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1.
Nature ; 621(7978): 336-343, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37674081

RESUMO

Birds are descended from non-avialan theropod dinosaurs of the Late Jurassic period, but the earliest phase of this evolutionary process remains unclear owing to the exceedingly sparse and spatio-temporally restricted fossil record1-5. Information about the early-diverging species along the avialan line is crucial to understand the evolution of the characteristic bird bauplan, and to reconcile phylogenetic controversies over the origin of birds3,4. Here we describe one of the stratigraphically youngest and geographically southernmost Jurassic avialans, Fujianvenator prodigiosus gen. et sp. nov., from the Tithonian age of China. This specimen exhibits an unusual set of morphological features that are shared with other stem avialans, troodontids and dromaeosaurids, showing the effects of evolutionary mosaicism in deep avialan phylogeny. F. prodigiosus is distinct from all other Mesozoic avialan and non-avialan theropods in having a particularly elongated hindlimb, suggestive of a terrestrial or wading lifestyle-in contrast with other early avialans, which exhibit morphological adaptations to arboreal or aerial environments. During our fieldwork in Zhenghe where F. prodigiosus was found, we discovered a diverse assemblage of vertebrates dominated by aquatic and semi-aquatic species, including teleosts, testudines and choristoderes. Using in situ radioisotopic dating and stratigraphic surveys, we were able to date the fossil-containing horizons in this locality-which we name the Zhenghe Fauna-to 148-150 million years ago. The diversity of the Zhenghe Fauna and its precise chronological framework will provide key insights into terrestrial ecosystems of the Late Jurassic.


Assuntos
Aves , Dinossauros , Fósseis , Animais , China , Dinossauros/anatomia & histologia , Dinossauros/classificação , Ecossistema , Mosaicismo , Filogenia , Aves/anatomia & histologia , Aves/classificação , História Antiga , Membro Posterior
2.
J Ethnobiol Ethnomed ; 16(1): 52, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32928240

RESUMO

BACKGROUND: The loss of traditional ecological knowledge in endangered language communities is a cause of concern worldwide. Given the state of current knowledge, it is difficult to say whether language and TEK transmission levels are correlated, i.e. whether the erosion of one is accompanied by erosion of the other. This case study, focusing on a small Indigenous language from northern Australia, represents a first step towards a systematic investigation of this question. METHODS: Speakers of the language Kune (which is currently being transmitted to small children in the community) were asked to identify and name a number of common birds and plants known to occur on Kune traditional lands, through a series of audiovisual stimuli. RESULTS: There was a weak correlation between speaker age and performance for the plant naming task, but not for the birds. Analysis of the ethnotaxa that were or were not named by individual participants showed that only a small number of plants and birds (approx. 13% and 7% respectively) were known to all participants, while many (approx. 30% and 26% respectively) could only be named by one participant, i.e. the oldest. Edible ethnotaxa were common among the plants and birds that could be named by many people. There was a tendency among younger speakers to use a single umbrella term to label similar-looking species from large genera, such as Acacia, whereas older people would have had distinct labels for each species. CONCLUSIONS: Performance in the plant and bird naming tasks was lower than expected for a community where language transmission to younger generations is high. The loss of certain plant and bird names from the active lexicons of some younger Kune speakers may be due to lifestyle change, particularly in terms of food habits, or due to inter-individual differences in life histories. Differences between the transmission of plant and bird names may be due to more frequent interactions with edible plants, as compared to birds.


Assuntos
Etnobotânica/educação , Disseminação de Informação , Conhecimento , Idioma , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Animais , Austrália , Aves/classificação , Ecologia , Etnicidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Plantas/classificação , Adulto Jovem
3.
Biol Rev Camb Philos Soc ; 95(4): 889-910, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32097520

RESUMO

Mixed-species animal groups (MSGs) are widely acknowledged to increase predator avoidance and foraging efficiency, among other benefits, and thereby increase participants' fitness. Diversity in MSG composition ranges from two to 70 species of very similar or completely different phenotypes. Yet consistency in organization is also observable in that one or a few species usually have disproportionate importance for MSG formation and/or maintenance. We propose a two-dimensional framework for understanding this diversity and consistency, concentrating on the types of interactions possible between two individuals, usually of different species. One axis represents the similarity of benefit types traded between the individuals, while the second axis expresses asymmetry in the relative amount of benefits/costs accrued. Considering benefit types, one extreme represents the case of single-species groups wherein all individuals obtain the same supplementary, group-size-related benefits, and the other extreme comprises associations of very different, but complementary species (e.g. one partner creates access to food while the other provides vigilance). The relevance of social information and the matching of activities (e.g. speed of movement) are highest for relationships on the supplementary side of this axis, but so is competition; relationships between species will occur at points along this gradient where the benefits outweigh the costs. Considering benefit amounts given or received, extreme asymmetry occurs when one species is exclusively a benefit provider and the other a benefit user. Within this parameter space, some MSG systems are constrained to one kind of interaction, such as shoals of fish of similar species or leader-follower interactions in fish and other taxa. Other MSGs, such as terrestrial bird flocks, can simultaneously include a variety of supplementary and complementary interactions. We review the benefits that species obtain across the diversity of MSG types, and argue that the degree and nature of asymmetry between benefit providers and users should be measured and not just assumed. We then discuss evolutionary shifts in MSG types, focusing on drivers towards similarity in group composition, and selection on benefit providers to enhance the benefits they can receive from other species. Finally, we conclude by considering how individual and collective behaviour in MSGs may influence both the structure and processes of communities.


Assuntos
Comportamento Animal/fisiologia , Biodiversidade , Aves/classificação , Peixes/classificação , Mamíferos/classificação , Répteis/classificação , Animais , Técnicas de Observação do Comportamento , Evolução Biológica , Aves/fisiologia , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/fisiologia , Peixes/fisiologia , Mamíferos/fisiologia , Comportamento Predatório/fisiologia , Répteis/fisiologia , Comportamento Espacial/fisiologia , Fatores de Tempo
4.
J Ethnobiol Ethnomed ; 15(1): 46, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477132

RESUMO

BACKGROUND: Hornbills are known to play an important role in rainforests as agents of seed dispersal. Decades of scientific research has led to a vital body of knowledge on hornbill taxonomy, ecology, distribution, and conservation status. However, the traditional ecological knowledge (TEK) that local people possess on hornbills has largely been underexplored. In 2018, we collaborated with the Iban people of Temburong, Brunei Darussalam, to study their TEK on hornbills. METHOD: We collaborated with the members of the Iban community from four longhouses and four villages in Temburong, Brunei Darussalam. Our study adopts a qualitative approach; we used detailed semi-directive interviews and brief semi-structured interviews to gather data. The semi-directive interviews documented the TEK related to Hornbills in detail while the brief semi-structured interviews assessed the current status of TEK in the age group of 18-40 years. RESULTS: The results show that the Iban ethnotaxonomy recognises seven folk species of hornbills, with Asian Black Hornbill (Anthracoceros malayanus) and Oriental Pied Hornbill (Anthracoceros albirostris) considered as a single folk species. The Iban TEK on diet and reproductive behaviour of hornbills complement existing scientific records, with the Iban TEK providing additional locale-specific information on the dietary preferences, abundance and conservation threats. However, the average Iban member has lost much of this TEK, and it is the subsistence hunters and agriculturists who have conserved it. CONCLUSION: There is an urgent need for encouraging transmission of knowledge from the hunters and agriculturists to others through ecotourism and conservation ventures. Our study adds further support to the understanding that the TEK of local communities is an important source of locale-specific knowledge on species of high conservation value such as hornbills.


Assuntos
Aves/classificação , Ecologia , Conhecimento , Adolescente , Adulto , Animais , Brunei , Conservação dos Recursos Naturais , Etnicidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dispersão de Sementes , Adulto Jovem
5.
Theriogenology ; 125: 140-151, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30415112

RESUMO

It is unquestinable that artificial insemination (AI) offers many benefits to avian conservation programs, but a serious impediment towards implementing AI for wild species is the development of effective techniques to consistently collect good quality ejaculates. Thus, we aimed to examine the success rate of electro-stimulation (ES) in collecting semen from 49 unconditioned males from orders Piciformes, Strigiformes, Accipitriformes, Cathartiformes, Galiformes, Anseriformes and Psittaciformes at different times of the year. Sixty out of 299 ES attempts provided ejaculates with sperm, but collection success rates varied widely (0-50%) depending on the species. Except for swans whose greater results were registered during spring-summer, males from most orders responded better to ES during winter-spring, suggesting seasonal variations on semen collection success rates. Overall, ES enabled successful semen collection from males of unproven and proven fertility under mixed pairing conditions. However, the highest success rate occurred in paired males with fertile clutches (40.6%) followed by unpaired males (22.1%), paired males without clutches (13.9%), and paired males with infertile clutches (6.8%). Behavioral responses of male birds to electrical impulses were also recorded to assess any discomfort during semen collection. Furthermore, macroscopic and microscopic analysis provided ejaculate parameters from several species, even from orders that hitherto have never been assessed for semen collection, which may serve as a starting point in the future. Altogether, these findings demonstrate the feasibility of ES in collecting semen from unpaired, unconditioned and non-imprinted males from a variety of bird orders. In the medium to long term, the use of this technique in both captive and free-ranging populations offers new perspectives to ensure genetic diversity in avian conservation programs.


Assuntos
Aves/fisiologia , Estimulação Elétrica/métodos , Animais , Aves/classificação , Ejaculação , Masculino , Estações do Ano , Sêmen , Análise do Sêmen/veterinária , Manejo de Espécimes/veterinária , Coleta de Tecidos e Órgãos
6.
Proc Natl Acad Sci U S A ; 115(45): 11555-11560, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30348768

RESUMO

We describe a specimen of the basal ornithuromorph Archaeorhynchus spathula from the Lower Cretaceous Jiufotang Formation with extensive soft tissue preservation. Although it is the fifth specimen to be described, unlike the others it preserves significant traces of the plumage, revealing a pintail morphology previously unrecognized among Mesozoic birds, but common in extant neornithines. In addition, this specimen preserves the probable remnants of the paired lungs, an identification supported by topographical and macro- and microscopic anatomical observations. The preserved morphology reveals a lung very similar to that of living birds. It indicates that pulmonary specializations such as exceedingly subdivided parenchyma that allow birds to achieve the oxygen acquisition capacity necessary to support powered flight were present in ornithuromorph birds 120 Mya. Among extant air breathing vertebrates, birds have structurally the most complex and functionally the most efficient respiratory system, which facilitates their highly energetically demanding form of locomotion, even in extremely oxygen-poor environments. Archaeorhynchus is commonly resolved as the most basal known ornithuromorph bird, capturing a stage of avian evolution in which skeletal indicators of respiration remain primitive yet the lung microstructure appears modern. This adds to growing evidence that many physiological modifications of soft tissue systems (e.g., digestive system and respiratory system) that characterize living birds and are key to their current success may have preceded the evolution of obvious skeletal adaptations traditionally tracked through the fossil record.


Assuntos
Aves/anatomia & histologia , Fósseis/anatomia & histologia , Pulmão/anatomia & histologia , Oxigênio/fisiologia , Respiração , Adaptação Fisiológica , Animais , Evolução Biológica , Aves/classificação , Aves/fisiologia , China , Extinção Biológica , Plumas/anatomia & histologia , Plumas/fisiologia , Voo Animal/fisiologia , Fósseis/história , História Antiga , Pulmão/fisiologia , Filogenia
7.
Nat Commun ; 9(1): 246, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29362437

RESUMO

Seabirds drastically transform the environmental conditions of the sites where they establish their breeding colonies via soil, sediment, and water eutrophication (hereafter termed ornitheutrophication). Here, we report worldwide amounts of total nitrogen (N) and total phosphorus (P) excreted by seabirds using an inventory of global seabird populations applied to a bioenergetics model. We estimate these fluxes to be 591 Gg N y-1 and 99 Gg P y-1, respectively, with the Antarctic and Southern coasts receiving the highest N and P inputs. We show that these inputs are of similar magnitude to others considered in global N and P cycles, with concentrations per unit of surface area in seabird colonies among the highest measured on the Earth's surface. Finally, an important fraction of the total excreted N (72.5 Gg y-1) and P (21.8 Gg y-1) can be readily solubilized, increasing their short-term bioavailability in continental and coastal waters located near the seabird colonies.


Assuntos
Aves/fisiologia , Ecossistema , Nitrogênio/metabolismo , Fósforo/metabolismo , Migração Animal/fisiologia , Animais , Regiões Antárticas , Aves/classificação , Conservação dos Recursos Naturais , Água Doce , Geografia , Ciclo do Nitrogênio , Oceanos e Mares , Água do Mar , Especificidade da Espécie
8.
Nat Commun ; 8: 14141, 2017 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-28139644

RESUMO

Enantiornithes are the most successful clade of Mesozoic birds. Here, we describe a new enantiornithine bird, Cruralispennia multidonta gen. et sp. nov., from the Protopteryx-horizon of the Early Cretaceous Huajiying Formation of China. Despite being among the oldest known enantiornithines, Cruralispennia displays derived morphologies that are unexpected at such an early stage in the evolution of this clade. A plough-shaped pygostyle, like that of the Ornithuromorpha, evolved convergently in the Cruralispennia lineage, highlighting the homoplastic nature of early avian evolution. The extremely slender coracoid morphology was previously unknown among Early Cretaceous enantiornithines but is common in Late Cretaceous taxa, indicating that by 131 million years ago this clade had already experienced considerable morphological differentiation. Cruralispennia preserves unusual crural feathers that are proximally wire-like with filamentous distal tips, a new morphotype previously unknown among fossil or modern feathers, further increasing the known diversity of primitive feather morphologies.


Assuntos
Evolução Biológica , Aves/anatomia & histologia , Plumas/anatomia & histologia , Fósseis/anatomia & histologia , Animais , Aves/classificação , Aves/fisiologia , China , Plumas/fisiologia , História Antiga , Filogenia , Coluna Vertebral
9.
Zhongguo Zhong Yao Za Zhi ; 42(23): 4593-4597, 2017 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-29376257

RESUMO

To provide theoretical basis for the traceability and quality evaluation of edible bird's nests (EBNs), the Cytb sequence was applied to identify the origin of EBNs. A total of 39 experiment samples were collected from Malaysia, Indonesia, Vietnam and Thailand. Genomic DNA was extracted for the PCR reaction. The amplified products were sequenced. 36 sequences were downloaded from Gen Bank including edible nest swiftlet, black nest swiftlet, mascarene swiftlet, pacific swiftlet and germain's swiftlet. MEGA 7.0 was used to analyze the distinction of sequences by the method of calculating the distances in intraspecific and interspecific divergences and constructing NJ and UPMGA phylogenetic tree based on Kimera-2-parameter model. The results showed that 39 samples were from three kinds of EBNs. Interspecific divergences were significantly greater than the intraspecific one. Samples could be successfully distinguished by NJ and UPMGA phylogenetic tree. In conclusion, Cytb sequence could be used to distinguish the origin of EBNs and it is efficient for tracing the origin species of EBNs.


Assuntos
Aves/classificação , Código de Barras de DNA Taxonômico , Animais , DNA , Indonésia , Malásia , Filogenia , Tailândia , Vietnã
10.
J Ethnobiol Ethnomed ; 11: 75, 2015 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-26520061

RESUMO

BACKGROUND: Studies on indigenous knowledge of fauna particular birds and its potential use in biodiversity conservation and management are rare globally. Characteristics used in creating indigenous bird names in many Ghanaian languages are undocumented. The main aim of this study is to answer the question "whether indigenous bird naming systems by the Akan tribes in Ghana follow scientific nomenclature and whether indigenous Akan bird knowledge can potentially help improve bird conservation efforts in Ghana. METHODS: Purposive sampling technique was employed in selecting 10 respondents from 25 communities in the five administrative districts in the Central Region. The study was conducted between November 2014 and March 2015. A mixed method approach was adopted in the data collection including key person interviews, focus group discussion, and structured interview supported by a participatory field observation. RESULTS: Indigenous people in the study area have reported 143 species of birds belonging to 44 families representing 57 % of total number of species with known local names in Ghana. The study revealed that just as Latin and common English naming systems, indigenous Akan bird names originated from features of the bird, including plumage, vocalizations or behavioural characteristics and belief systems of the indigenous people. The study also discovered that indigenous people in the study area have distinct names for different species within a particular family for most of the birds they could identify. However, they occasionally assign a single general name for either the entire family or all species therein. CONCLUSIONS: The study found evidence to support the prediction that indigenous bird naming systems in the Akan language follow scientific nomenclature. Indigenous knowledge and understanding of birds in the study area can be tapped and used in conservation planning and monitoring of birds. This research thus provides sufficient evidence to prove that indigenous knowledge by the Akan tribes in the study area can be useful in bird conservation and monitoring programs in Ghana. Further research in other Ghanaian languages is recommended.


Assuntos
Aves/classificação , Conservação dos Recursos Naturais , Terminologia como Assunto , Adolescente , Adulto , Idoso , Animais , Etnicidade , Feminino , Gana , Humanos , Conhecimento , Masculino , Pessoa de Meia-Idade , Adulto Jovem
11.
J Ethnobiol Ethnomed ; 10: 55, 2014 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-25012812

RESUMO

BACKGROUND: Studies on popular names of birds help to understand the relationship between human beings and birds and it also contributes to the field of ornithology. METHODS: This study aims to register the ethnotaxonomy of birds in the village of Pedra Branca, Santa Teresinha municipality, Bahia State, Brazil, by cataloguing and identifying their popular names, besides understanding the ethnoclassification system of local bird species. The ethno-ornithological data were obtained by means of semi-structured open interviews, and projective tests. RESULTS: We interviewed 48 residents and, in order to identify species, we chose five informants with a more detailed knowledge on local avifauna. We registered 139 common names, distributed into 108 ethnospecies and 33 synonyms, referring to 117 species. Nomenclatural criteria more frequently used were vocalization and coloring patterns. Following Berlin's principles of ethnobiological classification, three hierarchical levels were registered: life form, generic and specific, with three types of correspondence between Linnaean and folk classification systems. The bird life form ("pássaro" in Portuguese) was associated only to wild species. CONCLUSIONS: The ethno-ornithological research in Pedra Branca Village has contributed with new information on popular nomenclature of birds and their etymology, showing that folk knowledge on birds is conveyed within the community.


Assuntos
Aves/classificação , Animais , Brasil , Etnologia
12.
J Ethnobiol Ethnomed ; 9: 81, 2013 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-24321280

RESUMO

BACKGROUND: We report on a comparative ethno-ornithological study of Zapotec and Cuicatec communities in Northern Oaxaca, Mexico that provided a challenge to some existing descriptions of folk classification. Our default model was the taxonomic system of ranks developed by Brent Berlin. METHODS: Fieldwork was conducted in the Zapotec village of San Miguel Tiltepec and in the Cuicatec village of San Juan Teponaxtla, using a combination of ethnographic interviews and pile-sorting tests. Post-fieldwork, Principal Component Analysis using NTSYSpc V. 2.11f was applied to obtain pattern variation for the answers from different participants. RESULTS AND CONCLUSION: Using language and pile-sorting data analysed through Principal Component Analysis, we show how both Zapotec and Cuicatec subjects place a particular emphasis on an intermediate level of classification.These categories group birds with non-birds using ecological and behavioral criteria, and violate a strict distinction between symbolic and mundane (or 'natural'), and between 'general-purpose' and 'single-purpose' schemes. We suggest that shared classificatory knowledge embodying everyday schemes for apprehending the world of birds might be better reflected in a multidimensional model that would also provide a more realistic basis for developing culturally-informed conservation strategies.


Assuntos
Aves/classificação , Conservação dos Recursos Naturais , Etnologia , Indígenas Norte-Americanos , Zoologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Cultura , Feminino , Humanos , Julgamento , Masculino , México , Pessoa de Meia-Idade , Adulto Jovem
13.
Rev Biol Trop ; 60(1): 65-73, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22458209

RESUMO

Although sugar-water feeders are commonly used by enthusiasts to attract hummingbirds, little is known about how they affect hummingbird behavior and flower use. We studied the highland hummingbird assemblage of Cerro de La Muerte, Costa Rica, both at a site with permanent feeders (La Georgina Restaurant) and further from it. We examined how feeder use and monopolization affected seasonal changes in pollen loads during four sampling periods, including dry and wet seasons, from 2003-2005. We expected that species monopolizing the feeders would carry little or no pollen whatsoever, and would have pollen loads characterized by low floral diversity, in contrast with species less dependent on feeders. We obtained pollen samples from 183 individuals of four hummingbird species captured around the feeders using mist nets, which were compared with a pollen reference collection of plants with a pollination syndrome by hummingbirds. The same methods were implemented at a site 3km away from the feeders. Feeder usage was quantified by counting the number of times hummingbirds drank from the feeders in periods of 4min separated by 1min. The effects of hummingbird species and season on pollen load categories were assessed using a nominal logistic regression. The alpha species at the site, the Fiery-throated Hummingbird (Panterpe insignis), dominated the feeders during the dry season. Meanwhile, in the wet season, feeder usage was more evenly distributed across species, with the exception of the Volcano Hummingbird, Selasphorus flammula, which occupies the last place in the dominance hierarchy. Pollen loads of hummingbirds captured near feeders were low in abundance (more than 50% of captured individuals had zero or low pollen loads), and low in species richness (96% of the hummingbirds with pollen from only one plant genus, Centropogon). Overall pollen loads increased during the dry season coinciding with peaks in flower availability, although the majority of captured hummingbirds carried no pollen. Mist nets located 3km from La Georgina returned few captures (one-to-three specimens) per sampling date, contrasting with observations made before feeders were present. These results suggest that sugar-water feeders gather hummingbirds in over considerable distances drawing them away from flowers. The competitive and antagonistic pattern shown between feeders and flowers indicate that natural pollination system could be significantly altered. Supplementing hummingbirds with food seems likely to interfere with pollination networks already stressed by many anthropogenic effects.


Assuntos
Adaptação Biológica/fisiologia , Aves/fisiologia , Comportamento Alimentar/fisiologia , Pólen , Polinização/fisiologia , Animais , Aves/classificação , Costa Rica , Densidade Demográfica , Estações do Ano
14.
Rev. biol. trop ; 60(1): 65-73, Mar. 2012. graf, tab
Artigo em Inglês | LILACS | ID: lil-657763

RESUMO

Although sugar-water feeders are commonly used by enthusiasts to attract hummingbirds, little is known about how they affect hummingbird behavior and flower use. We studied the highland hummingbird assemblage of Cerro de La Muerte, Costa Rica, both at a site with permanent feeders (La Georgina Restaurant) and further from it. We examined how feeder use and monopolization affected seasonal changes in pollen loads during four sampling periods, including dry and wet seasons, from 2003-2005. We expected that species monopolizing the feeders would carry little or no pollen whatsoever, and would have pollen loads characterized by low floral diversity, in contrast with species less dependent on feeders. We obtained pollen samples from 183 individuals of four hummingbird species captured around the feeders using mist nets, which were compared with a pollen reference collection of plants with a pollination syndrome by hummingbirds. The same methods were implemented at a site 3km away from the feeders. Feeder usage was quantified by counting the number of times hummingbirds drank from the feeders in periods of 4min separated by 1min. The effects of hummingbird species and season on pollen load categories were assessed using a nominal logistic regression. The alpha species at the site, the Fiery-throated Hummingbird (Panterpe insignis), dominated the feeders during the dry season. Meanwhile, in the wet season, feeder usage was more evenly distributed across species, with the exception of the Volcano Hummingbird, Selasphorus flammula, which occupies the last place in the dominance hierarchy. Pollen loads of hummingbirds captured near feeders were low in abundance (more than 50% of captured individuals had zero or low pollen loads), and low in species richness (96% of the hummingbirds with pollen from only one plant genus, Centropogon). Overall pollen loads increased during the dry season coinciding with peaks in flower availability, although the ...


El uso de comederos constituye una práctica común para atraer colibríes, a pesar de que sabemos poco acerca de sus efectos sobre las relaciones ecológicas entre colibríes y sus plantas asociadas. Estudiamos el grupo de colibríes del Cerro de La Muerte, Costa Rica, en un sitio con comederos permanentes (Restaurante La Georgina), así como en un lugar alejado de los comederos. Analizamos cómo el uso y monipolización estacional de los comederos afectaba la carga de polen en cuatro períodos de muestreo entre 2003 y 2005. Esperábamos que las especies que monopolizaban los comederos tuvieran poco o cero polen, y si lo presentaban que la carga de polen estuviera representada por pocas especies en comparación con especies menos dependientes de los comederos. En la estación seca, la especie alfa Panterpe insignis, dominó los comederos. En la estación lluviosa el uso de comederos fue más equitativo. La carga de polen fue muy baja en abundancia (50% de los colibríes tenían poco o cero polen) y diversidad (96% de los colibríes tenían polen solamente del género Centropogon). Encontramos una relación competitiva y antagonística entre la visitación de comederos y la abundancia de flores. La carga de polen aumentó en la estación seca al haber más flores, aunque la mayoría de los colibríes capturados no tenían polen. Durante la estación lluviosa, cuando hay menos flores disponibles, el uso de comederos aumenta y la carga de polen disminuye. El uso de comederos interfiere en redes de polinización y se combina con otros efectos antropológicos negativos, tales como el calentamiento global, fragmentación de hábitats, cambio en el uso del suelo, que hacen más difícil la conservación de complejas redes tróficas.


Assuntos
Animais , Adaptação Biológica/fisiologia , Aves/fisiologia , Comportamento Alimentar/fisiologia , Pólen , Polinização/fisiologia , Aves/classificação , Costa Rica , Densidade Demográfica , Estações do Ano
15.
Ying Yong Sheng Tai Xue Bao ; 22(6): 1579-84, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21941762

RESUMO

Abstract: To deeply understand how the morphological features of plants affect the visiting of pollen- and seed dispersal birds is beneficial to elucidate the ecological and evolutionary consequences of plant-bird interactions. In this paper, a comparative study was conducted on the avian pollen- and seed dispersal networks across four tropical rainforest habitats having experienced different levels of anthropological disturbance in Southwest China. It was observed that the inter-active network of plant-frugivorous bird was highly asymmetrical, while that of plant-seed dispersal bird was not asymmetrical. The differences between the two networks mainly manifested in the bird abundance, bird movable capability, and plant features attracting bird visiting. The understanding of these differences allowed us to reveal the mutualistic relationship between plant and bird.


Assuntos
Aves/fisiologia , Comportamento Alimentar/fisiologia , Frutas/fisiologia , Néctar de Plantas/fisiologia , Árvores/fisiologia , Animais , Aves/classificação , China , Conservação dos Recursos Naturais/métodos , Ecossistema , Pólen/fisiologia , Dispersão de Sementes/fisiologia , Sementes/fisiologia , Árvores/crescimento & desenvolvimento , Clima Tropical
16.
Braz. j. vet. res. anim. sci ; 48(5): 370-377, 2011.
Artigo em Português | LILACS | ID: lil-687006

RESUMO

Considerando a importância comercial da perdiz (Rhynchotus rufescens), implantaram-se algumas biotecnologias reprodutivas. Trinta animais, provenientes da FCAV-UNESP/Jaboticabal (2007-2008), foram aleatoriamente distribuídos em grupos: controle (sem selênio orgânico) e tratamento (com 0,2 a 0,8 mg de selênio em 1000 kg de ração ). Coletou-se sêmen por excitação manual, que foi aliquotado em pools com 150 μL. Mensuraram-se volume, motilidade, vigor, número de espermatozoides, concentração e morfologia espermáticas. Diluíram-se 20 μl de sêmen em 300 μl de solução fisiológica para testes complementares (Integridade das membranas acrossomal e plasmática). Contaram-se 200 células, por teste, e classificaram-nas: 1) Acrossomo Íntegro: cor lilás e Não-Íntegro: róseo; 2) Células Vivas (não coradas) e Mortas (coradas). Os dados foram analisados pelo SAS, System for Windows. Os resultados dos pools com e sem selênio foram: as variáveis volume, motilidade, vigor, número de espermatozoides, concentração, integridade acrossomal e integridade da membrana plasmática não apresentaram resultados significantes, porém encontrou-se uma menor porcentagem de espermatozoides com peça intermediária fortemente dobrada, nos animais tratados com selênio em relação aos não tratados (1,33 ± 0,53 vs. 3,78 ± 0,69, respectivamente; p = 0.0107). De fato, sabe-se que o selênio tem papel importante na estrutura dos espermatozoides20. A deficiência de selênio está associada com danos na arquitetura da peça intermediária do espermatozóide.


Due to the commercial importance of the red-winged tinamou (Rhynchotus rufescens), for the past few years, the employment of reproductive biotechnologies has been attempted. Thirty animals were randomly assigned into two groups: control group (no selenium) and treatment group (supplemented with 0,2 a 0,8 mg selenium/ 1000 kg ration). Animals were allocated at the FCAV – UNESP/Jaboticabal (2007-2008). Semen collections were performed by digital manipulation and divided in pools of at least 150 μL. After the immediate evaluation of motility, vigour, concentration and morphology, an aliquot of 20 μL was diluted in 300 μL of physiologic solution in order to test acrosome and membrane integrities, which were performed by counting 200 cells for each test. Cells were evaluated as follows: 1) Intact acrosome: lilac acrosome; Non-intact acrosome: pink acrosome; 2) Live cells: non stained; Dead: stained. Data was statistically analysed using the SAS System for Windows. No differences were found between treatment and control groups for volume, motility, vigour, mean number of spermatozoa per animal, concentration, Intact acrosome, Intact membrane. The difference found on midpiece sperm defect (Se = 1,33 ± 0,53 and control = 3,78 ± 0,69, p = 0.0107) may be due to the damages caused by the selenium deficiency to the architecture of the midpiece, which compromises sperm mobility and fertilization capacity.


Assuntos
Animais , Aves/classificação , Selênio/química , Sêmen/metabolismo , Reprodução , Sêmen
17.
Evolution ; 64(10): 2820-39, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20561048

RESUMO

Visual signals are shaped by variation in the signaling environment through a process termed sensory drive, sometimes leading to speciation. However, the evidence for sensory drive in acoustic signals is restricted to comparisons between highly dissimilar habitats, or single-species studies in which it is difficult to rule out the influence of undetected ecological variables, pleiotropic effects, or chance. Here we assess whether this form of sensory drive-often termed "acoustic adaptation"-can generate signal divergence across ecological gradients. By studying avian communities in two Amazonian forest types, we show that songs of 17 "bamboo-specialist" bird species differ in predictable ways from their nearest relatives in adjacent terra firme forest. We also demonstrate that the direction of song divergence is correlated with the sound transmission properties of habitats, rather than with genetic divergence, ambient noise, or pleiotropic effects of mass and bill size. Our findings indicate that acoustic adaptation adds significantly to stochastic processes underlying song divergence, even when comparing between habitats with relatively similar structure. Furthermore, given that song differences potentially contribute to reproductive isolation, these findings are consistent with a wider role for sensory drive in the diversification of lineages with acoustic mating signals.


Assuntos
Adaptação Fisiológica , Evolução Biológica , Aves/fisiologia , Ecologia , Vocalização Animal/fisiologia , Estimulação Acústica , Animais , Aves/classificação , Fenótipo , Seleção Genética , Especificidade da Espécie , Processos Estocásticos
18.
Mar Pollut Bull ; 61(1-3): 115-23, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20153484

RESUMO

The Severn Estuary and Bristol Channel encompass a number of designated sites supporting populations of waterbirds and seabirds that are of national or international importance, including the Severn Estuary and Burry Inlet Special Protection Areas (SPAs)/Ramsar Sites and Carmarthen Bay, the UK's first marine SPA. Here, we provide an overview of the present numbers and trends of the waterbirds and seabirds using these sites, updating previous reviews undertaken prior to these designations. We further provide a summary of the main issues that have affected the status of the area's bird populations. Declines in the numbers of waders on the Severn Estuary and the southwest over the last two decades have been linked to climate change. The Sea Empress oil-spill impacted both breeding seabirds and the wintering Common Scoters in Carmarthen Bay, though numbers of the latter recovered 3years after the spill. At the Burry Inlet, Oystercatcher numbers have fallen over the last 25years and considerable research has been undertaken into the conflict with cockle and mussel fisheries. A long-term study at Cardiff Bay, at the mouth of the Severn, revealed a significant impact on the survival of Redshanks following its impoundment and has helped to further understanding of responses of waterbirds to estuarine habitat loss. The potential impacts of the construction of a tidal power scheme on the Severn Estuary are also discussed.


Assuntos
Aves , Ecossistema , Rios , Água do Mar , Animais , Aves/classificação , Aves/crescimento & desenvolvimento , Charadriiformes/classificação , Charadriiformes/crescimento & desenvolvimento , Vazamento de Resíduos Químicos , Clima , Geografia , Petróleo/toxicidade , Dinâmica Populacional , Fatores de Tempo , Reino Unido , Movimentos da Água , Poluentes Químicos da Água/toxicidade
20.
Nature ; 447(7146): 844-7, 2007 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-17565365

RESUMO

An evolutionary trend of decreasing size is present along the line to birds in coelurosaurian theropod evolution, but size increases are seen in many coelurosaurian subgroups, in which large forms are less bird-like. Here we report on a new non-avian dinosaur, Gigantoraptor erlianensis, gen. et sp. nov., from the Late Cretaceous Iren Dabasu Formation of Nei Mongol, China. Although it has a body mass of about 1,400 kg, a phylogenetic analysis positions this new taxon within the Oviraptorosauria, a group of small, feathered theropods rarely exceeding 40 kg in body mass. A histological analysis suggests that Gigantoraptor gained this size by a growth rate considerably faster than large North American tyrannosaurs such as Albertosaurus and Gorgosaurus. Gigantoraptor possesses several salient features previously unknown in any other dinosaur and its hind limb bone scaling and proportions are significantly different from those of other coelurosaurs, thus increasing the morphological diversity among dinosaurs. Most significantly, the gigantic Gigantoraptor shows many bird-like features absent in its smaller oviraptorosaurian relatives, unlike the evolutionary trend seen in many other coelurosaurian subgroups.


Assuntos
Evolução Biológica , Aves/anatomia & histologia , Aves/classificação , Dinossauros/anatomia & histologia , Dinossauros/classificação , Animais , Tamanho Corporal , China , História Antiga , Filogenia , Esqueleto , Fatores de Tempo
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