Male anurans emit different call types in specific social contexts. Such calls represent a communication pathway for species recognition, mate choice, and male-male competition mediation. The acoustic parameters of these calls can be under directional and/or stabilizing selection due to female choice, which influences intra- and inter-individual call variation. Herein, we investigated the inter-year variation of the advertisement and aggressive calls of the gladiator frog Boana goiana, analysing a temporal series encompassing 18 years of sampling (1996-2014). We measured and analysed the following acoustic parameters: call duration, call repetition rate, number of pulses, pulse duration, pulse repetition rate, and dominant frequency. For both call types, the dominant frequency was classified as a static parameter (CVintra < 5%), while call duration was a dynamic parameter (CVintra > 12%). The advertisement call of B. goiana presents the attributes that could allow individual recognition in the chorus, and we suggest that the aggressive calls might also be important for the individual recognition process. Pulse duration of the advertisement and aggressive calls decreased over the years, as well as the repetition rate of the aggressive calls, which could be related to male body size decrease over the years probably related to habitat alteration. This study provides data on the variation of anuran acoustic features over the longest time span ever analysed. Such studies are less invasive and useful for conservation purposes, since they can detect changes in the reproductive behaviour of populations that might be under environmental modification pressure.
Dendropsophus cruzi (Pombal Bastos, 1998) is a small hylid (male snout-to-vent length = 16.3-19.4 mm; female SVL = 21.3-25.0 mm) that is allocated in the D. microcephalus group (Faivovich et al. 2005). It is commonly found in Open and forested areas from Central Brazil to Provincia Velasco, Departamento de Santa Cruz, Bolivia (Frost 2017; Tessarolo et al. 2016). Pombal Bastos (1998) described the advertisement call of D. cruzi as a single pulsed note. Posteriorly, studies uncovered relationships between dominant frequency variation in the advertisement calls of D. cruzi and variation in the SVL and mass of males (Bastos et al. 2003), as well as the existence of a clinal geographic pattern in the variation of acoustic parameters of these calls (Tessarolo et al. 2016). However, the acoustic communication in anurans is usually mediated by more than one vocalization type (Toledo et al. 2015). Due the importance of call types in the social context of anurans (e.g., Reichert 2011; Forti et al. 2017), we expand the vocal repertoire of D. cruzi by describing its aggressive call.
Changes in the natural landscape and the indiscriminate use of pesticides can have a major impact on aquatic environments and have contributed to the worldwide decline of amphibian populations. In the present study, we sampled tadpoles of three anuran amphibians (Boana albopunctata, Physalaemus cuvieri, and Dendropsophus minutus) from ponds in six different agricultural landscapes of the Brazilian Cerrado savanna and evaluated whether and to what extent genotoxic and mutagenic damage was related to land use (the amount of forest and agricultural remnants, and related physicochemical factors) and the presence of pesticides in the water of the study ponds. We also evaluated the hepatotoxicity in P. cuvieri, which was the most abundant species at five of the six sampling points. Clomazone and Atrazine were the most common pesticides found in the ponds. The B. albopunctata and P. cuvieri tadpoles presented similar patterns of DNA damage among the sampling points. The least DNA damage was found in the D. minutus tadpoles, although this species was present in only one of the study ponds. More binucleated and anucleated cells were observed in B. albopunctata, but there was no significant variation among species in terms of the number of micronuclei or other erythrocytic nuclear abnormalities. Land use and physicochemical factors did not explain the variation in the DNA damage observed in the three anurans. The hepatotoxicity analyses of P. cuvieri revealed the presence of a series of alterations, including the enlargement of the sinusoids, vacuolization of the hepatocytes, the infiltration of inflammatory cells, hepatic steatosis, and dilation of the blood vessels. The interaction between physicochemical factors and the biomarkers analyzed in this study is complex. In particular, it will be important to better elucidate which factors are contributing, either directly or indirectly, to the decline of anuran amphibian populations, especially in threatened biomes, such the the Brazilian Cerrado. In this case, we would encourage further in situ studies that assess the ecotoxicology of the landscape, together with the systematic monitoring of aquatic environments, in order to guarantee the long‐term integrity of amphibian populations, and those of other organisms that play an essential functional role in the ecosystem.
The replacement of natural landscapes by anthropic environments has led to habitat loss and consequently, to the decline and extinction of many species populations. Several strategies, such as the creation of protected areas (PAs) and payment for ecosystem services have been adopted to mitigate the consequences of this biodiversity crisis. In Rio Verde, Goiás, Brazil, a Water Producer Program (WPP) was established, which provides payment for ecosystem services for the maintenance of riparian vegetation in the region of the Ribeirão Abóbora, a river which supplies the city and metropolitan area. In the absence of environmental diagnostic studies in the region, this present study contributes to reducing some knowledge gaps, through the: (i) characterization of the landscape in the WPP area, (ii) characterization of species of fauna (amphibians, birds, fish, and medium and large terrestrial mammals) and woody flora that occur in this area, and (iii) comparison of species diversity (fauna and flora) found in our study area with the diversity observed in the Cerrado protected area network. Our results reveal a low native vegetation cover (~21% of total area), but we recorded 300 total species: 20 species of anuran amphibians, 100 birds, 10 fish, 16 terrestrial mammals (medium and large), and 154 woody plants. Our sample comprises species considered endemic to the Cerrado (e.g., Anuran - Barycholos terntezi and Mammal - Callithrix penicillata), threatened species (e.g., Mammals - Herpailurus yagouaroundi, Myrmecophaga tridactyla and Tapirus terrestris), and exotic invasive species (Mammal - Sus scrofa). The results presented in this study are relevant and may help in the proposal of management actions within the scope of this important program of payment for environmental services.
The vocalisations of anurans are one of their principal forms of communication and are mainly used for specific recognition involving the attraction of reproductive mates and territorial defense. In this study, we analysed the advertisement calls of 101 individuals from a population of Scinax fuscomarginatus sampled in the type locality of S. pusillus (currently under the synonymy of S. fuscomarginatus). Specifically, we investigated acoustic variation at several levels: intraindividual, interindividual, throughout the night, and across six breeding seasons by analysing temporal and spectral parameters. We identified that all parameters of the advertisement call can be used for individual recognition, with the maximum frequency having the greatest potential. We then observed that all other acoustic parameters were influenced by the predictor variables, with the exception of maximum frequency. The air temperature negatively influenced call duration, number of pulses, dominant frequency and minimum frequency; while it positively influenced pulse rate and call rate during the breeding season. Furthermore, with the exception of call duration and pulse rate, the other acoustic parameters varied significantly across the different nocturnal periods. This study provides data on the variation in S. fuscomarginatus acoustic features. Besides, we also discuss the implications of individual recognition. Studies that consider different sources of variation for the same population of a given species are uncommon, but of paramount importance for understanding the behavioural dynamics of the population. Keywords: advertisement call, behaviour, individual recognition, sexual-selection
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