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1.
PLoS One ; 15(12): e0243937, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33332425

RESUMO

Translocated captive-bred predators are less skilled at hunting than wild-born predators and more prone to starvation post-release. Foraging in an unfamiliar environment presents many further risks to translocated animals. Knowledge of the diet and foraging behaviour of translocated animals is therefore an important consideration of reintroductions. We investigated the diet of the endangered meso-predator, the eastern quoll Dasyurus viverrinus. We also opportunistically observed foraging behaviour, enabling us to examine risks associated with foraging. Sixty captive-bred eastern quolls were reintroduced to an unfenced reserve on mainland Australia (where introduced predators are managed) over a two year period (2018, 2019). Quolls were supplementary fed macropod meat but were also able to forage freely. Dietary analysis of scats (n = 56) revealed that quolls ate macropods, small mammals, birds, invertebrates, fish, reptiles and frogs, with some between-year differences in the frequency of different diet categories. We also observed quolls hunting live prey. Quolls utilised supplementary feeding stations, indicating that this may be an important strategy during the establishment phase. Our study demonstrated that, in a novel environment, captive-bred quolls were able to locate food and hunt live prey. However, foraging was not without risks; with the ingestion of toxic substances and foraging in dangerous environments found to be potentially harmful. Knowledge of the diet of reintroduced fauna in natural landscapes is important for understanding foraging behaviour and evaluating habitat suitability for future translocations and management.


Assuntos
Comportamento Animal/fisiologia , Comportamento Alimentar/fisiologia , Marsupiais/fisiologia , Animais , Anuros/fisiologia , Austrália , Ecossistema , Carne , Comportamento Predatório/fisiologia
2.
PLoS One ; 15(9): e0237374, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877404

RESUMO

Large predators play important ecological roles, yet many are disproportionately imperiled. In marine systems, artificial reefs are often deployed to restore degraded reefs or supplement existing reefs, but it remains unknown whether these interventions benefit large predators. Comparative field surveys of thirty artificial and natural reefs across ~200 km of the North Carolina, USA coast revealed large reef-associated predators were more dense on artificial than natural reefs. This pattern was associated with higher densities of transient predators (e.g. jacks, mackerel, barracuda, sharks) on artificial reefs, but not of resident predators (e.g., grouper, snapper). Further analyses revealed that this pattern of higher transient predator densities on artificial reefs related to reef morphology, as artificial reefs composed of ships hosted higher transient predator densities than concrete reefs. The strength of the positive association between artificial reefs and transient predators increased with a fundamental habitat trait-vertical extent. Taller artificial reefs had higher densities of transient predators, even when accounting for habitat area. A global literature review of high trophic level fishes on artificial and natural habitats suggests that the overall pattern of more predators on artificial habitats is generalizable. Together, these findings provide evidence that artificial habitats, especially those like sunken ships that provide high vertical structure, may support large predators.


Assuntos
Recifes de Corais , Comportamento Predatório/fisiologia , Animais , Peixes/fisiologia , Geografia , Estados Unidos
3.
PLoS Biol ; 18(9): e3000818, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32960897

RESUMO

Humans profoundly impact landscapes, ecosystems, and animal behavior. In many cases, animals living near humans become tolerant of them and reduce antipredator responses. Yet, we still lack an understanding of the underlying evolutionary dynamics behind these shifts in traits that affect animal survival. Here, we used a phylogenetic meta-analysis to determine how the mean and variability in antipredator responses change as a function of the number of generations spent in contact with humans under 3 different contexts: urbanization, captivity, and domestication. We found that any contact with humans leads to a rapid reduction in mean antipredator responses as expected. Notably, the variance among individuals over time observed a short-term increase followed by a gradual decrease, significant for domesticated animals. This implies that intense human contact immediately releases animals from predation pressure and then imposes strong anthropogenic selection on traits. In addition, our results reveal that the loss of antipredator traits due to urbanization is similar to that of domestication but occurs 3 times more slowly. Furthermore, the rapid disappearance of antipredator traits was associated with 2 main life-history traits: foraging guild and whether the species was solitary or gregarious (i.e., group-living). For domesticated animals, this decrease in antipredator behavior was stronger for herbivores than for omnivores or carnivores and for solitary than for gregarious species. By contrast, the decrease in antipredator traits was stronger for gregarious, urbanized species, although this result is based mostly on birds. Our study offers 2 major insights on evolution in the Anthropocene: (1) changes in traits occur rapidly even under unintentional human "interventions" (i.e., urbanization) and (2) there are similarities between the selection pressures exerted by domestication and by urbanization. In all, such changes could affect animal survival in a predator-rich world, but through understanding evolutionary dynamics, we can better predict when and how exposure to humans modify these fitness-related traits.


Assuntos
Comportamento Animal/fisiologia , Evolução Biológica , Carnívoros/fisiologia , Atividades Humanas , Comportamento Predatório/fisiologia , Animais , Carnívoros/classificação , Domesticação , Ecossistema , Atividades Humanas/tendências , Humanos , Traços de História de Vida , Fenótipo , Urbanização/tendências
4.
PLoS One ; 15(9): e0228367, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32976485

RESUMO

The Zigzag ladybird beetle, Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae), is a biological control agent that feeds on a variety of aphid species. Life table and predation data of C. sexmaculata were collected under laboratory conditions at 25±2°C, 60±5% RH and L14: D10 h in connection with feeding on four different aphid species; Lipaphis erysimi (Kaltenbach), Myzus persicae (Sulzer), Aphis nerii (Boyer de Fonscolombe) and Diuraphis noxia (Mordvilko). Larval development of C. sexmaculata was long when fed on M. persicae (12.18 days) and shorter on D. noxia (10.64 days). The male's lifespan was longer on M. persicae (26.70 days) and shorter on L. erysimi (23.67 days). Fecundity was maximum when the beetle was fed D. noxia (316.8 eggs/female) and minimum on M. persicae (199.1 eggs/female). Net reproductive rate, intrinsic rate of increase and finite rate of increase were highest on D. noxia with values of 158.4 (offspring individual-1), 0.22 d-1, and 1.24 d-1, respectively whereas the respective parameters were lowest on L. erysimi (99.5 offspring individual-1, 0.19 d-1, and 1.20 d-1, respectively). However, the mean of the generation (T) was shorter on A. nerii (22.48 d-1) and longer on M. persicae (24.68 d-1). Based on life table parameters obtained under laboratory conditions, the most appropriate host of C. sexmaculata was D. noxia. This study should help us to improve mass rearing and use of C. sexmaculata in the biological control of aphids on field and horticultural crops.


Assuntos
Afídeos/parasitologia , Besouros/fisiologia , Controle Biológico de Vetores/métodos , Comportamento Predatório/fisiologia , Animais , Afídeos/fisiologia , Feminino , Fertilidade/fisiologia , Larva , Tábuas de Vida , Longevidade/fisiologia , Masculino , Paquistão
5.
PLoS One ; 15(8): e0233627, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804928

RESUMO

We studied avian development in 49 to 153 species of temperate and tropical New World passerine birds to determine how growth rates, and incubation and nestling periods, varied in relation to other life-history traits. We collected growth data and generated unbiased mass and tarsus growth rate estimates (mass n = 92 species, tarsus n = 49 species), and measured incubation period (n = 151) and nestling period (n = 153), which we analyzed with respect to region, egg mass, adult mass, clutch size, parental care type, nest type, daily nest predation rate (DMR), and nest height. We investigated covariation of life-history and natural-history attributes with the four development traits after controlling for phylogeny. Species in our lowland tropical sample grew 20% (incubation period), 25% (mass growth rate), and 26% (tarsus growth rate) more slowly than in our temperate sample. Nestling period did not vary with respect to latitude, which suggests that tropical songbirds fledge in a less well-developed state than temperate species. Suboscine species typically exhibited slower embryonic and post-embryonic growth than oscine passerines regardless of their breeding region. This pattern of slow development in tropical species could reflect phylogenetic effects based on unknown physiological attributes. Time-dependent nest mortality was unrelated to nestling mass growth rate, tarsus growth rate, and incubation period, but was significantly associated with nestling period. This suggests that nest predation, the predominant cause of nest loss in songbirds, does not exert strong selection on physiologically constrained traits, such as embryonic and post-embryonic growth, among our samples of temperate and lowland tropical songbird species. Nestling period, which is evolutionarily more labile than growth rate, was significantly shorter in birds exposed to higher rates of nest loss and nesting at lower heights, among other traits. Differences in life-history variation across latitudes provide insight into how unique ecological characteristics of each region influence physiological processes of passerines, and thus, how they can shape the evolution of life histories. While development traits clearly vary with respect to latitude, trait distributions overlap broadly. Life-history and natural history associations differ for each development trait, which suggests that unique selective pressures or constraints influence the evolution of each trait.


Assuntos
Aves Canoras/crescimento & desenvolvimento , Animais , Evolução Biológica , Clima , Tamanho da Ninhada , Análise Discriminante , Ecossistema , Feminino , Traços de História de Vida , Modelos Lineares , Masculino , Michigan , Modelos Biológicos , Comportamento de Nidação/fisiologia , Oregon , Panamá , Filogenia , Comportamento Predatório/fisiologia , Reprodução/fisiologia , Seleção Genética , Aves Canoras/classificação , Aves Canoras/fisiologia , Especificidade da Espécie , Tarso Animal/crescimento & desenvolvimento , Clima Tropical
6.
PLoS One ; 15(8): e0236249, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804964

RESUMO

BACKGROUND: The insect predator Coccinella septempunctata can effectively control many types of pests, such as aphids, whiteflies, and small lepidopteran larvae. We previously found that C. septempunctata fed an artificial diet showed diminished biological properties(e.g. fecundity, egg hatching rate, survival rate, etc.) compared with those fed natural prey (Aphis craccivora), likely due to different nutritional characteristics of the diet. In this study, we used transcriptome sequencing analysis to identify nutrition- and metabolism-related genes of C. septempunctata that were differentially expressed depending on diet. METHODOLOGY/PRINCIPAL FINDINGS: The Illumina HiSeq2000 was used to sequence 691,942,058 total clean reads from artificial diet-fed and A. craccivora-fed C. septempunctata libraries, and the clean reads were assembled using Trinity de novo software (Tabel 2). Comparison of transcriptome sequences revealed that expression of 38,315 genes was affected by the artificial diet, and 1,182 of these genes showed a significant change in expression levels (FDR ≤ 0.05,|log2FC|≥1, "FC" stands for "fold change"). These differentially expressed genes (DEGs) were likely associated with the decreased egg laying capacity, hatching rate, longevity, and increased sex ratio (♀:♂) of adult C. septempunctata observed in the group fed the artificial diet. Furthermore, in the most DEGs metabolic pathways for C. septempunctata feeding on the artificial diet accumulated amino acid metabolic pathways, lipid metabolic pathways, and starch and glucose metabolism were down-regulated. CONCLUSIONS/SIGNIFICANCE: We found some differentially expressed genes and metabolic pathways are related to nutrition, from which a more informative feedback for diet formulation was obtained and the artificial diet could be more efficiently optimized.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal/genética , Afídeos , Besouros/fisiologia , Genes de Insetos , Comportamento Predatório/fisiologia , Aminoácidos/metabolismo , Animais , Regulação para Baixo , Fertilidade/fisiologia , Perfilação da Expressão Gênica , Glucose/metabolismo , Metabolismo dos Lipídeos/genética , Longevidade/fisiologia , Redes e Vias Metabólicas/genética , Controle Biológico de Vetores/métodos , Razão de Masculinidade , Amido/metabolismo , Sequenciamento Completo do Exoma
7.
PLoS One ; 15(7): e0236489, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32726365

RESUMO

Ground-nesting birds face many challenges to reproduce successfully, with nest predation being the main cause of reproductive failure. Visual predators such as corvids and egg-eating raptors, are among the most common causes of nest failure; thus, parental strategies that reduce the risk of visual nest predation should be favored by selection. To date, most research has focused on egg crypsis without considering adult crypsis, although in natural circumstances the eggs are covered by an incubating parent most of the time. Here we use a ground-nesting shorebird, the Kentish plover (Charadrius alexandrinus) as model species to experimentally test whether decoy parents influence nest predation. Using artificial nests with a male decoy, a female decoy or no decoy, we found that the presence of a decoy increased nest predation (N = 107 nests, p < 0.001). However, no difference was found in predation rates between nests with a male versus female decoy (p > 0.05). Additionally, we found that nests in densely vegetated habitats experienced higher survival compared to nests placed in sparsely vegetated habitats. Nest camera images, predator tracks and marks left on eggs identified the brown-necked raven (Corvus ruficollis) as the main visual nest predator. Our study suggests that the presence of incubating parents may enhance nest detectability to visual predators. However, parents may reduce the predation risk by placing a nest in sites where they are covered by vegetation. Our findings highlight the importance of nest site selection not only regarding egg crypsis but also considering incubating adult camouflage.


Assuntos
Aves/fisiologia , Comportamento de Nidação/fisiologia , Reprodução/fisiologia , Animais , Ecossistema , Feminino , Óvulo/fisiologia , Densidade Demográfica , Comportamento Predatório/fisiologia , Cimentos de Resina/química
8.
PLoS One ; 15(7): e0235312, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32663204

RESUMO

Wild boar are considered one the world's worst invasive species and linked to biodiversity loss, competition for resources, predation of native species, and habitat modifications. In this study, we use camera traps to evaluate whether the invasive wild boar had an effect on the medium-sized mammal community of a protected area in southern Brazil. Based on photographic records, we evaluated whether the presence and relative abundance of wild boar was associated with a decrease in diversity or change in activity of medium-sized mammals. All comparisons were made between samples where wild boar were present or absent. The records of each camera during a season were considered a sample. The wild boar was the fourth most common species in the study area being present in 7.8% of the photographic records. The species richness of mammals was not negatively affected by the occurrence of wild boar and most common species did not exhibit changes in the daily activity pattern. However, we recorded an increase in the time elapsed between an observation of wild boar and the record of the next species relative to the average latency period observed among other mammalian species. This average latency period was similar to that observed in the case of large predators such as Puma, and its increase could be reflective partly of the avoidance of native species to wild boar. Nevertheless, our results show that the effect of invasive wild boar on the mammal community is not large as expected.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Espécies Introduzidas , Sus scrofa/fisiologia , Animais , Brasil , Ecossistema , Mamíferos , Comportamento Predatório/fisiologia , Suínos/fisiologia
9.
Proc Biol Sci ; 287(1931): 20200970, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32673558

RESUMO

Ocean warming impacts the fitness of marine ectothermic species, leading to poleward range shifts, re-shuffling of communities, and changes in ecosystem services. While the detrimental effects of summer heat waves have been widely studied, little is known about the impacts of winter warming on marine species in temperate regions. Many species benefit from low winter temperature-induced reductions in metabolism, as these permit conservation of energy reserves that are needed to support reproduction in spring. Here, we used a unique outdoor mesocosm system to expose a coastal predator-prey system, the sea star Asterias and the blue mussel Mytilus, to different winter warming scenarios under near-natural conditions. We found that the body condition of mussels decreased in a linear fashion with increasing temperature. Sea star growth also decreased with increasing temperature, which was a function of unaltered predation rates and decreased mussel body condition. Asterias relative digestive gland mass strongly declined over the studied temperature interval (ca twofold). This could have severe implications for reproductive capacity in the following spring, as digestive glands provide reserve compounds to maturing gonads. Thus, both predator and prey suffered from a mismatch of energy acquisition versus consumption in warmer winter scenarios, with pronounced consequences for food web energy transfer in future oceans.


Assuntos
Bivalves/fisiologia , Mudança Climática , Comportamento Predatório/fisiologia , Água do Mar/química , Estrelas-do-Mar/fisiologia , Animais , Ecossistema , Cadeia Alimentar , Oceanos e Mares , Estações do Ano , Inanição , Temperatura
10.
Sci Rep ; 10(1): 9462, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32528013

RESUMO

The asymmetric mandibles of termites are hypothetically more efficient, rapid, and powerful than the symmetric mandibles of snap-jaw ants or termites. We investigated the velocity, force, precision, and defensive performance of the asymmetric mandibular snaps of a termite species, Pericapritermes nitobei. Ultrahigh-speed recordings of termites revealed a new record in biological movement, with a peak linear velocity of 89.7-132.4 m/s within 8.68 µs after snapping, which caused an impact force of 105.8-156.2 mN. High-speed video recordings of ball-strike experiments on termites were analysed using the principle of energy conservation; the left mandibles precisely hit metal balls at the left-to-front side with a maximum linear velocity of 80.3 ± 15.9 m/s (44.0-107.7 m/s) and an impact force of 94.7 ± 18.8 mN (51.9-127.1 mN). In experimental fights between termites and ant predators, Pe. nitobei killed 90-100% of the generalist ants with a single snap and was less likely to harm specialist ponerine ants. Compared with other forms, the asymmetric snapping mandibles of Pe. nitobei required less elastic energy to achieve high velocity. Moreover, the ability of P. nitobei to strike its target at the front side is advantageous for defence in tunnels.


Assuntos
Formigas/fisiologia , Isópteros/fisiologia , Mandíbula/fisiologia , Animais , Fenômenos Biomecânicos/fisiologia , Comportamento Predatório/fisiologia
11.
PLoS One ; 15(5): e0229055, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32396558

RESUMO

Camera traps are a unique survey tool used to monitor a wide variety of mammal species. Camera trap (CT) data can be used to estimate animal distribution, density, and behaviour. Attractants, such as scent lures, are often used in an effort to increase CT detections; however, the degree which the effects of attractants vary across species is not well understood. We investigated the effects of scent lure on mammal detections by comparing detection rates between 404 lured and 440 unlured CT stations sampled in Alberta, Canada over 120 day survey periods between February and August in 2015 and 2016. We used zero-inflated negative binomial generalized linear mixed models to test the effect of lure on detection rates for a) all mammals, b) six functional groups (all predator species, all prey, large carnivores, small carnivores, small mammals, ungulates), and c) four varied species of management interest (fisher, Pekania pennanti; gray wolf, Canis lupus; moose, Alces alces; and Richardson's ground squirrel; Urocitellus richardsonii). Mammals were detected at 800 of the 844 CTs, with nearly equal numbers of total detections at CTs with (7110) and without (7530) lure, and variable effects of lure on groups and individual species. Scent lure significantly increased detections of predators as a group, including large and small carnivore sub-groups and fisher specifically, but not of gray wolf. There was no effect of scent lure on detections of prey species, including the small mammal and ungulate sub-groups and moose and Richardson's ground squirrel specifically. We recommend that researchers explicitly consider the variable effects of scent lure on CT detections across species when designing, interpreting, or comparing multi-species surveys. Additional research is needed to further quantify variation in species responses to scent lures and other attractants, and to elucidate the effect of attractants on community-level inferences from camera trap surveys.


Assuntos
Carnívoros/fisiologia , Odorantes , Comportamento Predatório/fisiologia , Lobos/fisiologia , Alberta , Distribuição Animal/fisiologia , Animais , Cervos/fisiologia , Humanos , Feromônios/química , Gravação em Vídeo
12.
Neuron ; 107(2): 320-337.e6, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32473094

RESUMO

In the eye, the function of same-type photoreceptors must be regionally adjusted to process a highly asymmetrical natural visual world. Here, we show that UV cones in the larval zebrafish area temporalis are specifically tuned for UV-bright prey capture in their upper frontal visual field, which may use the signal from a single cone at a time. For this, UV-photon detection probability is regionally boosted more than 10-fold. Next, in vivo two-photon imaging, transcriptomics, and computational modeling reveal that these cones use an elevated baseline of synaptic calcium to facilitate the encoding of bright objects, which in turn results from expressional tuning of phototransduction genes. Moreover, the light-driven synaptic calcium signal is regionally slowed by interactions with horizontal cells and later accentuated at the level of glutamate release driving retinal networks. These regional differences tally with variations between peripheral and foveal cones in primates and hint at a common mechanistic origin.


Assuntos
Células Fotorreceptoras de Vertebrados/fisiologia , Comportamento Predatório/fisiologia , Células Fotorreceptoras Retinianas Cones/fisiologia , Peixe-Zebra/fisiologia , Animais , Sinalização do Cálcio , Simulação por Computador , Ácido Glutâmico/metabolismo , Larva , Luz , Transdução de Sinal Luminoso , Células Horizontais da Retina/fisiologia , Sinapses/fisiologia , Transcriptoma , Raios Ultravioleta , Campos Visuais
13.
Sci Rep ; 10(1): 7861, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398794

RESUMO

Both close inbreeding and extreme outbreeding may negatively affect direct fitness. Optimal outbreeding theory suggests that females should preferentially mate with distantly related males. (K)in breeding theory suggests that, at similar direct fitness costs of close inbreeding and extreme outbreeding, females should prefer close kin to non-kin. Empirical evidence of plastic female choice for an optimal balance between close inbreeding and extreme outbreeding remains elusive. We tested the combined predictions of optimal outbreeding and (k)in breeding theories in predatory mites Phytoseiulus persimilis from two origins, Sicily and Greece, which suffer from both close inbreeding and extreme outbreeding depression. In three separate experiments, virgin females were presented binary choices between familiar and unfamiliar brothers, and between familiar/unfamiliar brothers and distant kin or non-kin. Females of Greece but not Sicily preferred unfamiliar to familiar brothers. Females of both origins preferred distant kin to unfamiliar and familiar brothers but preferred unfamiliar brothers to non-kin. Females of Sicily but not Greece preferred familiar brothers to non-kin. The suggested kin recognition mechanisms are phenotype matching and direct familiarity, with finer-tuned recognition abilities of Greece females. Overall, our experiments suggest that flexible mate choice by P. persimilis females allows optimally balancing inclusive fitness trade-offs.


Assuntos
Ácaros/fisiologia , Comportamento Sexual Animal/fisiologia , Comportamento Social , Acrilatos , Animais , Cruzamento , Feminino , Grécia , Endogamia , Masculino , Ácaros/classificação , Plásticos , Comportamento Predatório/fisiologia , Reprodução/fisiologia , Sicília
14.
Proc Natl Acad Sci U S A ; 117(23): 12885-12890, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32457164

RESUMO

Camouflage patterns prevent detection and/or recognition by matching the background, disrupting edges, or mimicking particular background features. In variable habitats, however, a single pattern cannot match all available sites all of the time, and efficacy may therefore be reduced. Active color change provides an alternative where coloration can be altered to match local conditions, but again efficacy may be limited by the speed of change and range of patterns available. Transparency, on the other hand, creates high-fidelity camouflage that changes instantaneously to match any substrate but is potentially compromised in terrestrial environments where image distortion may be more obvious than in water. Glass frogs are one example of terrestrial transparency and are well known for their transparent ventral skin through which their bones, intestines, and beating hearts can be seen. However, sparse dorsal pigmentation means that these frogs are better described as translucent. To investigate whether this imperfect transparency acts as camouflage, we used in situ behavioral trials, visual modeling, and laboratory psychophysics. We found that the perceived luminance of the frogs changed depending on the immediate background, lowering detectability and increasing survival when compared to opaque frogs. Moreover, this change was greatest for the legs, which surround the body at rest and create a diffuse transition from background to frog luminance rather than a sharp, highly salient edge. This passive change in luminance, without significant modification of hue, suggests a camouflage strategy, "edge diffusion," distinct from both transparency and active color change.


Assuntos
Adaptação Biológica/fisiologia , Anuros/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Pigmentação da Pele/fisiologia , Animais , Cor , Simulação por Computador , Ecossistema , Furões/fisiologia , Humanos , Modelos Biológicos , Comportamento Predatório/fisiologia
15.
Sci Rep ; 10(1): 6780, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32321937

RESUMO

In a warming ocean, temperature variability imposes intensified peak stress, but offers periods of stress release. While field observations on organismic responses to heatwaves are emerging, experimental evidence is rare and almost lacking for shorter-scale environmental variability. For two major invertebrate predators, we simulated sinusoidal temperature variability (±3 °C) around todays' warm summer temperatures and around a future warming scenario (+4 °C) over two months, based on high-resolution 15-year temperature data that allowed implementation of realistic seasonal temperature shifts peaking midpoint. Warming decreased sea stars' (Asterias rubens) energy uptake (Mytilus edulis consumption) and overall growth. Variability around the warming scenario imposed additional stress onto Asterias leading to an earlier collapse in feeding under sinusoidal fluctuations. High-peak temperatures prevented feeding, which was not compensated during phases of stress release (low-temperature peaks). In contrast, increased temperatures increased feeding on Mytilus but not growth rates of the recent invader Hemigrapsus takanoi, irrespective of the scale at which temperature variability was imposed. This study highlights species-specific impacts of warming and identifies temperature variability at the scale of days to weeks/months as important driver of thermal responses. When species' thermal limits are exceeded, temperature variability represents an additional source of stress as seen from future warming scenarios.


Assuntos
Asterias/fisiologia , Aquecimento Global , Invertebrados/fisiologia , Mytilus edulis/fisiologia , Temperatura , Aclimatação/fisiologia , Animais , Braquiúros/fisiologia , Mudança Climática , Ecossistema , Invertebrados/classificação , Comportamento Predatório/fisiologia , Estações do Ano , Água do Mar , Especificidade da Espécie
16.
Mol Phylogenet Evol ; 149: 106839, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32325195

RESUMO

Alveolates are a major supergroup of eukaryotes encompassing more than ten thousand free-living and parasitic species, including medically, ecologically, and economically important apicomplexans, dinoflagellates, and ciliates. These three groups are among the most widespread eukaryotes on Earth, and their environmental success can be linked to unique innovations that emerged early in each group. Understanding the emergence of these well-studied and diverse groups and their innovations has relied heavily on the discovery and characterization of early-branching relatives, which allow ancestral states to be inferred with much greater confidence. Here we report the phylogenomic analyses of 313 eukaryote protein-coding genes from transcriptomes of three members of one such group, the colponemids (Colponemidia), which support their monophyly and position as the sister lineage to all other known alveolates. Colponemid-related sequences from environmental surveys and our microscopical observations show that colponemids are not common in nature, but they are diverse and widespread in freshwater habitats around the world. Studied colponemids possess two types of extrusive organelles (trichocysts or toxicysts) for active hunting of other unicellular eukaryotes and potentially play an important role in microbial food webs. Colponemids have generally plesiomorphic morphology and illustrate the ancestral state of Alveolata. We further discuss their importance in understanding the evolution of alveolates and the origin of myzocytosis and plastids.


Assuntos
Alveolados/classificação , Comportamento Predatório/fisiologia , Alveolados/genética , Alveolados/ultraestrutura , Animais , Biodiversidade , Geografia , Filogenia , Subunidades Ribossômicas Menores/genética
17.
J Morphol ; 281(6): 653-661, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32333693

RESUMO

The expression of inducible morphological defenses in Daphnia in response to a single predator is a well-known phenomenon. However, predator-specific modifications of the same defensive traits as an adaption to different predator regimes is so far only described for Daphnia barbata. It is unknown if this accounts only for this species or if it is a more widespread, general adaptive response in the genus Daphnia. In the present study, we therefore investigated whether a clone of the pond-dwelling species Daphnia similis responds to different predatory invertebrates (Triops cancriformis; Notonecta maculata) with the expression of predator-specific modifications of the same defensive traits. We showed that Triops-exposed individuals express a significantly longer tail-spine, while body width decreased in comparison to control individuals. Additionally, they also expressed inconspicuous defenses, that is, significantly longer spinules on the dorsal ridge. The Notonecta-exposed D. similis showed a significantly longer tail-spine, longer spinules and a larger spinules bearing area on the dorsal ridge than control individuals as well. However, a geometric morphometric analysis of the head shape revealed significant, predator-specific changes. Triops-exposed individuals expressed a flattened head shape with a pronounced dorsal edge, while Notonecta-exposed individuals developed a high and strongly rounded head. Our study describes so far unrecognized inducible defenses of D. similis against two predators in temporary waters. Furthermore, the predator-dependent change in head shape is in concordance with the 'concept of modality', which highlights the qualitative aspect of natural selection caused by predators.


Assuntos
Cladóceros/anatomia & histologia , Daphnia/anatomia & histologia , Água Doce , Comportamento Predatório/fisiologia , Animais , Cabeça/anatomia & histologia , Fenótipo , Análise de Componente Principal
18.
Nat Commun ; 11(1): 1527, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32235853

RESUMO

Species interactions are widely thought to be strongest in the tropics, potentially contributing to the greater number of species at lower latitudes. Yet, empirical tests of this "biotic interactions" hypothesis remain limited and often provide mixed results. Here, we analyze 55 years of catch per unit effort data from pelagic longline fisheries to estimate the strength of predation exerted by large predatory fish in the world's oceans. We test two central tenets of the biotic interactions hypothesis: that predation is (1) strongest near the equator, and (2) positively correlated with species richness. Counter to these predictions, we find that predation is (1) strongest in or near the temperate zone and (2) negatively correlated with oceanic fish species richness. These patterns suggest that, at least for pelagic fish predation, common assumptions about the latitudinal distribution of species interactions do not apply, thereby challenging a leading explanation for the latitudinal gradient in species diversity.


Assuntos
Peixes/fisiologia , Geografia , Comportamento Predatório/fisiologia , Animais , Biodiversidade , Oceanos e Mares , Filogenia , Especificidade da Espécie , Fatores de Tempo
19.
Sci Rep ; 10(1): 6637, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313143

RESUMO

Rhynocoris longifrons (Hemiptera: Reduviidae) is a generalist predator of many cotton insect pests. The hiding behaviour of this predator, which is one of the key factors of predation success, was investigated under screen house conditions. Moreover, we evaluated its biocontrol potential against Aphis gossypii (Hemiptera: Aphididae), Dysdercus cingulatus (Hemiptera: Pyrrhocoridae), Phenacoccus solenopsis (Hemiptera: Pseudococcidae), and Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) under screen house and field conditions. Results showed that R. longifrons life stages preferred to hide under small pebbles in the screen house tests. All the R. longifrons life stages showed a biocontrol potential against the four insect pests under screen house conditions. However, their biocontrol potential had not varied in relation to day and night hours. Augmentative releases of R. longifrons were carried out for two seasons such as South-west monsoon, 2011 and post-monsoon, 2012. The augmentative release of R. longifrons reduced significantly insect pests on cotton. In fact, the release of this predator in cotton fields was capable to reduce the population of H. armigera (50%), P. solenopsis (28%), D. cingulatus (18.8%), and A. gossypii (11.8%) during the rain fed condition (south-west monsoon season). During irrigated condition (post-monsoon season), populations of D. cingulatus were reduced by 26%, than P. solenopsis (20.6%), and A. gossypii (16.8%). Except ants, no negative impact was reported on other natural enemies present in the cotton field. Significantly higher crop yield and cost benefit ratio was observed in the predator release plots indicating that R. longifrons can be used in an integrated pest management program for multiple cotton pests.


Assuntos
Afídeos/fisiologia , Hemípteros/fisiologia , Lepidópteros/fisiologia , Estágios do Ciclo de Vida/fisiologia , Controle Biológico de Vetores/métodos , Comportamento Predatório/fisiologia , Reduviidae/fisiologia , Animais , Feminino , Gossypium/parasitologia , Índia , Masculino , Fotoperíodo , Estações do Ano
20.
PLoS One ; 15(4): e0231471, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348341

RESUMO

Multivariate geometric designs for mixture experiments and response surface methodology (RSM) were tested as a means of optimizing plant mixtures to support generalist predatory arthropods. The mixture design included 14 treatment groups, each comprised of six planters and having a proportion of 0.00, 0.17, 0.33, 0.66, or 1.00 of each plant species. The response variable was the frequency of predators trapped on sticky card traps placed in each group and replaced 2 times per week. The following plant species were used: Spring 2017: Euphorbia milii, E. heterophylla, and Phaseolus lunatus; Summer 2017: E. milii, Fagopyrum esculentum, and Chamaecrista fasciculata; and, Summer 2018: E. milii, F. esculentum, and Portulaca umbraticola. Predator occurrence was influenced by: 1) Linear mixture effects, which indicated that predator occurrence was driven by the amount of a single plant species in the mixture; or, 2) Nonlinear blending effects, which indicated that the plant mixture itself had emergent properties that contributed to predator occurrence. Predator abundance was highest in the Spring 2017 experiment and both linear mixture effects and nonlinear blending effects were observed. Predator occurrence decreased in subsequent experiments, which were conducted in the warmer summer months. In both Summer experiments, only linear mixture effects were observed, indicating that predator occurrence was driven by the amount of a single plant species in the test mixtures: Euphorbia milii in 2017 and Portulaca umbraticola in 2018. The results showed that not only did the species composition of a plant mixture drive predator occurrence but that proportionality of species contributed to the outcome as well. This suggests that, when formulating a plant mixture to aid in conservation biological control consideration should be given to the proportion of each plant species included in the mixture. RSM can be an important tool for achieving the goal of optimizing mixtures of plants for conservation biological control.


Assuntos
Artrópodes/fisiologia , Comportamento Predatório/fisiologia , Animais , Comportamento Alimentar/fisiologia , Plantas , Estações do Ano
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