On the distinctive call of a threatened phenotype of Allobates femoralis (Anura: Aromobatidae) and its recognition by allopatric conspecific males

ABSTRACT The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk.

On the distinctive call of a threatened phenotype of Allobates femoralis (Anura: Aromobatidae) and its recognition by allopatric conspecific males

The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk.(AU)

On the distinctive call of a threatened phenotype of Allobates femoralis (Anura: Aromobatidae) and its recognition by allopatric conspecific males

The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk.

Advertisement and release calls of Phyllomedusa ayeaye (Anura: Hylidae) with comments on the social context of emission

Male calls play different roles in anuran social organization, such as spacing, territoriality and female attraction. However, calls and associated behaviors remain poorly described for many anuran species. Here we describe the advertisement and release calls of the tree frog Phyllomedusa ayeaye (Lutz, 1966) and report on the social context of emissions and a physical combat. Approximately 35 minutes of digital recordings were obtained from 34 hours of observations at one breeding site in the state of Minas Gerais, southeastern Brazil. Bioacoustic analysis showed that males emitted two types of advertisement calls: 1) simple call (a sequence of short pulsed notes) and 2) composite call (a sequence of short pulsed notes followed by a long pulsed note). Composite calls were emitted more frequently during more intense chorus activity, with various active males at the breeding site. The release call was also composed by short pulsed notes, with a wider spectrum of frequencies and emitted more rapidly than the advertisement calls. Our results suggest that the composite call of P. ayeaye may represent a mixed advertisement call. Long notes might be the aggressive part directed to males, whereas short notes directed to females. Our description of call types, their functions, and male physical interactions will be useful for studies investigating the systematics and behavior of Phyllomedusa species.

Advertisement and release calls of Phyllomedusa ayeaye (Anura: Hylidae) with comments on the social context of emission

Male calls play different roles in anuran social organization, such as spacing, territoriality and female attraction. However, calls and associated behaviors remain poorly described for many anuran species. Here we describe the advertisement and release calls of the tree frog Phyllomedusa ayeaye (Lutz, 1966) and report on the social context of emissions and a physical combat. Approximately 35 minutes of digital recordings were obtained from 34 hours of observations at one breeding site in the state of Minas Gerais, southeastern Brazil. Bioacoustic analysis showed that males emitted two types of advertisement calls: 1) simple call (a sequence of short pulsed notes) and 2) composite call (a sequence of short pulsed notes followed by a long pulsed note). Composite calls were emitted more frequently during more intense chorus activity, with various active males at the breeding site. The release call was also composed by short pulsed notes, with a wider spectrum of frequencies and emitted more rapidly than the advertisement calls. Our results suggest that the composite call of P. ayeaye may represent a mixed advertisement call. Long notes might be the aggressive part directed to males, whereas short notes directed to females. Our description of call types, their functions, and male physical interactions will be useful for studies investigating the systematics and behavior of Phyllomedusa species.(AU)

How do males of Hypsiboas goianus (Hylidae: Anura) respond to conspecific acoustic stimuli?

Acoustic communication plays an important role in the social behavior of anurans. Acoustic signals, which can be used in different contexts such as mate attraction and territory defense, may mediate social interactions among individuals. Herein, we used playback experiments to test whether males of Hypsiboas goianus (Lutz, 1968) change their vocal behavior in response to conspecific advertisement calls. Specifically, we used different field playback experiments in which we modified the time interval between advertisement calls to simulate males with distinct states of motivation (Sequence A and B). We did not observe differences in the acoustic response of males of H. goianus between the two types of field playback experiments. On the other hand, we observed that H. goianus males reduce the dominant frequency of the advertisement call and increase the rate of aggressive calls in response to a conspecific competitor. Our results suggest that the acoustic plasticity observed in males of H. goianus represents an aggressive response that allows repelling conspecific individuals.

How do males of Hypsiboas goianus (Hylidae: Anura) respond to conspecific acoustic stimuli?

Acoustic communication plays an important role in the social behavior of anurans. Acoustic signals, which can be used in different contexts such as mate attraction and territory defense, may mediate social interactions among individuals. Herein, we used playback experiments to test whether males of Hypsiboas goianus (Lutz, 1968) change their vocal behavior in response to conspecific advertisement calls. Specifically, we used different field playback experiments in which we modified the time interval between advertisement calls to simulate males with distinct states of motivation (Sequence A and B). We did not observe differences in the acoustic response of males of H. goianus between the two types of field playback experiments. On the other hand, we observed that H. goianus males reduce the dominant frequency of the advertisement call and increase the rate of aggressive calls in response to a conspecific competitor. Our results suggest that the acoustic plasticity observed in males of H. goianus represents an aggressive response that allows repelling conspecific individuals.(AU)

Vocal repertory of Scinax littoreus (Anura: Hylidae) with comments on the advertisement call of the Scinax perpusillus species group

The Scinax perpusillus species group consists of thirteen bromeligenous treefrogs, of which only six have had their acoustic parameters appropriately described. In this work, we present the vocal repertory of Scinax littoreus (Peixoto, 1988) based on recordings obtained from three different populations in the state of Rio de Janeiro, Brazil. Based on our observations we suggest that the vocal repertory of S. littoreus is composed of two distinct types of calls. The call named type A, which corresponds to a long series of multipulsed notes, is likely to have a mating function. This type of call is similar to that reported for Scinax arduous Peixoto, 2002, Scinax peixotoi Brasileiro, Haddad, Sawaya & Martins, 2007, and Scinax perpusillus (Lutz & Lutz, 1939). However, the type A call of S. littoreus is nonetheless readily distinguishable from the comparable call observed in other congeneric species. The call named type B, which exhibits a multipulsed structure, presumably has an aggressive function. We observed that different types of calls could be emitted alone or combined according to the social context. Additionally, we discuss problems involving comparisons of call parameters among species belonging to the S. perpusillus species group, provide an updated geographic distribution map, discuss the conservation status of the included species, and emphasize the importance of acoustic data for the recognition of species groups within Scinax.

Vocal repertory of Scinax littoreus (Anura: Hylidae) with comments on the advertisement call of the Scinax perpusillus species group

The Scinax perpusillus species group consists of thirteen bromeligenous treefrogs, of which only six have had their acoustic parameters appropriately described. In this work, we present the vocal repertory of Scinax littoreus (Peixoto, 1988) based on recordings obtained from three different populations in the state of Rio de Janeiro, Brazil. Based on our observations we suggest that the vocal repertory of S. littoreus is composed of two distinct types of calls. The call named type A, which corresponds to a long series of multipulsed notes, is likely to have a mating function. This type of call is similar to that reported for Scinax arduous Peixoto, 2002, Scinax peixotoi Brasileiro, Haddad, Sawaya & Martins, 2007, and Scinax perpusillus (Lutz & Lutz, 1939). However, the type A call of S. littoreus is nonetheless readily distinguishable from the comparable call observed in other congeneric species. The call named type B, which exhibits a multipulsed structure, presumably has an aggressive function. We observed that different types of calls could be emitted alone or combined according to the social context. Additionally, we discuss problems involving comparisons of call parameters among species belonging to the S. perpusillus species group, provide an updated geographic distribution map, discuss the conservation status of the included species, and emphasize the importance of acoustic data for the recognition of species groups within Scinax.

Vocal repertory of Scinax littoreus (Anura: Hylidae) with comments on the advertisement call of the Scinax perpusillus species group

The Scinax perpusillus species group consists of thirteen bromeligenous treefrogs, of which only six have had their acoustic parameters appropriately described. In this work, we present the vocal repertory of Scinax littoreus (Peixoto, 1988) based on recordings obtained from three different populations in the state of Rio de Janeiro, Brazil. Based on our observations we suggest that the vocal repertory of S. littoreus is composed of two distinct types of calls. The call named type A, which corresponds to a long series of multipulsed notes, is likely to have a mating function. This type of call is similar to that reported for Scinax arduous Peixoto, 2002, Scinax peixotoi Brasileiro, Haddad, Sawaya & Martins, 2007, and Scinax perpusillus (Lutz & Lutz, 1939). However, the type A call of S. littoreus is nonetheless readily distinguishable from the comparable call observed in other congeneric species. The call named type B, which exhibits a multipulsed structure, presumably has an aggressive function. We observed that different types of calls could be emitted alone or combined according to the social context. Additionally, we discuss problems involving comparisons of call parameters among species belonging to the S. perpusillus species group, provide an updated geographic distribution map, discuss the conservation status of the included species, and emphasize the importance of acoustic data for the recognition of species groups within Scinax.

Estudo da hierarquia de camundongos swiss webster através do úso de sistemas com gaiolas interligadas / Study of hierarchy swiss webter mice through the use of interconnected systems cages (ISC)

O camundongo em biotério é um animal social, agressivo e extremamente territorialista. As relações entre o indivíduo e o grupo assim como sua busca em acesso a reprodu- ção e alimento promove a estruturação de uma ordem hierárquica. Esta hierarquia é classicamente associada a quem agride (dominante) e quem é agredido (subordinado). Através do uso do sistema de gaiolas interligadas (SGI), buscamos esclarecer a dinâmica desta estrutura e a posição do indivíduo dependendo do momento. Além disso, também podemos verificar as relações de afinidade entre os indivíduos e a caracterização do indi- víduo em relação ao perfil de dominância/subordinação. Nossos resultados demonstram que os camundongos da linhagem Swiss Webster em biotério são capazes de formar relações de afinidade (fraternais) quando agrupados jovens e preferindo ficar entre seus semelhantes quando reagrupados na idade adulta. A dominância é realizada por apenas um indivíduo e sugerimos que o objetivo desta atitude seja o acesso exclusivo a uma determinada área e possivelmente ao alimento e acasalamento. Quando dividimos em duas categorias, o dominante protege seus semelhantes e agride prevalentemente os indivíduos da categoria contrária. Os subordinados podem variar entre os que buscam a dominância (disputantes) e os indivíduos que buscam não se envolver nos episódios agressivos (neutros). Há um indivíduo que sofre até 90% das atitudes agressivas do dominante, chamamos esta categoria como “subordinado alvo”.

The mice in animal facilities are a social animal, aggressive and extremely territorial. The relationship between the individual and the group as well as their search access to feed, reproduction and promotes structuring a hierarchical order. This hierarchy is classically associated with aggressors (dominant) and who is attacked (subordinate). Through the use of Interconnected Systems Cages (ISC), we find to clarify the dy- namics of this structure and the social position (depending on the period observed). Our results show that the lineage Swiss Webster mice are capable of forming affinity relations (fraternal) when grouped young. These animals prefer to remain among their fellows after the regrouping. The dominance is performed by only one individual and suggest that the goal of this attitude is the exclusive access to a particular area and encouraging to food and mating. When divided into two categories, the dominant protects his fellow of opposite category to attacks. Subordinates may vary between those who find dominance (disputants) and individuals who find not to engage in aggressive episodes (neutral). There is an individual who suffers up to 90% of the aggressive actions of the dominant call this category as “subordinate target”.

Estudo da hierarquia de camundongos swiss webster através do úso de sistemas com gaiolas interligadas / Study of hierarchy swiss webter mice through the use of interconnected systems cages (ISC)

O camundongo em biotério é um animal social, agressivo e extremamente territorialista. As relações entre o indivíduo e o grupo assim como sua busca em acesso a reprodu- ção e alimento promove a estruturação de uma ordem hierárquica. Esta hierarquia é classicamente associada a quem agride (dominante) e quem é agredido (subordinado). Através do uso do sistema de gaiolas interligadas (SGI), buscamos esclarecer a dinâmica desta estrutura e a posição do indivíduo dependendo do momento. Além disso, também podemos verificar as relações de afinidade entre os indivíduos e a caracterização do indi- víduo em relação ao perfil de dominância/subordinação. Nossos resultados demonstram que os camundongos da linhagem Swiss Webster em biotério são capazes de formar relações de afinidade (fraternais) quando agrupados jovens e preferindo ficar entre seus semelhantes quando reagrupados na idade adulta. A dominância é realizada por apenas um indivíduo e sugerimos que o objetivo desta atitude seja o acesso exclusivo a uma determinada área e possivelmente ao alimento e acasalamento. Quando dividimos em duas categorias, o dominante protege seus semelhantes e agride prevalentemente os indivíduos da categoria contrária. Os subordinados podem variar entre os que buscam a dominância (disputantes) e os indivíduos que buscam não se envolver nos episódios agressivos (neutros). Há um indivíduo que sofre até 90% das atitudes agressivas do dominante, chamamos esta categoria como “subordinado alvo”.(AU)

The mice in animal facilities are a social animal, aggressive and extremely territorial. The relationship between the individual and the group as well as their search access to feed, reproduction and promotes structuring a hierarchical order. This hierarchy is classically associated with aggressors (dominant) and who is attacked (subordinate). Through the use of Interconnected Systems Cages (ISC), we find to clarify the dy- namics of this structure and the social position (depending on the period observed). Our results show that the lineage Swiss Webster mice are capable of forming affinity relations (fraternal) when grouped young. These animals prefer to remain among their fellows after the regrouping. The dominance is performed by only one individual and suggest that the goal of this attitude is the exclusive access to a particular area and encouraging to food and mating. When divided into two categories, the dominant protects his fellow of opposite category to attacks. Subordinates may vary between those who find dominance (disputants) and individuals who find not to engage in aggressive episodes (neutral). There is an individual who suffers up to 90% of the aggressive actions of the dominant call this category as “subordinate target”.(AU)

Perfil da neoplasia mamária canina e sua relação com a poluição atmosférica

O câncer de mama vem apresentando considerável aumento nos últimos tempos. A literatura sugere que a poluição atmosférica urbana associa-se a neoplasias. Entre os monitores de poluição, o cão tem se mostrado adequado por apresentar grau de exposição à poluição semelhante ao seu dono. Assim, objetivamos estudar o comportamento epidemiológico da neoplasia de mama em cães e sua associação com material particulado atmosférico. Foram incluídos neste estudo observacional transversal, 212 cães de uma clínica veterinária privada de referência para tratamento oncológico em São Paulo. Os dados foram obtidos retrospectivamente de prontuários entre 2008 e 2011 e complementados com ligação telefônica aos proprietários dos animais para coleta de dados sobre tabaco e tempo de moradia no local. A poluição foi estimada pela média do PM10 fornecidos pelos monitores da CETESB. Estratificamos buffers de exposição à poluição por análise espacial dos animais em vias de trânsito rápido, vias arteriais, vias locais e coletoras, como alta, média e baixa exposição respectivamente. Os dados foram analisados por testes de qui-quadrado e regressão logística. A neoplasia de mama incidiu em cadelas de idade avançada (9,582,64 anos), não ovariosalpingohisterectomizadas (68,4%) e em estadiamento clínico avançado (41,5%), sendo responsável direta por 67,4% dos óbitos ocorridos. Houve predomínio de raça poodle (22%) e dieta comercial (50,5%). Poucos cães faziam uso de anticoncepcionais (9%) ou apresentaram pseudociese (31,1%). A maioria (65,5%) apresentou os tipos histológicos carcinoma complexo e carcinoma túbulo-papilífero, seguido por carcinoma sólido (14,6%). O tabaco associou-se aos tumores mais agressivos. O MP10 mostrou associação com carcinoma sólido (RC 3,69; IC 95%: 1,10-12,35) e pior prognóstico (p=0,07). A análise espacial mostrou predomínio de casos na zona Sul da cidade (68,4%), maior concentração em vias de média exposição (51,4%) e tendência a pior prognóstico (p=0,05) nos animais submetidos a alta exposição. Concluímos que na região estudada, o câncer de mama em cães apresenta comportamento agressivo, diagnóstico tardio e a poluição urbana pode estar relacionada ao seu desenvolvimento.

Mammary tumors have shown considerable increase in recent times. The literature suggests that urban air pollution is associated with malignancies. Among pollution monitors, the dog has been adequate for presenting level of pollution exposure similar to its owner. Therefore, we aimed to study the epidemiological behavior of breast cancer in dogs at the city of São Paulo and its association with atmospheric particulate matter. This cross-sectional observational study includes 212 dogs from a private veterinary clinic thats reference for cancer treatment in São Paulo. Data were obtained retrospectively from medical records between 2008 and 2011, and supplemented with telephone call to animal owners, in order to collect data on tobacco and residence time on location. Exposure of pollution was estimated by average PM10 monitors provided by CETESB. Also stratified buffers of exposure to pollution, by spatial analysis, in large, arterial and side streets as high, medium and low exposure respectively. Data were analyzed for chi-square test and logistic regression. Breast cancer incidence was observed in advanced aged female dogs (9,582,64 years), not spayed (68,4%) in advanced clinical staging (41,5), and was directly responsible for 67,4% of death. It was more common in poodle breed (22%) and commercial diet (50,5%). Few dogs were using contraceptives (9%) or showed pseudopregnancy (31,1%). Most of them (65,5%) showed histologic types complex carcinoma and tubule-papillary carcinoma, followed by solid carcinoma (14,6%). Tobacco was associated with more aggressive tumors. PM10 associated with solid carcinoma (OR 3,69; IC 95% 1,10-12,35) and poor prognosis (p=0,07). Spatial analysis showed a predominance of cases in the south zone of the city (68,4%), greater concentration on medium exposure streets (51,4%) and poor prognosis (p=0,005) in animals subjected to high exposure. We concluded that breast cancer in dogs show aggressive behavior at the studied region, mostly of late diagnosis, and that urban air pollution exposure may be correlated to its development.

Breeding activity of Scinax centralis (Anura, Hylidae) in Central Brazil

From January, 1997 to April, 1998, we studied breeding activity in a population of Scinax centralis Pombal & Bastos, 1996, in the state of Goiás, inside the Cerrado Biome, Brazil. The behavior of males and females in the choruses, the relationships between environmental variables and the presence of individuals, the spatial distribution pattern, amplexus and clutches were analyzed. The breeding season occurred from November to May. The majority of males began to call when they entered the chorus; they were defending their calling sites against other males. We found a positive correlation between the number of females and males in the choruses, but no significant correlation was observed between the operational sexual ratio (OSR, number of reproducing females/number of reproducing males) and the number of calling males. OSR was highly male-biased; on average, there were 40 males for each female. The presence of individuals was positively correlated with air temperature of two previous days and negatively correlated with rainfall on the observation day. Generally, males were non-randomly distributed and satellite males were observed. Females were larger and heavier than males. Egg number, but not diameter of the egg, was correlated with the female size.

Entre janeiro de 1997 e abril de 1998, estudou-se a atividade reprodutiva em uma população de Scinax centralis Pombal & Bastos, 1996 no estado de Goiás, no bioma Cerrado, Brasil. Analisou-se o comportamento de machos e fêmeas nos agregados reprodutivos, as relações entre variáveis ambientais e a presença de indivíduos, o padrão de distribuição espacial, amplexos e desovas. A estação reprodutiva ocorreu de novembro a maio. A maioria dos machos começou a vocalizar quando entrou nos agregados; defendendo seus sítios de canto contra outros machos. Nós encontramos uma correlação positiva entre o número de fêmeas e de machos presentes no coro, mas não entre a razão sexual operacional (RSO, número de fêmeas reprodutivas/número de machos reprodutivos). A RSO foi altamente desviada para os machos; em média, haviam 40 machos para cada fêmea. A presença de indivíduos foi correlacionada positivamente com a temperatura do ar dos dois dias anteriores e negativamente correlacionada com a chuva do dia da observação. Geralmente, a distribuição espacial dos machos era uniforme. Machos satellites foram observados. As fêmeas eram maiores e mais pesadas que os machos. O número de ovos, mas não o diâmetro, está correlacionado com o tamanho da fêmea.

Breeding activity of Scinax centralis (Anura, Hylidae) in Central Brazil

From January, 1997 to April, 1998, we studied breeding activity in a population of Scinax centralis Pombal & Bastos, 1996, in the state of Goiás, inside the Cerrado Biome, Brazil. The behavior of males and females in the choruses, the relationships between environmental variables and the presence of individuals, the spatial distribution pattern, amplexus and clutches were analyzed. The breeding season occurred from November to May. The majority of males began to call when they entered the chorus; they were defending their calling sites against other males. We found a positive correlation between the number of females and males in the choruses, but no significant correlation was observed between the operational sexual ratio (OSR, number of reproducing females/number of reproducing males) and the number of calling males. OSR was highly male-biased; on average, there were 40 males for each female. The presence of individuals was positively correlated with air temperature of two previous days and negatively correlated with rainfall on the observation day. Generally, males were non-randomly distributed and satellite males were observed. Females were larger and heavier than males. Egg number, but not diameter of the egg, was correlated with the female size.

Entre janeiro de 1997 e abril de 1998, estudou-se a atividade reprodutiva em uma população de Scinax centralis Pombal & Bastos, 1996 no estado de Goiás, no bioma Cerrado, Brasil. Analisou-se o comportamento de machos e fêmeas nos agregados reprodutivos, as relações entre variáveis ambientais e a presença de indivíduos, o padrão de distribuição espacial, amplexos e desovas. A estação reprodutiva ocorreu de novembro a maio. A maioria dos machos começou a vocalizar quando entrou nos agregados; defendendo seus sítios de canto contra outros machos. Nós encontramos uma correlação positiva entre o número de fêmeas e de machos presentes no coro, mas não entre a razão sexual operacional (RSO, número de fêmeas reprodutivas/número de machos reprodutivos). A RSO foi altamente desviada para os machos; em média, haviam 40 machos para cada fêmea. A presença de indivíduos foi correlacionada positivamente com a temperatura do ar dos dois dias anteriores e negativamente correlacionada com a chuva do dia da observação. Geralmente, a distribuição espacial dos machos era uniforme. Machos satellites foram observados. As fêmeas eram maiores e mais pesadas que os machos. O número de ovos, mas não o diâmetro, está correlacionado com o tamanho da fêmea.