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1.
Zoology (Jena) ; 148: 125948, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34343745

RESUMO

Morphology of the pygidial glands and chemical compositions of their secretion were analysed in the adults of three selected ground beetle taxa. Secretions of pygidial glands of Cychrus (Cychrus) semigranosus, Patrobus atrorufus and Pterostichus (Platysma) niger were chemically tested. Additionally, pygidial glands of the latter two species were investigated using bright-field microscopy and nonlinear microscopy and morphological features of the glands were described in detail. Both C. (C.) semigranosus and P. atrorufus were studied for the first time in terms of chemical ecology, while the latter species was analysed for the first time in terms of pygidial gland morphology. Altogether, eight compounds were detected in the dichloromethane extracts of the pygidial gland secretions of the three ground beetle taxa analysed. The simplest secretion mixtures were present in C. (C.) semigranosus and P. atrorufus (with two compounds each), while the extract of P. (P.) niger contained five compounds. The presence of 1-tetradecanol in the secretion of P. (P.) niger represents the first finding of this compound from the pygidial gland secretion extracts of ground beetles.


Assuntos
Estruturas Animais/fisiologia , Secreções Corporais/química , Besouros/fisiologia , Animais , Besouros/classificação , Feminino , Masculino , Especificidade da Espécie
2.
Zoology (Jena) ; 147: 125941, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34126327

RESUMO

Flamingos inhabit specialized habitats and breed in large colonies, building their nests on islands that limit the access of terrestrial predators. Many aspects of their uropygial gland are still unknown. The uropygial gland, a sebaceous organ exclusive to birds, shares some histological features among species such as the presence of a capsule, adenomers with stratified epithelium and secondary and primary chambers. We found that the uropygial gland of the Chilean Flamingo (Phoenicopterus chilensis) displays most of these characteristics but lacks a primary storage chamber. This absence may be an adaptation to their aquatic environment. The uropygial secretion of this species has a variety of glycoconjugates while its lipid moiety is largely dominated by waxes and minor amounts of triacylglycerols and fatty acids. Mass spectrometry analysis of the preen wax showed branched fatty acids of varied chain length and unbranched fatty alcohols, resulting in a complex mixture of wax esters and no differences between sexes were observed. The glycoconjugates present in the preen secretion could play a role as antimicrobial molecules, as suggested for other bird species, while the absence of diester waxes in flamingos might be related with their nesting habits and limited exposure to predation. Our results were evaluated according to physiological and ecological aspects of the flamingo's biology.


Assuntos
Estruturas Animais/fisiologia , Aves/fisiologia , Secreções Corporais/química , Estruturas Animais/anatomia & histologia , Animais , Secreções Corporais/fisiologia , Feminino , Masculino , Tamanho do Órgão , Especificidade da Espécie
3.
Proc Natl Acad Sci U S A ; 118(10)2021 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-33658360

RESUMO

Located in the forelegs, katydid ears are unique among arthropods in having outer, middle, and inner components, analogous to the mammalian ear. Unlike mammals, sound is received externally via two tympanic membranes in each ear and internally via a narrow ear canal (EC) derived from the respiratory tracheal system. Inside the EC, sound travels slower than in free air, causing temporal and pressure differences between external and internal inputs. The delay was suspected to arise as a consequence of the narrowing EC geometry. If true, a reduction in sound velocity should persist independently of the gas composition in the EC (e.g., air, [Formula: see text]). Integrating laser Doppler vibrometry, microcomputed tomography, and numerical analysis on precise three-dimensional geometries of each experimental animal EC, we demonstrate that the narrowing radius of the EC is the main factor reducing sound velocity. Both experimental and numerical data also show that sound velocity is reduced further when excess [Formula: see text] fills the EC. Likewise, the EC bifurcates at the tympanal level (one branch for each tympanic membrane), creating two additional narrow internal sound paths and imposing different sound velocities for each tympanic membrane. Therefore, external and internal inputs total to four sound paths for each ear (only one for the human ear). Research paths and implication of findings in avian directional hearing are discussed.


Assuntos
Estruturas Animais , Meato Acústico Externo , Gryllidae , Audição/fisiologia , Membrana Timpânica , Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Animais , Meato Acústico Externo/anatomia & histologia , Meato Acústico Externo/fisiologia , Gryllidae/anatomia & histologia , Gryllidae/fisiologia , Membrana Timpânica/anatomia & histologia , Membrana Timpânica/fisiologia
4.
Sci Rep ; 11(1): 378, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33432089

RESUMO

Quantitative assessment of soft tissue elasticity is crucial to a broad range of applications, such as biomechanical modeling, physiological monitoring, and tissue diseases diagnosing. However, the modulus measurement of soft tissues, particularly in vivo, has proved challenging since the instrument has to reach the site of soft tissue and be able to measure in a very short time. Here, we present a simple method to measure the elastic modulus of soft tissues on site by exploiting buckling of a long slender bar to quantify the applied force and a spherical indentation to extract the elastic modulus. The method is realized by developing a portable pen-sized instrument (EPen: Elastic modulus pen). The measurement accuracies are verified by independent modulus measures using commercial nanoindenter. Quantitative measurements of the elastic modulus of mouse pancreas, healthy and cancerous, surgically exposed but attached to the body further confirm the potential clinical utility of the EPen.


Assuntos
Estruturas Animais/fisiologia , Fenômenos Biomecânicos/fisiologia , Elasticidade/fisiologia , Tecnologia de Fibra Óptica/instrumentação , Animais , Biofísica/instrumentação , Módulo de Elasticidade , Feminino , Tecnologia de Fibra Óptica/métodos , Teste de Materiais , Camundongos , Camundongos Transgênicos , Microtecnologia/instrumentação , Aplicativos Móveis , Tono Muscular/fisiologia , Fenômenos Fisiológicos Musculoesqueléticos , Agulhas , Estresse Mecânico
5.
Curr Opin Insect Sci ; 42: 84-89, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33038534

RESUMO

Many insects forage, oviposit or inject venom in their prey by penetrating or cutting through substrates. From a physical perspective, cutting involves creation of new free surfaces. The cutting parts of insects, such as their mandibles or ovipositor tips, are often zinc-enriched and hardened as compared to the other cuticular regions. Whereas tip hardening is key to their ability to penetrate surfaces, it is often also important for probes to be maneuverable through substrates. How do insect probes negotiate the trade-off between cutting and steering through substrates of diverse stiffness? To address this question, we review the morphology, mechanics, and adaptations in the cutting parts of various insects. Understanding these mechanisms will allow us to develop biomimetic tools, including agricultural and surgical tools, that can both cut and steer through diverse substrates.


Assuntos
Estruturas Animais/fisiologia , Materiais Biomiméticos , Comportamento Alimentar/fisiologia , Insetos/fisiologia , Oviposição , Adaptação Biológica , Estruturas Animais/anatomia & histologia , Animais , Fenômenos Biomecânicos , Insetos/anatomia & histologia , Zinco
6.
PLoS One ; 15(8): e0237499, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833963

RESUMO

Herein we describe Ocrepeira klamt sp. n. (Araneae: Araneidae), a new orb-weaving spider species from a Colombian páramo, which was formerly inaccessible for scientific studies due to decades long armed conflicts. Both, phenotypic and molecular data are used to confirm genus affiliation, and the new species is placed into phylogenetic context with other araneid spiders. Morphological characteristics and ecological notes of Ocrepeira klamt sp. n. are reported together with the sequence of the barcoding region of cytochrome c oxidase subunit I (COI) to provide a comprehensive description of the spider, facilitating future identification beyond taxonomic experts. With this study we contribute to the taxonomic knowledge that is required to inventory the hyper diverse yet threatened ecosystem of the Colombian páramos.


Assuntos
Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Aranhas/anatomia & histologia , Aranhas/classificação , Distribuição Animal , Animais , Colômbia , Código de Barras de DNA Taxonômico , Ecossistema , Complexo IV da Cadeia de Transporte de Elétrons/genética , Filogenia , Aranhas/fisiologia
7.
J Morphol ; 281(9): 1018-1028, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32621639

RESUMO

Many vertebrates are armored over all or part of their body. The armor may serve several functional roles including defense, offense, visual display, and signal of experience/capability. Different roles imply different tradeoffs; for example, defensive armor usually trades resistance to attack for maneuverability. The poachers (Agonidae), 47 species of scorpaeniform fishes, are a useful system for understanding the evolution and function of armor due to their variety and extent of armoring. Using publically available CT-scan data from 27 species in 16 of 21 genera of poachers we compared the armor to axial skeletal in the mid body region. The ratio of average armor density to average skeleton density ranged from 0.77 to 1.17. From a defensive point of view, the total investment in mineralization (volume * average density) is more interesting. There was 10 times the material invested in the armor as in the endoskeleton in some small, smooth plated species, like Aspidophoroides olrikii. At the low end, some visually arresting species like Percis japonica, had ratios as low as 2:1. We categorized the extent and type (impact vs. abrasion) in 34 Agonopsis vulsa across all 35+ plates in the eight rows along the body. The ventral rows show abrasive damage along the entire length of the fish that gets worse with age. Impact damage to head and tail plates gets more severe and occurs at higher rates with age. The observed damage rates and the large investment in mineralization of the armor suggest that it is not just for show, but is a functional defensive structure. We cannot say what the armor is defense against, but the abrasive damage on the ventrum implies their benthic lifestyle involves rubbing on the substrate. The impact damage could result from predatory attacks or from intraspecific combat.


Assuntos
Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Perciformes/anatomia & histologia , Perciformes/fisiologia , Estruturas Animais/ultraestrutura , Animais , Osso e Ossos/anatomia & histologia , Minerais/metabolismo , Comportamento Predatório
8.
PLoS One ; 15(5): e0232981, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32396580

RESUMO

Cell signaling pathways play key roles in coordinating cellular events in development. The Notch signaling pathway is highly conserved across all multicellular animals and is known to coordinate a multitude of diverse cellular events, including proliferation, differentiation, fate specification, and cell death. Specific functions of the pathway are, however, highly context-dependent and are not well characterized in post-traumatic regeneration. Here, we use a small-molecule inhibitor of the pathway (DAPT) to demonstrate that Notch signaling is required for proper arm regeneration in the brittle star Ophioderma brevispina, a highly regenerative member of the phylum Echinodermata. We also employ a transcriptome-wide gene expression analysis (RNA-seq) to characterize the downstream genes controlled by the Notch pathway in the brittle star regeneration. We demonstrate that arm regeneration involves an extensive cross-talk between the Notch pathway and other cell signaling pathways. In the regrowing arm, Notch regulates the composition of the extracellular matrix, cell migration, proliferation, and apoptosis, as well as components of the innate immune response. We also show for the first time that Notch signaling regulates the activity of several transposable elements. Our data also suggests that one of the possible mechanisms through which Notch sustains its activity in the regenerating tissues is via suppression of Neuralized1.


Assuntos
Equinodermos/fisiologia , Receptores Notch/fisiologia , Regeneração/fisiologia , Estruturas Animais/efeitos dos fármacos , Estruturas Animais/fisiologia , Animais , Elementos de DNA Transponíveis , Dipeptídeos/farmacologia , Regulação para Baixo/efeitos dos fármacos , Equinodermos/efeitos dos fármacos , Equinodermos/genética , Receptores Notch/antagonistas & inibidores , Receptores Notch/genética , Regeneração/efeitos dos fármacos , Regeneração/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Transcriptoma/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
9.
PLoS One ; 15(5): e0232450, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433692

RESUMO

Many insects show discontinuous respiration with three phases, open, closed, and fluttering, in which the spiracles open and close rapidly. The relative durations of the three phases and the rate of fluttering during the flutter phase vary for individual insects depending on developmental stage and activity, vary between insects of the same species, and vary even more between different species. We studied how the rate of oxygen uptake during the flutter phase depends on the rate of fluttering. Using a mathematical model of oxygen diffusion in the insect tracheal system, we derive a formula for oxygen uptake during the flutter phase and how it depends on the length of the tracheal system, percentage of time open during the flutter phase, and the flutter rate. Surprisingly, our results show that an insect can have its spiracles closed a high percentage of time during the flutter phase and yet receive almost as much oxygen as if the spiracles were always open, provided the spiracles open and close rapidly. We investigate the respiratory gain due to fluttering for four specific insects. Our formula shows that respiratory gain increases with body size and with increased rate of fluttering. Therefore, insects can regulate their rate of oxygen uptake by varying the rate of fluttering while keeping the spiracles closed during a large fraction of the time during the flutter phase. We also use a mathematical model to show that water loss is approximately proportional to the percentage of time the spiracles are open. Thus, insects can achieve both high oxygen intake and low water loss by keeping the spiracles closed most of the time and fluttering while open, thereby decoupling the challenge of preventing water loss from the challenge of obtaining adequate oxygen uptake.


Assuntos
Insetos/fisiologia , Modelos Biológicos , Oxigênio/fisiologia , Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Animais , Água Corporal/metabolismo , Himenópteros/fisiologia , Insetos/anatomia & histologia , Lepidópteros/fisiologia , Conceitos Matemáticos , Respiração , Mecânica Respiratória/fisiologia , Traqueia/anatomia & histologia , Traqueia/fisiologia
10.
Anat Rec (Hoboken) ; 303(1): 30-43, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-30332722

RESUMO

The serrasalmids: piranhas, pacus, and their relatives, are ubiquitous Neotropical fishes with diverse diets, ecologies, and behaviors. Serrasalmids have a bony, serrated keel which lines the underbellies of these fishes, the structure for which the family is named. We examined the diversity and structure of the keel in piranhas and allies using micro-computed tomography scanning in over 30 species of serrasalmids, a third of the species richness for the family, and for 95 total characiform specimens. The keel is highly diverse across serrasalmids, with serrae shape dictating the overall form of the keel. Serrae shape varies considerably among different species and even within keels themselves. The keel morphology can be divided into distinct anterior and posterior regions, as separated by the pelvic fins. Compared to other characiform fishes, serrasalmid skeletons are frequently damaged. Gouging perforations and signs of healing (serrae fusion) are common on the keel. We propose the keel is a defensive structure based on the high incidence of injury (>50%) in our dataset. This is the highest incidence of damage ever recorded in the skeletons of bony fishes. The loss of the anterior keel region in rheophilic taxa suggests competing performance demands and selective pressures on this structure. Competition and aggression among conspecifics or confamilials is a frequently invoked phenomenon for explaining animal weaponry and armor in terrestrial vertebrates. The keel in serrasalmids and other instances of armor in fishes could be complementary study systems for examining competitive rivalry in vertebrates. Anat Rec, 2018. © 2018 American Association for Anatomy.


Assuntos
Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Osso e Ossos/anatomia & histologia , Osso e Ossos/fisiologia , Caraciformes/anatomia & histologia , Caraciformes/fisiologia , Animais , Filogenia , Microtomografia por Raio-X
11.
Cell ; 179(6): 1382-1392.e10, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-31735497

RESUMO

Distributing learning across multiple layers has proven extremely powerful in artificial neural networks. However, little is known about how multi-layer learning is implemented in the brain. Here, we provide an account of learning across multiple processing layers in the electrosensory lobe (ELL) of mormyrid fish and report how it solves problems well known from machine learning. Because the ELL operates and learns continuously, it must reconcile learning and signaling functions without switching its mode of operation. We show that this is accomplished through a functional compartmentalization within intermediate layer neurons in which inputs driving learning differentially affect dendritic and axonal spikes. We also find that connectivity based on learning rather than sensory response selectivity assures that plasticity at synapses onto intermediate-layer neurons is matched to the requirements of output neurons. The mechanisms we uncover have relevance to learning in the cerebellum, hippocampus, and cerebral cortex, as well as in artificial systems.


Assuntos
Peixe Elétrico/fisiologia , Aprendizagem , Rede Nervosa/fisiologia , Potenciais de Ação/fisiologia , Estruturas Animais/citologia , Estruturas Animais/fisiologia , Animais , Axônios/metabolismo , Fenômenos Biofísicos , Peixe Elétrico/anatomia & histologia , Feminino , Masculino , Modelos Neurológicos , Plasticidade Neuronal , Comportamento Predatório , Sensação , Fatores de Tempo
12.
Sci Rep ; 9(1): 12742, 2019 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-31484970

RESUMO

Micropyles in insects are small openings that allow sperm entry into, and the number was usually decreased on unfertilized and (or) undeveloped eggs. However, reports showed that Harmonia axyridis, a reproductive success model, deposited similar number of micropyles on undeveloped and developing eggs. Thus, it was confusing whether micropyles in H. axyridis were unaffected. To solve this confusion, two experiments were conducted here. Firstly, virgin female and four different days delayed mating (DDM) experiments were conducted to reveal the effects of fertilization stimulus and delayed-fertilization. Secondly, intercrosses between a light-colored mutant (HAM, an adaptive deficiency) and wild type (HAW) were conducted to further reveal whether there were female and male interactions. We found that (1) eggs produced by virgin and DDM females had significantly less micropyles than control. Even so, more than 18 micropyles were observed on eggs following fertilization and, consequently, egg production as well as hatch rate was not negatively affected by mating delay; (2) number of micropyles was significantly varied among the four reciprocal crosses and virgin HAW female. Specifically, the heterozygous eggs (Cross-D) and wild-type homozygous eggs (Cross-B) respectively had the least and maximum micropyles, and eggs from virgin HAW female had significantly less micropyles compared to those from HAW female (Cross-B or Cross-C), but the number was significantly higher than those from HAM female (Cross-A or Cross-D). These results informed us that the number of micropyles in H. axyridis is plastic but maintaining a high-quantity that offers many benefits, which should contribute to its reproduction success.


Assuntos
Estruturas Animais/fisiologia , Besouros/fisiologia , Reprodução , Animais , Besouros/genética , Feminino , Fertilização , Masculino , Comportamento Sexual Animal
13.
PLoS One ; 14(8): e0221659, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31442282

RESUMO

Ticks are second only to mosquitoes as vectors of disease to humans and animals. Tick host detection is mainly ascribed to Haller's organ, a complex sensory structure on the tick foreleg that detects odors, carbon dioxide and heat, but these host detection mechanisms are not well understood. There is anecdotal evidence that ticks and other ectoparasites are attracted to heat, but it has never been demonstrated that they use radiant heat to detect hosts at a distance. In fact, previous attempts to do this have concluded that radiant heat was not used by ticks. Here we use a novel thermotaxis assay to investigate the detection range, temperature dependence and repellent sensitivity of heat perception in ticks and to identify the sensory organ responsible for this sense. We show that Amblyomma americanum and Dermacentor variabilis ticks can locate a human from several meters away by radiant heat sensed by the part of Haller's organ known as the capsule, a covered spherical pit organ. An aperture in the capsule cover confers directionality and highly reflective interior surfaces of the capsule concentrate radiation on the sensilla to sharpen directionality and increase sensitivity. Commercial insect repellents provide an effective means of personal protection against potentially infectious tick bites by hindering host-seeking behavior. Low concentrations of the insect repellents DEET, picaridin, 2-undecanone, citronellal and nootkatone eliminate thermotaxis without affecting olfaction-stimulated host-seeking behavior. Our results demonstrate that the tick Haller's organ capsule is a radiant heat sensor used in host-finding and that repellents disrupt this sense at concentrations that do not disrupt olfaction. We anticipate that this discovery will significantly aid insect repellent research and provide novel targets for the development of innovative integrated pest management programs and personal protection strategies for ectoparasites and vector-borne disease.


Assuntos
Estruturas Animais/fisiologia , Temperatura Alta , Repelentes de Insetos/farmacologia , Ixodidae/fisiologia , Estruturas Animais/efeitos dos fármacos , Animais , Bioensaio , Feminino , Ixodidae/efeitos dos fármacos , Masculino , Movimento
14.
PLoS One ; 14(7): e0218486, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31276510

RESUMO

Our understanding of spider reproductive biology is hampered by the vast anatomical diversity and difficulties associated with its study. Although authors agree on the two general types of female spider genitalia, haplogyne (plesiomorphic) and entelegyne (apomorphic), our understanding of variation within each group mostly concerns the external genital part, while the internal connections with the reproductive duct are largely unknown. Conventionally and simplistically, the spermathecae of haplogynes have simple two-way ducts, and those of entelegynes have separate copulatory and fertilization ducts for sperm to be transferred in and out of spermathecae, respectively. Sperm is discharged from the spermathecae directly into the uterus externus (a distal extension of the oviduct), which, commonly thought as homologous in both groups, is the purported location of internal fertilization in spiders. However, the structural evolution from haplo- to entelegyny remains unresolved, and thus the precise fertilization site in entelegynes is ambiguous. We aim to clarify this anatomical problem through a widely comparative morphological study of internal female genital system in entelegynes. Our survey of 147 epigyna (121 examined species in 97 genera, 34 families) surprisingly finds no direct connection between the fertilization ducts and the uterus externus, which, based on the homology with basal-most spider lineages, is a dead-end caecum in entelegynes. Instead, fertilization ducts usually connect with a secondary uterus externus, a novel feature taking over the functional role of the plesiomorphic uterus externus. We hypothesize that the transition from haplo- to entelegyny entailed not only the emergence of the two separate duct systems (copulatory, fertilization), but also involved substantial morphological changes in the distal part of the oviduct. Thus, the common oviduct may have shifted its distal connection from the uterus externus to the secondary uterus externus, perhaps facilitating discharge of larger eggs. Our findings suggest that the conventional model of entelegyne reproduction needs redefinition.


Assuntos
Estruturas Animais/fisiologia , Estruturas Animais/ultraestrutura , Modelos Biológicos , Aranhas/fisiologia , Aranhas/ultraestrutura , Animais , Feminino , Masculino , Reprodução/fisiologia
15.
Dev Biol ; 451(2): 134-145, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30974103

RESUMO

Tissue remodeling is broadly defined as the reorganization or restoration of existing tissues. Tissue remodeling processes are responsible for directing the development and maintenance of tissues, organs, and overall morphology of an organism. Therefore, studying the regulatory and mechanistic aspects of tissue remodeling allows one to decipher how tissue structure and function is manipulated in animals. As such, research focused on investigating natural tissue reorganization in animal model organisms has great potential for advancing medical therapies, in conjunction with tissue engineering and regenerative medicine. Here we discuss the molecular and cellular mechanisms responsible for tissue remodeling events that occur across several animal phyla. Notably, this review emphasizes the molecular and cellular mechanisms involved in embryonic and postnatal physiological tissue remodeling events, ranging from metamorphosis to bone remodeling during functional adaptation.


Assuntos
Estruturas Animais/fisiologia , Regeneração , Animais , Evolução Biológica , Matriz Extracelular/química , Matriz Extracelular/fisiologia , Humanos , Metamorfose Biológica , Modelos Animais , Transdução de Sinais , Engenharia Tecidual
16.
PLoS One ; 14(4): e0214889, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30995262

RESUMO

Atractaspidines are poorly studied, fossorial snakes that are found throughout Africa and western Asia, including the Middle East. We employed concatenated gene-tree analyses and divergence dating approaches to investigate evolutionary relationships and biogeographic patterns of atractaspidines with a multi-locus data set consisting of three mitochondrial (16S, cyt b, and ND4) and two nuclear genes (c-mos and RAG1). We sampled 91 individuals from both atractaspidine genera (Atractaspis and Homoroselaps). Additionally, we used ancestral-state reconstructions to investigate fang and diet evolution within Atractaspidinae and its sister lineage (Aparallactinae). Our results indicated that current classification of atractaspidines underestimates diversity within the group. Diversification occurred predominantly between the Miocene and Pliocene. Ancestral-state reconstructions suggest that snake dentition in these taxa might be highly plastic within relatively short periods of time to facilitate adaptations to dynamic foraging and life-history strategies.


Assuntos
Viperidae/classificação , Viperidae/genética , Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Animais , Citocromos b/genética , Evolução Molecular , Genes Mitocondriais , Genes RAG-1 , Genes mos , NADH Desidrogenase/genética , Filogenia , Comportamento Predatório , RNA Ribossômico 16S/genética , Fatores de Tempo , Viperidae/fisiologia
17.
PLoS One ; 14(2): e0213318, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30818343

RESUMO

In phytophagous sap-sucking insects, the precibarial valve plays an important role in sap ingestion. We used light and electron microspcopy to study the morphology and the ultrastructure of the precibarial valve of the meadow spittlebug, Philaenus spumarius (Hemiptera, Aphrophoridae), in order to better understand the operative mechanism of this structure. The precibarial valve revealed to be a complex structure with a bell-like invagination in the middle of the precibarium (on the epipharynx). Unlike the current hypothesis, we propose that the valve opens by dilator muscles and closes through cuticular and fluid tensions, the latter leading to morphological changes to the plane of the valve based on sap flow. Moreover, the presence of a precibarial secretory structure is described for the first time for auchenorrhynchan insects. In light of these observations, functions are hypothesized and discussed for this secretory structure.


Assuntos
Hemípteros/anatomia & histologia , Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Estruturas Animais/ultraestrutura , Animais , Hemípteros/fisiologia , Hemípteros/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Boca/anatomia & histologia , Boca/fisiologia , Boca/ultraestrutura , Faringe/anatomia & histologia , Faringe/fisiologia , Faringe/ultraestrutura
18.
Annu Rev Neurosci ; 42: 129-147, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-30786225

RESUMO

Across the animal kingdom, social interactions rely on sound production and perception. From simple cricket chirps to more elaborate bird songs, animals go to great lengths to communicate information critical for reproduction and survival via acoustic signals. Insects produce a wide array of songs to attract a mate, and the intended receivers must differentiate these calls from competing sounds, analyze the quality of the sender from spectrotemporal signal properties, and then determine how to react. Insects use numerically simple nervous systems to analyze and respond to courtship songs, making them ideal model systems for uncovering the neural mechanisms underlying acoustic pattern recognition. We highlight here how the combination of behavioral studies and neural recordings in three groups of insects-crickets, grasshoppers, and fruit flies-reveals common strategies for extracting ethologically relevant information from acoustic patterns and how these findings might translate to other systems.


Assuntos
Corte , Insetos/fisiologia , Reconhecimento Fisiológico de Modelo/fisiologia , Comportamento Sexual Animal/fisiologia , Vocalização Animal/fisiologia , Estruturas Animais/fisiologia , Animais , Drosophila/fisiologia , Feminino , Previsões , Gafanhotos/fisiologia , Gryllidae/fisiologia , Masculino , Preferência de Acasalamento Animal/fisiologia , Órgãos dos Sentidos/fisiologia , Especificidade da Espécie , Temperatura , Fatores de Tempo
19.
PLoS Biol ; 17(2): e2006507, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30730882

RESUMO

The unique avian vocal organ, the syrinx, is located at the caudal end of the trachea. Although a larynx is also present at the opposite end, birds phonate only with the syrinx. Why only birds evolved a novel sound source at this location remains unknown, and hypotheses about its origin are largely untested. Here, we test the hypothesis that the syrinx constitutes a biomechanical advantage for sound production over the larynx with combined theoretical and experimental approaches. We investigated whether the position of a sound source within the respiratory tract affects acoustic features of the vocal output, including fundamental frequency and efficiency of conversion from aerodynamic energy to sound. Theoretical data and measurements in three bird species suggest that sound frequency is influenced by the interaction between sound source and vocal tract. A physical model and a computational simulation also indicate that a sound source in a syringeal position produces sound with greater efficiency. Interestingly, the interactions between sound source and vocal tract differed between species, suggesting that the syringeal sound source is optimized for its position in the respiratory tract. These results provide compelling evidence that strong selective pressures for high vocal efficiency may have been a major driving force in the evolution of the syrinx. The longer trachea of birds compared to other tetrapods made them likely predisposed for the evolution of a syrinx. A long vocal tract downstream from the sound source improves efficiency by facilitating the tuning between fundamental frequency and the first vocal tract resonance.


Assuntos
Acústica , Estruturas Animais/fisiologia , Evolução Biológica , Modelos Biológicos , Animais , Aves/anatomia & histologia , Simulação por Computador , Laringe/fisiologia , Mamíferos/anatomia & histologia , Som , Traqueia/fisiologia , Vocalização Animal
20.
J Theor Biol ; 464: 104-111, 2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30593825

RESUMO

How can a water snail lock its door by an operculum? In this theoretical and experimental combined research, we revealed this by dissection, modeling and validation with a 3D printed technique. The operculum is a corneous or calcareous trapdoor-like sheet which attaches to the upper surface of the water snail's foot. It can plug the shell aperture by retracting the soft body when a predator or environmental threat is encountered. For a water snail (Pomacea canaliculata), the operculum can be locked in its shell rapidly. By optical microscope images, we found the operculum of P. canaliculata is a multilayered disk with a thicker center and thinner edge, which may be functionally influential for successful closing and opening the trapdoor. We filmed the locking in opercula of living snails, and designed an experiment to measure the deformation of opercula on the dead samples. We propose one mathematical model to describe the connections among geometry, sectionalized stiffness and the force for locking. By using 3D printing technique, we designed an operculum inspired locking mechanism to validate the theories we proposed. Under the same normal force, the water leakage rate of the bio-inspired structure can be reduced to 99% compared to the disk with uniform thickness. Our results reveal that the snail's operculum not only develops a light-weight trapdoor, but a locking mechanism which could serve as a valuable model for designing compliant locking mechanisms.


Assuntos
Estruturas Animais , Modelos Biológicos , Caramujos , Estruturas Animais/anatomia & histologia , Estruturas Animais/fisiologia , Animais , Caramujos/anatomia & histologia , Caramujos/fisiologia
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