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    V: Lightning Talks: Amphibians

    2021-07-26   11:45 - 12:20

    Moderator: David Green

    1.  11:45  VIRTUAL    Phytotelma-Breeding Frogs of the World – A New Online Resource. Richard Lehtinen*, The College of Wooster

    Of the great diversity of extant frogs, breeding in plant-held water bodies (phytotelmata) is a rare specialization. Nonetheless, phytotelma-breeding has evolved repeatedly in many different frog lineages and these species can show bizarre adaptations to life in these micro-aquatic habitats. To update old reviews and to provide a continuously revised online reference on various aspects of the biology of these frogs, I developed a simple website entitled “Phytotelma-Breeding Frogs of the World.” This review of the literature increases the known number of phytotelma-breeding frog species from the 102 known in 2004 to 269 today (an increase of 264%). Phytotelma-breeding frogs are currently known from 12 different frog families, the greatest number of species of which are from Hylidae (67 species), Dendrobatidae (64 species) and Microhylidae (53 species). For each of the 269 known species, the website provides summary information on larval diet, larval habitat, clutch size, ovum size and parental care behaviors (if any) as well as key literature references. I hope that this resource will be useful to the herpetological community and encourage future research on these specialized but often poorly studied frogs.

    2.  11:50  VIRTUAL    Responses of a Lakeside Anuran Community to Natural and Anthropogenic Disturbance. Victoria Tawa*, McGill University; David Green, McGill University

    Some intermediate levels of disturbance can be beneficial for biological diversity, but the extensive disturbances our environment is combatting can also result in the reduction and even the loss of important species. Due to their sensitivity and in the face of natural and anthropogenic disturbance, organisms like frogs and toads may serve as important bioindicators. Owing to the rarity of significant natural disturbances, questions concerning organism responses to disturbances have often been researched in controlled small-scale settings, while ecologically relevant analyses are extremely limited. In Long Point, Ontario, amphibians have experienced a chance overlap of major disturbance events: the planned removal of an invasive reed (Phragmites australis) and unexpected dune washout, resulting in complete landscape alteration. Using a Before-After-Control-Impact (BACI) design, I explore how these habitat modifications will affect various frog and toad species. This research will examine the population- and community-level responses of anurans using acoustic, wetland, and beach surveys. On the one hand, as a result of the method through which the invasive reed was removed, I predict oxygen levels in the water to be depleted and certain frog species to disappear from the area. On the other hand, I expect the natural washout to produce ideal breeding habitat for the federally endangered Fowler’s Toad (Anaxyrus fowleri), resulting in positive outcomes for this species. Insight from this research will provide a valuable contribution towards an improved understanding of the potentially interactive effects of multiple disturbance types on anurans in a natural field setting.

    3.  11:55  VIRTUAL    Microhabitat Use of a Crevice Dwelling Salamander. Megan Novak*, Clemson University; Kyle Barrett, Clemson University

    Species occurrence and abundance are both partially explained by the presence of suitable habitat. In many cases, ecologists describe habitat at the site or population scale; however, measures of within-site features (microhabitat) may also identify predictors of species’ abundance. Such assessments can help determine habitat suitability for sites with unknown occupancy status. Rock outcrops are embedded components of mountainous forest landscapes and are critical habitats for terrestrial salamanders such as the green salamander (Aneides aeneus). Most habitat suitability studies for the green salamander have been conducted on a macrohabitat (outcrop) level, neglecting the immediate microhabitat (rock crevices) these individuals interact with and the importance of within-habitat connectivity. Size and physiology limit green salamander movement capabilities, affecting foraging, predation evasion, and searching for mates. As a result of these constraints, I predicted crevices with features directly related to within-habitat connectivity would be more likely to be selected by a green salamander. I evaluated microhabitat features that contribute to both microclimate and within-habitat connectivity, including crevice width (cm), length (cm), depth (cm), temperature (°C), humidity (%), crevice density (1/m2), nearest crevice (cm), and nearest tree (m). We surveyed 424 crevices across 9 sites. 310 crevices did not have salamanders and were interpreted as available but unused microhabitat; 116 of the crevices were occupied. A global logistic regression model identified crevice width, canopy cover, and crevice density as significant features in predicting salamander presence. Current continuations of this work include estimating salamander abundance and survivability, as well as assessing genetic connectivity between subpopulations.

    4.  12:00  VIRTUAL    Color Variation and its Role in Speciation: a Hybrid Perspective. Florine Pascal*, CSU Northridge; Jeanne Robertson, CSU Northridge; Andres Vega, AMBICOR; Maria Akopyan, Cornell University

    Contact zones are well suited to studying the role of sexual selection in lineage divergence. The Red-Eyed Treefrog (Agalychnis callidryas) is a brightly colored and polymorphic frog that ranges throughout Central America. Populations differ greatly in leg color, size, call, and skin peptide composition, but a vast majority of the populations in Costa Rica and Panama are relatively monomorphic. Females (the choosier sex) prefer males of their own population over males with different traits, indicating that lineage divergence may evolve via reproductive isolation. Previously, we identified a contact zone between two A. callidryaslineages, consisting ofmultiple phenotypes and late generation hybrids.Here, we characterize the phenotypes from four populations of this contact zone, focusing primarily on color patterns. First, we tested whether color variation was categorical or fell along a continuum. Second, we used naturally occurring amplectant pairs to test for assortative mating. Preliminary analyses indicated complex, continuous color variation, with limited evidence of assortative mating. We discuss these findings in the context of the potential consequences of frequent hybridization between two diverging lineages.

    6.  12:10  VIRTUAL    Inhibitory Bacterial Diversity and Mucosome Function Differentiate Susceptibility of Appalachian Salamanders to Chytrid Fungal Infection. Randall R. Jimenez*, Smithsonian National Zoological Park and Conservation Biology Institute; Amy Carfagno, George Mason University; Luke Linhoff, Smithsonian National Zoological Park and Conservation Biology Institute; Brian Gratwicke, Smithsonian National Zoological Park and Conservation Biology Institute; Douglas C. Woodhams, University of Massachusetts Boston; Liana Soares Chafran, George Mason University; Molly C. Bletz, University of Massachusetts Boston; Barney Bishop, George Mason University; Carly Muletz-Wolz, Smithsonian National Zoological Park and Conservation Biology Institute

    Mucosal defenses are crucial in animals for protection against pathogens. Host antimicrobial defense peptides (AMPs) and skin-associated microbes are key components of mucosal immunity in amphibians. We studied defense mechanisms against chytrid pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans(Bsal), in four Appalachian salamander species with different Batrachochytriumsusceptibilities. We integrated molecular biology, network-thinking, and proteomics to understand how host and microbially-derived products on amphibian skin (hereby mucosome) serve as pathogen defenses across salamander species. Our results showed that eastern newts had the highest Bd prevalence, Bd infection intensities and mucosome function (i.e. ability to kill chytrid zoospores in vitro), while red-back salamanders had the lowest prevalence, infection intensities and mucosome function, and two-lined salamanders and seal salamanders were intermediates. We found that as Bd infection prevalence decreased Bd-inhibitory bacterial richness and relative abundance increased on hosts. In microbiome networks, red-back salamanders had the highest proportion of Bd-inhibitory bacteria hub taxa and positive interactions related to Bd-inhibitory hub bacteria. We found more candidate AMPs on salamanders with lower Bd susceptibility. We conclude that salamanders possess distinct innate mechanisms that affect chytrid fungi. Individuals with higher Bd intensity possess a strongly functioning mucosome, that may reduce the probability of disease development. Individuals with lower Bd prevalence possess higher richness and relative abundance of protective bacteria, that may reduce likelihood of Bd infecting skin. Our study improves our understanding of complex immune defense-mechanisms in salamanders.

    7.  12:15  VIRTUAL    Cutaneous Bacteria of the Spotted Salamander (Ambystoma maculatum) in Western New York. Richard Stevens*, Monroe Community College

    Amphibian skin has been found to be host to a diverse community of microorganisms. Cutaneous bacteria are thought to play a role in preventing the chytrid fungi, Batrachochytrium dendrobatidis and B. salamandrivorans and other diseases in amphibians. While there has been a recent increase in studies researching the microbiome of amphibians, there have been relatively few studies investigating the skin microbiome of salamanders and only one small study of the microbiome of ambystomid salamanders. This study attempts to provide insight into the components of the cutaneous microbiome of spotted salamanders, Ambystoma maculatum. Cutaneous bacteria were sampled from 33 spotted salamanders, including 26 adults, three juveniles, and three larvae and one metamorph. Bacteria were cultured on R2A agar in the lab and identified using sequencing of the 16S rRNA gene. A total of 33 distinct bacteria from 15 genera were identified. Among the bacterial species found was Janthinobacterium lividum, which is known to prevent chytrid fungal infection and is used to inoculate amphibians reintroduced to sites where they have been extirpated from chytridiomycosis. The majority of bacteria identified from salamanders had known antifungal properties.

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