Deirochelys Research Articles

An Evaluation of Western Chicken Turtle (Deirochelys reticularia miaria) Survey and Capture Protocols

The behaviors and activity season of Deirochelys reticularia miaria (Western Chicken Turtle) are poorly understood in Texas. Though distribution of D. r. miaria in the eastern portion of the state is widespread, turtle assemblage studies conducted within the range of the species in Texas have seldom documented its presence. There is a lack of formal protection for this subspecies and their habitat, and past research suggests that remaining habitat within the state is under threat from increasing urbanization. Therefore, the US Fish and Wildlife Service issued a 90-day finding that states listing the subspecies as threatened or endangered may be warranted. To provide survey recommendations for the western subspecies, we review species-wide capture techniques from the literature, recommend a survey season for D. r. miaria in Texas, and evaluate the efficacy and potential demographic biases of capture protocols implemented during field studies in the state in 2018 and 2019. We compared road surveys, dipnet surveys, seine surveys, night wading surveys, and two types of unbaited fyke net trap. Fyke nets were effective in every study that deployed them and captured D. r. miaria in this study at a rate of 0.25 captures per trap night. Dipnet surveys had the highest capture rate among active survey methods, but body size biases between methods were apparent. In Texas, road surveys yielded significantly lower capture rates than all other survey types. The best survey method selection will vary depending on research questions, budget, and time constraints. Utilizing proper survey protocols and understanding the activity season are crucial for performing effective studies on this species.

Fecundity, Female Maturation, and Nesting Season of Western Chicken Turtles (Deirochelys reticularia miaria) in Texas

The reproductive lifespans of turtles are consistently long, but reproductive cycles are under environmental control and thus can vary within species, populations, and individuals over time and space. Knowledge of turtle species' reproductive traits and their associated variances over time and space are critical to understanding the dynamics of turtle populations, especially those requiring management or conservation. Deirochelys reticularia is a species being considered for protection by the US Fish and Wildlife Service and contains 3 subspecies with some differences in reproductive characteristics of nesting season, annual nesting frequency, and egg retention. We collected ultrasound and x-radiograph data in Texas to identify the maturation size, nesting season, annual nesting frequency, and clutch size of female D. r. miaria in Texas. We observed no reproductive activity in individuals from 101 to 146 mm in plastron length (PL) and detected either unshelled eggs, shelled eggs, or both in individuals from 150 to 197 mm PL. Maturation sizes were similar to those in other regions and for other subspecies. We observed shelled clutches or nesting events from April to July, confirming a spring–summer nesting season in Texas consistent with other D. r. miaria sites and supporting the paradigm that the western subspecies does not follow the autumn–winter nesting season of the other subspecies. We found no evidence that individuals retain shelled eggs while aestivating or overwintering. Individuals nested up to 3 times/yr in Texas. Individuals laid 7–11 eggs and the mean clutch size was 9.2 eggs, similar to other regions and other subspecies. Nesting phenology is regionally variable, so management plans and policies for the species will need to consider that variation and potentially recognize management differences among D. reticularia subspecies.

Metabolic responses to increased temperatures in three semi-aquatic turtle species from the southeastern United States

Physiological maintenance of ectotherms is largely dependent on temperature. Abrupt changes in environmental conditions can cause shifts in energy budgets, with higher temperatures requiring more energy be devoted to maintenance functions, making less energy available for other activities. As a group, freshwater turtles are of conservation concern; thus, it is important to understand their physiological responses to temperature shifts, particularly given current climate change predictions. We quantified metabolic rates (MR) for three species of semi-aquatic turtles that vary in their degree of terrestriality and propensity to aestivate: chicken turtles (Deirochelys reticularia), eastern mud turtles (Kinosternon subrubrum), and eastern musk turtles (Sternotherus odoratus). Metabolic trials were performed using a flow-through respirometer at three environmentally-relevant temperatures: 25 °C, 30 °C, and 35 °C. As expected, MRs of turtles were significantly and positively associated with increases in mass and temperature. Pairwise comparisons revealed that D. reticularia exhibited significantly higher oxygen consumption rates (VO2) relative to K. subrubrum, which had significantly higher VO2 than S. odoratus. The combination of higher metabolic rates, the tendency to terrestrially aestivate, and declining quantity of high quality thermal habitats may place some semi-aquatic turtles at a disadvantage when considering future climate scenarios. Our findings, when combined with knowledge of other ecological traits, may be a useful tool for predicting relative sensitivities of turtle species to predicted climate change, particularly those species inhabiting seasonal wetlands.

Comparing Life Histories of the Shortest-Lived Turtle Known (Chicken Turtles, Deirochelys reticularia) with Long-Lived Blanding's Turtles (Emydoidea blandingii)

Evolutionary theories predict major differences in life-history trait values of long- and short-lived organisms. Such comparisons have not been possible for chelonians because no short-lived turtle was known until research revealed that chicken turtles (Deirochelys reticularia; DR) have a maximum longevity of 21 yrs. Life-history trait values of DR females are 1) age at maturity of females = 5–6 yrs; 2) clutches per season = 1.6; 3) annual fecundity = 6–8 female eggs per female; 4) average juvenile survivorship from age 1 to maturity = 0.60; and 5) low average annual adult survivorship = 0.66. We compared DR with the very long-lived Blanding's turtles (Emydoidea blandingii; EB) in Michigan. Over 14 yrs with no mortality (the minimum age at maturity of EB), the maximum potential fecundity produced by a single female embryo and her mature female offspring was 5 female eggs for EB and 1040 eggs for DR. Comparisons of life table output for approximately stable populations of DR and EB resulted in cohort generation times of 7 and 37 yrs, respectively. The life-history prediction that short-lived organisms should produce smaller offspring was not supported. Average wet mass of eggs is 10 g (8.4–11.3 g) for DR and 12 g (10–14 g) for EB; and average wet mass of hatchlings is 7.3 g (6–9 g) for DR and 9.3 g (6–13 g) for EB. Both differences are smaller than expected based on the difference in longevity. Short-lived female DR have an unusual tactic of investing in high fecundity and making substantial body size-specific investment in large eggs, which may reflect why juvenile survivorship had greater influence on population change rates than did adult survivorship. In contrast, adult survivorship had the greatest influence on population change rates of EB. Comparison of cohorts of 1000 female DR and EB hatchlings highlights the differences in life histories of short- and long-lived turtles: all DR would be dead by the time the last female EB had reached maturity at 21 yrs of age.

Inheritance

Inheritance Amanda Gomez (bio) Calling the devil is not the same as seeing him come. puerto rican proverb Like women washing their laundry at the shore's lip, the geese groom themselves. Some slow. Others quick and jabbing. What good is cleaning? My mother taught me to wash myself at least twice daily: morning and night. Strip my face as a nighttime prayer. I wanted to marry a man lighter than me, she once said, holding her wrist to my face. The landline erodes. Six-pack rings accrue with the waterweed in concrete rubble, locks an egret in its shallows. Below the waterline, a chicken turtle lingers. A cardboard ghost uncertain of its drowning. The first body part to succumb to old age is a woman's neck. This has nothing to do with hands. A tomato plant in late blight. Green unripe fruit with beetle-dark lesions, the dogs nudged with their snouts. [End Page 53] I rip disease like I've been taught. First, the brown dropped leaves. Then, the yellow-spotted curls. Infection always steals what is nourishing. We lose what we no longer inherit. A mother's trauma. A mother. After last night's thunderstorm, a cottontail kit is sluggish. Only hunger remains. She chews clover as she watches me pass. [End Page 54] Amanda Gomez Amanda Gomez is a Latinx poet residing in Virginia Beach, Virginia. She is the author of the chapbook Wasting Disease (Finishing Line Press, 2020), and her poetry can be read in print and online journals such as Academy of American Poets (online) and North American Review, among others. Copyright © 2021 University of Nebraska Press

ESTIVATION SITE SELECTION OF WESTERN CHICKEN TURTLES (DEIROCHELYS RETICULARIA MIARIA)

Western chicken turtles (Deirochelys reticularia miaria) spend most of the year estivating on land, but researchers know little about their choice of estivation locations, and understanding their terrestrial requirements is important for conservation efforts. Therefore, we used radio telemetry to examine the estivation locations of nine males and four females. We followed six of those males and three of those females for 2 years, and two males and one female for 3 years. We examined site fidelity and compared the habitat features of their estivation locations to the habitat available in the area. We found that males exhibited site fidelity across years, but females generally did not. We also found that D. r. miaria selected sites that contained small-mammal burrows, leaf litter, and <25% vegetative ground cover. There was no evidence of selection for sites with or without slopes. Because this species relies on estivation sites with specific characteristics, protecting suitable habitat is an important part of conservation efforts. This study can help to guide those efforts.

Good vibrations: a novel method for sexing turtles

The ability to accurately determine the sex of individuals is important for research and conservation efforts. While most species of turtle exhibit secondary sexual dimorphisms that can be used to reliably infer sex, there are some species that are very difficult to sex, and even within many dimorphic species, it is not uncommon to encounter individuals that appear to exhibit both male and female secondary sex characteristics. Therefore, we tested the novel method of using a vibrator to sex turtles by stimulating male turtles to evert their penises. We tested this method on males of four species (three families) with known sexual dimorphisms: spiny softshell turtles ( Apalone spinifera ; n = 14), western chicken turtles ( Deirochelys reticularia miaria ; n = 17), Mississippi mud turtles ( Kinosternon subrubrum hippocrepis ; n = 10), and common musk turtles ( Sternotherus odoratus ; n = 9). The method accurately sexed 100% of A. spinifera, 64.7% of D. r. miaria , 80.0% of K. s. hippocrepis , and 55.6% of S. odoratus. Despite the low success rates in some species, there are situations in which this method will be useful for researchers working with species that are difficult to sex using external morphological characteristics.

Development and validation of four environmental DNA assays for species of conservation concern in the South-Central United States

We describe the development and testing of qPCR assays to detect four species of amphibians and reptiles of conservation concern in the South Central United States through environmental DNA (eDNA) samples. The target species include the Ringed Salamander (Ambystoma annulatum), Three-toed Amphiuma (Amphiuma tridactylum), Crawfish Frog (Rana areolata), and Chicken Turtle (Deirochelys reticularia). A set of primers and probes amplifying a 64–72 bp target regions were designed for each species from DNA sequence data for either the mitochondrial Cytochrome Oxidase I or Cytochrome B gene. All assays were assessed for target specificity, with no evidence of amplification in closely related or sympatrically-distributed non-target species. In vitro tests indicate that all assays consistently detect focal species down to concentrations of 2 × 10− 9 pg/µL. We evaluated the utility of qPCR assays on the eDNA samples collected during field surveys across Eastern Oklahoma, focusing on counties with vouchered historical records for the target species. Although detection rates were low for field applications of the assays, positive detection of Ambystoma annulatum, Rana areolata, and Deirochelys reticularia, but not Amphiuma tridactylum, were recorded. These assays can provide a practical tool for a non-invasive, genetic monitoring program that allows for both rapid detection and tracking of native aquatic and semi-aquatic amphibian and reptile species of conservation concern.

Egg and clutch sizes of western chicken turtles (Deirochelys reticularia miaria)

Chicken turtles ( Deirochelys reticularia ) are generally characterized as having atypical reproductive characteristics relative to other sympatric emydids. However, the comparatively understudied western chicken turtle ( D. r. miaria ) has been shown to exhibit some reproductive characteristics that differ from the other subspecies. Therefore, we examined clutch and egg sizes from six D. r. miaria (13 clutches) in Oklahoma and compared the results to values that have been reported for the other two subspecies. Females nested up to three times per year, with clutches ranging from 8-13 eggs per clutch (mean = 10.9). The eggs were 19.4-25.3 mm wide (mean = 22.2 mm). These values are greater than the means reported for the other subspecies, but the differences were not statistically significant.

A Coconut-Eating Monitor Lizard? On An Unusual Case Of Frugivory In The Melanistic Sulawesi Water Monitor (Varanus Togianus)

During field work on Selayar Island off the coast of southwest Sulawesi, an adult male specimen of the melanistic Sulawesi water monitor (V. togianus) was found dead on a road south of the village of Benteng (6°7’10.73’’ S, 120°27’59.88’’ E) on 6 June 2006. The specimen had a snout-vent-length of 56.5 cm with the tail measuring 79.3 cm. Its head exhibited clear evidence from a lethal accident with a vehicle, while the remaining body showed no injuries. The specimen was collected to be examined in detail. In order to preserve and deposit it at the Museum Zoologicum Bogoriense (MZB Lac. 5951, field number K208), the venter was opened to remove all stomach contents and prey items. Surprisingly, no prey remains were recovered from the digestive tract, but instead an unidentifiable mass comprised of countless small pieces of a whitish hard substance. After flushing and cleaning, closer examination revealed that these were small pieces of coconut flesh and had filled out the body cavity of the lizard. Although the stomach contents of other voucher specimens of water monitor lizards collected from different localities on Sulawesi have not been investigated, some specimens disgorged the remains of scorpions, chicken, and sea turtle eggs when handled for examination. The coconut pieces of the Selayar specimen, however, represent the only case of frugivorous remains recorded. The Herpetological Bulletin Vol. 139. 2017. P: 41-42

Observations On Reproduction In the Western Chicken Turtle,Deirochelys reticularia miaria, In Louisiana

Abstract We collected reproductive data from six female Deirochelys reticularia miaria in northeastern Louisiana that were collected in January 1999, June 2001, and May of both 2002 and 2003. One female collected in late January was dissected and found to contain two size classes of enlarged ovarian follicles. Five additional females collected on land in May or June were all gravid; three of them were caught while digging a nest. Mean clutch size was 10.6 and mean egg size was 37.68 × 22.88 mm, with a mass of 11.69 g. The mean incubation period for 32 eggs was 84 days, and hatchling measurements were mean carapace length of 31.67 mm and mass of 8.32 g.

A new species of Spirorchis MacCallum, 1918 (Digenea: Schistosomatoidea) and Spirorchis cf. scripta from chicken turtle, Deirochelys reticularia (Emydidae), with an emendation and molecular phylogeny of Spirorchis.

Chicken turtles, Deirochelys reticularia (Latreille in Sonnini et Latreille) (Testudines: Emydidae) from Alabama, USA were infected by Spirorchis collinsi Roberts et Bullard sp. n. and Spirorchis cf. scripta. The new species is most easily differentiated from its congeners by the combination of having caeca that extend far beyond the genitalia, intercaecal genitalia positioned in the middle portion of the body, a testicular column that nearly abuts the caecal bifurcation, a cirrus sac positioned between the testes and ovary, a massive Mehlis' gland, an elongate, longitudinal metraterm that extends anteriad beyond the level of the ovary, a pre-ovarian genital pore, and a prominent, intercaecal Manter's organ. The specimens of S. cf. scripta differed from the holotype and published descriptions of Spirorchis scripta Stunkard, 1923 by several subtle morphological features, perhaps comprising intraspecific variation, but collectively warranted a detailed description herein. Based on examinations of the aforementioned specimens plus the holotype, paratypes and vouchers of morphologically-similar congeners, Spirorchis MacCallum, 1918 is emended to include the presence of oral sucker spines, a pharynx, lateral oesophageal diverticula ('plicate organ') and a median oesophageal diverticulum ('oeseophageal pouch'). Phylogenetic analysis of the nuclear large subunit rDNA (28S) recovered S. collinsi sister to Spirorchis picta Stunkard, 1923, > 99% similarity between S. cf. scripta and S. scripta, and a monophyletic Spirorchis MacCallum, 1918. No blood fluke infection has been reported previously from these drainages, Alabama, or this turtle species. This is the first new species of Spirorchis to be described from North America in 26 years.

Evaporative Water Loss Rates of Four Species of Aquatic Turtles from the Coastal Plain of the Southeastern United States

Abstract Many isolated wetlands in the southeastern United States are naturally ephemeral, productive habitats that can support a high diversity of aquatic reptiles. As wetlands begin to dry, reptile species exhibit different behavioral responses including overland dispersal and terrestrial aestivation. Regardless of strategy, one of the greatest risks to individual survival is desiccation. We measured evaporative water loss rates (EWL; % body mass lost per hour) and total % body mass lost over 24 h in four species of semiaquatic turtles that frequent isolated wetlands in the southeastern United States: Chicken Turtles (Deirochelys reticularia), Eastern Mud Turtles (Kinosternon subrubrum), Common Musk Turtles (Sternotherus odoratus), and Yellow-Bellied Sliders (Trachemys scripta scripta). Mean percent body mass lost over 24 h ranged from 4.44–10.26% among individuals, was negatively correlated with body mass and varied among species, with higher EWL rates occurring in species with reduced shell robustness...

The Spring–Summer Nesting and Activity Patterns of the Western Chicken Turtle (Deirochelys reticularia miaria)

The Eastern and Florida Chicken Turtle subspecies (Deirochelys reticularia reticularia and D. r. chrysea) exhibit nesting cycles that are atypical for aquatic North American turtles, with nesting occurring in the fall, winter, and early spring. The reproductive cycles of the western subspecies (D. r. miaria), however, have not been studied. Therefore, we monitored the reproductive status of female D. r. miaria in 2012 and 2013. In our populations, both male and female D. r. miaria were inactive on land from mid-July to mid-March. This differs from the activity patterns of the other subspecies in which females typically remain active into the fall and sometimes winter. Also, in contrast to the nesting patterns of D. r. reticularia and D. r. chrysea, female D. r. miaria developed follicles in the spring and summer (March–July) and contained eggs in the summer (May–July). Therefore, we conclude that the Western Chicken Turtle exhibits a nesting pattern that is more similar to that of other sympatric species ...

The Omnivorous Diet of the Western Chicken Turtle (Deirochelys reticularia miaria)

Chicken Turtles (Deirochelys reticularia) are morphologically adapted for carnivory, and this specialization has been corroborated by diet studies of the eastern and Florida subspecies (D. r. reticularia and D. r. chrysea, respectively). However, the diet of the western subspecies (D. r. miaria) has not been examined. To investigate this important aspect of this subspecies' ecology, we collected 54 fecal samples from 22 adult D. r. miaria and 13 samples from nine juvenile D. r. miaria in southeastern Oklahoma. White River Crayfish (Procambarus acutus) were found in 88.9% of adult samples (mean of 2.3 crayfish per sample), and appeared to be the dominant food source for adults. There was a significant positive relationship between turtle size and crayfish size, and on average the crayfish were 29.8 mm in carapace length. Insects representing six orders (predominantly Hemiptera and Coleoptera) were found in 57.4% of adult fecal samples. Surprisingly, plants were present in 92.6% of adult fecal samples. While most of the plant matter was unidentifiable, Common Rush (mostly seeds; Juncus effusus), Broadleaf Cattail (Typha latifolia), Giant Cutgrass (seeds; Zizaniopsis miliacea), and Purple-fringed Riccia (Ricciocarpus natans) were identified in several fecal samples. There was a significant difference between the diets of juveniles and adults, with juveniles consuming more insects, fewer crayfish, and fewer plants than adults. These results suggest both that there is an ontogenetic shift in the diet of D. r. miaria and that, unlike the other subspecies, D. r. miaria is demonstrably omnivorous.

Demographic and Reproductive Traits of Western Chicken Turtles,Deirochelys reticularia miaria, in Central Arkansas

The Chicken Turtle, Deirochelys reticularia, is an understudied species despite the fact that it is distributed across much of the southeastern United States. In addition, no previous study has been conducted on the western subspecies, D. r. miaria, even though it is considered rare and possibly in decline within portions of its range. A capture–recapture study was conducted over 3 yr on a population of D. r. miaria in central Arkansas to determine demographic and reproductive characteristics. The population approached a male bias (1.9:1) and consisted of few total individuals (N = 42). Reproductive traits, including clutch, egg, and hatchling size, appear to be similar between D. r. miaria and eastern populations. Annual survival estimates were similar among males, females, and juveniles (0.70, 0.70, and 0.69, respectively) and did not change over the course of the study. Although low compared with most turtles, similar results have been reported for other populations of D. reticularia, which suggests that the species may have a different life-history strategy than that of most other chelonians. Due to this difference, management practices are likely to affect D. r. miaria differently from other turtle species.

Ecology of Chicken Turtles (Deirochelys reticularia) in a Seasonal Wetland Ecosystem: Exploiting Resource and Refuge Environments

Abstract Chicken turtles (Deirochelys reticularia) were studied at Dry Bay, a Carolina bay wetland in South Carolina, USA, between 1994 and 2005. A total of 461 individual turtles was marked from 1993–1998. Minimum ages at maturity for males and females were 2 and 5 yr, respectively. All females reproduced each year, and 60% of reproductive females produced two clutches per season. Clutch size averaged 9.8 eggs, and both clutch and egg size increased with body size. Hatchlings averaged 29.2 mm PL, and body sizes were similar among years. Yearling survivorship varied from 7.0–43.0% (mean = 20.4%) among years. The highest survivorship of a hatchling cohort to age 5 was 0.21. Survivorships of juveniles and adults while in terrestrial refugia were higher than survivorships while in aquatic habitats. No adult females survived a 2-yr drought (2001–2003), and the bay was repopulated by mature males and juvenile females (most from the 1998 hatchling cohort) that had survived the extended drought in terrestrial re...

Habitat Use, Terrestrial Movements, and Conservation of the Turtle, Deirochelys reticularia in Virginia

Habitat Use, Terrestrial Movements, and Conservation of the Turtle, Deirochelys reticularia in Virginia

Morphological constraint on egg size: a challenge to optimal egg size theory?

Some freshwater turtles appear unable to produce eggs large enough to achieve the balance between size and number of eggs predicted by optimal egg size theory. We present evidence that pelvic girdle structure constrains egg size and thus offspring size in females of smaller-bodied species (Chrysemys picta and Deirochelys reticularia). The constraint is demonstrated by the correspondence of slopes of the increase of the pelvic aperture and egg width with increasing body size. This constraint appears to be relaxed in a larger-bodied species (Pseudemys scripta), in which the increase in pelvic aperture relative to body size is greater than the increase in egg width. This type of structural constraint on a reproductive trait should not occur unless there is strong selection on pelvic architecture for other functions, such as locomotion, support, and limb retraction, that prevent expansion of the pelvic aperture. Although other explanations may exist for other groups of organisms that appear to vary egg size, the large variation in egg size associated with body size in some species of turtles can be reconciled with optimal egg size theory only if a pelvic constraint model is accepted.

Biomass of Freshwater Turtles: A Geographic Comparison

Standing crop biomass of freshwater turtles and minimum annual biomass of egg production were calculated for marsh and farm pond habitats in South Caroling and in Michigan. The species in South Carolina included Chelydra serpentina, Deirochelys reticularia, Kinosternon subrubrum, Pseudemys floridana, P. scripta and Sternotherus odoratus. The species in Michigan were Chelydra serpentina, Chrysemys picta and Emydoidea blandingi. Biomass was also determined for a single species population of P. scripta on a barrier island near Charleston, South Carolina. Population density and biomass of Pseudemys scripta in Green Pond on Capers Island were higher than densities and biomass of the entire six-species community studied on the mainland. In both the farm pond and marsh habitat in South Carolina P. scripta was the numerically dominant species and had the highest biomass. In Michigan, Chrysemys picta was the numerically dominant species; however, the biomass of Chelydra serpentina was higher. The three-species community in Michigan in two marshes (58 kg ha/sup -1/ and 46 kg ha/sup -1/) and farm ponds (23 kg ha/sup -1/) had lower biomasses than did the six-species community in a South Carolina marsh (73 kg/sup -1/). Minimum annual egg production by all species in South Carolina averaged 1.93 kg ha/supmore » -1/ and in Michigan averaged 2.89 kg ha/sup -1/ of marsh.« less