Browsing by Author "Langford, Gabriel J."

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    A Comparative Analysis of the Commensal Diversity of Two Gopher Tortoise (Gopherus polyphemus) Populations in Central Florida
    (Florida Southern College, 2017-12) Martinet, Kristen; Langford, Gabriel J.
    Gopher tortoises (Gopherus polyphemus) are extremely important to Florida’s environments and have been called a keystone species. Gopher tortoises have earned this distinction because their burrows serve as shelter and foraging space for a plethora of different animals, also known as commensals, including invertebrates, reptiles, amphibians, mammals, and birds. Interestingly, the commensals that live in different areas may be different depending on the location and age of the gopher tortoise community. To determine the difference in commensal diversity between gopher tortoise populations, this study surveyed the commensals present in Circle B Bar Reserve, which has a relocated gopher tortoise population, and Lakeland Highland Scrubs, which has a natural, undisturbed population. Pit fall traps, motion-activated field cameras, and a burrow camera were used to survey the commensals that live among the gopher tortoises in both sites, and the diversity of each site’s commensals was analyzed. The two sites ultimately did not have significantly different commensal diversity, even though their gopher tortoise populations were present in their environments for very different lengths of time.
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    A Survey of Parasites from Anolis Lizards on Andros Island, Bahamas: Do Ecomorphs Host Similar Parasite Assemblages?
    (Florida Southern College, 2018-04) Brittain, Kaitlin; Langford, Gabriel J.
    The Anolis lizard ecomorphs of the Caribbean and Bahamian islands are a well-established example of both adaptive radiation and convergent evolution. However, due to a lack of parasite biodiversity surveys on these islands, it is unclear if the parasite fauna hosted by these lizards follow similar evolutionary pathways. This study attempts to determine if the parasites hosted by Anolis spp. display strict host specificity, which would indicate speciation events in-step with their hosts, or if the parasites have little specificity and are broadly distributed among the various lizard species. In 2015 and 2017, lizards were captured by hand and dissected as soon as possible after capture in three locations on Andros Island, Bahamas. First, an external exam was conducted to look for ticks and mites, then blood smears and fecal samples were taken to search for blood protozoans. Parasites and hosts were preserved and brought back to the Parasitology Lab at Florida Southern College. Preliminary results found the ground-trunk lizard, Anolis sagrei, to host nearly all species of parasites found in this study, whereas the treetop lizard, Anolis smaragdinus, hosted relatively few parasite species. We propose that this pattern is due to the parasites intermediate hosts being ground-dwelling insects which would be more likely to consumed by ground-trunk lizards. Overall, our findings suggest that the parasites of Anolis display moderate levels of host specificity, thus some species may have speciated with their hosts, while others are generalists.
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    Co-Occurrence of Haematoloechus complexus and Rhabdias joaquinensis in the Plains Leopard Frog from Nebraska
    (Allen Press, 2013) Langford, Gabriel J.; Vhora, M. Suhail; Bolek, Matthew G.; Janovy, John Jr.
    Species of Haematoloechus and Rhabdias both are ubiquitous lung parasites of frogs, yet surprisingly little research has been conducted on the interactions between these worms. In a small Nebraska stream, 256 Rhabdias joaquinensis and 225 Haematoloechus complexus were found in the lungs of Lithobates (=Rana) blairi. Thirty-six of the 44 (82%) frogs were co-infected with H. complexus and R. joaquinensis whereas 5 (11%) frogs were infected with only 1 species and 3 (7%) frogs were uninfected. Tests for association between H. complexus and R. joaquinensis found a significant positive relationship between the 2 parasites. Significant positive relationships in intensity of infection were found when both lungs were combined but not when lungs were considered individually. Tests for association between H. complexus and R. joaquinensis found no relationship between the worms in the anterior and posterior portions of the lungs. These data suggest that H. complexus and R. joaquinensis do not competitively exclude each other from the lungs of L. blairi in southeastern Nebraska.
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    Ecological factors responsible for the geographic distribution of Rhabdias joaquinensis: where do lungworms infect anurans in nature?
    (Allen Press, 2016-03) Langford, Gabriel J.; Janovy, John Jr.
    The lungworm Rhabdias joaquinensis (Nematoda: Rhabdiasidae) is a common parasite of anurans in eastern Nebraska, yet absent from the same hosts in western Nebraska. This study investigated the ecology of the lungworm’s free-living stages that reside in host feces and surrounding soils to establish the worm’s free-living niche in eastern Nebraska. Using a comparative method, this study also investigated the absence of lungworms in western Nebraska’s Sandhills. Soil composition, moisture, and temperature were experimentally varied in the laboratory to assess their effects on juvenile development and survival. Field mesocosm and host defecation experiments were used to determine where in nature lungworms survive and eventually infect frogs and toads and to discover if vegetation facilitates lungworm transmission to hosts. The results found loam soils were amenable to lungworm development, whereas soils with high clay or sand content produced few infective lungworms. Soil moisture <50 % did not support lungworm development. Infective juveniles successfully developed between 5 and 35 °C, albeit at different rates, whereas only a limited number of non-infective worms developed at 40 °C. Field studies found that shoreline environments supported lungworm development, and the majority of lungworm infections appear to occur within a zone of infection adjacent to shorelines in eastern Nebraska. The prevalence in vegetation mesocosms was 100 %, and a significantly higher mean abundance was found in toads from containers with vegetation than without. Overall, these experiments suggest that the spatial distribution of R. joaquinensis in Nebraska is constrained by the worm’s ability to survive and reproduce in a soil matrix.
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    Ecological factors responsible for the geographic distribution of Rhabdias joaquinensis: where do lungworms infect anurans in nature?
    (Parasitology Research, 2016-03) Langford, Gabriel J.; Janovy, John Jr.;
    The lungworm Rhabdias joaquinensis (Nematoda: Rhabdiasidae) is a common parasite of anurans in eastern Nebraska, yet absent from the same hosts in western Nebraska. This study investigated the ecology of the lungworm’s free-living stages that reside in host feces and surrounding soils to establish the worm’s free-living niche in eastern Nebraska. Using a comparative method, this study also investigated the absence of lungworms in western Nebraska’s Sandhills. Soil composition, moisture, and temperature were experimentally varied in the laboratory to assess their effects on juvenile development and survival. Field mesocosm and host defecation experiments were used to determine where in nature lungworms survive and eventually infect frogs and toads and to discover if vegetation facilitates lungworm transmission to hosts. The results found loam soils were amenable to lungworm development, whereas soils with high clay or sand content produced few infective lungworms. Soil moisture <50 % did not support lungworm development. Infective juveniles successfully developed between 5 and 35 °C, albeit at different rates, whereas only a limited number of non-infective worms developed at 40 °C. Field studies found that shoreline environments supported lungworm development, and the majority of lungworm infections appear to occur within a zone of infection adjacent to shorelines in eastern Nebraska. The prevalence in vegetation mesocosms was 100 %, and a significantly higher mean abundance was found in toads from containers with vegetation than without. Overall, these experiments suggest that the spatial distribution of R. joaquinensis in Nebraska is constrained by the worm’s ability to survive and reproduce in a soil matrix.
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    Ecology of the Eastern Ribbonsnake (Thamnophis sauritus) in southern Alabama with evidence of seasonal multiple broods
    (Herpetological Conservation and Biology, 2011-12) Langford, Gabriel J.; Borden, Joel A.; Nelson, David H.
    Studies are lacking on the ecology of the Eastern Ribbonsnake (Thamnophis sauritus), especially in the southern United States. We describe some aspects of the sexual dimorphism, sex ratio, feeding habits, reproductive biology, and seasonal activity of the Eastern Ribbonsnake in a southern Alabama Tupelo-Gum swamp from 2003-2005. We captured 339 Eastern Ribbonsnakes 379 times; females were significantly longer than males, but males had longer tails. Snakes were active year-round, and the longest straight-line distance travelled by any snake was 1,050 m. Snakes consumed only frogs (Hyla spp. and Lithobates spp.); a shift occurred when juveniles switched from feeding on tadpoles to adult frogs. We found females had an extended reproductive season, producing broods April-October. Two females double brooded during the 2004 reproductive season, with 99 and 118 days between broods. The average brood size for Eastern Ribbonsnakes from six females that produced eight broods was 14 ± 3.18 (range 9-19). A reduction in brood size occurred in both females that produced multiple broods, but no decrease in neonate snout-vent length was detected between broods. Overall, our study provides needed natural history data from a southern location and the first evidence for multiple broods in a wild, temperate snake.
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    Elucidating the life cycle and life history of Dero hylae (Naididae), a rare parasitic oligochaete from Florida tree frogs.
    (Journal of Parasitology, 2015-03) Andrews, Jessee M.; Childress, Jasmine N.; Iakovidis, Triantafilos J.; Langford, Gabriel J.
    Given their ubiquitous nature, it is surprising that more oligochaete annelid worms (Annelida: Clitellata) have not adopted an endoparasitic lifestyle. Exceptions, however, are the understudied members of the genus Dero (Allodero) that parasitize the ureters of tree frogs and toads. This study experimentally explores the life cycle and host specificity of Allodero hylae, the worm’s use of chemical cues in host searching, and its seasonal prevalence and abundance over a year-long collection period on the Florida Southern College campus. A total of 2,005 A. hylae was collected from the ureter, urinary bladder, or expressed urine of wild Osteopilus septentrionalis; a significant positive correlation was found between host snout–vent length and parasite intensity for female but not male hosts. Monthly prevalence of A. hylae reached a peak of 58% in April, but never dropped below 20% in any month; mean abundance peaked March–May, whereas few worms were recovered in December and January. Confirming a parasitic lifestyle, wildcollected hosts with intense infections, typically .40 worms, showed obvious dilatation of the ureter wall, and some young-of-the-year O. septentrionalis exposed to A. hylae in the laboratory were killed by the apparent rupture of the host’s ureter. The worm has a direct life cycle: worms expelled in the host’s urine are capable of locating and re-infecting other hosts within aquatic microhabitats such as bromeliad tanks, and worms can survive for weeks in a free-living environment, even undergoing a morphological change. Further, chemotaxis assays found a positive response to a tree frog attractant for worms recently removed from hosts. Overall, this study provides the first multifaceted investigation on the life history and ecology of any Allodero spp., which offers new insights into an understudied endoparasitic oligochaete.
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    Elucidating the life history and ecological aspects of Allodero hylae (Annelida: Clitellata: Naididae), a parasitic oligochaete of invasive Cuban tree frogs in Florida
    (Allen Press, 2015) Andrews, Jessee M.; Childress, Jasmine N.; Iakovidis, Triantafilos J.; Langford, Gabriel J.
    Given their ubiquitous nature, it is surprising that more oligochaete annelid worms (Annelida: Clitellata) have not adopted an endoparasitic lifestyle. Exceptions, however, are the understudied members of the genus Dero (Allodero) that parasitize the ureters of tree frogs and toads. This study experimentally explores the life cycle and host specificity of Allodero hylae, the worm's use of chemical cues in host searching, and its seasonal prevalence and abundance over a year-long collection period on the Florida Southern College campus. A total of 2,005 A. hylae was collected from the ureter, urinary bladder, or expressed urine of wild Osteopilus septentrionalis; a significant positive correlation was found between host snout–vent length and parasite intensity for female but not male hosts. Monthly prevalence of A. hylae reached a peak of 58% in April, but never dropped below 20% in any month; mean abundance peaked March–May, whereas few worms were recovered in December and January. Confirming a parasitic lifestyle, wild-collected hosts with intense infections, typically >40 worms, showed obvious dilatation of the ureter wall, and some young-of-the-year O. septentrionalis exposed to A. hylae in the laboratory were killed by the apparent rupture of the host's ureter. The worm has a direct life cycle: worms expelled in the host's urine are capable of locating and re-infecting other hosts within aquatic microhabitats such as bromeliad tanks, and worms can survive for weeks in a free-living environment, even undergoing a morphological change. Further, chemotaxis assays found a positive response to a tree frog attractant for worms recently removed from hosts. Overall, this study provides the first multifaceted investigation on the life history and ecology of any Allodero spp., which offers new insights into an understudied endoparasitic oligochaete.
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    Exploring Differential Gene Expression Profiles Of Dero (Allodero) Hylae In Their Parasitic And Free-Living Forms
    (bioRxiv, 2022-06-18) Bonham, Claire; Roguski, Ashley; Langford, Gabriel J.; Macrander, Jason
    Parasitism is ubiquitous in nature, yet little is known about the evolutionary mechanisms that lead to a parasitic lifestyle. Facultative parasites can switch between free-living and parasitic lifestyles, which may provide an opportunity to study the genetic mechanisms underlying a transition to parasitism. The oligochaete Dero (Allodero) hylae is a facultative parasite commonly found within the ureter of various anuran species, such as the Cuban Tree Frog (Osteopilus septentrionalis). Dero hylae makes passage through the frog’s cloaca, where it then infects the ureter. In the ureter, the worm loses free-living characteristics such as hair setae, dorsal setae, a digestive tract, and fossa with gills as it transitions to a parasitic lifestyle. Dero hylae may be expelled from its host during urination, when this occurs the worm will reacquire free-living characteristics. The focus of this study is to compare the differential gene expression profiles observed when this rapid morphological change takes place. Specimens of D. hylae were collected from wild Cuban Tree Frogs and either flash-frozen for their parasitic stage RNA profile or cultured for two weeks to produce their free-living stage and then flash-frozen. Using the sequenced RNA, a de novo transcriptome was assembled and differential gene expression RNA Tag-Seq analysis between the free-living and parasitic life forms was analyzed. Based on these results, we have identified 213 genes differentially expressed transcripts between the two life forms, 190 of these being up-regulated in the free-living life form. While over half of the differential genes recovered did not recover any significant BLAST hits, many of these genes did provide insight into which molecular signals are potentially used by D. hylae to lose and subsequently regrow their setae, digestive tract, and gills. This analysis provides significant insight into which differentially expressed genes are linked to drastic morphological changes observed in this rare oligochaete parasitism across the free-living and parasitic forms of D. hylae.
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    Invasive Parasites: A survey of endoparasites in Salvator merianae populations in Florida
    (Florida Southern College, 2021-05) Fonseca, Marisa; Langford, Gabriel J.
    The Argentine Black and White Tegu (Salvator meriane) is a large lizard native to South America that has been introduced to central and south Florida. With successful breeding populations in at least two locations, and the ability to acclimate to many temperate climates of the other southeastern states, it is becoming increasingly more important to monitor all biological aspects of this invasive lizard, including their parasites. No detailed published records exist on the endoparasites from these invasive populations. Thirty-one Argentine Black and White Tegus from central and southern Florida were necropsied to perform an extensive parasite examination of these invasive populations. The necropsies revealed that the tegus brought three species of exotic nematode to Florida from South America (Physaloptera tupinambae, Diaphanocephalus galeatus, Cruzia lauroi) and were also infected with Raillietiella orientalis, a pentastome introduced to Florida via invasive Burmese Pythons (Python bivittatus). The invasive pentastome is known to infect native snakes and cause harm to their respiratory tracts. It is unknown how the exotic parasites from the tegus will impact native Florida reptiles, however, the ability for R. orientalis to infect the Argentine Black and White Tegu could lead to the rapid spread of this invasive parasite throughout the southeastern United States.
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    Life History Traits and Spatial Ecology of the Striped Mud Turtle, Kinosternon baurii, in Central Florida
    (Florida Southern College, 2017-12) Stemle, Leyna R.; Langford, Gabriel J.
    The roles that turtles and tortoises (Testudines) play in their environments make them vital to protect, conserve, and study for the continued health of our world. In recent literature, the Striped Mud Turtle (Kinosternon baurii) has been studied only a minute amount in Florida. Radio telemetry was used at Circle B Bar Reserve (CBR) on nine K. baurii, and long-term mark and recapture and life history data was collected that was essential for determining the size of this population. It was hypothesized that these mud turtles do not have a large home range, and that their overall health would be excellent due to the general lack of anthropogenic factors in their environment on the reserve. Our data indicates that these mud turtles have a fairly small home range (1,111.2-14,395.5 m2) with some males and gravid females generally having a larger area that they frequent. The health of the turtles was generally very good, as our marked turtles had clear eyes, energetic movements, and sturdy bodies. The population in the main area in which we set traps appeared to be fairly small (estimated at 38 adult individuals with the software program MARK), and we recaptured many of the same turtles. However, we did catch unmarked turtles occasionally and the age of the turtles in the reserve was varied, as multiple age classes were found. The sex ratio of the main canal in the reserve was female skewed (65.4 % females, p-value= .26). The data that was collected has helped Circle B Bar Reserve (CBR) understand more about their mud turtle population and expand their knowledge of the wildlife they protect. With unexpected low numbers and a female-biased sex ratio, the future of K. baurii must be carefully monitored, especially with the continued rise of urbanization and a warmer climate. If a small population is continually found, management practices may become a key component in conserving mud turtles. With more knowledge on their ecology, population size and movements, Circle B and other reserves/parks can better accommodate these turtles for the maximum protection from anthropogenic effects in the future.
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    Movement and Physiology of Invasion Front Cane Toads (Rhinella marina) in Central Florida
    (Florida Southern College, 2021-04) Mazariegos, Kayleigh; Langford, Gabriel J.
    In Australia and Florida, cane toads (Rhinella marina) are an invasive species that have wreaked havoc on local ecosystems. Native to South and Central America, these toads secrete a toxin harmful to both fauna and humans, strongly impacting Florida wildlife. Previous studies in Australia have established that actively invading toads change morphologically to have longer limbs, greater speed, and greater endurance compared to those that remain established in a single population. However, our research in central Florida suggests that the opposite may be occurring at this invasion site. Our experimental studies on toads suggest that those at Florida invasion fronts have shorter limbs, lower muscle mass, and less endurance. In addition, surveys evaluating the movement of the invasion itself were taken over 6 years to follow the path of travel and establish mean migration across the state. Contrary to the rapid expansion in all directions seen in Australia, our invasion appears to follow human development such as roadways eastward from Tampa, Florida at a slow and steady pace. Additional research is required to establish a mechanism creating the discrepancies between the two populations of invasion and established toads in both Florida and Australia. Establishing the differences between the two groups can give key insight into the management strategy of this invasive species and help preserve the health of Florida's ecosystem.
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    Phenotypic Plasticity in the Relative Hind-Limb Growth of Lab-Reared Anolis sagrei: Replication of Experimental Results and a Test of Perch Diameter Preference
    (2014-06) Langford, Gabriel J.; Macedonia, Joseph M.; Bessette, Christopher W.; Matey, Jennifer L.; Raboin, Brittany A.; Schiffmacher, Ashley E.; Reynolds, Brett J.
    Several observational and experimental studies have shown that perch diameter has an impact on the development of hind-limb length (HL) in Anolis species. This 'phenotypic plasticity' in relative hind-limb growth (RHG) has implications for short-term and long-term adaptation to different structural habitats. Our study is the first to replicate research in which hatchling/juvenile Anolis sagrei were reared on narrow-diameter or broad-diameter dowels in a laboratory setting. Although subjects reared on different dowel diameters did not differ significantly in RHG at 5 weeks into the experiment, results at 15 weeks revealed a significant effect of treatment but not of sex: subjects in the broad ( N = 69) treatment group exhibited significantly greater RHG than did subjects in the narrow ( N = 61) treatment group. We extended this research with a novel follow-up study: we placed our lab-reared subjects into outdoor enclosures where they had a choice of narrow- or broad-diameter dowels on which to perch. Results showed that subjects in both treatment groups chose broad-diameter dowels as perches more often than narrow-diameter dowels. We offer several potential explanations for the strong preference of our subjects for broad-diameter dowels irrespective of the dowel diameter on which they were reared.
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    Transmission, host specificity, and seasonal occurrence of cyrtosomum penneri (nematoda: Atractidae) in lizards from Florida
    (Allen Press, 2013) Langford, Gabriel J.; Willobee, Brent A.; Isidoro, Luiz F.
    Experimental infections and field-collected lizards were used to investigate issues of transmission, host specificity, and seasonal occurrence in the nematode Cyrtosomum penneri (Cosmocercoidea: Atractidae). Anolis sagrei (87 males, 42 females) were captured from the Florida Southern College campus, Polk County, Florida, from October 2010 to September 2011, and 8,803 C. penneri were collected from their intestines. During the breeding season all sexually mature (SVL ≥34 mm) A. sagrei were infected, whereas juvenile lizards.