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All 32 Brazilian species of Parodia Speg (Cactaceae) occurring in Rio Grande do Sul State are considered threatened, according to the IUCN criteria. Until 2021, Parodia rechensis (CR) was known by only two small populations. However, a new population with over 400 individuals was discovered in 2021, prompting the study of its reproductive biology as a way to promote its conservation. Anthesis, breeding system, and natural pollination were studied in the field. The breeding system was studied by applying controlled pollination treatments to plants excluded from pollinators (bagged). Germination features were studied at the Seed Bank of the Porto Alegre Botanical Garden under controlled temperatures (20, 25, and 30 °C). The anthesis is diurnal and lasts for up to four days. The flowers offer pollen as the sole resource to the pollinators. The study species is unable to set fruit and seed without the agency of pollinators and has self-incompatible (unable to set fruit and seeds when pollinated with pollen of the same individual) characteristics that can considerably restrict its reproduction. Native bees of Halictidae and Apidae (Hymenoptera) are the main pollinators, with a smaller contribution of Melyridae (Coleoptera) and Syrphidae (Diptera). Natural fruit set is moderate (≤64%, per individual), but the species presents vegetative growth, producing several branches from the mother plant. Seeds showed the optimum germination rate at 20 °C and an inhibition of 75% in germinability at 30 °C. Our findings suggest the need to manage the species' habitat to guarantee the permanency of the plants and healthy populations of pollinators as well. Our findings raise concerns about the germination and establishment of new individuals in the context of rising temperatures caused by climate change. Suggestions for the possible management of the extant populations are made. [ABSTRACT FROM AUTHOR]

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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. [ABSTRACT FROM AUTHOR]