Christopher A. Phillips

Intersexuality and the cricket frog decline: historic and geographic trends.

Exposure to anthropogenic endocrine disruptors has been listed as one of several potential causes of amphibian declines in recent years. We examined gonads of 814 cricket frogs (Acris crepitans) collected in Illinois and deposited in museum collections to elucidate relationships between the decline of this species in Illinois and the spatial and temporal distribution of individuals with intersex gonads. Compared with the preorganochlorine era studied (1852–1929), the percentage of intersex cricket frogs increased during the period of industrial growth and initial uses of polychlorinated biphenyls (PCBs) (1930–1945), was highest during the greatest manufacture and use of p,p-dichlorodiphenyltrichloroethane (DDT) and PCBs (1946–1959), began declining with the increase in public concern and environmental regulations that reduced and then prevented sales of DDT in the United States (1960–1979), and continued to decline through the period of gradual reductions in environmental residues of organochlorine pesticides and PCBs in the midwestern United States (1980–2001). The proportion of intersex individuals among those frogs was highest in the heavily industrialized and urbanized northeastern portion of Illinois, intermediate in the intensively farmed central and northwestern areas, and lowest in the less intensively managed and ecologically more diverse southern part of the state. Records of deposits of cricket frog specimens into museum collections indicate a marked reduction in numbers from northeastern Illinois in recent decades. These findings are consistent with the hypothesis that endocrine disruption contributed to the decline of cricket frogs in Illinois.

Chrysosporium sp. Infection in Eastern Massasauga Rattlesnakes

To the Editor: During 2008, the ninth year of a long-term biologic monitoring program, 3 eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) with severe facial swelling and disfiguration died within 3 weeks after discovery near Carlyle, Illinois, USA. In spring 2010, a similar syndrome was diagnosed in a fourth massasauga; this snake continues to be treated with thermal and nutritional support and antifungal therapy. A keratinophilic fungal infection caused by Chrysosporium sp. was diagnosed after physical examination, histopathologic analysis, and PCR in all 4 snakes. The prevalence of clinical signs consistent with Chrysosporium sp. infection during 2000–2007 was 0.0%, and prevalence of Chrysosporium sp.–associated disease was 4.4% (95% confidence interval [CI] 1.1%–13.2%) for 2008 and 1.8% (95% CI 0.0%–11.1%) for 2010.

A riparian zone in southern Illinois as a potential dispersal corridor for reptiles and amphibians

Abstract We surveyed reptiles and amphibians in a core area (Wildcat Bluff/Heron Pond) and at four sites along the Cache River in southern Illinois, USA, to assess whether the existing riparian zone would serve as a dispersal corridor for these species. Only 14 of the 37 species found in the core area were detected at all sites along the river, and 17 species were not found at the three sites furthest downriver from the core area. In contrast to our expectations, wide (≥1000 m) areas of riparian habitat did not support greater numbers of species of reptiles and amphibians than narrow (≤100 m) areas. Proximity to the core area and local habitat heterogeneity appeared to best explain species richness at the sites surveyed. Examination of the literature on habitat requirements for the species found in the core area suggested that lack of upland habitats and of fishless pools, along with regular inundation of remaining riparian habitat, inhibit many species from occurring consistently throughout the corridor. Our results demonstrate the importance of including specific natural history requirements in the design of corridors, rather than simply relying on easy-to-measure parameters such as corridor width, especially for species with low vagility.

GEOGRAPHIC DISTRIBUTION OF MITOCHONDRIAL DNA VARIANTS AND THE HISTORICAL BIOGEOGRAPHY OF THE SPOTTED SALAMANDER, AMBYSTOMA MACULATUM

I analyzed geographic partitioning of mitochondrial DNA (mtDNA) restriction‐site variants in the spotted salamander, Ambystoma maculatum. Two highly divergent and geographically separate genetic lineages were identified that differed by a minimum of 19 restriction sites (6% sequence divergence). One of the lineages has a disjunct distribution with very closely related haplotypes occurring in Missouri, Arkansas, North Carolina, and Virginia. The other lineage is found in Michigan, Illinois, and Alabama. The geographic separation of highly divergent mtDNA haplotypes, a pattern that was predicted based on the sedentary nature of these salamanders, is evidence for long‐term barriers to gene flow. In contrast, the large‐scale disjunction of very similar haplotypes suggests recent, long‐distance gene flow and does not match the phylogeographic expectation for a small terrestrial vertebrate. I explain this potential contradiction in the level of importance assigned to gene flow by a scenario in which historical barriers to gene flow account for the two divergent mtDNA assemblages, but stochastic sorting of ancestral polymorphism is responsible for the large‐scale geographic disjunction. Ten of 16 populations collected in the Ozark Highlands were fixed for the same haplotype. I attribute this lack of detectable variation to recent colonization of this area, a hypothesis that is supported by paleoecological data and demonstrates the potential benefits of combining data from paleobotany, geology, and other disciplines to reconstruct the historical biogeography of a species.

Reptile road mortality around an oasis in the Illinois corn desert with emphasis on the endangered eastern Massasauga

Abstract Roads have numerous negative ecological effects on terrestrial fauna, and vehicular mortality can have significant demographic consequences for some species. We studied road mortality of reptiles around Carlyle Lake, Clinton County, Illinois, USA, from April 2000 through November 2002, to assess the impact of vehicular traffic and identify influential factors. Carlyle Lake, a popular tourism/recreation area, is situated in a larger agricultural landscape and is home to the largest Illinois population of the endangered Eastern Massasauga (Sistrurus catenatus). We documented 321 cases of reptile road mortality (84 individuals of six turtle species and 237 individuals of nine snake species) while driving our approx. 46 km study route roundtrip daily. Turtle road mortality was highest in May and June, and positively associated with precipitation and minimum daily temperature. Colubrid snake road mortality was highest in April and October, and positively associated with minimum daily temperature. We recorded 42 cases of road mortality of S. catenatus with the highest number occurring from mid-August to mid-September. Road mortality in S. catenatus was biased toward adult males, which show an increase in movement in August, coinciding with the peak of the mating season and a period of high tourist visitation. The traffic intensity on a road segment did not significantly affect the level of road mortality, but segments through high quality habitats had higher levels of mortality than segments through lower quality habitats. Based on our study on the ecology of S. catenatus, we make recommendations to reduce road mortality that should aid in the conservation of the Carlyle Lake population.

HEMATOLOGY, PLASMA BIOCHEMISTRY, AND ANTIBODIES TO SELECT VIRUSES IN WILD-CAUGHT EASTERN MASSASAUGA RATTLESNAKES (SISTRURUS CATENATUS CATENATUS) FROM ILLINOIS

During the 2004 field season, blood was collected from Eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) in the Carlyle Lake (Carlyle, Illinois, USA) and Allerton Park (Monticello, Illinois, USA) populations to derive baseline complete blood count and plasma biochemistry data and to assess the prevalence of antibodies to West Nile virus (WNV) and ophidian paramyxovirus (OPMV). Massasaugas were located for sampling through visual encounter surveys. Body weight, snout–vent length, total protein, globulins, sodium, and potassium were normally distributed among the survey population. Aspartate aminotransferase, creatine kinase, albumin, calcium, uric acid, white blood cell count, heterophils, lymphocytes, monocytes, eosinophils, and basophils were non-normally distributed within these animals. Female snakes had significantly shorter tail lengths; lower blood glucose, packed cell volumes, and absolute azurophil counts; and higher plasma calcium and phosphorus concentrations than did males. None of the snakes tested (n=21) were seropositive for WNV, whereas all (n=20) were seropositive for OPMV.

Leech Parasitism in a Turtle Assemblage: Effects of Host and Environmental Characteristics

Abstract Leeches are one of the most commonly observed parasites of freshwater turtles. We used baited hoop traps to capture 433 turtles belonging to five species (Apalone spinifera, Chelydra serpentina, Chrysemys picta, Sternotherus odoratus, and Trachemys scripta) to determine the host (species, microclimate use, sex, reproductive stage, and body size) and environmental characteristics (month of capture, turtle abundance, vegetation, turbidity, pond size, and availability of basking structures) that affected leech parasitism in Illinois ponds. Leech prevalence on turtles varied significantly among turtle species, was highest on bottom-walkers and adults, and varied throughout the year. Leech intensity was highest on larger turtles and in turbid ponds. The results from this study display the importance of utilizing turtle assemblages for examining overall trends in host–parasite dynamics, demonstrate the influence of environmental characteristics on leech parasitism, and provide baseline data for future studies examining leech parasitism on turtles.

Ongoing Health Assessment and Prevalence of Chrysosporium in the Eastern Massasauga (Sistrurus catenatus catenatus)

With the current rate of declines in global biodiversity, it is apparent that wildlife diseases are serving as additional threats to population declines and potentially species extinctions. Free-ranging Eastern Massasaugas (Sistrurus catenatus catenatus) have been reported susceptible to numerous health threats, one of which is a fatal fungal dermatitis. In response to the occurrence of the fungal dermatitis, a health survey and disease investigation was conducted on Eastern Massasaugas near Carlyle, Illinois in 2011. We captured 38 Eastern Massasaugas from March to April 2011. Polymerase chain reaction assays were performed from swabs collected from the faces of 34 snakes. We obtained hematologic data for 31 individuals, plasma biochemical data for 24, and toxicological data for 18. There was no evidence of Chrysosporium in any of the samples. Hematologic and plasma biochemistry parameters were consistent with previous health studies in the Carlyle population. Elemental toxicologic investigation of the plasma indicated variable levels of lead, copper, selenium, strontium, tin, iron, and zinc.

Structure and Composition of a Southern Illinois Freshwater Turtle Assemblage

Abstract We report on a six-year study (1994–1999) of a diverse turtle assemblage in Gallatin County, IL. Ten species of freshwater turtles representing four families were recorded. Species richness increased as a function of trap hours, with 3000 trap hours required to capture all species. The greatest density and biomass was for Trachemys scripta. Pseudemys concinna ranked second in density, but Chelydra serpentina ranked second highest in biomass. Females comprised the majority of the biomass in emydids, biomass ratios were even in Sternotherus odoratus, and males comprised the majority of the biomass in C. serpentina. Relative abundance did not significantly differ among the six years, although some uncommon species were not captured in all years.

Measuring Agreement and Discord among Hemagglutination Inhibition Assays Against Different Ophidian Paramyxovirus Strains in the Eastern Massasauga (Sistrurus catenatus catenatus)

Abstract At present, the hemagglutination inhibition (HI) assay is the sole commercially available serologic method available to detect exposure to ophidian paramyxovirus (OPMV) in snakes. During 2006, 26 eastern massasaugas (Sistrurus catenatus catenatus) were collected, and blood was sampled to determine their OPMV status. Samples from each snake were divided into 3 aliquots and tested by using commercially available HI assays against the 4 OPMV isolates used in the 3 laboratories that offer the service. All snakes were tested for antibodies by using HI assays against the green tree python (GTP), San Lucan rattlesnake (SLR), and Aruba Island rattlesnake (AIR) isolates. Twenty-five snakes were tested for antibodies against the western diamondback rattlesnake (WDR) isolate. All samples tested against the GTP and SLR were positive (26/26), whereas 56% (14/25) of the WDR assays were positive, and none (0/ 26) of the AIR assays yielded a positive result. There was 100% agreement between the GTP and SLR assays, and complete disagreement between the SLR and AIR, as well as the GTP and AIR assays. Kappa statistics for the GTP– WDR, SLR–WDR, GTP–AIR, SLR–AIR, and WDR–AIR indicated that the assays had less than chance agreement. The results demonstrate that current HI assays are not reliable as a sole diagnostic assay in the eastern massasauga. Furthermore, HI assays need to be evaluated by using other parameters to determine OPMV exposure in eastern massasaugas.