Body size, age distribution, and reproduction in a northern population of wood turtles (Clemmys insculpta)

1992 ◽  
Vol 70 (3) ◽  
pp. 462-469 ◽  
Author(s):  
Ronald J. Brooks ◽  
Cathy M. Shilton ◽  
Gregory P. Brown ◽  
Norman W. S. Quinn
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Partial Correlation ◽  
Age Distribution ◽  
Egg Mass ◽  
Female Size ◽  
After Effects ◽  
Mean Width ◽  
Wood Turtles ◽  
Provincial Park

A population of the wood turtle (Clemmys insculpta) was studied on the east side of Algonquin Provincial Park, Ontario, from 1987 to 1990. A total of 77 adults (56 females, 21 males) and 13 juveniles were captured, measured, and individually marked. Age at maturity was 17–18 years at a minimum carapace length of 185 mm for females and 199 mm for males. Our data supported the hypothesis that turtles in northern populations are larger and older at maturity than are those in southern populations. For 21 nests, mean clutch size was 8.8 eggs and egg mass was 96 g. Predators destroyed 15 of 17 nests in 1990, and had injured 60% of adult turtles observed. Therefore, our population had low recruitment, few juveniles, and high levels of predation on nests and adults. Comparisons among females refuted two predictions from optimal egg size theory. Mean width and mass, but not length, of eggs correlated positively with female size, and correlated positively with clutch size, even after effects of body size were removed by partial correlation. However, smaller females in the population had relatively longer eggs than did larger females, whereas the Algonquin females have absolutely smaller eggs than do much smaller females in a New Jersey population.

Clutch Mass, Offspring Mass, and Clutch Size: Body Mass Scaling and Taxonomic and Environmental Variation

2018 ◽  
pp. 68-97
Author(s):  
Douglas S. Glazier
Keyword(s):  
Life History ◽  
Body Size ◽  
Clutch Size ◽  
Body Mass ◽  
Life History Evolution ◽  
Offspring Size ◽  
Egg Mass ◽  
Mass Scaling ◽  
Scaling Relationships ◽  
Clutch Mass

In this chapter, I show how clutch mass, offspring (egg) mass, and clutch size relate to body mass among species of branchiopod, maxillipod, and malacostracan crustaceans, as well as how these important life history traits vary among major taxa and environments independently of body size. Clutch mass relates strongly and nearly isometrically to body mass, probably because of physical volumetric constraints. By contrast, egg mass and clutch size relate more weakly and curvilinearly to body mass and vary in inverse proportion to one another, thus indicating a fundamental trade-off, which occurs within many crustacean taxa as well. In general, offspring (egg) size and number and their relationships to body mass appear to be more ecologically sensitive and evolutionarily malleable than clutch mass. The body mass scaling relationships of egg mass and clutch size show much more taxonomic and ecological variation (log-log scaling slopes varying from near 0 to almost 1 among major taxa) than do those for clutch mass, a pattern also observed in other animal taxa. The curvilinear body mass scaling relationships of egg mass and number also suggest a significant, size-related shift in how natural selection affects offspring versus maternal fitness. As body size increases, selection apparently predominantly favors increases in offspring size and fitness up to an asymptote, beyond which increases in offspring number and thus maternal fitness are preferentially favored. Crustaceans not only offer excellent opportunities for furthering our general understanding of life history evolution, but also their ecological and economic importance warrants further study of the various factors affecting their reproductive success.

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.

Observations of body size, growth, and reproduction in Blanding's turtle (Emydoidea blandingii) from western Nebraska

1992 ◽  
Vol 70 (9) ◽  
pp. 1690-1695 ◽  
Author(s):  
John W. Rowe
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Carapace Length ◽  
Reproductive Output ◽  
Egg Mass ◽  
Mature Adult ◽  
Emydoidea Blandingii ◽  
Size Growth ◽  
Sexually Mature ◽  
Growth And Reproduction

Body size, growth, and reproduction of Emydoidea blandingii from several localities in western Nebraska were investigated. Female carapace length averaged 209.2 mm (214.8 mm for those known to be sexually mature). Adult male carapace length averaged 200.8 mm and was not significantly different from that of females, but males had pigmented tomia. Covariance analysis using carapace length as a covariate revealed that females had a significantly longer plastron and higher shell than males. Turtles showed a 70.1% increase in length of the left abdominal scute during the 1st year. Growth declined rapidly and became more constant about the 4th year (about 4–9% per year). Clutch size averaged 14.9, clutch wet mass averaged 168.5 g, and egg wet mass averaged 11.82 g. No measure of reproductive output (i.e., clutch size, clutch wet mass, relative clutch mass) or egg size (relative egg mass, egg wet mass, egg length, or egg width) was significantly correlated with maternal carapace length. Comparisons with other populations of E. blandingii are made.

Breeding traits of Hermann's tortoise Testudo hermanni hermanni in two western populations

2007 ◽  
Vol 28 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Marc Cheylan ◽  
Jean Pierre Nougarède ◽  
Aurelio Marín ◽  
Albert Bertolero
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Female Body ◽  
Egg Production ◽  
Reproductive Traits ◽  
Ebro Delta ◽  
Female Size ◽  
Female Body Size ◽  
Testudo Hermanni ◽  
Testudo Hermanni Hermanni

AbstractOver a period of two years we used radiology to investigate breeding traits in females of two western populations of the threatened Hermann's tortoise Testudo hermanni hermanni. The main purpose of the study was to see if reproductive traits – clutch size, clutch frequency, annual egg production and egg width – varied between populations in Corsica (France) and the Ebro Delta (Spain), and if these traits were affected by female body size and amounts of spring rainfall. All the breeding traits analysed were greater in the Corsican population than in the Ebro Delta population. These differences were also significant when we used female body size as a covariable. In both populations the amount of spring rainfall affected breeding traits but not clutch size. Nevertheless, only in the Corsican population did clutch frequency, annual egg production and egg width increase significantly in the year with a wet spring. Contrary to the predictions of Optimal Propagule Size theory, we found that egg size and clutch size increased with female size, and that both variables were independent. On the other hand, clutch frequency was not related to female body size. Thus, in the Hermann's tortoise, as clutch size did not change between years and clutch frequency was independent of female size, all females are able to increase their reproductive output in years with favourable conditions by increasing their clutch frequency. Nevertheless, other factors besides female size and rainfall may influence in a highly complex way variability in breeding traits among populations.

scholarly journals Lifetime Reproductive Success of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence of Lifespan, Nest Predation, and Body Size

The Auk ◽  
2007 ◽  
Vol 124 (3) ◽  
pp. 1010-1022 ◽  
Author(s):  
Michael T. Murphy
Keyword(s):  
New York ◽  
Body Size ◽  
Reproductive Success ◽  
Clutch Size ◽  
Small Body ◽  
Cost Of Reproduction ◽  
Large Female ◽  
Lifetime Reproductive Success ◽  
Female Size ◽  
Tyrannus Tyrannus

AbstractI report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus tyrannus) in central New York. I investigated the major correlates of LRS and specifically tested the hypothesis that small body size yields reproductive benefits. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and for longer-lived females separately. As in other species, lifespan was the strongest predictor of LRS, followed by the proportion of eggs laid that resulted in fledged young (P). Lifetime reproductive success varied positively with clutch size and, as predicted, inversely with body size (i.e., tarsus length) of females. However, variance partitioning indicated that most variation in LRS was attributable to the effects of lifespan and P, but that a substantial negative covariance existed between lifespan and P. The latter result was consistent with experimental evidence of a cost of reproduction in Eastern Kingbirds. Analysis of the correlates of lifespan, P, and clutch size showed that over a female's lifetime, (1) the longest-lived birds fledged an intermediate proportion of the eggs that they laid, (2) the most productive birds were of intermediate wing length, and (3) females with small tarsi produced the largest clutches and lost the fewest nests to predators. Hence, although lifespan was the dominant influence on LRS, negative effects of large female size appeared to be expressed through the influence of body size on other demographic parameters that contribute to LRS.Éxito Reproductivo Completo de Vida de Hembras de Tyrannus tyrannus: Influencia de la Duración de la Vida, la Depredación de Nidos y el Tamaño Corporal

scholarly journals The effects of climate on annual variation in reproductive output in Snapping Turtles (Chelydra serpentina)

2018 ◽  
Vol 96 (3) ◽  
pp. 221-228 ◽  
Author(s):  
A.R. Hedrick ◽  
H.M. Klondaris ◽  
L.C. Corichi ◽  
M.J. Dreslik ◽  
J.B. Iverson
Keyword(s):  
Climate Change ◽  
Clutch Size ◽  
Reproductive Output ◽  
Life History Traits ◽  
Annual Variation ◽  
Egg Mass ◽  
Female Size ◽  
Chelydra Serpentina ◽  
Snapping Turtles ◽  
Clutch Mass

Reptiles are highly dependent on climatic patterns to regulate their behavior and physiology, and studies of the effects of climate on the biology of organisms are increasingly important given expected climate change. Our study examined the effects of climate variation over 15 of the 26 years between 1990 and 2015 on the reproductive output of the Snapping Turtle (Chelydra serpentina (Linnaeus, 1758)). Egg mass, clutch size, and clutch mass (relative to body size) were significantly higher in years following warmer temperatures in September and October of the year before reproduction, but not related to temperatures in April and May just before reproduction. Of the above life-history traits, egg mass varied the least across years, and after warm autumns small turtles (225–285 mm carapace length) increased clutch mass by increasing clutch size but not egg mass. In contrast, under the same conditions, large turtles increased clutch mass by increasing egg mass but not clutch size. Our data suggest optimal egg mass may vary with female size. Climate change may already have impacted reproductive output in Snapping Turtles at the site because temperatures during September and October have increased about 0.5 °C each decade for the last 45 years.

The reproductive value of large females: consequences of shifts in demographic structure for population reproductive potential in Chinook salmon

2020 ◽  
Vol 77 (8) ◽  
pp. 1292-1301 ◽  
Author(s):  
Jan Ohlberger ◽  
Daniel E. Schindler ◽  
Randy J. Brown ◽  
Joel M.S. Harding ◽  
Milo D. Adkison ◽  
...  
Keyword(s):  
Body Size ◽  
Chinook Salmon ◽  
Reproductive Potential ◽  
Reference Points ◽  
Reproductive Value ◽  
Egg Mass ◽  
Female Size ◽  
Demographic Structure ◽  
Yukon River ◽  
Population Demographic

While conservation and fisheries management are often concerned with changes in population abundance and distribution, shifts in population age–size structure are commonly observed in response to human and environmental stressors. Chinook salmon (Oncorhynchus tshawytscha) have experienced widespread declines in mean age and size throughout their North American range. We investigated the consequences of declines in body size for spawner reproductive potential in terms of total egg mass per female. Our case study is the Yukon River where Chinook salmon have supported subsistence, commercial, and recreational fisheries. Using historical observations on individual body size from throughout the Yukon River and the relationship between female size and total egg mass from the Canadian portion, we estimate a decline in average female reproductive potential of 24%–35% since the 1970s. Because spawner abundances and the population sex ratio have not shown clear trends over time, our results suggest a reduced total population reproductive potential. Changes in spawner quality should be considered when developing management reference points, and conservation of population demographic structure may be necessary to sustain productive Chinook salmon systems.

Some aspects of reproduction in a Lake Erie population of Blanding's turtle, Emydoidea blandingii

1988 ◽  
Vol 66 (10) ◽  
pp. 2317-2319 ◽  
Author(s):  
Ross D. MacCulloch ◽  
Wayne F. Weller
Keyword(s):  
Clutch Size ◽  
Lake Erie ◽  
Relative Mass ◽  
Egg Mass ◽  
Female Size ◽  
Regression Analyses ◽  
Emydoidea Blandingii ◽  
Blanding's Turtle ◽  
Clutch Mass ◽  
Blanding’S Turtle

A Lake Erie population of Emydoidea blandingii produced clutches of slightly greater relative mass than those of other emydids. Regression analyses showed that both clutch mass and relative clutch mass were significantly related to both female mass and female size, while clutch size was also related to female size. Mean egg mass was not related to either clutch size or female size.

scholarly journals First evidence for a latitudinal body mass effect in extant Crocodylia and the relationships of their reproductive characters

2020 ◽  
Vol 129 (4) ◽  
pp. 875-887
Author(s):  
Rebecca J Lakin ◽  
Paul M Barrett ◽  
Colin Stevenson ◽  
Robert J Thomas ◽  
Matthew A Wills
Keyword(s):  
Clutch Size ◽  
Body Mass ◽  
Linear Models ◽  
Incubation Temperature ◽  
Mass Effect ◽  
Distribution Patterns ◽  
Egg Mass ◽  
Phylogenetically Independent Contrasts ◽  
Extant Species ◽  
Female Body Mass

Abstract Relationships between distribution patterns and body size have been documented in many endothermic taxa. However, the evidence for these trends in ectotherms generally is equivocal, and there have been no studies of effects in crocodylians specifically. Here, we examine the relationship between latitudinal distribution and body mass in 20 extant species of crocodylians, as well as the relationships between seven important reproductive variables. Using phylogenetically independent contrasts to inform generalized linear models, we provide the first evidence of a latitudinal effect on adult female body mass in crocodylians. In addition, we explore the relationships between reproductive variables including egg mass, hatchling mass and clutch size. We report no correlation between egg mass and clutch size, upholding previously reported within-species trends. We also find no evidence of a correlation between measures of latitudinal range and incubation temperature, contrasting with the trends found in turtles.

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

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