Evolutionary trade-offs between testes size and parenting in Neotropical glassfrogs.

In males, large testes size signifies high sperm production and is commonly linked to heightened sperm competition levels. It may also evolve as a response to an elevated risk of sperm depletion due to multiple mating or large clutch sizes. Conversely, weapons, mate or clutch guarding may allow individuals to monopolize mating events and preclude sperm competition, thereby reducing the selection of large testes. Herein, we examined how paternal care, sexual size dimorphism (SSD), weaponry and female fecundity are linked to testes size in glassfrogs. We found that paternal care was associated with a reduction in relative testes size, suggesting an evolutionary trade-off between testes size and parenting. Although females were slightly larger than males and species with paternal care tended to have larger clutches, there was no significant relationship between SSD, clutch size and relative testes size. These findings suggest that the evolution of testes size in glassfrogs is influenced by sperm competition risk, rather than sperm depletion risk. We infer that clutch guarding precludes the risk of fertilization by other males and consequently diminishes selective pressure for larger testes. Our study highlights the prominent role of paternal care in the evolution of testes size in species with external fertilization.

Black Sea Turtle (Chelonia mydas agassizii) Life History in the Sanctuary of Colola Beach, Michoacan, Mexico.

Sea turtles present strategies that have allowed them to survive and reproduce. They spend most of their lives in the sea, except when they emerge as hatchlings from the nest and when the adult females return to nest. Those moments of their life cycle are vital for their reproductive success, conservation, and knowledge of their biology. This study reports the life history traits exhibited by female black sea turtles from Colola Beach, Mexico using morphometric and reproductive data obtained during 15 sampling seasons (1985-2000, n = 1500). The results indicate that nesting females have a mean body size of 85.7 cm and reach sexual maturity at 24 years old at a minimum size of 68 cm. Females deposit a mean of 69.3 eggs per clutch, and the mean fecundity was 196.4 eggs per female per season. The remigration intervals of 3 and 5 years were the most frequent registered. The life history traits found in the black sea turtle population present the lowest values reported with respect to studies conducted in the Atlantic and Indo-Pacific green turtle populations, which supports the hypothesis that this population is recovering, since morphometric and reproductive data represent young nesting turtles.

Temperature variation in nests of Paleosuchus palpebrosus (Crocodylia: Alligatoridae) near the southern edge of the species´ range, Brazil / Variação da temperatura nos ninhos de Paleosuchus palpebrosus (Crocodylia: Alligatoridae) próximo ao limite sul da área de distribuição da espécie, Brasil

We monitored the temperature of seven Paleosuchus palpebrosus nests found on the banks of streams surrounding the Brazilian Pantanal, near the southern limit of the species´ distribution, between 2008 and 2013. The mean temperature of the nests between 45 and 68 days incubation, the presumed period of sex determination, varied between 26.1 and 31.5o C. Nest temperatures were 2 to 5°C higher than air temperatures, presumably due to metabolic heat of decay of material within the nests, but air temperature explained 10-50% of the variance in egg-chamber temperatures. The estimated incubation periods for nests from which eggs hatched were 80, 84, 86, 90 and 104 days with a mean of 89 (SD =9.23) days, though these are probably slight overestimates because eggs may have hatched in the period between inspections. For these nests, there was no significant relationship between mean temperature and incubation period (r2 = 0.23, p = 0.411).

Nós monitoramos a temperatura de sete ninhos de Paleosuchus palpebrosus encontrados nas margens de riachos ao redor do Pantanal, próximo ao limite sul da distribuição da espécie, entre 2008 e 2013. A temperatura média dos ninhos entre 45 e 68 dias de incubação, período presumido de determinação do sexo, variou entre 26,1 e 31,5o C. As temperaturas dos ninhos foram 2 a 5°C mais altas que as temperaturas do ar, presumivelmente devido ao calor metabólico de decomposição do material dentro dos ninhos, mas a temperatura do ar explicou 10-50% da variação na temperatura da câmara de ovo. Os períodos de incubação estimados para os ninhos dos quais os ovos eclodiram foram de 80, 84, 86, 90 e 104 dias com uma média de 89 (DP = 9,23) dias, embora sejam provavelmente pequenas superestimavas porque os ovos podem ter eclodido no período entre as inspeções. Para esses ninhos, não houve relação significativa entre temperatura média e período de incubação (r2 = 0,23, p = 0,411).

Nest temperature assessment in an American crocodile (Crocodylus acutus) population on the central coast of Oaxaca, Mexico.

The temperatures at which eggs of crocodilians are incubated plays an important role in embryo survival, rate of embryonic development and sex definition. The aim of this study was to assess the nest temperatures of an American crocodile (Crocodylus acutus) population on the central coast of Oaxaca state in Mexico. The fieldwork was carried out from February to June 2018 at Palmasola Lagoon, Oaxaca. Ten natural nests of C. acutus were carefully excavated to determine clutch size. When putting the eggs back in the nests, we placed a data logger in the center of the egg mass to determine the temperature parameters in the nest chamber environment, as well as the variation in temperature during the incubation period. All nests were revisited to count the number of hatched eggs (NHE) and to determine the hatching success (HS), along with the duration of the incubation period (IP). Hatching success was 89.04%. The mean clutch size in the American crocodile nests was 30.7 ± 7.83 eggs (ranging from 17 to 46 eggs), and the mean incubation period was 77.6 ± 5.89 days. The mean nest incubation temperature throughout the reproductive season was significantly different among nests. Based on the average temperature during the middle third of the incubation period, the nests should have produced both sexes, but with a higher proportion of males. This study tried to elucidate the impact of nest temperatures during the incubation period on embryo survival, as well as hatchling sex ratio in a local climate on the central coast of Oaxaca.

Breeding records of Leptotila rufaxilla (Aves: Columbidae) in southwestern Brazilian Amazon with notes on nesting in some regions of occurrence

We present new aspects of breeding biology of Gray-fronted Dove Leptotila rufaxilla, from five nests found between 2012 and 2014 in a lowland forest fragment in southwestern Brazil. The nests simple/platform shape were built at a mean height of 1.90 m above ground. The clutch size was two eggs white and elliptic, incubated for 15 days (based on three nests). We recorded predation in two nests still in incubation phase. Minimum hatch weight of nestlings was 10 g and young fledged with a mean mass of 56 g. The constant growth rate (K) of nestlings was 0.40 with a growth asymptote of 60.7 g. Daily survival rate, Mayfield and apparent nesting success in the incubation period was 90, 20 and 56%, respectively, while in the nestling period were all 100%. Our data and the contribution of citizen science showed that L. rufaxilla breeds over the year, mainly in the rainy season, both in southwestern Amazonia and in other regions of occurrence.

Presentamos nuevos aspectos de la biología reproductiva de la Yerutí Colorada Leptotila rufaxilla, de cinco nidos encontrados entre 2012 y 2014 en un fragmento de bosque de tierras bajas en el suroeste de Brasil. Los nidos con forma simple / plataforma se construyeron a una altura media de 1.90 m sobre el suelo. El tamaño de la puesta fue de dos huevos blancos y elípticos, incubados durante 15 días (basado en tres nidos). Registramos depredación en dos nidos aún en fase de incubación. El peso mínimo al nacer de los pichones fue de 10 g y los polluelos dejaron el nido con una masa media de 56 g. La tasa de crecimiento constante (K) de los pichones fue de 0.40 con una asíntota de crecimiento de 60.7 g. La tasa de supervivencia diaria, Mayfield y el éxito aparente de anidación en el período de incubación fue de 90, 20 y 56%, respectivamente, mientras que en el período de cría fueron todos de 100%. Nuestros datos y el aporte de la ciencia ciudadana mostraron que L. rufaxilla se reproduce durante el año, principalmente en la época de lluvias, tanto en el suroeste de la Amazonia como en otras regiones de ocurrencia.

Breeding biology and biometrics of Myiozetetes c. cayanensis (Aves: Tyrannidae) in southwest Brazilian Amazonia with breeding season in Brazil

Our study provides information on the breeding and biometrics of Rusty-Margined Flycatcher Myiozetetes cayanensis in southwest Brazilian Amazonia. M. cayanensis is distributed from Central America until north of South America. We made observations on reproduction and captures of this species in a terra firme forest fragment in the state of Acre, between 1999 and 2020 and we evaluated the breeding season in Brazil through citizen science data. We monitored nine nests between 2012 and 2020, built at a mean height of 1.8 m above ground. Clutch size was two, three or four eggs, incubated for 15 days. We monitored the development of six nestlings: minimum hatch weight was 2 g and young fledged with a mean mass of ca. 25.5 g. The constant growth rate (K) of nestlings was 0.18 with a growth asymptote of 22.8 g. Daily survival rate was 90% and 100% during the incubation and nestling periods, respectively. The Mayfield success in the incubation and nestling periods was 20 and 100%, respectively. Apparent nesting success in the incubation and nestling periods was 46 and 100%, respectively. We recorded a minimum longevity of 2 years, nine months and 26 days. The subspecies M. c. cayanensis start to nest mainly between the dry and rainy season in Brazil, overlapping with the molt period in southwest Amazonia.

Nuestro estudio proporciona información sobre la reproducción y la biometría del bienteveo alicastaño Myiozetetes cayanensis en el suroeste de la Amazonia brasileña. M. cayanensis se distribuye desde América Central hasta el norte de América del Sur. Realizamos observaciones sobre la reproducción y captura de esta especie en un fragmento de bosque de tierra firme en el estado de Acre, entre 1999 y 2020 y evaluamos la época de reproducción en Brasil mediante datos de ciencia ciudadana. Monitoreamos nueve nidos entre 2012 y 2020, construidos a una altura promedio de 1.8 m sobre el suelo. El tamaño de la puesta fue de dos, tres o cuatro huevos, incubados durante 15 días. Monitoreamos el desarrollo de seis polluelos: el peso mínimo al nacer fue de 2 g y los polluelos con una masa media de ca. 25.5 g. La tasa de crecimiento constante (K) de los polluelos fue de 0.18 con una asíntota de crecimiento de 22.8 g. La tasa de supervivencia diaria fue del 90% y 100% durante los períodos de incubación y cría, respectivamente. El éxito de Mayfield en los períodos de incubación y cría fue de 20 y 100%, respectivamente. El éxito aparente de anidación en los períodos de incubación y polluelo fue de 46 y 100%, respectivamente. Registramos una longevidad mínima de 2 años, nueve meses y 26 días. La subespecie M. c. cayanensis comienzan a anidar principalmente entre la estación seca y lluviosa en Brasil, superponiéndose con el período de muda en el suroeste de la Amazonia.

Reproductive ecology and territorial behavior of Boana goiana (Anura: Hylidae), a gladiator frog from the Brazilian Cerrado

ABSTRACT Anuran males and females adopt different reproductive and behavioral strategies in different contexts. We investigated the reproductive ecology and territorial behavior of the treefrog Boana goiana (B. Lutz, 1968) from the Brazilian Cerrado. We hypothesized that competitor density/proximity would increase the behavioral responses of B. goiana males, and that mating would be assortative. We also tested if the number of eggs correlates with female size and if there is a trade-off between clutch size and egg size. We conducted two territoriality experiments to test the effects of male size, competitor proximity and competitor density. Larger males called more in the presence of a second male. In the second experiment, the largest males emitted more calls and the distance to the nearest male increased as resident males called more. In both experiments, the number of calls was influenced by either male size or spacing between males. Some males behaved as satellites, probably to avoid fights. Our analyses indicate that females choose males with similar sizes to their own, corroborating our hypothesis of size-assortative mating. We found no relationships between female size and clutch size/volume, and between egg size and number of eggs per clutch. We also report multiple spawning for this species. The low incidence of physical combats and the spacing pattern indicate that this species relies almost solely on calls to resolve contests, which could be explained by low motivation, or simply because males avoid combats to decrease injury risks. Thus, acoustic or even multimodal communication seems crucial for social interactions of B. goiana.

Reproductive ecology and territorial behavior of Boana goiana (Anura: Hylidae), a gladiator frog from the Brazilian Cerrado

Anuran males and females adopt different reproductive and behavioral strategies in different contexts. We investigated the reproductive ecology and territorial behavior of the treefrog Boana goiana (B. Lutz, 1968) from the Brazilian Cerrado. We hypothesized that competitor density/proximity would increase the behavioral responses of B. goiana males, and that mating would be assortative. We also tested if the number of eggs correlates with female size and if there is a trade-off between clutch size and egg size. We conducted two territoriality experiments to test the effects of male size, competitor proximity and competitor density. Larger males called more in the presence of a second male. In the second experiment, the largest males emitted more calls and the distance to the nearest male increased as resident males called more. In both experiments, the number of calls was influenced by either male size or spacing between males. Some males behaved as satellites, probably to avoid fights. Our analyses indicate that females choose males with similar sizes to their own, corroborating our hypothesis of size-assortative mating. We found no relationships between female size and clutch size/volume, and between egg size and number of eggs per clutch. We also report multiple spawning for this species. The low incidence of physical combats and the spacing pattern indicate that this species relies almost solely on calls to resolve contests, which could be explained by low motivation, or simply because males avoid combats to decrease injury risks. Thus, acoustic or even multimodal communication seems crucial for social interactions of B. goiana.(AU)

Reproductive ecology and territorial behavior of Boana goiana (Anura: Hylidae), a gladiator frog from the Brazilian Cerrado

Anuran males and females adopt different reproductive and behavioral strategies in different contexts. We investigated the reproductive ecology and territorial behavior of the treefrog Boana goiana (B. Lutz, 1968) from the Brazilian Cerrado. We hypothesized that competitor density/proximity would increase the behavioral responses of B. goiana males, and that mating would be assortative. We also tested if the number of eggs correlates with female size and if there is a trade-off between clutch size and egg size. We conducted two territoriality experiments to test the effects of male size, competitor proximity and competitor density. Larger males called more in the presence of a second male. In the second experiment, the largest males emitted more calls and the distance to the nearest male increased as resident males called more. In both experiments, the number of calls was influenced by either male size or spacing between males. Some males behaved as satellites, probably to avoid fights. Our analyses indicate that females choose males with similar sizes to their own, corroborating our hypothesis of size-assortative mating. We found no relationships between female size and clutch size/volume, and between egg size and number of eggs per clutch. We also report multiple spawning for this species. The low incidence of physical combats and the spacing pattern indicate that this species relies almost solely on calls to resolve contests, which could be explained by low motivation, or simply because males avoid combats to decrease injury risks. Thus, acoustic or even multimodal communication seems crucial for social interactions of B. goiana.(AU)

Multiple nesting attempts and long breeding seasons of Mimus gilvus (Aves: Mimidae) in southeastern Brazil

This study describes aspects of the life history of the Tropical Mockingbird Mimus gilvus (Vieillot, 1808), including the breeding period, clutch size, nestlings and a list of plants used for nesting. Nests were monitored in an area of Restinga (sand-coastal plain) habitat in a protected area in southeastern Brazil. The data from 181 nests during five breeding seasons (2010-2014) showed that the Tropical Mockingbird has a long breeding season (26.1 ± 2.6 weeks) with up to two peaks of active nests from August to March. The breeding pairs made up to four nesting attempts in the same breeding season. The mean (± SD) clutch size was 2.4 ± 0.6 eggs (n = 169). The mean (± SD) incubation period was 14 ± 0.6 days, and the nestling remained in the nest for 14.5 ± 2.2 days. The nests were built on thirty plant species, and Protium icicariba (DC.) Marchand. was the plant species most commonly used for nesting. The breeding parameters of the Tropical Mockingbird are similar to those of other Mimidae species. The knowledge gained from this study makes the Tropical Mockingbird a good choice for future studies, particularly for testing ecological and evolutionary hypotheses regarding life history attributes, habitat selection and parental investment.(AU)

Multiple nesting attempts and long breeding seasons of Mimus gilvus (Aves: Mimidae) in southeastern Brazil

This study describes aspects of the life history of the Tropical Mockingbird Mimus gilvus (Vieillot, 1808), including the breeding period, clutch size, nestlings and a list of plants used for nesting. Nests were monitored in an area of Restinga (sand-coastal plain) habitat in a protected area in southeastern Brazil. The data from 181 nests during five breeding seasons (2010-2014) showed that the Tropical Mockingbird has a long breeding season (26.1 ± 2.6 weeks) with up to two peaks of active nests from August to March. The breeding pairs made up to four nesting attempts in the same breeding season. The mean (± SD) clutch size was 2.4 ± 0.6 eggs (n = 169). The mean (± SD) incubation period was 14 ± 0.6 days, and the nestling remained in the nest for 14.5 ± 2.2 days. The nests were built on thirty plant species, and Protium icicariba (DC.) Marchand. was the plant species most commonly used for nesting. The breeding parameters of the Tropical Mockingbird are similar to those of other Mimidae species. The knowledge gained from this study makes the Tropical Mockingbird a good choice for future studies, particularly for testing ecological and evolutionary hypotheses regarding life history attributes, habitat selection and parental investment.

Phenotypic plasticity in clutch size regulation among populations of a potential invasive fruit fly from environments that vary in host heterogeneity and isolation.

Phenotypic plasticity is thought to evolve in response to environmental unpredictability and can shield genotypes from selection. However, selection can also act on plastic traits. Egg-laying behaviour, including clutch size regulation, is a plastic behavioural trait among tephritid fruit flies. We compared plasticity in clutch size regulation among females of Anastrepha ludens populations stemming from environments that differed in the degree of predictability in egg-laying opportunities. Clutch size regulation in response to hosts of different sizes was compared among flies from (a) a wild, highly isolated population, (b) a wild population that switches seasonally from a small wild host fruit that varies greatly in abundance to an abundant large-sized commercial host, and (c) a laboratory population. Flies from all three populations adjusted clutch number and size according to host size. However, flies from the heterogeneous wild environment were more plastic in adjusting clutch size than flies from agricultural settings that also laid fewer eggs; yet both populations were more plastic in adjusting clutch size in line with host size when compared with laboratory females. When wild and orchard females encountered the largest host, clutch size was extremely variable and egg regulation did not follow the same trend. Heterogeneity in host availability in space and time appears to be as important as seasonal variation in host size in maintaining plastic clutch size regulation behaviour. In stable environments, there was a clear reduction in the plasticity of these traits.

Reproductive biology of the fossorial snake apostolepis gaboi (Elapomorphini): a threatened and poorly known species from the caatinga region

Knowledge of reproductive biology is essential to understand the intrinsic traits of any species and to elaborate effective conservation strategies, particularly for threatened species. Despite recent advances, knowledge on the reproductive biology of snakes remains deficient for most species, especially for tropical fossorial taxa. Apostolepis gaboi is a psammophilous, fossorial, and threatened snake endemic of the Quaternary Sand Dunes of the São Francisco River, Caatinga domain. Here, we present information on its reproductive biology based on macroscopic and microscopic data obtained from the examination of all specimens preserved in Brazilian museums. Specifically, we addressed sexual maturity, sexual dimorphism, clutch size, timing of gametogenesis, activity of the sexual segment of the kidney (SSK), and female sperm storage. Apostolepis gaboi is one of the smallest species of the genus. Females attain sexual maturity at larger body sizes and grow larger than males. However, adult females have relatively shorter tails than males. We found no sexual dimorphism in body circumference and head size. Clutch size is small and averages 4.5 eggs. All males from the wet season showed testes in spermiogenesis, ductus deferentia packed of sperm, and SSK hypertrophied and secretory. Secondary vitellogenesis also occurs in the wet season. Moreover, females in early vitellogenesis from the wet season showed sperm stored in the posterior infundibulum. Mating occurs in the second half of the wet season, as suggested by the finding of aggregations of sperm in the uterine lumen of a female in early secondary vitellogenesis. Mating is associated with gonadal activity in males. Sperm storage confers flexibility for females to ovulate at the most suitable time in an unpredictable habitat such as the Caatinga. Apostolepis gaboi exhibits similarities (association between mating and spermiogenesis, small clutch) and differences (absence of sexual dimorphism in head size and stoutness) compared with another Elapomorphini species. Lastly, we argue that some of the intrinsic traits of A. gaboi (small clutch and small body size) may increase its vulnerability to extinction, raising additional concerns to its conservation.

Breeding biology of Tyrannus melancholicus (Aves: Tyrannidae) in a restinga reserve of southeastern Brazil

Existing knowledge of the breeding success and life history characteristics of most Neotropical bird species is scarce. Here, we help fill this gap by analyzing aspects of the breeding biology of the Tropical Kingbird Tyrannus melancholicus (Vieillot, 1819), which is a good model for this kind of study as it is a common species occurring in various environments, including urban areas, but little is known about its life history. We provide results concerning the breeding period, clutch size, incubation and nestling periods, description of nests, eggs and nestlings, and the plants used for nest sites by this species. Fifty-four nests were monitored over two seasons (2012-2014) in a protected area in southeastern Brazil. Nesting began at the end of the dry season and the beginning of the rainy season. The frequency of active nests varied according to variations in rainfall for each breeding season analyzed. The means and standard deviations of the incubation period (14.2 ± 1.9 days), nestling period (15.1 ± 0.8 days) and clutch size (2.5 ± 0.7 eggs) were similar to values reported for other Neotropical passerines. Twenty-one plant species used as nest trees and for the construction of the nests were identified. The results show that T. melancholicus is not highly selective when choosing plant species used for nest construction.

Breeding biology of Tyrannus melancholicus (Aves: Tyrannidae) in a restinga reserve of southeastern Brazil

Existing knowledge of the breeding success and life history characteristics of most Neotropical bird species is scarce. Here, we help fill this gap by analyzing aspects of the breeding biology of the Tropical Kingbird Tyrannus melancholicus (Vieillot, 1819), which is a good model for this kind of study as it is a common species occurring in various environments, including urban areas, but little is known about its life history. We provide results concerning the breeding period, clutch size, incubation and nestling periods, description of nests, eggs and nestlings, and the plants used for nest sites by this species. Fifty-four nests were monitored over two seasons (2012-2014) in a protected area in southeastern Brazil. Nesting began at the end of the dry season and the beginning of the rainy season. The frequency of active nests varied according to variations in rainfall for each breeding season analyzed. The means and standard deviations of the incubation period (14.2 ± 1.9 days), nestling period (15.1 ± 0.8 days) and clutch size (2.5 ± 0.7 eggs) were similar to values reported for other Neotropical passerines. Twenty-one plant species used as nest trees and for the construction of the nests were identified. The results show that T. melancholicus is not highly selective when choosing plant species used for nest construction.(AU)

A new species of iguanid lizard, genus Stenocercus (Squamata, Iguania), from the Central Andes in Peru.

We describe a new species of Stenocercus from the montane forest of the right margin of the Marañón river in the northern portion of the Central Andes in northern Peru (Amazonas and La Libertad departments), at elevations ranging from 2300 to 3035 m. Stenocercus omari sp. nov. differs from other Stenocercus species, with the exception of S. amydrorhytus, S. chrysopygus, S. cupreus, S. johaberfellneri, S. latebrosus, S. melanopygus, S. modestus, S. ornatissimus, S. orientalis, and S. stigmosus, by having granular scales on the posterior surfaces of thighs, a conspicuous antehumeral fold and by lacking a vertebral crest. However, Stenocercus omari sp. nov. is easily distinguished from the aforementioned species, except S. orientalis, by the presence of prominently keeled dorsal head scales. The new species differs from S. orientalis by lacking a prominent oblique neck fold and by having a distinct deep postfemoral mite pocket.

Alometria reprodutiva de Podocnemis unifilis (Testudines: Podocnemididae) na várzea do baixo rio Amazonas, Santarém, Pará, Brasil

The body size of the organisms represents an important parameter, which may have consequences on their ecology, reproductive activities, evolution and development. Allometry relationship is the study of the size (or growth) of a body part in relation to the final size (or growth) of the organism. This study analyzed the allometric relationships between females of Podocnemis unifilis (Troschel, 1848), their eggs and hatchlings, and between nest features and the clutch in the flooded forest portion (várzea) of lower Amazon River, Santarém, state of Pará, Brazil. Podocnemis unifilis clutches' were monitored in the Tabuleiro da Água Preta during the reproductive cycle of 2009. The females found nesting were measured and the physical features of the nests were measured, and the latter were also marked with numbered stakes. The eggs and hatchlings of these nests were removed and counted, and their biometry was performed. The female parameters analyzed (straight-line carapace length and mass) were correlated with almost all the egg and hatchling variables, with the exception of the egg length and the hatchling mass. Future studies directed to the better understanding of how the environmental features influence nest features can be applied, being useful for more effective applications of management actions for the species.

O tamanho do corpo dos organismos representa um parâmetro importante, podendo gerar consequências na sua ecologia, atividades reprodutivas, evolução e desenvolvimento. Relação alométrica é o estudo do tamanho (ou do crescimento) de uma parte do corpo relacionado com o tamanho (ou crescimento) total do corpo do organismo. Este estudo analisou a relação alométrica entre as fêmeas de Podocnemis unifilis (Troschel, 1848) e seus ovos e filhotes e entre as características dos ninhos e a ninhada em uma área de várzea do baixo rio Amazonas, estado do Pará, Brasil. As ninhadas de P. unifilis foram monitoradas no Tabuleiro da Água Preta durante o período reprodutivo de 2009. As fêmeas encontradas desovando foram medidas e seus respectivos ninhos marcados com estacas numeradas e as características físicas mensuradas. Os ovos e filhotes destes ninhos foram retirados e contados, e tiveram seus dados biométricos tomados. Os parâmetros das fêmeas analisados (comprimento retilíneo da carapaça e massa) correlacionaram-se fortemente às variáveis dos ovos (variável x) e filhotes (variável y), exceto com o comprimento do ovo e com a massa do filhote. Estudos futuros direcionados para melhor compreensão de como as características ambientais influenciam nas ninhadas podem ser aplicados, sendo úteis no manejo da espécie.

Biologia reprodutiva de Taraba major (Aves, Thamnophilidae) na região do Pirizal, Porção Norte do Pantanal, Mato Grosso, Brasil

We describe some aspects of the reproductive biology of the Great Antshrike (Taraba major), such as: reproductive period, nests, eggs, nestlings, incubation period, and permanence of nestlings in the nest. The data were collected during the breeding seasons of 2009 and 2010 at Retiro Novo Farm, municipality of Poconé, Pantanal, Mato Grosso, Brazil. Nest searching was conducted through active searching and observation of adults carrying nest material or food for the nestlings. The nests were visited at intervals of three to four days. Fifty-one active nests were monitored. The reproductive period of the species lasted from October to December. The average time of nest construction was 06 ± 1.6 days (n = 08). Eggs were ovoid, white with brown spots scattered throughout their length. The mass, length, and average width of the eggs were 0.5 g, 6.1 ± 1 mm, and 26.8 ± 19.5 ± 1 mm, respectively (n = 74). Litter size ranged from two (n = 13) to three (n = 1) eggs. Both sexes built the nest and took turns during incubation. The average time of incubation was 15.5 ± 1.7 days (n = 08), and the nestling period ranged from 13.2 ± 1.6 days (n = 08).

O objetivo deste estudo é descrever aspectos da biologia reprodutiva de Taraba major tais como período reprodutivo, ninhos, ovos, ninhegos, tamanho de ninhada, período de incubação e permanência dos ninhegos no ninho. Os dados foram coletados durante as estações reprodutivas de 2009 e 2010, na fazenda Retiro Novo, município de Poconé, Pantanal, Mato Grosso, Brasil. A procura dos ninhos ocorreu de forma ativa e através da observação dos adultos transportando material para o ninho ou alimento para o filhote. Os ninhos foram visitados com intervalos de três a quatro dias. Foram monitorados 51 ninhos ativos. O período reprodutivo da espécie estendeu-se de outubro a dezembro. O tempo médio de construção dos ninhos foi de 06 ± 1,6 dias (n = 08). Os ovos são de formato ovóide, esbranquiçados com manchas marrons espalhadas por toda sua extensão. A massa, comprimento e largura média dos ovos foram 6,1 ± 0,5 g, 26,8 ± 1,5 mm, 19,5 ± 1,7 mm, respectivamente (n = 74). O tamanho da ninhada variou de dois (n = 13) a três (n = 1) ovos. Ambos os sexos constroem o ninho e revezam na incubação. O tempo médio de incubação foi de 15,5 ± 1,7 dias (n = 08), e a permanência dos ninhegos nos ninhos de 13,2 ± 1,6 dias (n = 08).

Alometria reprodutiva de Podocnemis unifilis (Testudines: Podocnemididae) na várzea do baixo rio Amazonas, Santarém, Pará, Brasil

The body size of the organisms represents an important parameter, which may have consequences on their ecology, reproductive activities, evolution and development. Allometry relationship is the study of the size (or growth) of a body part in relation to the final size (or growth) of the organism. This study analyzed the allometric relationships between females of Podocnemis unifilis (Troschel, 1848), their eggs and hatchlings, and between nest features and the clutch in the flooded forest portion (várzea) of lower Amazon River, Santarém, state of Pará, Brazil. Podocnemis unifilis clutches' were monitored in the Tabuleiro da Água Preta during the reproductive cycle of 2009. The females found nesting were measured and the physical features of the nests were measured, and the latter were also marked with numbered stakes. The eggs and hatchlings of these nests were removed and counted, and their biometry was performed. The female parameters analyzed (straight-line carapace length and mass) were correlated with almost all the egg and hatchling variables, with the exception of the egg length and the hatchling mass. Future studies directed to the better understanding of how the environmental features influence nest features can be applied, being useful for more effective applications of management actions for the species.

O tamanho do corpo dos organismos representa um parâmetro importante, podendo gerar consequências na sua ecologia, atividades reprodutivas, evolução e desenvolvimento. Relação alométrica é o estudo do tamanho (ou do crescimento) de uma parte do corpo relacionado com o tamanho (ou crescimento) total do corpo do organismo. Este estudo analisou a relação alométrica entre as fêmeas de Podocnemis unifilis (Troschel, 1848) e seus ovos e filhotes e entre as características dos ninhos e a ninhada em uma área de várzea do baixo rio Amazonas, estado do Pará, Brasil. As ninhadas de P. unifilis foram monitoradas no Tabuleiro da Água Preta durante o período reprodutivo de 2009. As fêmeas encontradas desovando foram medidas e seus respectivos ninhos marcados com estacas numeradas e as características físicas mensuradas. Os ovos e filhotes destes ninhos foram retirados e contados, e tiveram seus dados biométricos tomados. Os parâmetros das fêmeas analisados (comprimento retilíneo da carapaça e massa) correlacionaram-se fortemente às variáveis dos ovos (variável x) e filhotes (variável y), exceto com o comprimento do ovo e com a massa do filhote. Estudos futuros direcionados para melhor compreensão de como as características ambientais influenciam nas ninhadas podem ser aplicados, sendo úteis no manejo da espécie.

Biologia reprodutiva de Taraba major (Aves, Thamnophilidae) na região do Pirizal, Porção Norte do Pantanal, Mato Grosso, Brasil

We describe some aspects of the reproductive biology of the Great Antshrike (Taraba major), such as: reproductive period, nests, eggs, nestlings, incubation period, and permanence of nestlings in the nest. The data were collected during the breeding seasons of 2009 and 2010 at Retiro Novo Farm, municipality of Poconé, Pantanal, Mato Grosso, Brazil. Nest searching was conducted through active searching and observation of adults carrying nest material or food for the nestlings. The nests were visited at intervals of three to four days. Fifty-one active nests were monitored. The reproductive period of the species lasted from October to December. The average time of nest construction was 06 ± 1.6 days (n = 08). Eggs were ovoid, white with brown spots scattered throughout their length. The mass, length, and average width of the eggs were 0.5 g, 6.1 ± 1 mm, and 26.8 ± 19.5 ± 1 mm, respectively (n = 74). Litter size ranged from two (n = 13) to three (n = 1) eggs. Both sexes built the nest and took turns during incubation. The average time of incubation was 15.5 ± 1.7 days (n = 08), and the nestling period ranged from 13.2 ± 1.6 days (n = 08).

O objetivo deste estudo é descrever aspectos da biologia reprodutiva de Taraba major tais como período reprodutivo, ninhos, ovos, ninhegos, tamanho de ninhada, período de incubação e permanência dos ninhegos no ninho. Os dados foram coletados durante as estações reprodutivas de 2009 e 2010, na fazenda Retiro Novo, município de Poconé, Pantanal, Mato Grosso, Brasil. A procura dos ninhos ocorreu de forma ativa e através da observação dos adultos transportando material para o ninho ou alimento para o filhote. Os ninhos foram visitados com intervalos de três a quatro dias. Foram monitorados 51 ninhos ativos. O período reprodutivo da espécie estendeu-se de outubro a dezembro. O tempo médio de construção dos ninhos foi de 06 ± 1,6 dias (n = 08). Os ovos são de formato ovóide, esbranquiçados com manchas marrons espalhadas por toda sua extensão. A massa, comprimento e largura média dos ovos foram 6,1 ± 0,5 g, 26,8 ± 1,5 mm, 19,5 ± 1,7 mm, respectivamente (n = 74). O tamanho da ninhada variou de dois (n = 13) a três (n = 1) ovos. Ambos os sexos constroem o ninho e revezam na incubação. O tempo médio de incubação foi de 15,5 ± 1,7 dias (n = 08), e a permanência dos ninhegos nos ninhos de 13,2 ± 1,6 dias (n = 08).