Anurans exhibit a wide range of defensive strategies that have evolved under selective pressures from predators throughout their evolutionary history. This study reports, for the first time within the family Ranidae, the occurrence of tongue protrusion as a defensive behaviour in Lithobates palmipes (Spix, 1824), and describes its release call associated with stress situations and unwanted amplexus. Observations were conducted at the Estação Ecológica de Caetés, Pernambuco, Brazil, during field expeditions in August 2025. The recorded behaviours included thanatosis, cloacal discharge, tongue protrusion, and release call emission, revealing a diverse defensive repertoire for the species. The release call exhibited a short duration (0.05 ± 0.01 s) and a dominant frequency of 1406.25 ± 187.93 Hz, consistent with short-range defensive vocalisations. Tongue protrusion, a behaviour rarely documented in anurans, appears to reinforce thanatosis by confusing potential predators. These findings expand current knowledge of the antipredator strategies of L. palmipes and contribute to a broader understanding of behavioural diversity within Ranidae. Furthermore, they highlight the importance of ethological and bioacoustic studies for understanding the evolution and conservation of Neotropical amphibians.
Most amphibians rely on both aquatic and terrestrial environments throughout their life cycle. While the use and selection of aquatic habitats are well documented in many species, terrestrial habitats remain far less studied. The yellow-bellied toad (Bombina variegata) is a small, cryptic species whose terrestrial ecology is poorly known, particularly regarding the use and selection of resting sites. To address this gap, we tracked individuals using VHF transmitters during the breeding and post-breeding seasons, and characterized their terrestrial shelters. These shelters were used occasionally during the breeding season, either as resting sites near aquatic habitats or during movements, and more intensively after the breeding season, possibly in preparation for wintering. Shelters were found across a wide range of microhabitats, with selection primarily driven by the presence of holes and high woody debris cover. Distances between terrestrial shelters and the aquatic sites used varied greatly among individuals, highlighting the importance of maintaining suitable terrestrial habitats within several hundred meters around aquatic sites. This study emphasizes the importance of considering terrestrial microhabitats in forest management for the conservation of this species.
The global amphibian biodiversity crisis is significantly driven by the fungal pathogen Batrachochytrium dendrobatidis (Bd), contributing to declines in populations of hundreds of species and dozens of species extinctions over the last half-century. While the pathogen is widely distributed across at least 26 European nations, it remains undocumented in many regions of the Balkans. This study reports the first detection of Bd within populations of the genus Bombina in Croatia, based on field surveys conducted during the vernal and autumnal seasons of 2023 and 2024. Surveys targeted 19 distinct sites in Papuk Nature Park across an altitudinal gradient (87 m to 864 m), focusing on ephemeral aquatic microhabitats such as shallow temporary ponds and roadside ditches. Molecular screening of 82 individuals via quantitative PCR (qPCR) confirmed the pathogen in eight individuals across four ponds. Infections were identified in yellow-bellied toads (Bombina variegata) and their hybrids, while all sampled fire-bellied toads (B. bombina) tested negative. These results confirm the regional establishment of Bd in Croatia. Given the relative isolation of the infected locations and the low likelihood of the pet trade as a distribution factor, spread via biological vectors or natural hydrological connectivity seems likely. The presence of Bd in these isolated populations introduces a serious long-term threat to their viability, emphasizing the need for monitoring, targeted conservation, and in situ mitigation strategies to prevent sudden population collapses.
Amphibians face severe global decline, making a comprehensive understanding of their ecological interactions essential for effective conservation planning. Among these interactions, leeches (Hirudinea) play an intricated role, acting both as ectoparasites and macrophagous predators. While the parasitic interactions between these taxa have been largely explored, the role of leeches as active predators of amphibians remains less documented, especially for caudate taxa. Here, we report a predation event of a horse leech (Haemopis sp.) on a larva of fire salamander (Salamandra salamandra) taking place in northern Italy. To our knowledge, this is the first scientific record involving a member of the genus Salamandra, and potentially it may represent the first documented case of leech predation on a caudata larva. This observation thus highlights a potentially overlooked trophic interaction that may contribute to larval mortality and population dynamics.
We evaluated the critical spatial scales for estimating the relative abundance of the forest green tree frog (Zhangixalus arboreus) and the black-spotted pond frog (Pelophylax nigromaculatus), both of which utilize paddy fields for breeding, in rural landscapes in northeastern Japan. Visiting each of the 42 sites established in the Shonai region five times between May and June 2023, we record the presence or absence of advertisement calls from the target species. We constructed the Royle-Nichols models to explain the repeated presence or absence data by the proportion of surrounding paddy fields, along with other landscape factors and weather conditions. The proportion of surrounding paddy fields was prepared for a radius ranging from 100 to 1,500 m. Through these analyses, we determined the optimal spatial scale, assessing the effects of spatial scale dependency. The optimal spatial scale for elucidating the relative abundance of the two frog species was the narrowest buffer size, with a radius of 100 m, underscoring the greater explanatory power of a finer spatial scale. This optimal spatial scale holds significance for various conservation and land use planning purposes. The trend for the forest green tree frog remained consistent as the scale changed, with a higher relative abundance estimated in environments featuring a moderate amount of surrounding paddy fields. Conversely, the impact of the surrounding landscape on the black-spotted pond frog varied with spatial scale, indicating spatial scale dependency. This dependency may be attributed to differences in sensitivity to the surrounding landscape between these species.
