolapse, were given food either ad libitum or controlled to reach proportionately 0·8 or 0·6 of the body weight of birds fed ad libitum at 24 weeks of age. Two pens of five turkeys from each treatment were photostimulated at 24 and 30 weeks of age. Each turkey was autopsied after it had laid its first egg. The relationships between egg weight and body weight, and between the weight of abdominal fat, diameter of the vent and distance between the pubic bones and egg weight were studied by regression analysis. Egg weight was a function of body weight raised to the power 0·29 which was significantly different from the allometric relationship for Galliform species of 0·64. There was no evidence that differences existed in the quantity of abdominal fat which could impede oviposition and contribute to oviducal prolapse. There were strain differences in the diameter of the vent and distance between the pubic bones in relation to egg weight but the smallest and largest strains were similar. It was concluded that artificial selection had changed the species relationship between egg weight and body mass and that the susceptibility to oviducal prolapse in sire line turkeys was probably physiological in origin.

Fecundity, egg size and the influence of rainfall in an isolated population of malleefowl (Leipoa ocellata)

2005 ◽  
Vol 32 (7) ◽  
pp. 639 ◽  
Author(s):  
David Priddel ◽  
Robert Wheeler
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
New South ◽  
Extended Period ◽  
Early Summer ◽  
Egg Laying ◽  
Daily Maximum ◽  
Isolated Population ◽  
South Wales ◽  
The Mean

An isolated population of malleefowl (Leipoa ocellata) at Yalgogrin in New South Wales, Australia, was studied intensively between 1986–87 and 1998–99. During this period the population produced 124 clutches, comprising a total of 1705 eggs. The number of clutches per annum varied between 5 and 15. Eggs were laid between mid-August and mid-February, with 90% laid between the last week of September and the first week of January. The mean date of laying of the first egg of each clutch (±s.d.) was 21 September ± 13 days and the mean date of the last egg was 23 December ± 19 days. The mean duration of egg laying varied significantly between years (range 70–117 days) and was negatively correlated with the daily maximum ambient temperature in December. Cool temperatures and rain in early summer prolonged the laying season. The mean interval between laying was 6.4 ± 1.1 days (range 3–12 days), with eggs laid at a faster rate during the first half of the laying period. Overall, mean clutch size was 14.1 ± 5.8 (range 1–28). Large clutches were the result of an extended period of laying rather than an increase in the rate of laying. Mean clutch size was greatest when laying extended into mid-February. The best predictor of clutch size was rainfall between May and December – the interval spanning both nest construction and egg laying. The mean volume of all measured eggs (n = 1362) was 162.1 ± 9.0 mL (range 99–200 mL). Egg volume varied during the laying period, with those eggs laid early or late in the breeding season being smaller. Eggs at Yalgogrin were, on average, 10.5% smaller than those recorded at nearby Pulletop.

Clutch Initiation Dates, Clutch Size, and Egg Size of the American Oystercatcher in Virginia

The Auk ◽  
1984 ◽  
Vol 101 (4) ◽  
pp. 855-867 ◽  
Author(s):  
Erica Nol ◽  
Allan J. Baker ◽  
Michael D. Cadman
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Egg Laying ◽  
American Oystercatcher ◽  
Mode 2 ◽  
Haematopus Palliatus ◽  
Clutch Initiation ◽  
Mode 3 ◽  
One Year ◽  
Breeding Seasons

AbstractThe timing of egg laying, clutch size, and egg size of the American Oystercatcher (Haematopus palliatus) were studied over six consecutive breeding seasons in Virginia. Synchrony of laying dates occurred in each of five localities of the study area in at least one year. Mean clutch size was 2.8 eggs (mode = 3) in first clutches and 2.4 eggs (mode = 2) in replacement clutches. Individual females laid replacement clutches of the same size and laid eggs of similar average volume in all years. A change in mate had little effect on the date on which females initiated their first clutches in successive years. The average egg size in a clutch was correlated with the size of the laying female. Egg-size ordering occurred within clutches, the first-laid egg being smaller than the second egg and about equal in volume to the third. We propose that the second egg is largest because it has the highest probability of hatching, and the resulting sibling hierarchy reduces the frequency of sibling competition.

scholarly journals Estimating Repeatability of Egg Size

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 500-503 ◽  
Author(s):  
Paul L. Flint ◽  
Robert F. Rockwell ◽  
James S. Sedinger
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Size Variation ◽  
Egg Laying ◽  
Nested Model ◽  
Sequence Number ◽  
Nested Design ◽  
Black Brant ◽  
Laying Sequence ◽  
Analytical Approaches

Abstract Measures of repeatability have long been used to assess patterns of variation in egg size within and among females. We compared different analytical approaches for estimating repeatability of egg size of Black Brant. Separate estimates of repeatability for eggs of each clutch size and laying sequence number varied from 0.49 to 0.64. We suggest that using the averaging egg size within clutches results in underestimation of variation within females and thereby overestimates repeatability. We recommend a nested design that partitions egg-size variation within clutches, among clutches within females, and among females. We demonstrate little variation in estimates of repeatability resulting from a nested model controlling for egg laying sequence and a nested model in which we assumed laying sequence was unknown.

Proximate determination of clutch size in lesser black-backed gulls: the roles of food supply and body condition

1993 ◽  
Vol 71 (2) ◽  
pp. 273-279 ◽  
Author(s):  
Mark Bolton ◽  
Pat Monaghan ◽  
David C. Houston
Keyword(s):  
Clutch Size ◽  
Body Condition ◽  
Food Supply ◽  
Egg Size ◽  
Flight Muscle ◽  
Muscle Protein ◽  
Pectoral Muscle ◽  
Territory Quality ◽  
Additional Energy ◽  
Protein Levels

Though many authors have demonstrated an adaptive relationship between food supply or territory quality and clutch size, the proximate mechanism by which clutch size is determined remains largely unknown. A series of supplementary feeding experiments on lesser black-backed gulls (Larus fuscus) is used in conjunction with a new technique to measure pectoral muscle protein levels in live birds to investigate the relationships between food supply, body condition, and clutch size. Comparisons across treatments revealed a positive relationship between the level of flight muscle protein at the start of laying and clutch size, but not egg size. In a year when the clutch sizes of unfed birds were reduced, suggesting low food availability, gulls provided with a protein supplement had higher levels of flight muscle protein at the start of laying and laid larger clutches than birds that received no food supplement. In contrast, gulls provided with an additional energy source (fat) did not attain higher protein levels or lay larger clutches than unfed gulls. In a second year, when unfed gulls laid larger clutches, which were typical for the species, supplements of two different protein types (fish and egg) had no effect on clutch size, though egg-fed females laid considerably (10%) larger eggs. However, there were no detectable differences in condition between treatments at the start of laying, suggesting that though flight muscle protein levels may be of importance in determining clutch size, they may be of lesser significance for egg size, which may be largely influenced by dietary intake.

Sign in / Sign up

Export Citation Format

Share Document