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1.
Nat Commun ; 11(1): 4491, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901033

RESUMO

The functionality of the nervous system requires transmission of information along axons with high speed and precision. Conductance velocity depends on axonal diameter whereas signaling precision requires a block of electrical crosstalk between axons, known as ephaptic coupling. Here, we use the peripheral nervous system of Drosophila larvae to determine how glia regulates axonal properties. We show that wrapping glial differentiation depends on gap junctions and FGF-signaling. Abnormal glial differentiation affects axonal diameter and conductance velocity and causes mild behavioral phenotypes that can be rescued by a sphingosine-rich diet. Ablation of wrapping glia does not further impair axonal diameter and conductance velocity but causes a prominent locomotion phenotype that cannot be rescued by sphingosine. Moreover, optogenetically evoked locomotor patterns do not depend on conductance speed but require the presence of wrapping glial processes. In conclusion, our data indicate that wrapping glia modulates both speed and precision of neuronal signaling.


Assuntos
Drosophila melanogaster/fisiologia , Animais , Animais Geneticamente Modificados , Axônios/fisiologia , Diferenciação Celular , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Larva/citologia , Larva/fisiologia , Locomoção/fisiologia , Modelos Neurológicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Neuroglia/citologia , Neuroglia/fisiologia , Optogenética , Sistema Nervoso Periférico/citologia , Sistema Nervoso Periférico/fisiologia , Fenótipo , Receptores de Fatores de Crescimento de Fibroblastos/fisiologia , Transdução de Sinais
2.
Ecotoxicol Environ Saf ; 205: 111289, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32949839

RESUMO

The Deepwater Horizon oil spill released 3.19 million barrels of crude oil into the Gulf of Mexico, making it the largest oil spill in U.S. history. Weathering and the application of dispersants can alter the solubility of compounds within crude oil, thus modifying the acute toxicity of the crude oil to aquatic life. The primary aim of our study was to determine the lasting impact of early-life stage sheepshead minnow (Cyprinodon variegatus variegatus) exposure to weathered, unweathered and dispersed crude oil on prey capture, male aggression, novel object interaction and global DNA methylation. Embryos were exposed from 1 to 10 dpf to water accommodations of crude oil and were raised to adulthood in artificial seawater. Our results suggest exposure to crude oil did not result in lasting impairment of complex behavioral responses of male sheepshead minnow. Exposure to dispersed weathered oil, however, decreased border dwelling in response to a novel object (i.e. decreased anxiety). Principal component analysis revealed that exposure to weathered oil had no overarching effect, but that unweathered crude oil increased variability in exploratory behaviors but decreased variability in anxiety-associated behaviors. Further work is needed to understand the effects of oil exposure on fish behavior and the potential ecological impact of subtle behavioral changes in fishes.


Assuntos
Comportamento Animal/efeitos dos fármacos , Peixes Listrados/fisiologia , Larva/efeitos dos fármacos , Poluição por Petróleo/efeitos adversos , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Metilação de DNA/efeitos dos fármacos , Ecologia , Golfo do México , Peixes Listrados/genética , Larva/genética , Larva/fisiologia , Masculino , Água do Mar/química , Tempo (Meteorologia)
3.
PLoS Biol ; 18(9): e3000828, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32936797

RESUMO

Many herbivorous insects are mono- or oligophagous, having evolved to select a limited range of host plants. They specifically identify host-plant leaves using their keen sense of taste. Plant secondary metabolites and sugars are thought to be key chemical cues that enable insects to identify host plants and evaluate their quality as food. However, the neuronal and behavioral mechanisms of host-plant recognition are poorly understood. Here, we report a two-factor host acceptance system in larvae of the silkworm Bombyx mori, a specialist on several mulberry species. The first step is controlled by a chemosensory organ, the maxillary palp (MP). During palpation at the leaf edge, the MP detects trace amounts of leaf-surface compounds, which enables host-plant recognition without biting. Chemosensory neurons in the MP are tuned with ultrahigh sensitivity (thresholds of attomolar to femtomolar) to chlorogenic acid (CGA), quercetin glycosides, and ß-sitosterol (ßsito). Only if these 3 compounds are detected does the larva make a test bite, which is evaluated in the second step. Low-sensitivity neurons in another chemosensory organ, the maxillary galea (MG), mainly detect sucrose in the leaf sap exuded by test biting, allowing larvae to accept the leaf and proceed to persistent biting (feeding). The two-factor host acceptance system reported here may commonly underlie stereotyped feeding behavior in many phytophagous insects and determine their feeding habits.


Assuntos
Bombyx/fisiologia , Comportamento de Escolha , Dieta , Comportamento Alimentar/fisiologia , Larva/fisiologia , Papilas Gustativas/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Comportamento Animal/fisiologia , Bombyx/anatomia & histologia , Bombyx/crescimento & desenvolvimento , Células Quimiorreceptoras/fisiologia , Quimiotaxia/fisiologia , Sinais (Psicologia) , Comportamento Exploratório/fisiologia , Interações Hospedeiro-Parasita/fisiologia , Larva/anatomia & histologia , Larva/citologia , Morus/química , Folhas de Planta/química , Paladar/fisiologia , Papilas Gustativas/anatomia & histologia
4.
Bull Environ Contam Toxicol ; 105(3): 387-392, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32757041

RESUMO

Systematic studies on the impact of environmental pollution on the survival adaptability of amphibians are relatively few. In this study, Bufo raddei tadpoles from two places with totally different backgrounds of heavy metal pollution were chosen to explore the effects of heavy metal pollution on fitness and swimming performance of tadpoles, the physiological effects were investigated as well. The tadpoles at GS 25, GS 30 and GS 35 were collected randomly from the two study sites and were exposed to different environmental temperatures. The results showed that heavy metal enrichment and antioxidant levels were significantly higher in the tadpoles under long-term heavy metal stress. Meanwhile, heavy metal pollution affected the adaptability of tadpoles to environmental change and decreased the swimming performance of the tadpoles. Unexpected, the tadpoles from heavy metal-polluted area also showed some adaptive changes, mainly reflected in the increase in swimming endurance.


Assuntos
Larva/fisiologia , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bufonidae , Poluentes Ambientais , Poluição Ambiental , Larva/efeitos dos fármacos , Metais Pesados/análise , Natação
6.
PLoS One ; 15(8): e0236791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760094

RESUMO

In May 2010 the large white butterfly, Pieris brassicae L. (Lepidoptera: Pieridae), was discovered to have established in New Zealand. It is a Palearctic species that-due to its wide host plant range within the Brassicaceae-was regarded as a risk to New Zealand's native brassicas. New Zealand has 83 native species of Brassicaceae including 81 that are endemic, and many are threatened by both habitat loss and herbivory by other organisms. Initially a program was implemented to slow its spread, then an eradication attempt commenced in November 2012. The P. brassicae population was distributed over an area of approximately 100 km2 primarily in urban residential gardens. The eradication attempt involved promoting public engagement and reports of sightings, including offering a bounty for a two week period, systematically searching gardens for P. brassicae and its host plants, removing host plants, ground-based spraying of insecticide to kill eggs and larvae, searching for pupae, capturing adults with nets, and augmenting natural enemy populations. The attempt was supported by research that helped to progressively refine the eradication strategy and evaluate its performance. The last New Zealand detection of P. brassicae occurred on 16 December 2014, the eradication program ceased on 4 June 2016 and P. brassicae was officially declared eradicated from New Zealand on 22 November 2016, 6.5 years after it was first detected and 4 years after the eradication attempt commenced. This is the first species of butterfly ever to have been eradicated worldwide.


Assuntos
Brassicaceae/parasitologia , Borboletas/crescimento & desenvolvimento , Animais , Borboletas/fisiologia , Ecossistema , Herbivoria , Controle de Insetos , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Larva/fisiologia , Nova Zelândia , Óvulo/efeitos dos fármacos , Vespas/fisiologia
7.
PLoS One ; 15(8): e0237259, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760156

RESUMO

Spent mushroom substrate is made from the waste remaining after the harvest of mushrooms. Here, we evaluated the potential of five spent edible fungi (Auricularia cornea, Lentinus edodes, Pleurotus eryngii, P. citrinopileatus and P. ostreatus) substrates as feed sources for Tenebrio molitor larvae. Young larvae did not survive on any substrate except the spent L. edodes substrate (36.7%). The survival rates in young larvae were similar among the different diets in which wheat bran or rice bran was replaced with 0, 20, 30, 40, 50, or 60% spent L. edodes substrate. The weights of the surviving larvae were decreased only when 70% of wheat bran and > 40% of rice bran was replaced with spent L. edodes substrate. In addition, the middle-aged larvae fed wheat bran only were significantly larger than those fed diets with 30~60% spent L. edodes substrate in dry feed, but the larvae of all treatments failed to pupate. Whereas the green feed was added in dry feed, there were no significant differences in pupal weight, pupation rate, pupal duration, adult emergence, or deformed adults among the three treatments in middle-aged larvae that were fed on diets containing 0, 30, or 40% spent L. edodes substrate. Collectively, these results suggest that spent L. edodes substrate has considerable potential to be used as a partial replacement (< 40%) of conventional feed for T. molitor, and spent mushroom substrate waste may be recycled as feed material for resource insects.


Assuntos
Agaricales/metabolismo , Ração Animal , Tenebrio/fisiologia , Ração Animal/microbiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Larva/crescimento & desenvolvimento , Larva/fisiologia , Tenebrio/crescimento & desenvolvimento
8.
Nat Commun ; 11(1): 4171, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32820176

RESUMO

Spiralia is a large, ancient and diverse clade of animals, with a conserved early developmental program but diverse larval and adult morphologies. One trait shared by many spiralians is the presence of ciliary bands used for locomotion and feeding. To learn more about spiralian-specific traits we have examined the expression of 20 genes with protein motifs that are strongly conserved within the Spiralia, but not detectable outside of it. Here, we show that two of these are specifically expressed in the main ciliary band of the mollusc Tritia (also known as Ilyanassa). Their expression patterns in representative species from five more spiralian phyla-the annelids, nemerteans, phoronids, brachiopods and rotifers-show that at least one of these, lophotrochin, has a conserved and specific role in particular ciliated structures, most consistently in ciliary bands. These results highlight the potential importance of lineage-specific genes or protein motifs for understanding traits shared across ancient lineages.


Assuntos
Motivos de Aminoácidos/genética , Cílios/genética , Invertebrados/genética , Proteínas/genética , Animais , Anelídeos/classificação , Anelídeos/genética , Anelídeos/fisiologia , Evolução Biológica , Cílios/fisiologia , Comportamento Alimentar/fisiologia , Perfilação da Expressão Gênica/métodos , Invertebrados/classificação , Invertebrados/fisiologia , Larva/genética , Larva/fisiologia , Locomoção/fisiologia , Moluscos/classificação , Moluscos/genética , Moluscos/fisiologia , Filogenia , Especificidade da Espécie
9.
PLoS Comput Biol ; 16(8): e1008080, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745134

RESUMO

Neural computation is determined by neurons' dynamics and circuit connectivity. Uncertain and dynamic environments may require neural hardware to adapt to different computational tasks, each requiring different connectivity configurations. At the same time, connectivity is subject to a variety of constraints, placing limits on the possible computations a given neural circuit can perform. Here we examine the hypothesis that the organization of neural circuitry favors computational flexibility: that it makes many computational solutions available, given physiological constraints. From this hypothesis, we develop models of connectivity degree distributions based on constraints on a neuron's total synaptic weight. To test these models, we examine reconstructions of the mushroom bodies from the first instar larva and adult Drosophila melanogaster. We perform a Bayesian model comparison for two constraint models and a random wiring null model. Overall, we find that flexibility under a homeostatically fixed total synaptic weight describes Kenyon cell connectivity better than other models, suggesting a principle shaping the apparently random structure of Kenyon cell wiring. Furthermore, we find evidence that larval Kenyon cells are more flexible earlier in development, suggesting a mechanism whereby neural circuits begin as flexible systems that develop into specialized computational circuits.


Assuntos
Modelos Neurológicos , Rede Nervosa , Sinapses/fisiologia , Animais , Drosophila melanogaster , Larva/citologia , Larva/fisiologia , Corpos Pedunculados/citologia , Corpos Pedunculados/fisiologia , Rede Nervosa/citologia , Rede Nervosa/fisiologia , Neurônios/citologia , Neurônios/fisiologia
10.
PLoS Biol ; 18(7): e3000462, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32697779

RESUMO

Most fish swim with body undulations that result from fluid-structure interactions between the fish's internal tissues and the surrounding water. Gaining insight into these complex fluid-structure interactions is essential to understand how fish swim. To this end, we developed a dedicated experimental-numerical inverse dynamics approach to calculate the lateral bending moment distributions for a large-amplitude undulatory swimmer that moves freely in three-dimensional space. We combined automated motion tracking from multiple synchronised high-speed video sequences, computation of fluid dynamic stresses on the swimmer's body from computational fluid dynamics, and bending moment calculations using these stresses as input for a novel beam model of the body. The bending moment, which represent the system's net actuation, varies over time and along the fish's central axis due to muscle actions, passive tissues, inertia, and fluid dynamics. Our three-dimensional analysis of 113 swimming events of zebrafish larvae ranging in age from 3 to 12 days after fertilisation shows that these bending moment patterns are not only relatively simple but also strikingly similar throughout early development and from fast starts to periodic swimming. This suggests that fish larvae may produce and adjust swimming movements relatively simply, yet effectively, while restructuring their neuromuscular control system throughout their rapid development.


Assuntos
Análise Numérica Assistida por Computador , Natação/fisiologia , Peixe-Zebra/fisiologia , Animais , Fenômenos Biomecânicos , Fertilização , Larva/fisiologia , Modelos Biológicos , Movimento (Física) , Cauda
11.
Artigo em Inglês | MEDLINE | ID: mdl-32613481

RESUMO

Plutella xylostella, is the main pest infesting Brassica crops, and products based on Bacillus thuringiensis (Bt) are frequently used in strategies for its biocontrol. The present study aimed to evaluate whether a Bt-based bioinsecticide affects the predation behavior of Ceraeochrysa cincta when preying on P. xylostella. Three larval instars of the predator and the eggs and second-instar larvae of the moth were used, with the prey either untreated or treated with a Bt-based product (Xentari®). Results showed that, the first larval instar of C. cincta presented a type II functional response when preying upon untreated eggs, and a type III response when preying upon Bt-treated eggs, while the second and third instars presented type II and III responses, respectively, in both situations. The predator's first and third larval instars presented a type II functional response when preying upon untreated larvae and a type III response when preying upon Bt-treated larvae. However, the predator's second-instar larvae showed a type II response in both treatments. The results obtained allowed us to conclude that the Bt-based insecticide tested affects the predation behavior of the first-instar larvae of C. cincta on eggs and of both the first- and third-instar larvae of this predator on P. xylostella larvae.


Assuntos
Bacillus thuringiensis/química , Controle de Insetos , Insetos/fisiologia , Inseticidas/administração & dosagem , Controle Biológico de Vetores , Comportamento Predatório , Animais , Brasil , Insetos/efeitos dos fármacos , Resistência a Inseticidas , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Óvulo/efeitos dos fármacos , Óvulo/crescimento & desenvolvimento
12.
PLoS One ; 15(6): e0230222, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603332

RESUMO

Conservation efforts are increasingly being challenged by a rapidly changing environment, and for some aquatic species the use of captive rearing or selective breeding is an attractive option. However, captivity itself can impose unintended artificial selection known as domestication selection (adaptation to culture conditions) and is relatively understudied for most marine species. To test for domestication selection in marine bivalves, we focused on a fitness-related trait (larval starvation resistance) that could be altered under artificial selection. Using larvae produced from a wild population of Crassostrea virginica and a selectively bred, disease-resistant line we measured growth and survival during starvation versus standard algal diet conditions. Larvae from both lineages showed a remarkable resilience to food limitation, possibly mediated by an ability to utilize dissolved organic matter for somatic maintenance. Water chemistry analysis showed dissolved organic carbon in filtered tank water to be at concentrations similar to natural river water. We observed that survival in larvae produced from the aquaculture line was significantly lower compared to larvae produced from wild broodstock (8 ± 3% and 21 ± 2%, respectively) near the end of a 10-day period with no food (phytoplankton). All larval cohorts had arrested growth and depressed respiration during the starvation period and took at least two days to recover once food was reintroduced before resuming growth. Respiration rate recovered rapidly and final shell length was similar between the two treatments Phenotypic differences between the wild and aquaculture lines suggest potential differences in the capacity to sustain extended food limitation, but this work requires replication with multiple selection lines and wild populations to make more general inferences about domestication selection. With this contribution we explore the potential for domestication selection in bivalves, discuss the physiological and fitness implications of reduced starvation tolerance, and aim to inspire further research on the topic.


Assuntos
Crassostrea/fisiologia , Domesticação , Larva/fisiologia , Inanição/fisiopatologia , Animais , Carbono/metabolismo , Crassostrea/metabolismo , Larva/metabolismo , Nitrogênio/metabolismo , Respiração , Inanição/metabolismo
13.
Proc Biol Sci ; 287(1931): 20201273, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32693722

RESUMO

Many insects survive internal freezing, but the great complexity of freezing stress hinders progress in understanding the ultimate nature of freezing-induced injury. Here, we use larvae of the drosophilid fly, Chymomyza costata to assess the role of mitochondrial responses to freezing stress. Respiration analysis revealed that fat body mitochondria of the freeze-sensitive (non-diapause) phenotype significantly decrease oxygen consumption upon lethal freezing stress, while mitochondria of the freeze-tolerant (diapausing, cold-acclimated) phenotype do not lose respiratory capacity upon the same stress. Using transmission electron microscopy, we show that fat body and hindgut mitochondria swell, and occasionally burst, upon exposure of the freeze-sensitive phenotype to lethal freezing stress. By contrast, mitochondrial swelling is not observed in the freeze-tolerant phenotype exposed to the same stress. We hypothesize that mitochondrial swelling results from permeability transition of the inner mitochondrial membrane and loss of its barrier function, which causes osmotic influx of cytosolic water into the matrix. We therefore suggest that the phenotypic transition to diapause and cold acclimation could be associated with adaptive changes that include the protection of the inner mitochondrial membrane against permeability transition and subsequent mitochondrial swelling. Accumulation of high concentrations of proline and other cryoprotective substances might be a part of such adaptive changes as we have shown that freezing-induced mitochondrial swelling was abolished by feeding the freeze-sensitive phenotype larvae on a proline-augmented diet.


Assuntos
Congelamento , Insetos/fisiologia , Mitocôndrias , Aclimatação , Animais , Drosophilidae , Larva/fisiologia
14.
PLoS Biol ; 18(7): e3000712, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32663220

RESUMO

Tools enabling closed-loop experiments are crucial to delineate causal relationships between the activity of genetically labeled neurons and specific behaviors. We developed the Raspberry Pi Virtual Reality (PiVR) system to conduct closed-loop optogenetic stimulation of neural functions in unrestrained animals. PiVR is an experimental platform that operates at high temporal resolution (70 Hz) with low latencies (<30 milliseconds), while being affordable (

Assuntos
Comportamento Animal/fisiologia , Drosophila melanogaster/fisiologia , Optogenética , Córtex Sensório-Motor/fisiologia , Realidade Virtual , Animais , Quimiotaxia , Larva/fisiologia , Luz , Locomoção , Masculino , Neurônios/fisiologia , Odorantes , Sensação/fisiologia , Software , Paladar/fisiologia , Peixe-Zebra
15.
Proc Natl Acad Sci U S A ; 117(32): 19347-19358, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32723830

RESUMO

Bacterial intracellular symbiosis (endosymbiosis) is widespread in nature and impacts many biological processes. In holometabolous symbiotic insects, metamorphosis entails a complete and abrupt internal reorganization that creates a constraint for endosymbiont transmission from larvae to adults. To assess how endosymbiosis copes-and potentially evolves-throughout this major host-tissue reorganization, we used the association between the cereal weevil Sitophilus oryzae and the bacterium Sodalis pierantonius as a model system. S. pierantonius are contained inside specialized host cells, the bacteriocytes, that group into an organ, the bacteriome. Cereal weevils require metabolic inputs from their endosymbiont, particularly during adult cuticle synthesis, when endosymbiont load increases dramatically. By combining dual RNA-sequencing analyses and cell imaging, we show that the larval bacteriome dissociates at the onset of metamorphosis and releases bacteriocytes that undergo endosymbiosis-dependent transcriptomic changes affecting cell motility, cell adhesion, and cytoskeleton organization. Remarkably, bacteriocytes turn into spindle cells and migrate along the midgut epithelium, thereby conveying endosymbionts to midgut sites where future mesenteric caeca will develop. Concomitantly, endosymbiont genes encoding a type III secretion system and a flagellum apparatus are transiently up-regulated while endosymbionts infect putative stem cells and enter their nuclei. Infected cells then turn into new differentiated bacteriocytes and form multiple new bacteriomes in adults. These findings show that endosymbiosis reorganization in a holometabolous insect relies on a synchronized host-symbiont molecular and cellular "choreography" and illustrates an adaptive feature that promotes bacteriome multiplication to match increased metabolic requirements in emerging adults.


Assuntos
Enterobacteriaceae/fisiologia , Simbiose , Gorgulhos/crescimento & desenvolvimento , Gorgulhos/microbiologia , Animais , Fenômenos Fisiológicos Bacterianos , Evolução Biológica , Sistema Digestório/microbiologia , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/fisiologia , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Feminino , Larva/crescimento & desenvolvimento , Larva/microbiologia , Larva/fisiologia , Masculino , Metamorfose Biológica , Gorgulhos/fisiologia
16.
PLoS One ; 15(7): e0236174, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32722719

RESUMO

To escape or alleviate low temperatures in winter, insects have evolved many behavioral and physiological strategies. The purple stem borer, Sesamia inferens (Walker) is currently reported to be expanding their northern distributions and causing damage to summer maize in Xinxiang, China. However, their method of coping with the lower temperature in the new northern breeding area in winter is largely unknown. This paper investigates the overwinter site of S. inferens, and identifies the cold hardiness of larvae collected from a new breeding area in winter and explores a potential distribution based on low temperature threshold and on species distribution model MaxEnt. The results show that the overwintering location of the S. inferens population is more likely to be underground with increasing latitude and the population gradually moved down the corn stalk and drilled completely underground in later winter (February) in the north. The cold hardiness test shows the species is a moderate freeze-tolerant one, and Supercooling Points (SCP), Freezing Points (FP) and the incidence of mortality during the middle of winter (January, SCP: -7.653, FP: -6.596) were significantly lower than early winter (October) or late winter (March). Distribution in the new expansion area was predicted and the survival probability area was below N 35° for the Air Lower Lethal Temperature (ALLT50) and below N 40° for the Underground Lower Lethal Temperature (ULLT50). The suitable habitat areas for S. inferens with MaxEnt were also below N 40°. This study suggests the overwinter strategies of S. inferens have led to the colonization of up to a five degree more northerly overwintering latitude.


Assuntos
Aclimatação/fisiologia , Mariposas/fisiologia , Animais , Comportamento Animal , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Estações do Ano , Temperatura
17.
Nat Commun ; 11(1): 3608, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32681028

RESUMO

Invasive predators can exert strong selection on native populations. If selection is strong enough, populations could lose the phenotypic variation caused by adaptation to heterogeneous environments. We compare frog tadpoles prior to and 14 years following invasion by crayfish. Prior to the invasion, populations differed in their intrinsic developmental rate, with tadpoles from cold areas reaching metamorphosis sooner than those from warm areas. Following the invasion, tadpoles from invaded populations develop faster than those from non-invaded populations. This ontogenetic shift overwhelmed the intraspecific variation between populations in a few generations, to the point where invaded populations develop at a similar rate regardless of climate. Rapid development can have costs, as fast-developing froglets have a smaller body size and poorer jumping performance, but compensatory growth counteracts some costs of development acceleration. Strong selection by invasive species can disrupt local adaptations by dampening intraspecific phenotypic variation, with complex consequences on lifetime fitness.


Assuntos
Espécies Introduzidas , Larva/fisiologia , Aclimatação , Adaptação Fisiológica , Animais , Anuros/classificação , Anuros/crescimento & desenvolvimento , Anuros/fisiologia , Astacoidea/fisiologia , Tamanho Corporal , Clima , Larva/classificação , Larva/crescimento & desenvolvimento
18.
PLoS One ; 15(6): e0234605, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555587

RESUMO

Fisheries and aquaculture industries worldwide remain reliant on seed supply from wild populations, with their success and sustainability dependent on consistent larval recruitment. Larval dispersal and recruitment in the marine environment are complex processes, influenced by a multitude of physical and biological factors. Biophysical modelling has increasingly been used to investigate dispersal and recruitment dynamics, for optimising management of fisheries and aquaculture resources. In the Fiji Islands, culture of the black-lip pearl oyster (Pinctada margaritifera) is almost exclusively reliant on wild-caught juvenile oysters (spat), through a national spat collection programme. This study used a simple Lagrangian particle dispersal model to investigate current-driven larval dispersal patterns, identify potential larval settlement areas and compare simulated with physical spat-fall, to inform targeted spat collection efforts. Simulations successfully identified country-wide patterns of potential larval dispersal and settlement from 2012-2015, with east-west variations between bi-annual spawning peaks and circulation associated with El Niño Southern Oscillation. Localised regions of larval aggregation were also identified and compared to physical spat-fall recorded at 28 spat collector deployment locations. Significant and positive correlations at these sites across three separate spawning seasons (r(26) = 0.435; r(26) = 0.438; r(26) = 0.428 respectively, p = 0.02), suggest high utility of the model despite its simplicity, for informing future spat collector deployment. Simulation results will further optimise black-lip pearl oyster spat collection activity in Fiji by informing targeted collector deployments, while the model provides a versatile and highly informative toolset for the fishery management and aquaculture of other marine taxa with similar life histories.


Assuntos
Distribuição Animal , Aquicultura/métodos , Pinctada/fisiologia , Animais , Fiji , Larva/fisiologia
19.
PLoS One ; 15(6): e0234572, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555588

RESUMO

The Asian mosquito, Aedes albopictus (Skuse), is an invasive mosquito which has become one of the most important vectors of dengue, Zika, and chikungunya viruses worldwide. This species was reported for the first time in Cameroon in early 2000s and became the dominant Aedes species in the urban areas in the southern part of Cameroon but remain poorly characterized. Here, we assessed the susceptibility profile of A. albopictus collected throughout Cameroon and investigated the potential resistance mechanisms involved. Immature stages of A. albopictus were collected between March and July 2017 in 15 locations across Cameroon and reared until G1/G2 generation. Larval, adult bioassays, and synergists [piperonyl butoxide (PBO) and diethyl maleate (DEM)] assays were carried out according to WHO recommendations. F1534C mutation was genotyped in field collected adults (Go) using allele specific PCR. All tested populations were susceptible to both larvicides, temephos and Bacillus thuringiensis israelensis (Bti), after larval bioassays. Adult bioassays revealed a high level of resistance of A. albopictus to 4% DDT with mortality rates ranging from 12.42% in Bafang to 75.04% in Kumba. The resistance was reported also in 0.05% deltamethrin, 0.25% permethrin, and 0.1% propoxur in some locations. A loss of susceptibility to 0.1% bendiocarb was found in one of three populations analysed. A full susceptibility to 1% fenitrothion were observed across the country. A full recovery or partial of susceptibility was observed in A. albopictus when pre-exposed to PBO or DEM and then to DDT and permethrin, respectively. The F1534C kdr mutation was not detected in A. albopictus. This study showed that the susceptibility profile of A. albopictus to insecticide vary according to the sampling location and insecticides used. These findings are useful to planning vector control program against arbovirus vectors in Cameroon and can be used as baseline data for further researches.


Assuntos
Aedes/fisiologia , Resistência a Inseticidas/efeitos dos fármacos , Inseticidas/farmacologia , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Doenças Transmitidas por Vetores/transmissão , Animais , Camarões , Larva/fisiologia
20.
PLoS One ; 15(6): e0234637, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555675

RESUMO

The drastic decline of bees is associated with several factors, including the immune system suppression due to the increased exposure to pesticides. A widely used method to evaluate these effects on these insects' immune systems is the counting of circulating hemocytes in the hemolymph. However, the extraction of hemolymph from larvae is quite difficult, and the collected material is frequently contaminated with other tissues and gastrointestinal fluids, which complicates counting. Therefore, the present work established a high quality and easily reproducible method of extracting hemolymph from honeybee larvae (Apis mellifera), the extraction with ophthalmic scissors. Extraction methods with the following tools also were tested: 30G needle, fine-tipped forceps, hypodermic syringe, and capillaries tubes. The hemolymph was obtained via an incision on the larvae's right side for all methods, except for the extraction with ophthalmic scissors, in which the hemolymph was extracted from the head region. To assess the purity of the collected material, turbidity analyses of the samples using a turbidimeter were proposed, tested, and evaluated. The results showed that the use of ophthalmic scissors provided the clearest samples and was free from contamination. A reference range between 22,432.35 and 24,504.87 NTU (nephelometric turbidity units) was established, in which the collected samples may be considered of high quality and free from contamination.


Assuntos
Abelhas/fisiologia , Hemolinfa/citologia , Manejo de Espécimes/instrumentação , Animais , Larva/fisiologia , Manejo de Espécimes/métodos , Instrumentos Cirúrgicos
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