Molecular sexing and intersexual differences in the morphometry of the Hangnest Tody-Tyrant Hemitriccus nidipendulus (Passeriformes: Rhynchocyclidae)

Variation in the morphometry of individuals in a population may result from natural or sexual selection. In the present study we investigated morphometric differences between males and females of a bird species endemic to the Brazilian Atlantic Forest, the Hangnest Tody-Tyrant, Hemitriccus nidipendulus (Wied, 1831), with no apparent sexual dimorphism. All individuals (n = 56) were sexed by PCR amplification of the intronic fragments of the CHDZ/CHDW alleles obtained from blood samples, and 12 morphometric measurements were recorded. The molecular configuration was similar to that described for other species of Passeriformes, with males presenting a single band of approximately 360 base pairs (bp), and females with two bands of 360 and 400 bp. Males had significantly larger tarsi and wings than the females, while the females had two larger beak measurements. This indicates that differential selection pressures may be modeling the morphometry of the Hangnest Tody-Tyrant. In the males, larger tarsi and wings may be beneficial for the exploration of the habitat or the acquisition of potential mates, while females with larger beaks may be able to exploit larger food items and forage more efficiently. However, these hypotheses need to be tested empirically in future studies.

Molecular sexing and intersexual differences in the morphometry of the Hangnest Tody-Tyrant Hemitriccus nidipendulus (Passeriformes: Rhynchocyclidae)

Variation in the morphometry of individuals in a population may result from natural or sexual selection. In the present study we investigated morphometric differences between males and females of a bird species endemic to the Brazilian Atlantic Forest, the Hangnest Tody-Tyrant, Hemitriccus nidipendulus (Wied, 1831), with no apparent sexual dimorphism. All individuals (n = 56) were sexed by PCR amplification of the intronic fragments of the CHDZ/CHDW alleles obtained from blood samples, and 12 morphometric measurements were recorded. The molecular configuration was similar to that described for other species of Passeriformes, with males presenting a single band of approximately 360 base pairs (bp), and females with two bands of 360 and 400 bp. Males had significantly larger tarsi and wings than the females, while the females had two larger beak measurements. This indicates that differential selection pressures may be modeling the morphometry of the Hangnest Tody-Tyrant. In the males, larger tarsi and wings may be beneficial for the exploration of the habitat or the acquisition of potential mates, while females with larger beaks may be able to exploit larger food items and forage more efficiently. However, these hypotheses need to be tested empirically in future studies.(AU)

Heterogeneity of bird communities in a mosaic of habitats on a restinga ecosystem in southeast Brazil

Restinga occurs as a narrow band of coastal habitats throughout the Atlantic Forest, although it presents considerable variation in vegetation structure, which likely contributes to heterogeneity in species inhabiting this endangered ecosystem. The goal of this study is to examine how variation in vegetation and abiotic conditions in the restinga ecosystem may contribute to heterogeneity of bird communities in Restinga de Jurubatiba, Brazil. Temperature, relative humidity, and vegetation structure were sampled to characterize four sites (dry forest, flooded forest, open scrub and closed scrub). Birds were sampled using observations, mist-netting and voice recordings. Results indicate that major differences of all variables occur between forest and scrub in both vegetation and birds. In addition, differences also exist within forests and within scrub, resulting in considerable heterogeneity among sampled areas. Scrub sites were richer in bird species (n = 58) than forest sites (n = 41), while closed scrub had the most species (n = 49). Also, 64% (47 of 73) of bird species were exclusive to forest or scrub habitats. Scrub habitats were more similar to each other than forest habitats. Normalized Difference Vegetation Index (NDVI) calculated from satellite images distinguished scrub sites and may be useful to monitor changes in vegetation patches through time. The restinga ecosystem is quite heterogeneous with considerable turnover in bird species composition and differences in vegetation structure. Forest strips may serve as connectors on the landscape and to help maintain species diversity and conservation of forest species. Also, this highly dynamic ecosystem, which includes a mosaic of habitat types, likely promotes resilience of bird populations under changing conditions.

Heterogeneity of bird communities in a mosaic of habitats on a restinga ecosystem in southeast Brazil

Restinga occurs as a narrow band of coastal habitats throughout the Atlantic Forest, although it presents considerable variation in vegetation structure, which likely contributes to heterogeneity in species inhabiting this endangered ecosystem. The goal of this study is to examine how variation in vegetation and abiotic conditions in the restinga ecosystem may contribute to heterogeneity of bird communities in Restinga de Jurubatiba, Brazil. Temperature, relative humidity, and vegetation structure were sampled to characterize four sites (dry forest, flooded forest, open scrub and closed scrub). Birds were sampled using observations, mist-netting and voice recordings. Results indicate that major differences of all variables occur between forest and scrub in both vegetation and birds. In addition, differences also exist within forests and within scrub, resulting in considerable heterogeneity among sampled areas. Scrub sites were richer in bird species (n = 58) than forest sites (n = 41), while closed scrub had the most species (n = 49). Also, 64% (47 of 73) of bird species were exclusive to forest or scrub habitats. Scrub habitats were more similar to each other than forest habitats. Normalized Difference Vegetation Index (NDVI) calculated from satellite images distinguished scrub sites and may be useful to monitor changes in vegetation patches through time. The restinga ecosystem is quite heterogeneous with considerable turnover in bird species composition and differences in vegetation structure. Forest strips may serve as connectors on the landscape and to help maintain species diversity and conservation of forest species. Also, this highly dynamic ecosystem, which includes a mosaic of habitat types, likely promotes resilience of bird populations under changing conditions.(AU)

The rate of visitation by Amazilia fimbriata (Apodiformes: Trochilidae) influences seed production in Tillandsia stricta (Bromeliaceae)

Legitimate flowers visitors pollinate the flower during the visit and thus influence the production of fruits and seeds. We tested whether the visitation rate of potential pollinators is associated with the amount of seeds per fruit produced by the self-compatible bromeliad Tillandsia stricta (Bromeliaceae). We determined whether hummingbirds are legitimate visitors by testing for a correlation between visits and pollination (seed production) at the Guapiaçú Ecological Reserve (Reserva Ecológica de Guapiaçú), state of Rio de Janeiro. We tested 30 flowers, five of which were also monitored to test the possibility of spontaneous self-pollination. The remaining 25 flowers were exposed to floral visitors. Twenty-two flowers formed fruits and seeds, from which three formed seeds without floral visits. The hummingbird Amazilia fimbriata (Gmelin, 1788) was the only legitimate visitor. The average number (± standard deviation) of seeds was 27 units (±15) per fruit. The floral visitation rate by A. fimbriata was 6.6 (±3.4) visits/per flower. The number of floral visits and the amount of seed produced were positively correlated (r² = 0.58, p 0.01). Thus, A. fimbriata is a legitimate floral visitor of T. stricta, and influences seed production per fruit in this bromeliad.

The rate of visitation by Amazilia fimbriata (Apodiformes: Trochilidae) influences seed production in Tillandsia stricta (Bromeliaceae)

Legitimate flowers visitors pollinate the flower during the visit and thus influence the production of fruits and seeds. We tested whether the visitation rate of potential pollinators is associated with the amount of seeds per fruit produced by the self-compatible bromeliad Tillandsia stricta (Bromeliaceae). We determined whether hummingbirds are legitimate visitors by testing for a correlation between visits and pollination (seed production) at the Guapiaçú Ecological Reserve (Reserva Ecológica de Guapiaçú), state of Rio de Janeiro. We tested 30 flowers, five of which were also monitored to test the possibility of spontaneous self-pollination. The remaining 25 flowers were exposed to floral visitors. Twenty-two flowers formed fruits and seeds, from which three formed seeds without floral visits. The hummingbird Amazilia fimbriata (Gmelin, 1788) was the only legitimate visitor. The average number (± standard deviation) of seeds was 27 units (±15) per fruit. The floral visitation rate by A. fimbriata was 6.6 (±3.4) visits/per flower. The number of floral visits and the amount of seed produced were positively correlated (r² = 0.58, p 0.01). Thus, A. fimbriata is a legitimate floral visitor of T. stricta, and influences seed production per fruit in this bromeliad.(AU)

Missing for the last twenty years: the case of the southernmost populations of the Tropical Mockingbird Mimus gilvus (Passeriformes: Mimidae)

The Tropical Mockingbird Mimus gilvus (Vieillot, 1808) is a widespread species in the Neotropics, but its southernmost populations in Brazil are ecologically (and possibly taxonomically) distinct, occurring only along the coast in restinga vegetation. Once considered the most common bird in restinga, it is becoming increasingly rare, likely due to habitat loss and illegal capture of nestlings. We conducted field surveys to provide an up-to-date distribution of the Tropical Mockingbird in the southernmost portion of the species' range, in the state of Rio de Janeiro, supplying an estimate of its current regional population size and conservation status. We surveyed 21 restinga remnants in Rio de Janeiro, covering all major restinga areas in the state. For sites where the species' presence was confirmed through transect line surveys, we estimated the local population size. The species was found at only four sites. The mean local population density was 52 individuals per km-2. The estimated current and historical Extent of Occurrence (EOO) were 256 km2 and 653 km2, respectively. Combining the population size and EOO results, we estimated that the population of the state of Rio de Janeiro currently ranges from 2,662 to 13,312 individuals, corresponding to an estimated reduction of 61% to 92% in population size in the last 20 years. The species, therefore, can be considered "Endangered" in the state of Rio de Janeiro. We recommend that a taxonomic study of the southernmost populations is carried out in order to clarify whether they represent a different, likely threatened species. We also recommend that the environmental regulations that protect restingas are used towards the protection of these populations.

Missing for the last twenty years: the case of the southernmost populations of the Tropical Mockingbird Mimus gilvus (Passeriformes: Mimidae)

The Tropical Mockingbird Mimus gilvus (Vieillot, 1808) is a widespread species in the Neotropics, but its southernmost populations in Brazil are ecologically (and possibly taxonomically) distinct, occurring only along the coast in restinga vegetation. Once considered the most common bird in restinga, it is becoming increasingly rare, likely due to habitat loss and illegal capture of nestlings. We conducted field surveys to provide an up-to-date distribution of the Tropical Mockingbird in the southernmost portion of the species' range, in the state of Rio de Janeiro, supplying an estimate of its current regional population size and conservation status. We surveyed 21 restinga remnants in Rio de Janeiro, covering all major restinga areas in the state. For sites where the species' presence was confirmed through transect line surveys, we estimated the local population size. The species was found at only four sites. The mean local population density was 52 individuals per km-2. The estimated current and historical Extent of Occurrence (EOO) were 256 km2 and 653 km2, respectively. Combining the population size and EOO results, we estimated that the population of the state of Rio de Janeiro currently ranges from 2,662 to 13,312 individuals, corresponding to an estimated reduction of 61% to 92% in population size in the last 20 years. The species, therefore, can be considered "Endangered" in the state of Rio de Janeiro. We recommend that a taxonomic study of the southernmost populations is carried out in order to clarify whether they represent a different, likely threatened species. We also recommend that the environmental regulations that protect restingas are used towards the protection of these populations.(AU)

Behavioral event occurrence differs between behavioral states in Sotalia guianensis (Cetarctiodactyla: Delphinidae) dolphins: a multivariate approach

Difficulties in quantifying behavioral events can cause loss of information about cetacean behavior, especially behaviors whose functions are still debated. The lack of knowledge is greater for South American species such as Sotalia guianensis (Van Benédén, 1864). Our objective was to contextualize the behavioral events inside behavioral states using a Permutational Multivariate Analysis of Variance (MANOVA). Three events occurred in the Feeding, Socio-Sexual and Travelling states (Porpoising, Side flop, Tail out dive), and five events occurred in the Feeding and Travelling states (Back flop, Horizontal jump, Lobtail, Spy-hop, Partial flop ahead). Three events (Belly exposure, Club, and Heading) occurred exclusively in the Socio-sexual state. Partial Back flop and Head flop occurred exclusively in the Feeding state. For the events that occurred in multiple states, we observed that some events occurred more frequently in one of the states (p 0.001), such as Lobtail, Tail out dive horizontal Jump, Partial flop ahead and Side flop. Our multivariate analysis, which separated Socio-sexual behavior from Feeding and Travelling, showed that the abundance of behavioral events differs between states. This differentiation indicates that some events are associated with specific behavioral states. Almost 40% of the events observed were exclusively performed in one state, which indicates a high specialization for some events. Proper discrimination and contextualization of behavioral events may be efficient tools to better understand dolphin behaviors. Similar studies in other habitats and with other species, will help build a broader scenario to aid our understanding of the functions of dolphin behavioral events.

Behavioral event occurrence differs between behavioral states in Sotalia guianensis (Cetarctiodactyla: Delphinidae) dolphins: a multivariate approach

Difficulties in quantifying behavioral events can cause loss of information about cetacean behavior, especially behaviors whose functions are still debated. The lack of knowledge is greater for South American species such as Sotalia guianensis (Van Benédén, 1864). Our objective was to contextualize the behavioral events inside behavioral states using a Permutational Multivariate Analysis of Variance (MANOVA). Three events occurred in the Feeding, Socio-Sexual and Travelling states (Porpoising, Side flop, Tail out dive), and five events occurred in the Feeding and Travelling states (Back flop, Horizontal jump, Lobtail, Spy-hop, Partial flop ahead). Three events (Belly exposure, Club, and Heading) occurred exclusively in the Socio-sexual state. Partial Back flop and Head flop occurred exclusively in the Feeding state. For the events that occurred in multiple states, we observed that some events occurred more frequently in one of the states (p 0.001), such as Lobtail, Tail out dive horizontal Jump, Partial flop ahead and Side flop. Our multivariate analysis, which separated Socio-sexual behavior from Feeding and Travelling, showed that the abundance of behavioral events differs between states. This differentiation indicates that some events are associated with specific behavioral states. Almost 40% of the events observed were exclusively performed in one state, which indicates a high specialization for some events. Proper discrimination and contextualization of behavioral events may be efficient tools to better understand dolphin behaviors. Similar studies in other habitats and with other species, will help build a broader scenario to aid our understanding of the functions of dolphin behavioral events.(AU)