Samanta Iop

Anurans of Turvo State Park: testing the validity of Seasonal Forest as a new biome in Brazil

The composition of the anuran community of Turvo State Park was compared with that of other localities of Mesophytic semideciduous Forest, aiming to test the hypothesis that localities situated nearest the Misiones nucleus support the new phytogeographic unit, known as Tropical Seasonal Forests Region. In total 32 amphibian species were recorded in the park area and surroundings: Anura, 30 native species and one exotic; Gymnophiona, one species. The ordination among the 20 localities of Seasonal Forest showed the formation of three groups with 45% similarity: group 1, composed of localities of south-eastern and central western regions; group 2, composed of the localities of the transitional portion with the Atlantic Forest sensu stricto and group 3, composed of the southern localities. The consolidation of the second group, which includes the occurrence of endemic species, supports the proposal of a new phytogeographic unit.

Extension of the geographical distribution of two anuran species for Rio Grande do Sul State, Brazil, with comments on natural history

We record for the first time Crossodactylus schmidti (Anura: Hylodidae) and Proceratophrys avelinoi (Anura: Cycloramphidae) from Rio Grande do Sul State, Brazil, based on individuals captured in an area of Mesophytic Semideciduous Forest, the Parque Estadual do Turvo, located in the northwest region of the state. These records extend the geographical range for both species in about 60 km from the nearest known locality, the Municipality of San Vicente, Misiones, Argentina. We provide a characterization of the calling site used by males of Crossodactylus schmidti, and we also determined the niche breadth of P. avelinoi regarding to the use of water bodies.

Diversidade de formigas na Floresta Nacional de Chapecó, Santa Catarina, Brasil

A mirmecofauna da Floresta Nacional de Chapeco, Gleba I, foi estudada por coletas semanais realizadas de dezembro de 2003 a dezembro de 2004. Foram utilizadas armadilhas do tipo malaise, pit-fall, iscas com sardinha, iscas com glicose, rede de varredura, guarda-chuva entomologico e funil de Berlese. Tres constituicoes vegetais foram amostradas, sendo pinus, eucalipto e Floresta Ombrofila Mista e Floresta Estacional Decidual. Foram capturadas 137.019 especimes de nove subfamilias, 18 tribos, 36 generos e 121 especies. Os indices de diversidade de Margalef obtidos foram 9,9; 9,7 e 12,6; de Shannon e Wiener 3,0; 3,2 e 3,4 e de equitabilidade de 0,69; 0,73 e 0,74, para as areas com pinus, eucalipto e mata nativa, respectivamente. Estes resultados indicam uma distribuicao mais uniforme na comunidade da mata nativa, caracterizando-se como um importante reservatorio especies de formigas no Oeste catarinense.

Social interactions in a neotropical stream frog reveal a complex repertoire of visual signals and the use of multimodal communication

Visual communication has evolved independently in several families of frogs and is complex in diurnal stream frogs. In addition to isolated visual and acoustic signals, some species may emit multimodal displays characterized by the association of these signals. Through the analysis of focal recordings obtained in situ in southern Brazil, we investigated the visual and multimodal communication in the diurnal stream frog Crossodactylus schmidti. We found a complex visual repertoire of nine signals used in intraspecific communication, of which the signal Both legs kicking was described for the first time. Males, females and juveniles emitted visual signals, but males had a larger repertoire and used most signals in agonistic interactions. The four most common visual signals, Toe flagging, Limb lifting, Body jerking and Running-jumping, were emitted predominantly upon rocks in the stream bed. The emission of isolated visual and acoustic signals, as well as audiovisual displays with simultaneous or temporally coupled components, demonstrates that the communication in C. schmidti is complex and that the multimodal displays may have different functions. We discuss the historical, behavioural, ecological factors which may have influenced the evolution of the visual repertoire of C. schmidti, and how the ritualization of derived activities similar to visual signals may have led to the evolution of part of the repertoire. This study provides novel results on visual and multimodal communication for the genus Crossodactylus and demonstrates that C. schmidti represents an appropriate model for studies of complex displays.

Communication in a noisy environment: short-term acoustic adjustments and the underlying acoustic niche of a Neotropical stream-breeding frog

Acoustically active animals may show long- and short-term adaptations in acoustic traits for coping with ambient noise. Given the key role of calls in anurans’ life history, long- and short-term adaptations are expected in species inhabiting noisy habitats. However, to disentangle such adaptations is a difficult task, incipiently addressed for Neotropical frogs. We investigated if males of a stream-breeding frog (Crossodactylus schmidti) adjust call traits according to the background noise, and if the signal-to-noise ratio (SNR) varies between call harmonics and along call notes. We measured sound pressure levels of calls and noise in the field and used a fine-scale acoustic analysis to describe the signal and noise structure and test for noise-related call adjustments. The multi-note harmonic call of C. schmidti greatly varied in the spectral structure, including a trend for increasing note amplitude along the call, a wide frequency bandwidth of the 2nd harmonic, a minor call frequency modulation due to a trend for increasing note frequency within the same harmonic, and a major call frequency modulation due to the variable location of the dominant harmonic along the call. Calls had significantly higher frequencies than the noise at the range of the 1st and the 2nd call harmonics, and significantly louder sound pressure than the noise at the range of all harmonics. Males emitted the majority of call notes showing positive SNR, and though males also emitted some notes with negative SNR, when a given harmonic was negative the other harmonics in the same note did not tend to be SNR-negative. Our results indicate that male C. schmidti show short-term acoustic adjustments that make the advertisement call effective for coping with the interference of the stream-generated noise. We suggest that the call spectral plasticity serves for coping with temporary changes in the background noise, whilst we also discuss the possibility that the redundant, harmonic-structured call may have evolved to diminish masking interference on the acoustic signal by the background noise. This is the first study to uncouple noise-related acoustic adjustments and putative long-term acoustic adaptations for a Hylodidae, providing insights on behavioral plasticity and signal evolution of stream-breeding frogs.

Amphibia, Anura, Hylidae, Hypsiboas curupi Garcia, Faivovich and Haddad, 2007: first record for the state of Rio Grande do Sul, Brazil

The genus Hypsiboas includes 80 species of neotropical hylid frogs (Frost 2009), subdivided into seven species groups (Faivovich et al. 2005). The H. pulchellus group is the richest one, with 31 species (Garcia et al. 2007; Kwet 2008). Among them, the H. semiguttatus complex has a very problematic taxonomy, because for a long time populations of H. semiguttatus in Brazil (in the hills of the Serra do Mar, in Paraná, Santa Catarina and Rio Grande do Sul states) and in Argentina (in the province of Misiones) were considered as a single species. However, recent studies indicated that some of these populations represent different species (Garcia et al. 2007; Kwet 2008). Based on specimens of the H. semiguttatus complex, Garcia et al. (2007) described a new species: Hypsiboas curupi (Figure 1), using specimens from Misiones, Argentina. In the same study, the authors pointed out the potential occurrence of the species in the Brazilian state of Paraná. Four occurrences were cited for Paraná, of specimens apparently belonging to H. curupi, but vocalizations and tadpole data that could corroborate this identification were missing at that time (Garcia et al. 2007). Subsequently, Brusquetti and Lavilla (2008) broadened the distribution of H. curupi to three localities in Paraguay.

Calling Activity of a Stream-Breeding Frog from the Austral Neotropics: Temporal Patterns of Activity and the Role of Environmental Factors

Abstract:  Animal activity patterns can be influenced by selection pressures from local environmental conditions that might fluctuate at different temporal scales. Although studies with frog species and local populations can suggest how variation of environmental factors affects activity patterns, this topic has received little coverage for Neotropical diurnal frogs that inhabit streams, particularly for subtropical species. We described the temporal patterns of calling activity of Schmidts Spinythumb Frogs (Crossodactylus schmidti) in southern Brazil and investigated the role of environmental factors on this activity. We recorded local environmental variables and monitored calling activity from October 2011 to September 2012, by counting the number of calling males and the number of emitted calls at hourly intervals throughout the day. Male frogs engaged in calling activity year-round, despite the local climatic seasonality. There was no seasonality in the number of calling males or in the number of calls; moreover, variation in photoperiod did not affect the duration of the calling activity throughout the year. Crossodactylus schmidti showed a predominantly diurnal calling activity, with a spike in the early morning followed by a gradual increase in activity during daytime hours, and a subsequent decrease in activity at dusk. Environmental factors had varying effects on calling activity: (1) monthly activity was positively associated with accumulated rainfall and air temperature; (2) early morning activity was greater when air temperatures were higher; and, (3) daytime calling activity was positively associated with light intensity. Whereas our results do not preclude the effect of other environmental factors in the calling behavior of male C. schmidti, accumulated rainfall, air temperature, and light intensity appear to be abiotic regulators of this activity at the analyzed temporal scales. We discuss the biological implications of these environmental factors in the calling activity and reproduction of C. schmidti, and compare the observed patterns with those of other taxa of diurnal stream-breeding frogs. RESUMO: Os padrões de atividade animal podem ser influenciados por pressões seletivas de condições ambientais locais que podem flutuar em diferentes escalas temporais. Embora estudos com espécies de anuros e populações locais podem sugerir como a variação de fatores ambientais afeta os padrões de atividade, este assunto tem recebido pouca cobertura para anuros diurnos neotropicais que habitam riachos, particularmente para espécies subtropicais. Nós descrevemos os padrões temporais da atividade de vocalização de uma rã diurna de riacho (Schmidt’s Spinythumb Frogs, Crossodactylus schmidti) no sul do Brasil e investigamos o papel dos fatores ambientais sobre esta atividade. Nós registramos variáveis ambientais locais e monitoramos a atividade de vocalização entre outubro de 2011 e setembro de 2012, através da contagem do número de machos em atividade de canto e do nú mero de cantos emitidos em intervalos de uma hora ao longo do dia. Os machos estiveram em atividade de vocalização durante todo o ano, apesar da típica sazonalidade climática local. Não houve sazonalidade no número de machos ativos ou no número de cantos emitidos; além disso, a variação no fotoperíodo não afetou a duração da atividade de vocalização ao longo do ano. Crossodactylus schmidti apresentou uma atividade de canto predominantemente diurna, com um pico no início da manhã seguido de um aumento gradual da atividade durante o dia, e uma subsequente diminuição da atividade ao anoitecer. Os fatores ambientais tiveram efeitos variáveis sobre a atividade de vocalizaçã o: (1) a atividade mensal foi positivamente associada à precipitação acumulada e à temperatura do ar; (2) a atividade do início da manhã foi maior quando as temperaturas do ar eram mais altas; e, (3) a atividade diurna foi positivamente associada com a intensidade luminosa. Apesar dos nossos resultados não excluírem o efeito de outros fatores ambientais no comportamento de vocalização dos machos de C. schmidti, a precipitação acumulada, a temperatura do ar e intensidade luminosa parecem ser reguladores abióticos da atividade de vocalização nas escalas temporais analisadas. Nós discutimos as implicações biológicas destes fatores ambientais sobre a atividade de canto e reprodução de C. schmidti, e comparamos os padrões observados com os de outros táxons de rãs diurnas de riachos.

New records of Crossodactylus schmidti Gallardo, 1961 (Anura: Hylodidae) for the state of Rio Grande do Sul, Brazil, with data on morphometry and an updated geographic distribution map

Crossodactylus schmidti Gallardo, 1961 is a diurnal frog inhabiting rocky streams in forested areas, recently considered as a threatened species in the Brazilian states of Rio Grande do Sul and Santa Catarina. Herein we present four new population records of C. schmidti for the northwestern region of Rio Grande do Sul state and discuss the major impacts that may be threatening the species in the state. Additionally, we present an updated map of the current known species distribution and compare morphometric data among populations from Rio Grande do Sul state and Parana state, in Brazil, and from the province of Misiones, Argentina, based on the examination of voucher specimens available from herpetological collections.

Hematophagous Flies Attracted to Frog Calls in a Preserved Seasonal Forest of the Austral Neotropics, with a Description of a New Species of Corethrella (Diptera: Corethrellidae).

The signaler-eavesdropper interaction has been investigated for a wide range of organisms, and although many flies feed on calling frogs, this dynamic has been addressed only poorly in the austral Neotropics. We investigated this interaction in southern Brazil using pairs of suction traps (acoustic + silent) broadcasting frog calls or an artificial white noise in ponds and streams. From 139 sessions, flies of the genera Corethrella (Corethrellidae), Forcipomyia (Ceratopogonidae) and Uranotaenia (Culicidae) were collected, including five Corethrella species, the most abundant of which was previously unknown and is formally described here. Additionally, we present the southernmost records of Corethrella lopesi, C. alticola and C. atricornis. Numbers of Forcipomyia midges and Uranotaenia mosquitoes did not differ between silent traps and traps broadcasting frog calls, and did not differ between white noise traps and adjacent silent traps. However, the number of female Corethrella was significantly higher in traps broadcasting calls of the pond-breeding frog P. aff. gracilis compared to adjacent silent traps; calls of this frog attracted the five Corethrella species and also collected significantly more female Corethrella than the white noise. By evaluating different taxa of flies and broadcasting different sounds, we demonstrated that Corethrella midges were attracted only to the acoustic cue of P. aff. gracilis calls, while Forcipomyia and Uranotaenia were captured in traps by chance. Our results suggest that female Corethrella feed on males of the common pond-breeding frog P. aff. gracilis in southern Brazil, and highlight the utility of frog call traps in revealing the diversity of Corethrella in the austral Neotropics.

Expansion of the geographical distribution of Trachycephalus typhonius (Linnaeus, 1758) (Anura: Hylidae): First record for the state of Rio Grande do Sul, Brazil

We report the first record of Trachycephalus typhonius for the state of Rio Grande do Sul, Brazil, based on individuals found in the municipalities of Roque Gonzales and Salvador das Missoes. The original vegetation of these municipalities is characterized as Mesophytic Semideciduous Forest (Atlantic Domain), currently replaced by agricultural activities and urbanization. This record expands the geographical distribution area of this species by approximately 270 km from the nearest known locality, Iguazu, Misiones province, Argentina.