Phenology has an important effect on the life strategies of species that live in temporary waters. Predaceous aquatic insects are key components of communities associated with seasonal ponds. Since the life cycles of these predators and their prey are unusual in that they occur at different moments of the pond hydroperiod, differences in temporal overlap could change the strength of their interactions. This study analyzed the phenology of the giant water bug Belostoma bifoveolatum and its prey. Breeding phenology, nymph population and prey phenology were studied extensively in three wetlands during the spring season. Experimental trials were carried out to evaluate prey consumption and prey preference. The results showed a strong overlap in phenology between the water bug and the Pleurodema thaul frog. The timing of tadpole and water bug nymph hatching could ensure high survival levels of the early immature stages of this insect. As giant water bugs develop, their prey selectivity experiences a shift, older nymphs and adults having a higher impact on tadpoles. The fluctuating climate of the Patagonian region probably influences the phenology of predator-prey assemblages in seasonal communities, and may have the potential to drive feeding performance and the strength of interspecific interactions.

Neotropical amphibians play important roles as preys and predators in freshwater and terrestrial ecosystems. The subfamily Pseudinae includes small and medium-sized frogs within three genera representing 13 valid species. Most published records of predation on Pseudinae frogs are anecdotic and scarce. Herein, we provide five new reports of predation and presenting a detailed literature review on Pseudinae predation, with 15 studies published between 1983-2017. Pseudinae species were preyed at both day and night by a wide variety of predators, principally birds. Adults were preyed upon more frequently than juveniles and tadpoles. In the present study, most predators were diurnal, with birds accounting for most records. A variety of invertebrates prey on anurans, but water bugs and spiders are the most common ones. In the present study, water bugs comprised 75 % of the Pseudinae predation records by invertebrates. However, anuran predation by invertebrates remains poorly documented. Thus, the description of new cases of predation accompanied by a review of the data available in the literature is crucial to understanding Neotropical food webs.

The objectives of this study were to describe the calling sites and identify the reproductive modes for the anuran assemblage in a temporary pond associated to a floodplain system in a Neotropical region in Southern Brazil. In this study we analyzed the influence of temperature, rainfall and hydroperiod on the calling activity of an anuran assemblage. A total of 19 amphibian collections were carried out over a year (from September 2004 to August 2005). Seventeen anuran species of six families were identified: Bufonidae (1), Cycloramphidae (1), Hylidae (6), Leiuperidae (4), Leptodactylidae (4) and Microhylidae (1); however, only fifteen species were observed in calling activity. Three reproductive modes were observed for the community, and the habitat use was temporally and spatially partitioned. 66.7% of the species had the generalized aquatic mode. The anurans presented a prolonged calling activity, and only Chaunus fernandezae presented an explosive pattern. While rainfall for the previous 24 h, air temperature and water depth influenced the calling activity of many anuran species over the studied period, daily rainfall, rainfall for the previous 24 h and water temperature did not influence it.

Small wetlands are particularly important habitats for amphibians due to their close dependence on these habitats for their critical life-story functions. The constant degradation of wetland systems has been considered as one of the main causes for the declining of the anuran population observed around the world, including in southern Brazil. The objective of this study was to analyze the richness, abundance, and composition of the amphibian assemblage in a small pond associated to a floodplain system in a Neotropical region in Southern Brazil over a year. A total of 19 amphibian samplings were carried out over a year (from September 2004 to August 2005), and the survey was made in five transects (30 x 2 m) distributed at random along the studied pond. A total of 17 anuran species distributed in six families (Bufonidae, Cycloramphidae, Hylidae, Leiuperidae, Leptodactylidae, and Microhylidae) were observed. The Hylidae family represented 35.3% of the total species, and 22.0% of the total individuals observed over the studied period. Rhinella fernandezae was the most abundant species, representing 24.7% of the all collected individuals. The amphibian richness and abundance did not show any variation during the study period and between phases with and without superface water. However, the anuran composition changed between periods with surface water and without surface water. Air temperature and rainfall did not influence the amphibian richness and abundance. The high diversity and abundance of the anuran observed (17 species and 332 individuals) point to the need to include small wetlands in the biodiversity conservation programs in Southern Brazil, mainly when 90% have already disappeared due to anthropic activities. But these results should serve as hypotheses for long-term investigations in a larger area.

Here we report two cases of predation on Eupemphix nattereri by Lethocerus delpontei and L. annulipes in farm ponds.