scholarly journals Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Diversity ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 72 ◽  
Author(s):  
John P. Vanek ◽  
Gary A. Glowacki
Keyword(s):  
Population Structure ◽  
Sex Ratios ◽  
Monitoring Program ◽  
Chrysemys Picta ◽  
Adult Survival ◽  
Sampling Location ◽  
Road Mortality ◽  
Population Declines ◽  
Road Density ◽  
Painted Turtles

Turtles are particularly susceptible to the negative impacts of urbanization due to low mobility and a life history strategy emphasizing long generation times and high adult survival. In addition to declines directly through habitat loss, urbanization has been hypothesized to limit populations of aquatic turtles through changes in population structure, as adult females are disproportionally killed on and near roads, leading to male-biased populations, which can lead to population declines or local extirpations. The purpose of this study was to better understand how urbanization impacts the sex ratios of painted turtles (Chrysemys picta) in an urban ecosystem, as empirical results linking male-biased turtle populations to roads and urbanization are mixed. Using eight years of trapping data from a long-term monitoring program in a suburb of Chicago, IL, USA, we report one of the most male-biased populations ( x ¯ = 75% male) of turtles in the USA, consistent with prevailing road mortality hypotheses. However, we found no evidence that male-biased populations were related to road density or the amount of protected area around a sampling location and found that impervious surface (a metric of urbanization) was weakly related to less male-biased populations. Our results highlight the importance of replicating ecological studies across space and time and the difficulty in assessing population structure in aquatic turtles. We suggest that active conservation measures may be warranted for the continued persistence of urban turtle populations.

Sex determination in northern painted turtles: effect of incubation at constant and fluctuating temperatures

1985 ◽  
Vol 63 (11) ◽  
pp. 2543-2547 ◽  
Author(s):  
Lin Schwarzkopf ◽  
Ronald J. Brooks
Keyword(s):  
Sex Determination ◽  
Sex Ratios ◽  
Chrysemys Picta ◽  
Temperature Dependent ◽  
Northern Population ◽  
Painted Turtles ◽  
Threshold Temperatures ◽  
Warm Summer ◽  
Summer Temperatures ◽  
Fluctuating Temperatures

Temperature-dependent sex determination was studied in a northern population of painted turtles (Chrysemys picta) in both laboratory and field. Eggs incubated at constant temperatures of 30 and 32 °C produced females only, whereas those kept at 22, 24, and 26 °C produced males only. Both sexes occurred at 20 and 28 °C. The threshold temperatures (temperatures producing 50% males) were estimated to be 27.5 and 20.0 °C, and were similar to those reported for more southerly populations of C. picta. In both 1983 (a relatively warm summer) and 1984 (an average summer), temperatures in natural nests regularly fluctuated above and below both threshold temperatures. Mean nest temperatures were warmer in 1983 than in 1984, but were not useful to predict nest sex ratios. Mean nest temperatures were not similar to constant temperatures in their effect on sex ratio. Sex ratios in nests could be described best by the total number of hours for which the temperature at each nest was intermediate to the two threshold temperatures. Sex ratios (proportion male) of hatchlings in 1983 and 1984 were similar and female biased (0.12 and 0.13, respectively).

scholarly journals HATCHLING SEX RATIOS AND LOCOMOTOR PERFORMANCE OF MIDLAND PAINTED TURTLES (CHRYSEMYS PICTA MARGINATA)

2014 ◽  
pp. 3-6 ◽  
Author(s):  
Jason T. Cotter ◽  
Chris A. Sheil
Keyword(s):  
Sex Ratios ◽  
Canopy Cover ◽  
Chrysemys Picta ◽  
Locomotor Performance ◽  
Righting Response ◽  
Painted Turtles ◽  
Data Loggers ◽  
Statistical Effect ◽  
Thermosensitive Period ◽  
Nesting Season

The primary objectives of this study were to understand how canopy cover and nest temperatures affect hatchling sex ratios and locomotor performance (i.e., swimming sprint speed and righting response) of Chrysemys picta marginata nests. Seventeen nests were monitored with temperature data-loggers during the 2009 nesting season and found to contain 100% male-biased clutches with a mean nest temperature range of 20.0–24.0°C during the thermosensitive period (TSP). The percentage of canopy cover over each nest was inversely and significantly correlated with mean nest temperatures experienced during the TSP. Mean nest temperatures (MNT) did not have a statistical effect on either measure of locomotor performance; however, there was an observed trend toward increased performance with increased MNT.

Male Bias in Road-kills of Macropods

1997 ◽  
Vol 24 (1) ◽  
pp. 21 ◽  
Author(s):  
Graeme Coulson
Keyword(s):  
Population Structure ◽  
Sex Ratios ◽  
Insufficient Data ◽  
Road Mortality ◽  
Male Bias ◽  
Red Kangaroo ◽  
Significant Bias ◽  
Macropus Rufus ◽  
Wallabia Bicolor

I determined the sex of a total of 251 road-kills of six macropod species in southern Australia over a 13-year period. There was a significant bias towards males in five species, ranging from 65 to 92% males, but there was no difference from parity in the red kangaroo, Macropus rufus. Male eastern grey kangaroos, M. giganteus, and male western grey kangaroos, M. fuliginosus, probably behave in ways that expose them to vehicles more than females. Male-biased road-kills of swamp wallabies, Wallabia bicolor, may reflect skewed population sex ratios. There are insufficient data on the behaviour and population structure of the red-necked wallaby, M. rufogriseus, and rufous-bellied pademelon, Thylogale billardierii, to determine which explanation is responsible for male-biased road mortality in these species.

Effects of substrate water potential and fluctuating temperatures on sex ratios of hatchling painted turtles (Chrysemys picta)

1984 ◽  
Vol 62 (8) ◽  
pp. 1491-1494 ◽  
Author(s):  
Gary L. Paukstis ◽  
William H. N. Gutzke ◽  
Gary C. Packard
Keyword(s):  
Water Potential ◽  
Sex Ratios ◽  
Chrysemys Picta ◽  
Nest Sites ◽  
Painted Turtles ◽  
Ecological Implications ◽  
Males And Females ◽  
Gravid Females ◽  
Fluctuating Temperatures ◽  
Selection Of

Sex ratios of hatchling painted turtles (Chrysemys picta) are influenced by the hydric environment when eggs are exposed to fluctuating temperatures similar to those encountered in natural nests. When temperature varies between 18 and 30 °C over the course of a single day, nearly equal numbers of males and females hatch from eggs held on wet substrates, but, primarily, males emerge from eggs on dry substrates. The influence of the hydric environment on sex ratios of painted turtles developing in natural nests has important ecological implications, and may be a factor influencing both selection of nest sites by gravid females and sex ratios of hatchlings.

Temporal Variation in Growth Rate and Age at Maturity of Male Painted Turtles, Chrysemys picta

1993 ◽  
Vol 130 (2) ◽  
pp. 314 ◽  
Author(s):  
Nat B. Frazer ◽  
Judith L. Greene ◽  
J. Whitfield Gibbons
Keyword(s):  
Growth Rate ◽  
Temporal Variation ◽  
Chrysemys Picta ◽  
Age At Maturity ◽  
Painted Turtles

Helminths of Chrysemys picta belli in Manitoba including Polystomoides pauli sp.n. (Monogenea: Polystomatidae)

1979 ◽  
Vol 57 (5) ◽  
pp. 1046-1051 ◽  
Author(s):  
Shannon F. Timmers ◽  
Paul D. Lewis Jr.
Keyword(s):  
Oral Mucosa ◽  
Chrysemys Picta ◽  
First Report ◽  
Painted Turtles ◽  
Species Inquirendae

One new monogenean is described and 11 other helminths are reported from painted turtles from eastern Manitoba. Polystomoides pauli sp.n. from the host's oral mucosa most closely resembles P. coronatum (Leidy) and P. oris Paul. It differs from the former in having more and larger genital coronet spines, and possession of anterior cecal diverticula, and from the latter in size, larger number of genital coronet spines, and possession of great hooks with entire, not bifid, roots. Price's emendation of P. coronatum to include five species he held to be its synonyms is rejected; and the five species, P. opacum Stunkard, P. megacotyle Stunkard, P. microcotyle Stunkard, P. albicollis MacCallum, and P. digitatum MacCallum are designated species inquirendae. Polystomoides coronatum is restricted to the redescription given for it by Stunkard. The trematodes Crepidostomum sp., Eustomos chelydrae, Microphallus opacus, Protenes angustus, Spirorchis parvus, S. scripta, Telorchis attenuatus, and T. corti, the cestode Proteocephalus sp., and the nematodes Serpinema trispinosa and Spiroxys contortus are reported from Chrysemys picta belli. Except for P. angustus, all represent first reports from turtles in Canada. This is the first report of E. chelydrae from the host stomach, and the second report of M. opacus from naturally infected turtles.

Patterns and Possible Significance of Water Exchange by Flexible-Shelled Eggs of Painted Turtles (Chrysemys picta)

1981 ◽  
Vol 54 (1) ◽  
pp. 165-178 ◽  
Author(s):  
Gary C. Packard ◽  
Mary J. Packard ◽  
Thomas J. Boardman
Keyword(s):  
Water Exchange ◽  
Chrysemys Picta ◽  
Painted Turtles
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