Maternal and environmental influences on growth and survival of embryonic and hatchling snapping turtles (Chelydra serpentina)

1991 ◽  
Vol 69 (10) ◽  
pp. 2667-2676 ◽  
Author(s):  
Ronald J. Brooks ◽  
Michele L. Bobyn ◽  
David A. Galbraith ◽  
James A. Layfield ◽  
E. Graham Nancekivell
Keyword(s):  
Egg Size ◽  
Hatching Success ◽  
Egg Quality ◽  
Incubation Temperature ◽  
Egg Mass ◽  
Chelydra Serpentina ◽  
Growth And Survival ◽  
Snapping Turtles ◽  
Rates Of Growth ◽  
Hatching Rates

Clutches of six female snapping turtles (Chelydra serpentina) each were distributed among six incubators set at one of three constant temperatures (22.0, 25.6, and 28.6 °C) in either a wet (−100 kPa) or a dry (−500 kPa) vermiculite substrate. We tested for influences of egg mass, clutch, and incubation temperature and moisture on survival of embryos and hatchlings, on size at hatching, and on rate of post-hatching growth over 7 months. Intraclutch variation in egg mass had no effect on embryonic mortality. Mass at hatching was correlated with egg mass, but neither variable was related significantly to post-hatching survival or rate of growth. Eggs incubated at the highest temperature produced smaller hatchlings which subsequently grew more slowly than those from eggs incubated at the low and intermediate temperatures. Eggs incubated at the intermediate temperature produced larger turtles at 7 months post-hatching than did eggs incubated at the low or high temperatures. Eggs incubated in wet substrates produced larger hatchlings than those in dry substrates, but post-hatching growth rates were independent of these effects of moisture. Eggs incubated at the two extreme temperatures produced mostly females; those at 25.6 °C produced only males. Interclutch variation was significant for egg mass, mass at hatching, and survival of embryos, and was the most important influence on variation in post-hatching rates of growth. These results indicate that egg size and size at hatching may not be useful indicators of intraspecific variation in egg quality or post-hatching success in turtles, unless differences among clutches and embryonic thermal experience are also considered, particularly in relation to parental investment in the amount, quality, and apportionment of the egg's yolk.

Effects of a sudden increase in natural mortality of adults on a population of the common snapping turtle (Chelydra serpentina)

1991 ◽  
Vol 69 (5) ◽  
pp. 1314-1320 ◽  
Author(s):  
Ronald J. Brooks ◽  
Gregory P. Brown ◽  
David A. Galbraith
Keyword(s):  
Clutch Size ◽  
Research Area ◽  
Effective Density ◽  
Egg Mass ◽  
Sudden Increase ◽  
Chelydra Serpentina ◽  
Density Dependent ◽  
Snapping Turtles ◽  
The Mean ◽  
Clutch Mass

A northern population of snapping turtles (Chelydra serpentina) centred around Lake Sasajewun in the Wildlife Research Area in Algonquin Park, Ontario, has been studied and individually marked since 1972. From 1972 to 1985, annual mortality and survivorship of adult females had been estimated at 1 and 96.6%, respectively, and only six dead turtles were found. Lake Sasajewun's population of C. serpentina was estimated in 1978–1979 and 1984–1985 at 38 and 47 adults, respectively. From 1976 to 1987, total number of nests found in the study area remained fairly constant and there were no significant changes in mean clutch size, mean clutch mass, or mean egg mass. On the main nest site, recruitment from 1976 to 1987 was 1.15 (1.8%) new females per year. From 1987 to 1989, we found 34 dead adult snapping turtles in the Wildlife Research Area. Observations of freshly dead animals indicated that most were killed by otters (Lutra canadensis) during the turtles' winter hibernation. A few uninjured turtles also died of septicemia in early spring shortly after emerging from hibernation. The estimated number of adults in Lake Sasajewun was 31 in 1988–1989, and the minimum number of adult residents known to be alive in the lake dropped from 47 in 1986 to 16 in 1989. In 1986 and 1987, annual adult female survivorship was estimated at 80 and 55%, respectively, and estimated numbers of nesting females declined from 82 in 1986 to 71 and 55 in 1987 and 1988, respectively. The actual number of nests found declined by 38 and 20% over the same periods. Although no significant differences occurred in mean egg mass or mean clutch size between 1987 and 1989 and earlier years, the mean clutch mass in 1988 was larger than in 1977 or 1978. This difference appeared to be due to a gradual increase in the mean age and body size of breeding females rather than to density-dependent changes. Recruitment into the adult breeding female population in 1987–1989 remained less than two individuals per year. Hatchling survival and number of juveniles were low throughout the study. Our observations support the view that populations of species with high, stochastic juvenile mortality and long adult life spans may be decimated quickly by increased mortality of adult animals, particularly if numbers of juveniles and immigrants are low. Recovery of such populations should be very slow because of a lack of effective density-dependent response in reproduction and recruitment.

Geographic variation in snapping turtle (Chelydra serpentina serpentina) egg components across a longitudinal transect

2004 ◽  
Vol 82 (1) ◽  
pp. 102-109 ◽  
Author(s):  
Michael S Finkler ◽  
Anthony C Steyermark ◽  
Kate E Jenks
Keyword(s):  
Water Content ◽  
Geographic Variation ◽  
Egg Quality ◽  
Egg Mass ◽  
Female Size ◽  
Chelydra Serpentina ◽  
Shell Mass ◽  
Snapping Turtle ◽  
Air Temperatures ◽  
Egg Components

Common snapping turtles (Chelydra serpentina serpentina) have an extensive range across North America, inhabiting aquatic habitats in diverse thermal and hydric climates. Although geographic variation in reproductive characters such as female size, clutch size, and egg mass have been investigated, little is known about geographic variation in egg components. In this study, we examined variation in the water content, solid content, and shell mass of snapping turtle eggs from four populations dispersed along a longitudinal geographic transect (Pennsylvania, Michigan, Minnesota, and Nebraska). Initial egg mass and dry shell mass were similar among these four populations. However, water contents of eggs correlated positively with longitude, whereas dry content mass correlated negatively with longitude. Moreover, water content of eggs correlated negatively with the average number of days per year where average air temperatures exceeded 15 °C in a particular region (an indicator of regional thermal climate), and dry content of eggs correlated positively with both the number of days per year where average air temperatures exceeded 15 °C and the average total precipitation for the months of May through September (an indicator of regional hydric climate). These findings suggest that egg content (and perhaps egg quality) in this wide-ranging species of turtle varies in a manner reflecting differences in climate.

Effects of parental quality and egg size on growth and survival of herring gull chicks

2000 ◽  
Vol 78 (6) ◽  
pp. 967-973 ◽  
Author(s):  
T S Risch ◽  
F C Rohwer
Keyword(s):  
Egg Size ◽  
Character Displacement ◽  
Egg Mass ◽  
Chick Survival ◽  
High Quality ◽  
Growth And Survival ◽  
Parental Quality ◽  
Trade Offs ◽  
Structural Growth ◽  
Experimental Treatments

We performed a clutch-transfer experiment with herring gulls (Larus argentatus) to quantify how parental attributes and egg size affect chick growth and survival. The quality of parents was assessed by their average egg mass. There was no association between hatching success and egg mass in either unmanipulated or experimental nests. Among experimental treatments, the high-quality parents had a significantly higher chick survival rate than low-quality parents in 1991 and when data from 1990 and 1991 were pooled. A positive effect of egg size on chick survival was apparent only when data from both years were pooled. Chicks raised by high-quality parents had higher structural growth rates (tarsus) than chicks raised by low-quality parents. We discount the likelihood for selection of larger eggs because egg size has trade-offs with other life-history traits that have a strong influence on fitness. Despite the correlation between parental quality and chick survival, we doubt that there is character displacement for greater parental quality. Parental quality is probably affected by nutrition and is expected to have low heritability.

Egg Size and Egg Quality

2012 ◽  
Author(s):  
Tony D. Williams
Keyword(s):  
Life History ◽  
Egg Size ◽  
Egg Quality ◽  
Life History Trait ◽  
Egg Mass ◽  
Optimum Size ◽  
High Quality ◽  
Mate Quality ◽  
Good Proxy ◽  
Egg Components

This chapter deals with variations in egg size and egg quality. Egg size is a highly variable life-history trait, with up to twofold differences in egg mass among individual females within a population. Larger eggs contain absolutely more major egg components (shell, albumen, yolk) and absolutely more of several minor egg components (maternally derived antibodies and antioxidants), and, in this regard, egg size is a good proxy for egg quality. Many studies assume that high-quality females produce large, high-quality eggs, but it is equally plausible that individual females produce eggs of the optimum size and quality for their phenotype or genotype. Either way, the aspects of a female's phenotype that would determine maximum or optimum egg size are unknown, although these are not primarily factors such as age, experience, body condition, or mate quality that continue to be the focus of much current work.

scholarly journals Embryonic temperature influences juvenile temperature choice and growth rate in snapping turtles Chelydra serpentina.

1998 ◽  
Vol 201 (3) ◽  
pp. 439-449
Author(s):  
S O'Steen
Keyword(s):  
Growth Rate ◽  
Incubation Temperature ◽  
Chelydra Serpentina ◽  
Adult Males ◽  
Male And Female ◽  
Egg Incubation ◽  
Snapping Turtles ◽  
Behavioral Physiology ◽  
Incubation Temperatures ◽  
Embryonic Temperature

Snapping turtles (Chelydra serpentina) demonstrate temperature-dependent sex determination (TSD): intermediate egg incubation temperatures (23-27 degreesC) produce males, while extreme temperatures produce females. Snapping turtles are also sexually dimorphic: adult males are typically larger than females. Previous researchers hypothesized that male-producing egg temperatures enhanced the growth rate of juvenile turtles, resulting in the adult dimorphism and potentially providing an adaptive benefit for TSD. In reptiles, the choice of ambient temperature can also influence growth. I measured the effect of egg incubation temperature on juvenile growth rate and water temperature choice of C. serpentina. Eggs were incubated in the laboratory at 21.5, 24.5, 27.5 or 30.5 degreesC to produce both sexes, all males, both sexes or all females, respectively. Egg temperature was linearly and negatively correlated with growth rate of both male and female juveniles. Thus, growth was enhanced, but not maximized, by male-producing egg temperatures. Egg temperature was also negatively correlated with juvenile temperature choice such that, on average, turtles from 21.5 degreesC eggs selected 28 degreesC water, while turtles from 30.5 degreesC eggs chose 24.5 degreesC water. Additionally, these temperature choices were highly repeatable, even following a 6 month hibernation period at 7 degreesC. Thus, while male egg temperatures do not directly maximize growth, multiple effects of embryonic temperature may combine to create long-lasting differences in the behavioral physiology of male and female C. serpentina. Such differences could be important to the ecology and evolution of TSD.

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.

Influence of incubation temperature and substrate on eggs and embryos of the garden lizard, Calotes versicolor (Daud.)

2002 ◽  
Vol 23 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Srinivas Saidapur ◽  
Rajkumar Radder ◽  
Bhagyashri Shanbhag
Keyword(s):  
Ambient Temperature ◽  
Hatching Success ◽  
Incubation Temperature ◽  
Developmental Rate ◽  
Egg Mass ◽  
Cotton Wool ◽  
Different Temperatures ◽  
Calotes Versicolor ◽  
Periodic Exposure ◽  
Incubation Temperatures

AbstractThe influence of incubation temperature and substrate on hatching success, duration of incubation and hatchlings' traits in Calotes versicolor was studied experimentally. The eggs were incubated in soil at 1) ambient (27°C±2 s), 2) ambient temperature and exposed to 35°C for 1 or 3hrs/day, 3) constant 30°C, 33°C and 35°C. In another experiment soil, sand or cotton wool was used as incubation substrate at ambient temperature. Duration of incubation was inversely related to incubation temperature. Hatching success was high at ambient (93%), at 30°C (89%) and for eggs exposed to 1 hr (94%) or 3 hr/day to 35°C (93%) compared to those at 33°C (59%) and 35°C (53%). Egg mass increased until hatching, but with a temporal difference in the gain at different temperatures. At high temperatures, it increased rapidly. Eggs incubated at ambient temperature and 1 or 3 hrs exposure to 35°C produced hatchlings heavier than their sibs that hatched at 30°C, 33°C or 35°C. Smaller size of hatchlings at higher incubation temperatures was due to early hatching and low utilization of yolk. Incubation substrate had no influence on offspring traits but hatching success was low (84 ± 9%) in cotton wool. Thus, incubation of eggs in soil or sand at ambient temperature with a periodic exposure to high tolerable temperature provides an optimum balance between developmental rate, hatching success and hatchling quality in C. versicolor.

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