Rubriky

Hlavná stránka Vyhľadávanie Diskusné fórum Antikvariát Výstavy a predajné stretnutia ("burzy")LiteratúraHerpetofauna SRVivaristika na známkachŽabčonoviny

Články a iné

TeraristikaAkvaristikaReportážeNápady pre VásZo svetaAktuality Fotogaléria

Inzercia

DarujemKúpimPredám

CITES

Na SlovenskuV ČecháchVšeobecneOficiálne stránky

Ostatné

Kontakt Linky Naše bannery Reklama

The Herpetological Journal Volume 32, Number 2, April 2022

Effects of aquatic and terrestrial habitats on the skin microbiome and growth rate of juvenile alpine newts Ichthyosaura alpestris
pp. 51-58
Author: Christopher J. Michaels

Abstract: Cutaneous bacterial communities can be crucial in modulating amphibian-pathogen interactions, but are highly sensitive to environmental conditions. Many amphibians, in particular salamandrid newts, may inhabit aquatic or terrestrial habitats after metamorphosis. These different conditions can alter the cutaneous bacterial communities of animals and so affect both the susceptibility of individuals to disease and their potential to transmit pathogens to others. Furthermore, different environments may influence the fitness of individuals through impacts on growth rates. I investigated the impact of aquatic and terrestrial environments on the cutaneous bacterial communities and growth rates in the alpine newt (Icthyosaura alpestris). This species is invasive in the UK and has been reported as carrier of amphibian pathogenic chytrid fungus. I show that aquatic animals, although growing faster, present less diverse communities, lacking in species that inhibit Batrachochytrium dendrobatidis (Bd) in vitro. My data suggest that aquatic and terrestrial phases in amphibians may influence their susceptibility to disease and I suggest that this likely impacts the way in which pathogens, especially Bd, spread in the environment.

Keywords: Amphibians; cutaneous bacterial communities; microbiomes; Bd; captivity, Batrachochytrium dendrobatidis, mutialistic bacteria, ex situ conservation

How does the feeding behaviour of the common forest toad Rhinella henseli (Anura: Bufonidae) vary in space and time? Trophic ecology, chemical and antimicrobial activity
pp. 59-69
Authors: Douglas da Silva Huning, Fabiana Tonial, Mateus Oliveira, Noeli Zanella, Júlia de Moraes Brandalise, Kielli Guerra, Natália Ficanha & Carla Denise Tedesco

Abstract: Studies in trophic and chemical ecology, in particular in amphibians, have gained increasing attention in recent years, given that this is the vertebrate group that has suffered the greatest decline in recent years, caused by the degradation of natural ecosystems and emerging diseases. The assessment of food preferences and prey availability between areas and seasons provides important parameters for the understanding of the population dynamics of leaf-litter toads. The study of the secretions of the parotoid macroglands of these toads also provides insights into the role of these secretions in fighting frog pathogens and their potential applications to combat pathogens that are harmful to humans. In the present study, we describe the trophic ecology of Rhinella henseli (Lutz, 1934), and the variation in its diet between seasons and areas. We also attempt to identify the chemical composition of the secretions of the parotoid macrogland found in the parotoid glands and test their potential antimicrobial activity. We sampled two toad populations in the Atlantic Forest of southern Brazil. The composition of the diet was analysed by season (warm vs. cool) and study area, with the prey items being identified to genus, whenever possible, and classified using the Index of Relative Importance. The parotoid secretions were removed manually from the parotoid glands and analysed via HPLC-MS/MS. We ran microdilution and agar plug diffusion tests to assess antimicrobial activity. The principal prey of these toads are large ants, primarily Pachycondyla sp., which vary in abundance between seasons and, to a lesser extent, between areas. We identified 21 chemical compounds, primarily steroidal bufadienolides. One of the populations presented a subset of 14 of these 21 compounds, reflecting the variation in their spatial distribution. These compounds presented anti-pathogenic properties against Candida albicans and, to a lesser extent, Staphylococcus saprophyticus. Our results indicate that the diet of R. henseli varies significantly between areas and seasons, as do the secretions of their parotoid macroglands between areas. The toxins exhibit antimicrobial activity, although the compounds must be tested in isolation to confirm this.

Keywords: Ecochemistry, Niche breadth, Ground-dwelling toads, Ants, Bioprospecting

Supplementary materials for 02.How does the feeding behaviour of the common forest toad Rhinella henseli (Anura: Bufonidae) vary in space and time? Trophic ecology, chemical and antimicrobial activity
Authors: Douglas da Silva Huning, Fabiana Tonial, Mateus Oliveira, Noeli Zanella, Júlia de Moraes Brandalise, Kielli Guerra, Natália Ficanha & Carla Denise Tedesco

Reproductive ecology of the Amaral's Blind Snake Trilepida koppesi in an area of Cerrado in south-eastern Brazil
pp. 70-79
Authors: Rebeca Stella Khouri, Bruno Ferreto Fiorillo, Henrique Bartolomeu Braz, Jorge Henry Maciel, Selma Maria Almeida-Santos & Marcio Martins

Abstract: Studies on reproductive biology have largely contributed to the understanding of snake ecology. However, detailed reproductive data are scarce for many groups, particularly blind snakes. Here, we describe the reproductive biology of Trilepida koppesi (Leptotyphlopidae), a widely distributed species in the savannas of south-central Brazil. We describe its macro- and microscopic reproductive anatomy, female reproductive cycle, potential clutch size, seasonal activity, and sexual dimorphism of a population from south-eastern Brazil. Males have plurilobulated testes. Spermiogenesis occurs in early spring (October), when gonads and kidneys show a textured surface, the sexual segment of the kidney is hypertrophied, and the ductus deferentia are opaque and packed with sperm. Females have only the right oviduct, which shows developed epithelium and uterine glands in spring. Mating likely occurs in spring (October–December), and females store sperm in infundibular receptacles until ovulation between late spring and early summer. Potential clutch size ranges from three to five eggs. Females grow larger than males. The synchrony between spermiogenesis and mating defines the male cycle as prenuptial, which is considered the ancestral state of Squamata. These results agree with the hypothesis of conservative parameters for the group.

Keywords: reproductive morphology, sexual dimorphism, Scolecophidia, clutch size, female sperm storage

Supplementary materials for 03.Reproductive ecology of the Amaral's Blind Snake Trilepida koppesi in an area of Cerrado in south-eastern Brazil
Authors: Rebeca Stella Khouri, Bruno Ferreto Fiorillo, Henrique Bartolomeu Braz, Jorge Henry Maciel, Selma Maria Almeida-Santos & Marcio Martins

Flashy male Jamaican anoles Anolis grahami show accelerated telomere attrition
pp. 80-84
Authors: Luiza F Passos, Gerardo Garcia & Robert Young

Abstract: Secondary sexual traits have evolved through sexual selection, many species have developed signals that can indicate their level of other fitness-relevant traits such as fight ability. Previous studies have shown that male sexual signals are honest signals about quality in an intrasexual context, demonstrating a direct relationship between the signal’s design and the fighting ability of its possessor. However, signals can be costly since conspicuous signals are more likely to attract predators or be energetically expensive. Here we have analysed if dewlap size and colouration were reliable signs of a male’s bite force, and the physiological costs associated with larger dewlaps and intense colouration in Jamaican anoles (Anolis grahami). We analysed dewlap size and colouration against bite force, and telomere attrition. Our results supported the hypothesis that dewlap size and colour intensity are honest predictors of an individual’s fighting potential as indicated by bite force. However, we have also found a relationship between colour intensity with higher telomere attrition rates, thereby indicating a possible cost of this trait for the individual.

Keywords: Bite force, Dewlap, Telomere, Sexual selection

Embryonic morphology in two species of the Physalaemus signifer clade (Anura: Leptodactylidae)
pp. 85-92
Authors: Marianna Isabella Rosa Rodrigues De Oliveira, Jimena Grosso, Marcelo Felgueiras Napoli, Luiz Norberto Weber & Florencia Vera Candioti

Abstract: We studied the embryonic morphology of Physalaemus camacan and P. signifer, two small foam-nesting frogs endemic to the Atlantic Forest. We analysed the development of transient embryonic structures and of the larval oral disc. These embryos have features typical of most congeneric species, such as the kyphotic dorsal curvature, three pairs of gills and the configuration of hatching and adhesive glands. Main differences regarding embryos of the P. cuvieri clade are the larger size and yolk provision at tailbud stage, less developed external gills and an apparently novel pattern of oral marginal papilla ontogeny. While some shifts could be correlated with variant modes of oviposition, others appear to be developmental modifications not related with ecomorphological aspects.

Keywords: adhesive glands, external gills, hatching gland, Leiuperinae, oral disc

| Vytlačiť článok |

Šéfredaktor | 17.6.2022 04:44 | 0 komentárov | 138x


www.aquabooks.cz zoochov.cz