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1.
PLoS One ; 15(4): e0232193, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348334

RESUMO

Insect wings are highly evolved structures with aerodynamic and structural properties that are not fully understood or systematically modeled. Most species in the insect order Odonata have permanently deployed high aspect ratio wings. Odonata have been documented to exhibit extraordinary flight performance and a wide range of interesting flight behaviors that rely on agility and efficiency. The characteristic three-dimensional corrugated structures of these wings have been observed and modeled for a small number of species, with studies showing that corrugations can provide significant aerodynamic and structural advantages. Comprehensive museum collections are the most practical source of Odonata wing, despite the risk of adverse effects caused by dehydration and preservation of specimens. Museum specimens are not to be handled or damaged and are best left undisturbed in their display enclosures. We have undertaken a systematic process of scanning, modeling, and post-processing the wings of over 80 Odonata species using a novel and accurate method and apparatus we developed for this purpose. The method allows the samples to stay inside their glass cases if necessary and is non-destructive. The measurements taken have been validated against micro-computed tomography scanning and against similar-sized objects with measured dimensions. The resulting publicly available dataset will allow aeronautical analysis of Odonata aerodynamics and structures, the study of the evolution of functional structures, and research into insect ecology. The technique is useable for other orders of insects and other fragile samples.


Assuntos
Odonatos/anatomia & histologia , Asas de Animais/anatomia & histologia , Animais , Bases de Dados Factuais , Voo Animal/fisiologia , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional/instrumentação , Imageamento Tridimensional/métodos , Microscopia Eletrônica de Varredura , Modelos Anatômicos , Museus , Odonatos/classificação , Odonatos/fisiologia , Fotogrametria/instrumentação , Austrália do Sul , Asas de Animais/fisiologia , Asas de Animais/ultraestrutura , Microtomografia por Raio-X
2.
Am Nat ; 194(5): 707-724, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31613669

RESUMO

Intersexual signals that reveal developmental or mating status in females have evolved repeatedly in many animal lineages. Such signals have functions in sexual conflict over mating and can therefore influence sexually antagonistic coevolution. However, we know little about how female signal development modifies male mating harassment and thereby sexual conflict. Here, we combine phylogenetic comparative analyses of a color polymorphic damselfly genus (Ischnura) with behavioral experiments in one target species to investigate the evolutionary origin and current adaptive function of a developmental female color signal. Many Ischnura species have multiple female color morphs, which include a male-colored morph (male mimics) and one or two female morphs that differ markedly from males (heterochrome females). In Ischnura elegans, males and male-mimicking females express a blue abdominal patch throughout postemergence life. Using phenotypic manipulations, we show that the developmental expression of this signaling trait in heterochrome females reduces premating harassment prior to sexual maturity. Across species this signal evolved repeatedly, but in heterochrome females its origin is contingent on the signal expressed by co-occurring male-mimicking females. Our results suggest that the co-option of a male-like trait to a novel female antiharassment function plays a key role in sexual conflict driven by premating interactions.


Assuntos
Odonatos/anatomia & histologia , Caracteres Sexuais , Adaptação Biológica , Animais , Evolução Biológica , Cor , Feminino , Masculino , Odonatos/fisiologia , Fenótipo , Comportamento Sexual Animal
3.
IET Nanobiotechnol ; 13(8): 857-859, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31625527

RESUMO

The transparent wing of the dragonfly Aeshna cyanea has been investigated using scanning electron microscopy (SEM), optical microscopy (OPM), energy-dispersive X-ray spectroscopy (EDS) and reflectance spectroscopy. Four cells (D1-D4) were studied and classified according to their general morphology. The OPM depicted the vein-joint characterised by the distribution of resilin. EDS technique showed common elements such as carbon, oxygen, and chlorine. SEM analysis revealed thin membranes reinforced with a network of hallow veins. Spikes and round shape of microstructures were identified. The roughness of the pruinosity was estimated, which indicates the shape and curvature of the microstructures that essentially play a significant role in the optical response observed. The study can be essential to design and improve micro-air vehicles.


Assuntos
Odonatos/anatomia & histologia , Odonatos/citologia , Animais , Forma Celular , Tamanho Celular , Proteínas de Insetos/metabolismo , Microscopia/veterinária , Microscopia Eletrônica de Varredura/veterinária , Odonatos/ultraestrutura , Veias/anatomia & histologia , Veias/citologia , Veias/ultraestrutura , Asas de Animais/anatomia & histologia , Asas de Animais/irrigação sanguínea , Asas de Animais/citologia , Asas de Animais/metabolismo
4.
An Acad Bras Cienc ; 91(4): e20190302, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31664309

RESUMO

The beautifully colored damselflies included in Neoneura Selys are divided in 28 species known from North, Central and South America. Larval stage is little known, only seven species were described at this stage. We describe and illustrate the final instar larva of Neoneura confundens for the first time. Adults associated to this larva correspond to the blue form of the species and are also discussed and illustrated. The larva of N. confundens is similar to other Neoneura larvae, showing 1 premental seta and a well-marked nodus in caudal lamellae, but it can be differentiated by having fringed posterior margin in all tibiae and in middle and hind tarsi, among other characters. A key to known larvae of Neoneura and new records extending the species range in the southern cone are provided.


Assuntos
Larva/anatomia & histologia , Odonatos/anatomia & histologia , Animais , Tamanho Corporal , Feminino , Larva/classificação , Masculino , Odonatos/classificação , América do Sul , Tíbia
5.
PLoS One ; 14(10): e0223241, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31593578

RESUMO

The genus Franciscobasis Machado & Bedê, 2016 is endemic to the Serra da Canastra National Park in Minas Gerais state, Brazil. Two species of Franciscobasis were described simultaneously with the genus description: F. franciscoi and F. sonia, the latter described only from females. Through morphological and molecular analysis, we investigated if F. sonia may represent the young female of F. franciscoi. Resulting data did not present adequate differences between females to characterize them as different species. Therefore, we suggest that F. sonia is a junior synonym of F. franciscoi, and the female of F. franciscoi goes through a complex ontogenetic color change.


Assuntos
Odonatos/classificação , Odonatos/fisiologia , Animais , Brasil , Feminino , Masculino , Odonatos/anatomia & histologia , Odonatos/genética , Parques Recreativos
6.
FEMS Microbiol Lett ; 366(16)2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31504480

RESUMO

It is often claimed that Antoni van Leeuwenhoek was secretive about his methods. However, closer examination of his letters suggests that this reputation was not always deserved. Some letters were not published in the Royal Society Proceedings, and others were edited. This paper describes the repetition of his experiments with the eyes of bees and dragonflies using his own account of his experiments, despite the fact that only one of the four letters was published in the Proceedings.


Assuntos
Abelhas/anatomia & histologia , Biologia/história , Córnea/anatomia & histologia , Microscopia/métodos , Odonatos/anatomia & histologia , Animais , História do Século XVII , História do Século XVIII
7.
Am Nat ; 194(2): 268-275, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31318285

RESUMO

Reproductive interference is widespread, despite the theoretical expectation that it should be eliminated by reproductive character displacement (RCD). A possible explanation is that females of sympatric species are too similar phenotypically for males to distinguish between them, resulting in a type of evolutionary dilemma or catch-22 in which reproductive interference persists because male mate recognition (MR) cannot evolve until female phenotypes diverge further, and vice versa. Here we illustrate and test this hypothesis with data on rubyspot damselflies (Hetaerina spp.). First, reproductive isolation owing to male MR breaks down with increasing interspecific similarity in female phenotypes. Second, comparing allopatric and sympatric populations yielded no evidence for RCD, suggesting that parallel divergence in female coloration and male MR in allopatry determines the level of reproductive isolation on secondary contact. Whenever reproductive isolation depends on male MR and females of sympatric species are phenotypically similar, the evolutionary catch-22 hypothesis offers an explanation for the persistence of reproductive interference.


Assuntos
Odonatos/anatomia & histologia , Odonatos/fisiologia , Comportamento Sexual Animal , Animais , Cor , Feminino , Especiação Genética , Masculino , Fenótipo , Especificidade da Espécie , Asas de Animais/anatomia & histologia
8.
Philos Trans A Math Phys Eng Sci ; 377(2150): 20190132, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31177959

RESUMO

The flapping of the dragonfly forewing under in vivo condition has been analysed by image correlation technique to get an insight of its structural dynamics. The modal parameters such as flapping frequency, natural frequencies, mode shapes and modal strain have been obtained that will facilitate the biomimetic design of wings for micro air vehicles. The stigma, which is a pigmented spot at the leading edge of the wing near the tip having heavier mass, takes an active role in the real-time flapping by shaping its trajectory as eight-shaped, which enhances the drag coefficient and stroke efficiency. The extra mass on it and its removal transformed the trajectory into two different elliptical and oval shapes, respectively, which reduced the drag coefficient and stroke efficiency of the flapping wing by altering the flapping kinematics. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.


Assuntos
Modelos Biológicos , Odonatos , Asas de Animais , Animais , Fenômenos Biomecânicos , Odonatos/anatomia & histologia , Odonatos/fisiologia
9.
PLoS One ; 14(1): e0210370, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30625219

RESUMO

Citizen science and data collected from various volunteers have an interesting potential in aiding the understanding of many biological and ecological processes. We describe a mobile application that allows the public to map and report occurrences of the odonata species (dragonflies and damselflies) found in the Czech Republic. The application also helps in species classification based on observation details such as date, GPS coordinates, and the altitude, biotope, suborder, and colour. Dragonfly Hunter CZ is a free Android application built on the open-source framework NativeScript using the JavaScript programming language which is now fully available on Google Play. The server side is powered by Apache Server with PHP and MariaDB SQL database. A mobile application is a fast and accurate way to obtain data pertaining to the odonata species, which can be used after expert verification for ecological studies and conservation basis like Red Lists and policy instruments. We expect it to be effective in encouraging Citizen Science and in promoting the proactive reporting of odonates. It can also be extended to the reporting and monitoring of other plant and animal species.


Assuntos
Aplicativos Móveis , Odonatos , Altitude , Animais , Biodiversidade , República Tcheca , Ecossistema , Sistemas Especialistas , Feminino , Lógica Fuzzy , Masculino , Odonatos/anatomia & histologia , Odonatos/classificação , Estações do Ano , Voluntários
10.
Langmuir ; 35(6): 2422-2430, 2019 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-30628784

RESUMO

The waxy epicuticle of dragonfly wings contains a unique nanostructured pattern that exhibits bactericidal properties. In light of emerging concerns of antibiotic resistance, these mechano-bactericidal surfaces represent a particularly novel solution by which bacterial colonization and the formation of biofilms on biomedical devices can be prevented. Pathogenic bacterial biofilms on medical implant surfaces cause a significant number of human deaths every year. The proposed mechanism of bactericidal activity is through mechanical cell rupture; however, this is not yet well understood and has not been well characterized. In this study, we used giant unilamellar vesicles (GUVs) as a simplified cell membrane model to investigate the nature of their interaction with the surface of the wings of two dragonfly species, Austrothemis nigrescens and Trithemis annulata, sourced from Victoria, Australia, and the Baix Ebre and Terra Alta regions of Catalonia, Spain. Confocal laser scanning microscopy and cryo-scanning electron microscopy techniques were used to visualize the interactions between the GUVs and the wing surfaces. When exposed to both natural and gold-coated wing surfaces, the GUVs were adsorbed on the surface, exhibiting significant deformation, in the process of membrane rupture. Differences between the tensile rupture limit of GUVs composed of 1,2-dioleoyl- sn-glycero-3-phosphocholine and the isotropic tension generated from the internal osmotic pressure were used to indirectly determine the membrane tensions, generated by the nanostructures present on the wing surfaces. These were estimated as being in excess of 6.8 mN m-1, the first experimental estimate of such mechano-bactericidal surfaces. This simple model provides a convenient bottom-up approach toward understanding and characterizing the bactericidal properties of nanostructured surfaces.


Assuntos
Nanoestruturas/química , Lipossomas Unilamelares/química , Asas de Animais/química , Adsorção , Animais , Odonatos/anatomia & histologia , Fosfatidilcolinas/química , Molhabilidade
11.
Elife ; 82019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30642432

RESUMO

Many animals change their body color for visual signaling and environmental adaptation. Some dragonflies show wax-based color change and ultraviolet (UV) reflection, but the biochemical properties underlying the phenomena are totally unknown. Here we investigated the UV-reflective abdominal wax of dragonflies, thereby identifying very long-chain methyl ketones and aldehydes as unique and major wax components. Little wax was detected on young adults, but dense wax secretion was found mainly on the dorsal abdomen of mature males of Orthetrum albistylum and O. melania, and pruinose wax secretion was identified on the ventral abdomen of mature females of O. albistylum and Sympetrum darwinianum. Comparative transcriptomics demonstrated drastic upregulation of the ELOVL17 gene, a member of the fatty acid elongase gene family, whose expression reflected the distribution of very long-chain methyl ketones. Synthetic 2-pentacosanone, the major component of dragonfly's wax, spontaneously formed light-scattering scale-like fine structures with strong UV reflection, suggesting its potential utility for biomimetics.


Assuntos
Odonatos/efeitos da radiação , Pigmentação/efeitos da radiação , Raios Ultravioleta , Ceras/química , Abdome/anatomia & histologia , Animais , Cor , Epiderme/efeitos da radiação , Epiderme/ultraestrutura , Feminino , Genes de Insetos , Masculino , Odonatos/anatomia & histologia , Odonatos/genética , Odonatos/ultraestrutura , Filogenia , Solubilidade , Transcriptoma/genética , Regulação para Cima/genética , Molhabilidade
12.
Heredity (Edinb) ; 122(6): 893-905, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30542146

RESUMO

Although low levels of genetic structure are expected in highly widespread species, geographical and/or ecological factors can limit species distributions and promote population structure and morphological differentiation. In order to determine the effects of geographical isolation on population genetic structure and wing morphology, 281 individuals of the cosmopolitan odonate Pantala flavescens were collected from four continental (Central and South America) and five insular sites (Polynesian islands and the Maldives). COI sequences and eight microsatellite loci were used to characterize genetic diversity and genetic structure between and within locations. Linear and geometric morphometry were used to evaluate differences in the size and shape of wings. Genetic analysis showed a global genetic difference between the continental and insular sites. American locations did not show genetic structure, even in locations separated by a distance of 5000 km. Easter Island showed the lowest values of genetic diversity (mainly mitochondrial diversity) and the highest values of genetic differences compared to other insular and continental sites. Individuals from Easter Island showed smaller forewings, a different abdomen length to thorax length ratio, and a different configuration of anal loop in the hindwings. Thus, the greater isolation, smaller area, and young geological age seem to have determined the genetic and morphological differences in P. flavescens of Easter Island, where selection could promote a loss of migratory behavior and may improve other life history traits, such as reproduction. This work provides new insight into how microevolutionary processes operate in isolated populations of cosmopolitan species.


Assuntos
Odonatos/anatomia & histologia , Odonatos/genética , Animais , Variação Genética , Genética Populacional , Ilhas , Repetições de Microssatélites , Odonatos/crescimento & desenvolvimento , Filogenia , América do Sul
13.
An Acad Bras Cienc ; 90(3): 3017-3022, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304232

RESUMO

The American genus Argia, with more than 100 species described, is the most speciose genus of Odonata in the world. In this contribution, the final stadium larva of Argia serva, the southernmost distributed species of Argia, is described and diagnosed based on reared material from Martín García island, Buenos Aires, Argentina. The larva of this species can be easily separated from the other Argentinean Argia by the following combination of characters: sternum of S8 covered with spines (bare in A. translata); antennal segment 3 longer than 1+2 (equal to or shorter than 1+2 in A. joergenseni and A. jujuya); palpal setae absent (present in A. croceipennis). A key to the known larvae of Argia of the Southern Cone is provided.


Assuntos
Larva/anatomia & histologia , Larva/classificação , Odonatos/anatomia & histologia , Odonatos/classificação , Animais , Argentina , Larva/ultraestrutura , Microscopia Eletrônica de Varredura , Odonatos/ultraestrutura
14.
J Exp Biol ; 221(Pt 19)2018 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-30309956

RESUMO

An engineering examination of allometric and analogical data on the flight of giant Permian insects (Protodonata, Meganeura or griffinflies) indicates that previous estimates of the body mass of these insects are too low and that the largest of these insects (wingspan of 70 cm or more) would have had a mass of 100-150 g, several times greater than previously thought. Here, the power needed to generate lift and fly at the speeds typical of modern large dragonflies is examined together with the metabolic rate and subsequent heat generated by the thoracic muscles. This evaluation agrees with previous work suggesting that the larger specimens would rapidly overheat in the high ambient temperatures assumed in the Permian. Various extant mechanisms of thermoregulation are modelled and quantified, including behaviour, radiation and the constraints on convective respiration and evaporation imposed by air flow through spiracles. However, the effects of these on cooling an overheated insect are found to be limited. Instead, an examination of the heat budget in the flight medium indicates that, at about 1.6 bar (160 kPa), thermoregulation supply enters into equilibrium and, even at high ambient temperatures, overheating can be avoided and enough oxygen sourced. This approach indicates how fossil biology can be used to examine past atmospheres.


Assuntos
Regulação da Temperatura Corporal , Voo Animal/fisiologia , Odonatos/fisiologia , Consumo de Oxigênio/fisiologia , Asas de Animais/fisiologia , Animais , Atmosfera , Fenômenos Biomecânicos , Fósseis/anatomia & histologia , Modelos Biológicos , Odonatos/anatomia & histologia
15.
Proc Natl Acad Sci U S A ; 115(40): 9905-9910, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30224459

RESUMO

Insect wings are typically supported by thickened struts called veins. These veins form diverse geometric patterns across insects. For many insect species, even the left and right wings from the same individual have veins with unique topological arrangements, and little is known about how these patterns form. We present a large-scale quantitative study of the fingerprint-like "secondary veins." We compile a dataset of wings from 232 species and 17 families from the order Odonata (dragonflies and damselflies), a group with particularly elaborate vein patterns. We characterize the geometric arrangements of veins and develop a simple model of secondary vein patterning. We show that our model is capable of recapitulating the vein geometries of species from other, distantly related winged insect clades.


Assuntos
Voo Animal/fisiologia , Modelos Biológicos , Odonatos/anatomia & histologia , Odonatos/fisiologia , Asas de Animais/anatomia & histologia , Asas de Animais/fisiologia , Animais
16.
J Morphol ; 279(9): 1321-1335, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30117613

RESUMO

The development of the larval external morphology of Coryphaeschna perrensi is reported based primarily on a comparison of successive exuviae of reared specimens, with the second stadium larvae first described separately. Accentuated changes observable throughout successive moltings occur in some structures, such as the head capsule, labium, and anal appendages, allowing for the definition of characters with naturally ordered, polarized, and linear states (transformation series) by ontogenetic evidence. The terminal (less general) and nonterminal (more general) states of the described transformation series correspond by primary homology to the conditions found in larvae of other dragonfly species. Consequently, as the result of a parsimony analysis and subsequently ontogenetic rooting, the disposition of the states of 17 characters in a sample of final-stadium larvae of 23 species, representatives of the six Aeshnidae tribes (21) and Austropetaliidae (2), results in a hierarchical network comprising six distinct taxonomic levels of inclusion of C. perrensi. The levels correspond to Aeshnidae, Aeshninae, Aeshnini (part) + Gynacanthini, Coryphaeschna + Remartinia, Coryphaeschna, and Coryphaeschna except C. adnexa, which are groups previously recognized as monophyletic resulting from analyses considering adult morphology. Immature insect morphology coupled with ontogenetic observation presenting great potential to hypothesize phylogenetic relationships and investigate heterochronic events.


Assuntos
Odonatos/anatomia & histologia , Filogenia , Animais , Feminino , Larva/anatomia & histologia , Masculino
17.
J R Soc Interface ; 15(145)2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30158178

RESUMO

Insect wings show a high variability in wing venation. Selection for function, developmental pathways and phylogeny likely influenced wing vein diversification, however, quantitative data to estimate these influences and their interplay are missing. Here, it is tested how dragonfly wing vein configuration is influenced by functional demands, development, phylogeny and allometry using the concepts of modularity and integration. In an evolutionary context, modules are sets of characters that evolve in relative independence to other characters, while integration refers to a high degree of association between subparts of a structure. Results show allometric and phylogenetic signal in the wing shape variation, however, patterns of integration and modularity are not influenced by these two factors. Overall, dragonfly wings are highly integrated structures with almost no modular signal. Configuration changes in one wing vein or wing area thus influence wing shape as a whole. Moreover, the fore- and hindwings correlate with each other in their evolutionary shape variation supporting biomechanical data of wing interdependence. Despite the overall high degree of evolutionary integration, functional hypotheses of modularity could be confirmed for two wing areas, the arculus-triangle complex at the base of the wing which is responsible for passive wing folding especially during flapping flight and the location of the pterostigma, a coloured wing cell which is more heavy that other wing cells and passively regulates wing pitch as well as critical flight speeds during gliding. Although evolving as distinct modules, these specific vein regions also show high integration and evolve at the same rates like the whole wing which suggests an influence of these structures on the shape evolution of the rest of the wing. Their biomechanical role as passive regulators of wing corrugation and wing pitch suggests that these structures decisively influenced the evolution of advanced modern flight styles and explains their retention once they had evolved early within the lineage Odonatoptera.


Assuntos
Evolução Biológica , Voo Animal/fisiologia , Odonatos , Asas de Animais , Animais , Fenômenos Biomecânicos , Odonatos/anatomia & histologia , Odonatos/fisiologia , Asas de Animais/anatomia & histologia , Asas de Animais/fisiologia
18.
Sci Rep ; 8(1): 12141, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30108284

RESUMO

The largest insects to have ever lived were the giant meganeurids of the Late Palaeozoic, ancient stem relatives of our modern dragonflies. With wingspans up to 71 cm, these iconic insects have been the subject of varied documentaries on Palaeozoic life, depicting them as patrolling for prey through coal swamp forests amid giant lycopsids, and cordaites. Such reconstructions are speculative as few definitive details of giant dragonfly biology are known. Most specimens of giant dragonflies are known from wings or isolated elements, but Meganeurites gracilipes preserves critical body structures, most notably those of the head. Here we show that it is unlikely it thrived in densely forested environments where its elongate wings would have become easily damaged. Instead, the species lived in more open habitats and possessed greatly enlarged compound eyes. These were dorsally hypertrophied, a specialization for long-distance vision above the animal in flight, a trait convergent with modern hawker dragonflies. Sturdy mandibles with acute teeth, strong spines on tibiae and tarsi, and a pronounced thoracic skewness are identical to those specializations used by dragonflies in capturing prey while in flight. The Palaeozoic Odonatoptera thus exhibited considerable morphological specializations associated with behaviours attributable to 'hawkers' or 'perchers' among extant Odonata.


Assuntos
Voo Animal/fisiologia , Fósseis , Odonatos/fisiologia , Comportamento Predatório , Animais , Mandíbula/anatomia & histologia , Mandíbula/fisiologia , Odonatos/anatomia & histologia , Tamanho do Órgão , Paleontologia , Asas de Animais/anatomia & histologia
19.
An Acad Bras Cienc ; 90(3): 2865-2872, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30043908

RESUMO

Acanthagrion marinae sp. nov. (Holotype male: BRASIL, Mato Grosso do Sul, Campo Grande, UFMS, 20°29'56.26''S - 54°36'48.43''W, 547m, leg. M.E. Rodrigues, 03.ii.2015, collection code: VZYG437, MLP) is described and illustrated on the basis of 15 males. The new species belongs to the apicale species group by having horns on S10 and sclerotized hooks on tip of distal segment of the genital ligula. It can be easily distinguished from other species of the group by a combination of characters of the genital ligulae (presence of setae on segment two; absence of setae at flexure; distal lateral lobes of segment three absent). Notes on habitat and a modification of previous keys for the species of the apicale group are provided.


Assuntos
Ecossistema , Odonatos/anatomia & histologia , Odonatos/classificação , Animais , Brasil , Feminino , Masculino
20.
Bioinspir Biomim ; 13(4): 046007, 2018 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-29848791

RESUMO

Aquatic Anisopteran dragonfly larvae achieve respiration and propulsion by repetitive water jets flowing through their anal openings. Previous studies have shown that the tri-leaflet anal valves modulate the emerging jet by varying the opening size. We discovered that the valves are also capable of controlling the opening asymmetry by independent retraction of a leaflet. This study shows the effects of their valve asymmetry control on the respiratory and propulsive flows. Furthermore, the effects of size variation are re-evaluated using fluid momentum and power equations. Synchronized dual cameras recorded the valve movement and the flow generated by Aeshnidae sp. During the respiratory jetting, retraction of a single leaflet positions the opening in an off-centred locale, from which diagonally deflected jets emerge. The resulting flow field, together with the opening size modulation, implicates a reduction in the reinhalation of the exhaled jet and partial powering of the refilling process. Instead, during the propulsive jetting, concurrent partial retraction of the three leaflets results in the centred opening. The resulting jet flows straight, which has an implication for lowering form drag. Additionally, the propulsive aperture size control suggests improved thrust production. Our study highlights the significant influence that an asymmetrically positioned jet opening can have on biological jet flow. The findings inspire a new mechanism for jet vectoring that may prove useful for application in the broader engineering field.


Assuntos
Odonatos/fisiologia , Natação/fisiologia , Canal Anal/anatomia & histologia , Canal Anal/fisiologia , Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Animais , Fenômenos Biomecânicos , Biomimética , Hidrodinâmica , Larva/anatomia & histologia , Larva/fisiologia , Microscopia Confocal , Modelos Biológicos , Odonatos/anatomia & histologia , Reologia
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