Lunar periodic modulation of the circadian activity rhythm in a wild North Colombian night monkey (Aotus griseimembra).

South American night monkeys (genus Aotus) are the only nocturnal simian primates. Early activity recordings in North Colombian A. griseimembra monkeys kept under semi-natural conditions and extensive chronobiological studies carried out in laboratory settings revealed a strictly nocturnal behavior and strong activity enhancing (disinhibiting) effects of moonlight or corresponding luminosities during the dark time. To check whether the results from captive individuals correspond to the behavior of wild monkeys, we carried out long-term activity recordings of a wild female A. griseimembra in a tropical rainforest near San Juan de Carare, Northern Colombia. Our data from about 150 days of continuous activity records with an "Actiwatch Mini" (CamNtech, UK) accelerometer-data logger device, confirmed: (1) strictly nocturnal behavior, (2) a pronounced bimodal activity pattern with prominent peaks during dusk and dawn, and (3) a lunar periodic modulation (masking) of the night monkey's circadian activity rhythm due to distinct activity inhibiting effects of the absence of moonlight throughout the night. The results from this wild-living tropical night monkey are consistent with those from captive conspecifics studied decades earlier.

Daily activity patterns and occurrence of Leopardus guttulus (Carnivora, Felidae) in Lami Biological Reserve, southern Brazil / Padrões de atividade diária e ocorrência de Leopardus guttulus (Carnivora, Felidae) na Reserva Biológica do Lami, sul do Brasil

Daily activity patterns are important elements of species behavior that reflect how they interact with their environment and with other related species. To investigate these patterns is crucial to understand how environmental or community changes may affect this behavior in each particular species. Within the Felidae family, research becomes fundamental to assess how small wild cats respond to local conditions and pressures, once there is a large gap in studies addressing such issues. Leopardus guttulus (Hensel, 1872) is an endangered species classified as Vulnerable (VU) at a regional and global level, being threatened mainly by the loss and fragmentation of its habitats. The aim of this study is to document the daily activity patterns of L. guttulus at the Lami Biological Reserve, and the influence of seasonality and temperature on those patterns. We also aimed to quantify how many individuals were using the Biological Reserve during the study period and evaluate their permanence in the area. We obtained 25 independent records for L. guttulus, which was the only cat species recorded at the site during the study period. In general, the species presented a cathemeral habit, being active throughout the 24 hours of the day, but with a more crepuscular/nocturnal activity in the spring and summer. The relationship between the species activity and temperature showed that more than 70% of the records were obtained in a narrow range of 10-17°C. We identified at least two individuals that remained at the site from four to six months of the year, with a higher detection frequency between August and November. Our results showed some interesting trends for the temporal activity of L. guttulus, suggesting flexibility related to seasonality, and the importance of the biological reserve to the preservation of this cat species in the southern limit of its distribution.(AU)

Os padrões de atividade diária são elementos importantes do comportamento das espécies que refletem como elas interagem com seu ambiente e com outras espécies relacionadas. Investigar esses padrões é crucial para entender como as mudanças ambientais ou na comunidade podem afetar esse comportamento em cada espécie em particular. Dentro da família Felidae, os felinos silvestres de menor porte sofrem com uma grande lacuna de estudos nesse sentido, e pesquisas se tornam fundamentais para avaliar como eles respondem às condições e pressões locais. Leopardus guttulus (Hensel, 1872) é uma espécie ameaçada de extinção classificada como Vulnerável (VU) em nível regional e mundial, sendo ameaçada principalmente pela perda e fragmentação de seus habitats. O objetivo deste estudo é documentar o padrão de atividade diária de L. guttulus na Reserva Biológica do Lami e verificar a influência da sazonalidade e da temperatura nestes padrões. Nós também tentamos identificar o número de indivíduos usando a reserva biológica durante o período monitorado e avaliar o tempo de permanência destes na área. Obtivemos 25 registros independentes para L. guttulus, sendo a única espécie de felídeo silvestre registrada no local durante o período amostrado. No geral a espécie apresentou um hábito catemeral com atividade ao longo das 24 horas do dia, mas com uma maior atividade crepuscular/noturna nas estações da primavera e verão. A relação entre a atividade da espécie e a temperatura mostrou que mais de 70% dos registros foram obtidos em uma estreita faixa de temperatura de 10-17°C. Nós identificamos pelo menos dois indivíduos que permaneceram no local durante quatro a seis meses no ano, com maior frequência de detecção nos meses entre agosto e novembro. Nossos resultados demonstram algumas tendências interessantes sobre a atividade temporal de L. guttulus, sugerindo uma flexibilidade sazonal, e demonstram também a importância da reserva biológica para a preservação desta espécie no limite sul de sua distribuição.(AU)

Daily activity patterns and occurrence of Leopardus guttulus (Carnivora, Felidae) in Lami Biological Reserve, southern Brazil / Padrões de atividade diária e ocorrência de Leopardus guttulus (Carnivora, Felidae) na Reserva Biológica do Lami, sul do Brasil

Daily activity patterns are important elements of species behavior that reflect how they interact with their environment and with other related species. To investigate these patterns is crucial to understand how environmental or community changes may affect this behavior in each particular species. Within the Felidae family, research becomes fundamental to assess how small wild cats respond to local conditions and pressures, once there is a large gap in studies addressing such issues. Leopardus guttulus (Hensel, 1872) is an endangered species classified as Vulnerable (VU) at a regional and global level, being threatened mainly by the loss and fragmentation of its habitats. The aim of this study is to document the daily activity patterns of L. guttulus at the Lami Biological Reserve, and the influence of seasonality and temperature on those patterns. We also aimed to quantify how many individuals were using the Biological Reserve during the study period and evaluate their permanence in the area. We obtained 25 independent records for L. guttulus, which was the only cat species recorded at the site during the study period. In general, the species presented a cathemeral habit, being active throughout the 24 hours of the day, but with a more crepuscular/nocturnal activity in the spring and summer. The relationship between the species’ activity and temperature showed that more than 70% of the records were obtained in a narrow range of 10-17°C. We identified at least two individuals that remained at the site from four to six months of the year, with a higher detection frequency between August and November. Our results showed some interesting trends for the temporal activity of L. guttulus, suggesting flexibility related to seasonality, and the importance of the biological reserve to the preservation of this cat species in the southern limit of its distribution.

Os padrões de atividade diária são elementos importantes do comportamento das espécies que refletem como elas interagem com seu ambiente e com outras espécies relacionadas. Investigar esses padrões é crucial para entender como as mudanças ambientais ou na comunidade podem afetar esse comportamento em cada espécie em particular. Dentro da família Felidae, os felinos silvestres de menor porte sofrem com uma grande lacuna de estudos nesse sentido, e pesquisas se tornam fundamentais para avaliar como eles respondem às condições e pressões locais. Leopardus guttulus (Hensel, 1872) é uma espécie ameaçada de extinção classificada como Vulnerável (VU) em nível regional e mundial, sendo ameaçada principalmente pela perda e fragmentação de seus habitats. O objetivo deste estudo é documentar o padrão de atividade diária de L. guttulus na Reserva Biológica do Lami e verificar a influência da sazonalidade e da temperatura nestes padrões. Nós também tentamos identificar o número de indivíduos usando a reserva biológica durante o período monitorado e avaliar o tempo de permanência destes na área. Obtivemos 25 registros independentes para L. guttulus, sendo a única espécie de felídeo silvestre registrada no local durante o período amostrado. No geral a espécie apresentou um hábito catemeral com atividade ao longo das 24 horas do dia, mas com uma maior atividade crepuscular/noturna nas estações da primavera e verão. A relação entre a atividade da espécie e a temperatura mostrou que mais de 70% dos registros foram obtidos em uma estreita faixa de temperatura de 10-17°C. Nós identificamos pelo menos dois indivíduos que permaneceram no local durante quatro a seis meses no ano, com maior frequência de detecção nos meses entre agosto e novembro. Nossos resultados demonstram algumas tendências interessantes sobre a atividade temporal de L. guttulus, sugerindo uma flexibilidade sazonal, e demonstram também a importância da reserva biológica para a preservação desta espécie no limite sul de sua distribuição.

Daily activity patterns and occurrence of Leopardus guttulus (Carnivora, Felidae) in Lami Biological Reserve, southern Brazil

ABSTRACT Daily activity patterns are important elements of species behavior that reflect how they interact with their environment and with other related species. To investigate these patterns is crucial to understand how environmental or community changes may affect this behavior in each particular species. Within the Felidae family, research becomes fundamental to assess how small wild cats respond to local conditions and pressures, once there is a large gap in studies addressing such issues. Leopardus guttulus (Hensel, 1872) is an endangered species classified as Vulnerable (VU) at a regional and global level, being threatened mainly by the loss and fragmentation of its habitats. The aim of this study is to document the daily activity patterns of L. guttulus at the Lami Biological Reserve, and the influence of seasonality and temperature on those patterns. We also aimed to quantify how many individuals were using the Biological Reserve during the study period and evaluate their permanence in the area. We obtained 25 independent records for L. guttulus, which was the only cat species recorded at the site during the study period. In general, the species presented a cathemeral habit, being active throughout the 24 hours of the day, but with a more crepuscular/nocturnal activity in the spring and summer. The relationship between the species activity and temperature showed that more than 70% of the records were obtained in a narrow range of 10-17°C. We identified at least two individuals that remained at the site from four to six months of the year, with a higher detection frequency between August and November. Our results showed some interesting trends for the temporal activity of L. guttulus, suggesting flexibility related to seasonality, and the importance of the biological reserve to the preservation of this cat species in the southern limit of its distribution.

RESUMO Os padrões de atividade diária são elementos importantes do comportamento das espécies que refletem como elas interagem com seu ambiente e com outras espécies relacionadas. Investigar esses padrões é crucial para entender como as mudanças ambientais ou na comunidade podem afetar esse comportamento em cada espécie em particular. Dentro da família Felidae, os felinos silvestres de menor porte sofrem com uma grande lacuna de estudos nesse sentido, e pesquisas se tornam fundamentais para avaliar como eles respondem às condições e pressões locais. Leopardus guttulus (Hensel, 1872) é uma espécie ameaçada de extinção classificada como Vulnerável (VU) em nível regional e mundial, sendo ameaçada principalmente pela perda e fragmentação de seus habitats. O objetivo deste estudo é documentar o padrão de atividade diária de L. guttulus na Reserva Biológica do Lami e verificar a influência da sazonalidade e da temperatura nestes padrões. Nós também tentamos identificar o número de indivíduos usando a reserva biológica durante o período monitorado e avaliar o tempo de permanência destes na área. Obtivemos 25 registros independentes para L. guttulus, sendo a única espécie de felídeo silvestre registrada no local durante o período amostrado. No geral a espécie apresentou um hábito catemeral com atividade ao longo das 24 horas do dia, mas com uma maior atividade crepuscular/noturna nas estações da primavera e verão. A relação entre a atividade da espécie e a temperatura mostrou que mais de 70% dos registros foram obtidos em uma estreita faixa de temperatura de 10-17°C. Nós identificamos pelo menos dois indivíduos que permaneceram no local durante quatro a seis meses no ano, com maior frequência de detecção nos meses entre agosto e novembro. Nossos resultados demonstram algumas tendências interessantes sobre a atividade temporal de L. guttulus, sugerindo uma flexibilidade sazonal, e demonstram também a importância da reserva biológica para a preservação desta espécie no limite sul de sua distribuição.

Aging-related changes on social synchronization of circadian activity rhythm in a diurnal primate (Callithrix jacchus).

The input of environmental time cues and expression of circadian activity rhythms may change with aging. Among nonphotic zeitgebers, social cues from conspecific vocalizations may contribute to the stability and survival of individuals of social species, such as nonhuman primates. We evaluated aging-related changes on social synchronization of the circadian activity rhythm (CAR) in a social diurnal primate, the common marmoset. The activity of 18 male marmosets was recorded by actiwatches in two conditions. (1) Experimental - 4 young adult (5 ± 2 yrs of age) and 4 older (10 ± 2 yrs of age) animals maintained under LD 12/12 h and LL in a room with full insulation for light but only partial insulation for sound from vocalizations of conspecifics maintained outdoors in the colony; and (2) Control - 10 young adult animals maintained outdoors in the colony (5 animals as a control per age group). In LL, the CAR of young adults showed more stable synchronization with controls. Among the aged marmosets, two free-ran with τ > 24 h, whereas the other two showed relative coordination during the first 30 days in LL, but free-ran thereafter. These differences were reflected in the "social" phase angles (ψon and ψoff ) between rhythms of experimental and control animal groups. Moreover, the activity patterns of aged animals showed lower social synchrony with controls compared to young adults, with the time lags of the time series between each experimental group and control group being negative in aged and positive in young adult animals (t-test, p < 0.05). The index of stability of the CAR showed no differences according to age, while the intradaily variability of the CAR was higher in the aged animals during LD-resynchronization, who took additional days to resynchronize. Thus, the social modulation on CAR may vary with age in marmosets. In the aged group, there was a lower effect of social synchronization, which may be associated with aging-related changes in the synchronization and generation of the CAR as well as in system outputs.

Activity pattern of medium and large sized mammals and density estimates of Cuniculus paca (Rodentia: Cuniculidae) in the Brazilian Pampa / Padrão de atividade de mamíferos de médio e grande porte e estimativa da densidade de Cuniculus paca (Rodentia: Cuniculidae) no Pampa brasileiro

Between July 2014 and April 2015, we conducted weekly inventories of the circadian activity patterns of mammals in Passo Novo locality, municipality of Alegrete, southern Brazil. The vegetation is comprised by a grassy-woody steppe (grassland). We used two camera traps alternately located on one of four 1 km transects, each separated by 1 km. We classified the activity pattern of species by the percentage of photographic records taken in each daily period. We identify Cuniculus paca individuals by differences in the patterns of flank spots. We then estimate the density 1) considering the area of riparian forest present in the sampling area, and 2) through capture/recapture analysis. Cuniculus paca, Conepatus chinga and Hydrochoerus hydrochaeris were nocturnal, Cerdocyon thous had a crepuscular/nocturnal pattern, while Mazama gouazoubira was cathemeral. The patterns of circadian activity observed for medium and large mammals in this Pampa region (southern grasslands) may reflect not only evolutionary, biological and ecological affects, but also human impacts not assessed in this study. We identified ten individuals of C. paca through skin spot patterns during the study period, which were recorded in different transects and months. The minimum population density of C. paca was 3.5 individuals per km2 (resident animals only) and the total density estimates varied from 7.1 to 11.8 individuals per km2, when considering all individuals recorded or the result of the capture/recapture analysis, respectively.(AU)

De julho de 2014 a abril de 2015, realizamos levantamentos semanais para estudar padrões de atividade circadiana da mastofauna na localidade de Passo Novo, Alegrete, sul do Brasil. A vegetação é compreendida por savana estépica (campo). Utilizamos duas armadilhas fotográficas distribuídas alternadamente ao longo de quatro transectos, com extensão de 1 km e distantes cerca de 1 km entre si. Nós classificamos o padrão de atividade das espécies através da percentagem de fotos registradas em cada período diário. Nós identificamos indivíduos de Cuniculus paca através dos diferentes padrões de manchas nos flancos dos animais. Nós então estimamos a densidade 1) considerando a área de floresta ripária presente na área amostrada, e 2) através da análise de captura/recaptura. As espécies Cuniculus paca, Conepatus chinga e Hydrochoerus hydrochaeris foram classificadas como noturnas, Cerdocyon thous apresentou um padrão crepuscular/noturno, enquanto Mazama gouazoubira foi classificada como catemeral. O padrão de atividade circadiana observado para os mamíferos de médio e grande porte nessa região do Pampa (campos sulinos) pode refletir não só aspectos evolutivos, biológicos e ecológicos, mas também impactos humanos não avaliados nesse estudo. Através do padrão de manchas da pelagem de C. paca nós identificamos dez indivíduos durante o período de estudo, que foram registrados em diferentes transectos e meses. A densidade populacional mínima de C. paca foi de 3,5 ind/km2 (apenas indivíduos residentes) e a densidade total variou de 7,1 a 11,8 ind/km2, quando consideramos todos os indivíduos registrados ou com base em análises de captura e recaptura, respectivamente.(AU)

Activity pattern of medium and large sized mammals and density estimates of Cuniculus paca (Rodentia: Cuniculidae) in the Brazilian Pampa / Padrão de atividade de mamíferos de médio e grande porte e estimativa da densidade de Cuniculus paca (Rodentia: Cuniculidae) no Pampa brasileiro

Abstract Between July 2014 and April 2015, we conducted weekly inventories of the circadian activity patterns of mammals in Passo Novo locality, municipality of Alegrete, southern Brazil. The vegetation is comprised by a grassy-woody steppe (grassland). We used two camera traps alternately located on one of four 1 km transects, each separated by 1 km. We classified the activity pattern of species by the percentage of photographic records taken in each daily period. We identify Cuniculus paca individuals by differences in the patterns of flank spots. We then estimate the density 1) considering the area of riparian forest present in the sampling area, and 2) through capture/recapture analysis. Cuniculus paca, Conepatus chinga and Hydrochoerus hydrochaeris were nocturnal, Cerdocyon thous had a crepuscular/nocturnal pattern, while Mazama gouazoubira was cathemeral. The patterns of circadian activity observed for medium and large mammals in this Pampa region (southern grasslands) may reflect not only evolutionary, biological and ecological affects, but also human impacts not assessed in this study. We identified ten individuals of C. paca through skin spot patterns during the study period, which were recorded in different transects and months. The minimum population density of C. paca was 3.5 individuals per km2 (resident animals only) and the total density estimates varied from 7.1 to 11.8 individuals per km2, when considering all individuals recorded or the result of the capture/recapture analysis, respectively.

Resumo De julho de 2014 a abril de 2015, realizamos levantamentos semanais para estudar padrões de atividade circadiana da mastofauna na localidade de Passo Novo, Alegrete, sul do Brasil. A vegetação é compreendida por savana estépica (campo). Utilizamos duas armadilhas fotográficas distribuídas alternadamente ao longo de quatro transectos, com extensão de 1 km e distantes cerca de 1 km entre si. Nós classificamos o padrão de atividade das espécies através da percentagem de fotos registradas em cada período diário. Nós identificamos indivíduos de Cuniculus paca através dos diferentes padrões de manchas nos flancos dos animais. Nós então estimamos a densidade 1) considerando a área de floresta ripária presente na área amostrada, e 2) através da análise de captura/recaptura. As espécies Cuniculus paca, Conepatus chinga e Hydrochoerus hydrochaeris foram classificadas como noturnas, Cerdocyon thous apresentou um padrão crepuscular/noturno, enquanto Mazama gouazoubira foi classificada como catemeral. O padrão de atividade circadiana observado para os mamíferos de médio e grande porte nessa região do Pampa (campos sulinos) pode refletir não só aspectos evolutivos, biológicos e ecológicos, mas também impactos humanos não avaliados nesse estudo. Através do padrão de manchas da pelagem de C. paca nós identificamos dez indivíduos durante o período de estudo, que foram registrados em diferentes transectos e meses. A densidade populacional mínima de C. paca foi de 3,5 ind/km2 (apenas indivíduos residentes) e a densidade total variou de 7,1 a 11,8 ind/km2, quando consideramos todos os indivíduos registrados ou com base em análises de captura e recaptura, respectivamente.

Locomotor activity in males of Aedes aegypti can shift in response to females' presence.

BACKGROUND: The study of physiological and behavioral traits of mosquito vectors has been of growing relevance for the proposition of alternative methods for controlling vector-borne diseases. Despite this, most studies focus on the female's traits, including the behavior of host seeking, the physiology of disease transmission and the site-choice for oviposition. However, understanding the factors that lead to males' reproductive success is of utmost importance, since it can help building new strategies for constraining population growth. Male behavior towards mating varies widely among species and the communication between males and females is the first aspect securing a successful encounter. Here we used an automated monitoring system to study the profile of locomotor activity of Aedes aegypti males in response to female's presence in an adapted confinement tube. We propose a new method to quantify male response to the presence of females, which can be potentially tested as an indicator of the success of one male in recognizing a female for mating. RESULTS: Locomotor activity varies in daily cycles regulated by an endogenous clock and synchronized by external factors, such as light and temperature. Our results show the previously described startle response to light, which is displayed as a steep morning activity peak immediately when lights are on. Activity drops during the day and begins to rise again right before evening, happening about 1.5 h earlier in males than in females. Most interestingly, males' activity shows a double peak, and the second peak is very subtle when males are alone and relatively more pronounced when females are present in the confinement tubes. The switch in the peak of activity, measured by the herein suggested Peak Matching Index (PMI), was significantly different between males with and without females. CONCLUSIONS: The adapted monitoring system used here allowed us to quantify the response of individual males to nearby females in terms of the extent of the activity peak displacement. In this direction, we created the peak matching index (PMI), a new parameter that we anticipate could be interpreted as the inclination of males to respond to females' presence, and further tested as an indicator of the potential for finding females for mating.

Forced desynchronization model for a diurnal primate.

The circadian system is organized in a hierarchy of multiple oscillators, with the suprachiasmatic nucleus (SCN) as the master oscillator in mammals. The SCN is formed by a group of coupled cell oscillators. Knowledge of this coupling mechanism is essential to understanding entrainment and the expression of circadian rhythms. Some authors suggest that light-dark (LD) cycles with periods near the limit of entrainment may be good models for promoting internal desynchronization, providing knowledge about the coupling mechanism. As such, we evaluated the circadian activity rhythm (CAR) pattern of marmosets in LD cycles at lower limits of entrainment in order to study induced internal dissociation. To that end, two experiments were conducted: (1) 6 adult females were under symmetrical LD cycles T21, T22 and T21.5 for 60, 35 and 48 days, respectively; and (2) 4 male and 4 female adults were under T21 for 24 days followed by 18 days of LL, back to T21 for 24 days, followed by 14 days of LL. The CAR of each animal was continuously recorded. In experiment 1, vocalizations were also recorded. Under Ts shorter than 24 days, a dissociation pattern was observed for CAR and vocalizations. Two simultaneous circadian components emerged, one with the same period as the LD cycle, called the light-entrained component, and the other in free-running, denominated the non-light-entrained component. Both components were displayed in the CAR for all the animals in T21, five animals (83.3%) in T21.5 and two animals (33.3%) in T22. Our results are in accordance with the multioscillatory nature of the circadian system. Dissociation is partial synchronization to the LD cycle, with at least one group of oscillators synchronized by relative coordination and masking, while another group of oscillators free runs, but is also masked by the LD cycle. Since only T21 promoted the emergence of both circadian components in the circadian rhythms of all marmosets, it was considered the promoter period of circadian rhythm dissociation in this species, and is proposed as a good animal model for forced desynchronization in non-human diurnal primates.

Activity pattern of medium and large sized mammals and density estimates of Cuniculus paca (Rodentia: Cuniculidae) in the Brazilian Pampa

Abstract Between July 2014 and April 2015, we conducted weekly inventories of the circadian activity patterns of mammals in Passo Novo locality, municipality of Alegrete, southern Brazil. The vegetation is comprised by a grassy-woody steppe (grassland). We used two camera traps alternately located on one of four 1 km transects, each separated by 1 km. We classified the activity pattern of species by the percentage of photographic records taken in each daily period. We identify Cuniculus paca individuals by differences in the patterns of flank spots. We then estimate the density 1) considering the area of riparian forest present in the sampling area, and 2) through capture/recapture analysis. Cuniculus paca, Conepatus chinga and Hydrochoerus hydrochaeris were nocturnal, Cerdocyon thous had a crepuscular/nocturnal pattern, while Mazama gouazoubira was cathemeral. The patterns of circadian activity observed for medium and large mammals in this Pampa region (southern grasslands) may reflect not only evolutionary, biological and ecological affects, but also human impacts not assessed in this study. We identified ten individuals of C. paca through skin spot patterns during the study period, which were recorded in different transects and months. The minimum population density of C. paca was 3.5 individuals per km2 (resident animals only) and the total density estimates varied from 7.1 to 11.8 individuals per km2, when considering all individuals recorded or the result of the capture/recapture analysis, respectively.

Resumo De julho de 2014 a abril de 2015, realizamos levantamentos semanais para estudar padrões de atividade circadiana da mastofauna na localidade de Passo Novo, Alegrete, sul do Brasil. A vegetação é compreendida por savana estépica (campo). Utilizamos duas armadilhas fotográficas distribuídas alternadamente ao longo de quatro transectos, com extensão de 1 km e distantes cerca de 1 km entre si. Nós classificamos o padrão de atividade das espécies através da percentagem de fotos registradas em cada período diário. Nós identificamos indivíduos de Cuniculus paca através dos diferentes padrões de manchas nos flancos dos animais. Nós então estimamos a densidade 1) considerando a área de floresta ripária presente na área amostrada, e 2) através da análise de captura/recaptura. As espécies Cuniculus paca, Conepatus chinga e Hydrochoerus hydrochaeris foram classificadas como noturnas, Cerdocyon thous apresentou um padrão crepuscular/noturno, enquanto Mazama gouazoubira foi classificada como catemeral. O padrão de atividade circadiana observado para os mamíferos de médio e grande porte nessa região do Pampa (campos sulinos) pode refletir não só aspectos evolutivos, biológicos e ecológicos, mas também impactos humanos não avaliados nesse estudo. Através do padrão de manchas da pelagem de C. paca nós identificamos dez indivíduos durante o período de estudo, que foram registrados em diferentes transectos e meses. A densidade populacional mínima de C. paca foi de 3,5 ind/km2 (apenas indivíduos residentes) e a densidade total variou de 7,1 a 11,8 ind/km2, quando consideramos todos os indivíduos registrados ou com base em análises de captura e recaptura, respectivamente.

Daily activity patterns influence retinal morphology, signatures of selection, and spectral tuning of opsin genes in colubrid snakes.

BACKGROUND: Morphological divergences of snake retinal structure point to complex evolutionary processes and adaptations. The Colubridae family has a remarkable variety of retinal structure that can range from all-cone and all-rod to duplex (cone/rod) retinas. To explore whether nocturnal versus diurnal activity is responsible for constraints on molecular evolution and plays a role in visual opsin spectral tuning of colubrids, we carried out molecular evolution analyses of the visual opsin genes LWS, RH1, and SWS1 from 17 species and performed morphological analyses. RESULTS: Phylogenetic reconstructions of the RH1 and LWS recovered major clades characterized by primarily diurnal or primarily nocturnal activity patterns, in contrast with the topology for SWS1, which is very similar to the species tree. We found stronger signals of purifying selection along diurnal and nocturnal lineages for RH1 and SWS1, respectively. A blue-shift of the RH1 spectral peak is associated with diurnal habits. Spectral tuning of cone opsins did not differ among diurnal and nocturnal species. Retinas of nocturnal colubrids had many rows of photoreceptor nuclei, with large numbers of rods, labeled by wheat germ agglutinin (WGA), and two types of cones: large cones sensitive to long/medium wavelengths (L/M) and small cones sensitive to ultra-violet/violet wavelengths (UV/VS). In contrast, retinas of diurnal species had only one row of photoreceptor nuclei, with four types of cones: large and double L/M cones, small UV/VS cones, and a second group of small cones, labeled by WGA. CONCLUSIONS: For LWS gene, selection tests did not confirm different constraints related to activity pattern. For SWS1, stronger purifying selection in nocturnal lineages indicates divergent evolutionary pressures related to the activity pattern, and the importance of the short wavelength sensitivity at low light condition. Activity pattern has a clear influence on the signatures of selection and spectral tuning of RH1, with stronger purifying selection in diurnal lineages, which indicates selective pressure to preserve rhodopsin structure and function in pure-cone retinas. We suggest that the presence of four cone types in primarily diurnal colubrids might be related to the gain of color discrimination capacity.

Activity pattern of medium and large sized mammals and density estimates of Cuniculus paca (Rodentia: Cuniculidae) in the Brazilian Pampa

Abstract Between July 2014 and April 2015, we conducted weekly inventories of the circadian activity patterns of mammals in Passo Novo locality, municipality of Alegrete, southern Brazil. The vegetation is comprised by a grassy-woody steppe (grassland). We used two camera traps alternately located on one of four 1 km transects, each separated by 1 km. We classified the activity pattern of species by the percentage of photographic records taken in each daily period. We identify Cuniculus paca individuals by differences in the patterns of flank spots. We then estimate the density 1) considering the area of riparian forest present in the sampling area, and 2) through capture/recapture analysis. Cuniculus paca, Conepatus chinga and Hydrochoerus hydrochaeris were nocturnal, Cerdocyon thous had a crepuscular/nocturnal pattern, while Mazama gouazoubira was cathemeral. The patterns of circadian activity observed for medium and large mammals in this Pampa region (southern grasslands) may reflect not only evolutionary, biological and ecological affects, but also human impacts not assessed in this study. We identified ten individuals of C. paca through skin spot patterns during the study period, which were recorded in different transects and months. The minimum population density of C. paca was 3.5 individuals per km2 (resident animals only) and the total density estimates varied from 7.1 to 11.8 individuals per km2, when considering all individuals recorded or the result of the capture/recapture analysis, respectively.

Resumo De julho de 2014 a abril de 2015, realizamos levantamentos semanais para estudar padrões de atividade circadiana da mastofauna na localidade de Passo Novo, Alegrete, sul do Brasil. A vegetação é compreendida por savana estépica (campo). Utilizamos duas armadilhas fotográficas distribuídas alternadamente ao longo de quatro transectos, com extensão de 1 km e distantes cerca de 1 km entre si. Nós classificamos o padrão de atividade das espécies através da percentagem de fotos registradas em cada período diário. Nós identificamos indivíduos de Cuniculus paca através dos diferentes padrões de manchas nos flancos dos animais. Nós então estimamos a densidade 1) considerando a área de floresta ripária presente na área amostrada, e 2) através da análise de captura/recaptura. As espécies Cuniculus paca, Conepatus chinga e Hydrochoerus hydrochaeris foram classificadas como noturnas, Cerdocyon thous apresentou um padrão crepuscular/noturno, enquanto Mazama gouazoubira foi classificada como catemeral. O padrão de atividade circadiana observado para os mamíferos de médio e grande porte nessa região do Pampa (campos sulinos) pode refletir não só aspectos evolutivos, biológicos e ecológicos, mas também impactos humanos não avaliados nesse estudo. Através do padrão de manchas da pelagem de C. paca nós identificamos dez indivíduos durante o período de estudo, que foram registrados em diferentes transectos e meses. A densidade populacional mínima de C. paca foi de 3,5 ind/km2 (apenas indivíduos residentes) e a densidade total variou de 7,1 a 11,8 ind/km2, quando consideramos todos os indivíduos registrados ou com base em análises de captura e recaptura, respectivamente.