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1.
J Anim Ecol ; 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38706400

RESUMO

1. Individual niche specialization is widespread in natural populations and has key implications for higher levels of biological organization. This phenomenon, however, has been primarily quantified in resource niche axes, overlooking individual variation in environmental associations (i.e. abiotic conditions organisms experience). 2. Here, we explore what we can learn from a multidimensional perspective of individual niche specialization that integrates resource use and environmental associations into a common framework. 3. By combining predictions from theory and simple simulations, we illustrate how (i) multidimensional intraspecific niche variation and (ii) the spatiotemporal context of interactions between conspecifics scale up to shape emergent patterns of the population niche. 4. Contemplating individual specialization as a multidimensional, unifying concept across biotic and abiotic niche axes is a fundamental step towards bringing this concept closer to the n-dimensional niche envisioned by Hutchinson.


1. A especialização individual de nicho é prevalente em populações naturais e tem implicações importantes para níveis de organização biológica superiores. Esse fenômeno, entretanto, tem sido principalmente quantificado em eixos do nicho que representam o uso de recursos, negligenciando a variação individual em associações ambientais (i.e. as condições abióticas que organismos experimentam). 2. Aqui, exploramos o que podemos aprender a partir de uma perspectiva multidimensional da especialização individual que integra o uso de recursos e associações ambientais em uma abordagem única. 3. Ao combinar predições da teoria e simulações simples, ilustramos como (i) a variação intraespecífica multidimensional de nicho e (ii) o contexto espaço­temporal de interações entre conspecíficos podem moldar padrões emergentes do nicho de populações. 4. Encarar a especialização individual como um conceito multidimensional e unificador em eixos do nicho bióticos e abióticos é um passo fundamental na direção de aproximar esse conceito do nicho n­dimensional idealizado por Hutchinson.

2.
Parasit Vectors ; 17(1): 212, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730488

RESUMO

BACKGROUND: As a primary vector of bluetongue virus (BTV) in the US, seasonal abundance and diel flight activity of Culicoides sonorensis has been documented, but few studies have examined how time of host-seeking activity is impacted by environmental factors. This knowledge is essential for interpreting surveillance data and modeling pathogen transmission risk. METHODS: The diel host-seeking activity of C. sonorensis was studied on a California dairy over 3 years using a time-segregated trap baited with CO2. The relationship between environmental variables and diel host-seeking activity (start, peak, and duration of activity) of C. sonorensis was evaluated using multiple linear regression. Fisher's exact test and paired-sample z-test were used to evaluate the seasonal difference and parity difference on diel host-seeking activity. RESULTS: Host-seeking by C. sonorensis began and reached an activity peak before sunset at a higher frequency during colder months relative to warmer months. The time that host-seeking activity occurred was associated low and high daily temperature as well as wind speed at sunset. Colder temperatures and a greater diurnal temperature range were associated with an earlier peak in host-seeking. Higher wind speeds at sunset were associated with a delayed peak in host-seeking and a shortened duration of host-seeking. Parous midges reached peak host-seeking activity slightly later than nulliparous midges, possibly because of the need for oviposition by gravid females before returning to host-seeking. CONCLUSIONS: This study demonstrates that during colder months C. sonorensis initiates host-seeking and reaches peak host-seeking activity earlier relative to sunset, often even before sunset, compared to warmer months. Therefore, the commonly used UV light-baited traps are ineffective for midge surveillance before sunset. Based on this study, surveillance methods that do not rely on light trapping would provide a more accurate estimate of host-biting risk across seasons. The association of environmental factors to host-seeking shown in this study can be used to improve modeling or prediction of host-seeking activity. This study identified diurnal temperature range as associated with host-seeking activity, suggesting that Culicoides may respond to a rapidly decreasing temperature by shifting to an earlier host-seeking time, though this association needs further study.


Assuntos
Ceratopogonidae , Estações do Ano , Animais , Ceratopogonidae/fisiologia , Ceratopogonidae/virologia , California , Feminino , Temperatura , Indústria de Laticínios , Insetos Vetores/fisiologia , Insetos Vetores/virologia , Comportamento de Busca por Hospedeiro , Bovinos , Meio Ambiente , Vírus Bluetongue/fisiologia , Bluetongue/transmissão
3.
Evolution ; 78(6): 1174-1182, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38536734

RESUMO

Although diurnality is widespread across Lepidoptera and has evolved many times independently, its causes and ecological implications are yet poorly understood. The "Salient Aroma Hypothesis" (SAH) postulates that diurnal insect herbivores are overall more specialized in dietary breadth than species active at night. It is furthermore assumed that diurnality evolved more frequently in species that live in cooler environments. Using European geometrid moths as a model group, we tested whether diurnal activity in adults is associated with an increased larval dietary breadth as predicted by the SAH. We further investigated whether species that exclusively occur in colder regions or whose flight period is restricted to cool seasons are more likely to exhibit a diurnal flight activity. Contrary to expectation, we found no consistent differences in larval dietary breadth between diurnal and nocturnal species, and thus no support for the SAH. Diurnal activity occurred more frequently in species restricted to cold regions but not in species restricted to cool seasons. We conclude that diurnality could serve as an advantageous adaptation in cold environments, depending on further factors such as resource availability or predation pressure, but has no immediate consequences for larval dietary breadth.


Assuntos
Dieta , Larva , Mariposas , Animais , Mariposas/fisiologia , Larva/fisiologia , Ritmo Circadiano , Voo Animal , Estações do Ano , Odorantes/análise
4.
Environ Entomol ; 52(4): 730-739, 2023 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-37463285

RESUMO

Ornamental plant production in eastern Virginia nurseries have been greatly impacted by Systena frontalis (F.), also known as the red-headed flea beetle. With the advent of S. frontalis as a prevalent pest in the past 2 decades, baseline phenology and behavior are currently understudied within Virginia nurseries. This pest is costly to control due to insecticide expenses and loss of saleable plants. In 2021 and 2022, populations of this insect were monitored at 2 commercial nurseries in eastern Virginia in order to better understand their temporal and spatial population dynamics. Patterns that emerged indicated S. frontalis could have up to 3 generations in eastern Virginia, with peaks of adult abundance in June, late July, and late August to early September. Phenylethyl alcohol was tested as an adult attractant lure, but it was found to be ineffective under nursery conditions. Diel monitoring demonstrated these adults were most active from 1100 to 1500 h. Severity of defoliation at the leaf level increased linearly with increased density of adults, where 5 individuals defoliated up to 4% of any Hydrangea paniculata cv. 'Limelight' leaf in 1 wk under greenhouse conditions. Timing of scouting and insecticide sprays according to the adult activity peaks of the day and across the season may allow reduction in overall insecticide usage.


Assuntos
Besouros , Inseticidas , Animais , Virginia , Jardins
5.
J Exp Biol ; 226(15)2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37416981

RESUMO

Leafrollers (Lepidoptera: Tortricidae) are a large family of small moths containing over 10,000 species, many of which are crop pests. Grapholita molesta, Lobesia botrana and Cydia pomonella adults are sexually active before, during and after sunset, respectively. We wanted to determine whether being active at different times of the day and night is associated with differences in their visual system. Spectral sensitivity (SS) was measured with electroretinograms and selective adaptation with green, blue and ultraviolet light. SS curves could be fitted with a triple nomogram template which indicated the existence of three photoreceptor classes peaking at 355, 440 and 525 nm. The retinae showed clear regionalization, with fewer blue receptors dorsally. No differences among species or between sexes were found. Intracellular recordings in C. pomonella also revealed three photoreceptor classes with sensitivities peaking at 355, 440 and 525 nm. The blue photoreceptors showed inhibitory responses in the green part of the spectrum, indicating the presence of a colour-opponent system. Flicker fusion frequency experiments showed that the response speed was similar between sexes and species and fused at around 100 Hz. Our results indicate that the three species have the ancestral insect retinal substrate for a trichromatic colour vision, based upon the UV, blue and green-sensitive photoreceptors, and lack any prominent adaptations related to being active under different light conditions.


Assuntos
Visão de Cores , Mariposas , Animais , Células Fotorreceptoras , Retina , Células Fotorreceptoras de Vertebrados
6.
Proc Biol Sci ; 290(1999): 20230661, 2023 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-37192667

RESUMO

The assumption that activity and foraging are risky for prey underlies many predator-prey theories and has led to the use of predator-prey activity overlap as a proxy of predation risk. However, the simultaneous measures of prey and predator activity along with timing of predation required to test this assumption have not been available. Here, we used accelerometry data on snowshoe hares (Lepus americanus) and Canada lynx (Lynx canadensis) to determine activity patterns of prey and predators and match these to precise timing of predation. Surprisingly we found that lynx kills of hares were as likely to occur during the day when hares were inactive as at night when hares were active. We also found that activity rates of hares were not related to the chance of predation at daily and weekly scales, whereas lynx activity rates positively affected the diel pattern of lynx predation on hares and their weekly kill rates of hares. Our findings suggest that predator-prey diel activity overlap may not always be a good proxy of predation risk, and highlight a need for examining the link between predation and spatio-temporal behaviour of predator and prey to improve our understanding of how predator-prey behavioural interactions drive predation risk.


Assuntos
Lebres , Lynx , Animais , Ecossistema , Comportamento Predatório
7.
Proc Biol Sci ; 290(1996): 20230530, 2023 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-37040807

RESUMO

The visual ecology of early mammals remains poorly resolved. Studies of ancestral photopigments suggest an ancient transition from nocturnal to more crepuscular conditions. By contrast, the phenotypic shifts following the split of monotremes and therians-which lost their SWS1 and SWS2 opsins, respectively-are less clear. To address this, we obtained new phenotypic data on the photopigments of extant and ancestral monotremes. We then generated functional data for another vertebrate group that shares the same photopigment repertoire as monotremes: the crocodilians. By characterizing resurrected ancient pigments, we show that the ancestral monotreme underwent a dramatic acceleration in its rhodopsin retinal release rate. Moreover, this change was likely mediated by three residue replacements, two of which also arose on the ancestral branch of crocodilians, which exhibit similarly accelerated retinal release. Despite this parallelism in retinal release, we detected minimal to moderate changes in the spectral tuning of cone visual pigments in these groups. Our results imply that ancestral forms of monotremes and crocodilians independently underwent niche expansion to encompass quickly changing light conditions. This scenario-which accords with reported crepuscular activity in extant monotremes-may help account for their loss of the ultraviolet-sensitive SWS1 pigment but retention of the blue-sensitive SWS2.


Assuntos
Jacarés e Crocodilos , Opsinas , Animais , Opsinas/genética , Rodopsina , Filogenia , Evolução Biológica , Mamíferos
8.
Mov Ecol ; 11(1): 15, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36945057

RESUMO

BACKGROUND: Movement is central to understanding the ecology of animals. The most robustly definable segments of an individual's lifetime track are its diel activity routines (DARs). This robustness is due to fixed start and end points set by a 24-h clock that depends on the individual's quotidian schedule. An analysis of day-to-day variation in the DARs of individuals, their comparisons among individuals, and the questions that can be asked, particularly in the context of lunar and annual cycles, depends on the relocation frequency and spatial accuracy of movement data. Here we present methods for categorizing the geometry of DARs for high frequency (seconds to minutes) movement data. METHODS: Our method involves an initial categorization of DARs using data pooled across all individuals. We approached this categorization using a Ward clustering algorithm that employs four scalar "whole-path metrics" of trajectory geometry: 1. net displacement (distance between start and end points), 2. maximum displacement from start point, 3. maximum diameter, and 4. maximum width. We illustrate the general approach using reverse-GPS data obtained from 44 barn owls, Tyto alba, in north-eastern Israel. We conducted a principle components analysis (PCA) to obtain a factor, PC1, that essentially captures the scale of movement. We then used a generalized linear mixed model with PC1 as the dependent variable to assess the effects of age and sex on movement. RESULTS: We clustered 6230 individual DARs into 7 categories representing different shapes and scale of the owls nightly routines. Five categories based on size and elongation were classified as closed (i.e. returning to the same roost), one as partially open (returning to a nearby roost) and one as fully open (leaving for another region). Our PCA revealed that the DAR scale factor, PC1, accounted for 86.5% of the existing variation. It also showed that PC2 captures the openness of the DAR and accounted for another 8.4% of the variation. We also constructed spatio-temporal distributions of DAR types for individuals and groups of individuals aggregated by age, sex, and seasonal quadrimester, as well as identify some idiosyncratic behavior of individuals within family groups in relation to location. Finally, we showed in two ways that DARs were significantly larger in young than adults and in males than females. CONCLUSION: Our study offers a new method for using high-frequency movement data to classify animal diel movement routines. Insights into the types and distributions of the geometric shape and size of DARs in populations may well prove to be more invaluable for predicting the space-use response of individuals and populations to climate and land-use changes than other currently used movement track methods of analysis.

9.
Integr Zool ; 18(1): 143-156, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35195342

RESUMO

Widespread distribution of livestock in the natural habitats of large carnivores may negatively impact carnivore populations by reducing wild prey availability and increasing human-carnivore conflicts. In this study, we used camera-trapping data collected in the temperate forests of the Taihang Mountains in North China during 2016-2019 to examine whether and how free-ranging cattle affected habitat use and Diel activity patterns of the endangered North Chinese leopard (Panthera pardus japonensis) and its 2 wild prey species, Siberian roe deer (Capreolus pygargus), and wild boar (Sus scrofa). Residents were also interviewed to record livestock depredation events by leopards during 2015-2019. We found that roe deer spatially avoided sites frequented by cattle, but wild boar did not. In the growing seasons, leopards shared habitats with cattle and tended to increase their diurnal activities where cattle were present. All 3 study species exhibited fine-scale spatial-temporal segregation to cattle. Leopards selectively preyed on calves over adult cattle and livestock depredation frequency was positively correlated with the detection rates of cattle and wild prey, but not that of leopard. These findings not only show that through behavioral adaption large carnivores and their ungulate prey may persist under livestock disturbance, but also highlight how important proper livestock management is for conserving North Chinese leopards in this region. To enhance livestock management and mitigate human-leopard conflicts, we recommend specific actions, such as better guarding of free-ranging cattle or adoption of a captive farming system.


Assuntos
Carnívoros , Cervos , Panthera , Comportamento Predatório , Animais , Bovinos , Humanos , Conservação dos Recursos Naturais , Ecossistema , Gado , Sus scrofa
11.
Trends Ecol Evol ; 38(4): 324-336, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36402653

RESUMO

Animals are facing novel 'timescapes' in which the stimuli entraining their daily activity patterns no longer match historical conditions due to anthropogenic disturbance. However, the ecological effects (e.g., altered physiology, species interactions) of novel activity timing are virtually unknown. We reviewed 1328 studies and found relatively few focusing on anthropogenic effects on activity timing. We suggest three hypotheses to stimulate future research: (i) activity-timing mismatches determine ecological effects, (ii) duration and timing of timescape modification influence effects, and (iii) consequences of altered activity timing vary biogeographically due to broad-scale variation in factors compressing timescapes. The continued growth of sampling technologies promises to facilitate the study of the consequences of altered activity timing, with emerging applications for biodiversity conservation.


Assuntos
Biodiversidade , Ecossistema , Animais
12.
Evolution ; 76(12): 2879-2892, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36221224

RESUMO

Conspicuous colors (e.g., red, yellow, blue) have evolved numerous times across animals. But the function of this coloration can differ radically among species. Many species use this coloration as a sexual signal to conspecifics, whereas others use it as a warning signal to predators. Why do different species evolve conspicuous coloration in association with one function as opposed to the other? We address this question in terrestrial vertebrates (tetrapods) using phylogenetic approaches, and test whether day-night activities of species help determine these patterns. Using phylogenetic logistic regression, we found that conspicuous, sexually dimorphic coloration is significantly associated with diurnal lineages (e.g., many birds and lizards). By contrast, the evolution of warning signals was significantly associated with large-scale clades that were ancestrally nocturnal (e.g., snakes, amphibians), regardless of the current diel activity of species. Overall, we show that the evolution of conspicuous coloration as warning signals or sexual signals is influenced by the ecology of species, both recently and in the ancient past.


Assuntos
Lagartos , Animais , Filogenia , Lagartos/genética , Aves , Ecologia , Evolução Biológica , Comportamento Predatório , Cor
13.
J Med Entomol ; 59(5): 1500-1506, 2022 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-35976948

RESUMO

Mosquitoes and other blood feeding arthropods are vectors of pathogens causing serious human diseases, such as Plasmodium spp. (malaria), Wuchereria bancrofti (lymphatic filariasis), Borrelia burgdorferi (Lyme disease), and viruses causing dengue, Zika, West Nile, chikungunya, and yellow fever. Among the most effective strategies for the prevention of vector-borne diseases are those aimed at reducing human-vector interactions, such as insecticide applications and insecticide-treated bed nets (ITNs). In some areas where ITNs are widely used, behavioral adaptations have resulted in mosquitoes shifting their time of blood feeding to earlier or later in the night when the bed nets are not being employed. Little is known about the genetic basis of these behavioral shifts. We conducted quantitative trait locus (QTL) analysis using two strains of Culex pipiens sensu lato with contrasting blood feeding behaviors, wherein the lab adapted Shasta strain blood feeds at any time of the day or night, while the newly established Trinidad strain feeds only at night. We identified a single locus on chromosome 2 associated with the observed variation in feeding times. None of the core clock genes period, timeless, clock, cycle, PAR-domain protein 1, vrille, discs overgrown, cryptochrome 1, or cryptochrome 2 were located within the QTL region. We then monitored locomotor behavior to determine if they differed in their flight activity. The highly nocturnal Trinidad strain showed little daytime activity while the day-feeding Shasta strain was active during the day, suggesting blood feeding behavior and flight activity are physiologically linked.


Assuntos
Culex , Culicidae , Infecção por Zika virus , Zika virus , Animais , Criptocromos/genética , Culex/fisiologia , Culicidae/genética , Comportamento Alimentar , Humanos , Mosquitos Vetores/genética , Locos de Características Quantitativas , Zika virus/genética
14.
Zool Stud ; 60: e8, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35774260

RESUMO

The temporal-spatial resource use patterns of juvenile and adult Ocypode gaudichaudii were studied by comparing the zonation patterns and activity budgets of the two life stages at Culebra Beach, Panama. Burrow distribution of the crabs during the day and at night was studied over six months. Diurnal activity budgets of 46 crabs (22 juveniles and 24 adults) were determined by observing seven predominant behaviors upon emergence from their respective burrows when the burrow zone is uncovered after the tide recedes. The behaviors comprise three foraging-related activities (i.e., deposit-feeding, scavenging, and probing for food), the maintenance of burrow, walking, staying within the burrow, and resting at the burrow entrance. Juvenile crabs occupied a higher intertidal zone than the adults and had a higher emergence rate at night. This temporal-spatial habitat partitioning could possibly reduce intraspecific competition between the two life stages, thereby enabling their coexistence in the habitat as well as increasing the survival rate of the juveniles, potentially raising the carrying capacity of the population at Culebra Beach. All 46 crabs-regardless of life stage-spent the highest mean proportion of time on foraging-related activities. Out of the three feeding-related behaviors, adults spent most time on deposit-feeding while juveniles spent most time probing. Only juveniles scavenged. In both life stages, a similar proportion of time was spent maintaining the burrow and staying within the burrow.

15.
G3 (Bethesda) ; 12(8)2022 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-35640557

RESUMO

Understanding the targets of selection associated with changes in behavioral traits represents an important challenge of current evolutionary research. Owls (Strigiformes) are a diverse group of birds, most of which are considered nocturnal raptors. However, a few owl species independently adopted a diurnal lifestyle in their recent evolutionary history. We searched for signals of accelerated rates of evolution associated with a diurnal lifestyle using a genome-wide comparative approach. We estimated substitution rates in coding and noncoding conserved regions of the genome of seven owl species, including three diurnal species. Substitution rates of the noncoding elements were more accelerated than those of protein-coding genes. We identified new, owl-specific conserved noncoding elements as candidates of parallel evolution during the emergence of diurnality in owls. Our results shed light on the molecular basis of adaptation to a new niche and highlight the importance of regulatory elements for evolutionary changes in behavior. These elements were often involved in the neuronal development of the brain.


Assuntos
Estrigiformes , Adaptação Fisiológica/genética , Animais , Genoma , Genômica , Fenótipo , Estrigiformes/genética
16.
Ecol Evol ; 11(22): 15947-15960, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34824802

RESUMO

In nature, nothing is wasted, not even waste. Dung, composed of metabolic trash and leftovers of food, is a high-quality resource and the object of fierce competition. Over 800 dung beetle species (Scarabaeinae) compete in the South African dung habitat and more than 100 species can colonize a single dung pat. To coexist in the same space, using the same food, beetles divide the day between them. However, detailed diel activity periods and associated morphological adaptations have been largely overlooked in these dung-loving insects. To address this, we used a high-frequency trapping design to establish the diel activity period of 44 dung beetle species in their South Africa communities. This allowed us to conclude that the dung beetles show a highly refined temporal partitioning strategy, with differences in peak of activity even within the diurnal, crepuscular, and nocturnal guilds, independent of nesting behavior and taxonomic classification. We further analyzed differences in eye and body size of our 44 model species and describe their variability in external eye morphology. In general, nocturnal species are bigger than crepuscular and diurnal species, and as expected, the absolute and relative eye size is greatest in nocturnal species, followed by crepuscular and then diurnal species. A more surprising finding was that corneal structure (smooth or facetted) is influenced by the activity period of the species, appearing flat in the nocturnal species and highly curved in the diurnal species. The role of the canthus-a cuticular structure that partially or completely divides the dung beetle eye into dorsal and ventral parts-remains a mystery, but the large number of species investigated in this study nevertheless allowed us to reject any correlation between its presence and the nesting behavior or time of activity of the beetles.

17.
Evol Lett ; 5(5): 484-494, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34621535

RESUMO

Body temperature is a crucial variable in animals that affects nearly every aspect of their lives. Here we analyze for the first time largescale patterns in the evolution of body temperatures across terrestrial vertebrates (tetrapods: including amphibians, mammals, birds and other reptiles). Despite the traditional view that endotherms (birds and mammals) have higher body temperatures than ectotherms, we find they are not significantly different. However, rates of body-temperature evolution are significantly different, with lower rates in endotherms than ectotherms, and the highest rates in amphibians. We find that body temperatures show strong phylogenetic signal and conservatism over 350 million years of evolutionary history in tetrapods, and some lineages appear to have retained similar body temperatures over time for hundreds of millions of years. Although body temperatures are often unrelated to climate in tetrapods, we find that body temperatures are significantly related to day-night activity patterns. Specifically, body temperatures are generally higher in diurnal species than nocturnal species, both across ectotherms and, surprisingly, across endotherms also. Overall, our results suggest that body temperatures are significantly linked to phylogeny and diel-activity patterns within and among tetrapod groups, rather than just climate and the endotherm-ectotherm divide.

18.
Sensors (Basel) ; 21(20)2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34696028

RESUMO

Monitoring activity patterns of animals offers the opportunity to assess individual health and welfare in support of precision livestock farming. The purpose of this study was to use a triaxial accelerometer sensor to determine the diel activity of sheep on pasture. Six Perendale ewe lambs, each fitted with a neck collar mounting a triaxial accelerometer, were filmed during targeted periods of sheep activities: grazing, lying, walking, and standing. The corresponding acceleration data were fitted using a Random Forest algorithm to classify activity (=classifier). This classifier was then applied to accelerometer data from an additional 10 ewe lambs to determine their activity budgets. Each of these was fitted with a neck collar mounting an accelerometer as well as two additional accelerometers placed on a head halter and a body harness over the shoulders of the animal. These were monitored continuously for three days. A classification accuracy of 89.6% was achieved for the grazing, walking and resting activities (i.e., a new class combining lying and standing activity). Triaxial accelerometer data showed that sheep spent 64% (95% CI 55% to 74%) of daylight time grazing, with grazing at night reduced to 14% (95% CI 8% to 20%). Similar activity budgets were achieved from the halter mounted sensors, but not those on a body harness. These results are consistent with previous studies directly observing daily activity of pasture-based sheep and can be applied in a variety of contexts to investigate animal health and welfare metrics e.g., to better understand the impact that young sheep can suffer when carrying even modest burdens of parasitic nematodes.


Assuntos
Aceleração , Caminhada , Acelerometria , Algoritmos , Animais , Fazendas , Feminino , Ovinos
19.
Environ Pollut ; 291: 118108, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520946

RESUMO

Offshore human activities lead to increasing amounts of underwater noise in coastal and shelf environments, which may affect commercially-important benthic invertebrate groups like the re-stocked Helgoland European lobster (Homarus gammarus) in the German Bight (North Sea). It is crucial to understand the impact tonal low-frequency noises, like maritime transport and offshore energy operations, may have on substrate choice and lobsters' behavior to assess potential benefits or bottlenecks of new hard-substrate artificial offshore environments that become available. In this study, we investigated the full factorial effect of a tonal low-frequency noise and predator presence on young-of-year (YOY) European lobsters' in a diurnal and nocturnal experiment. Rocks and European oyster shells (Ostrea edulis) were offered as substrate to YOY lobsters for 3 h. Video recordings (n = 134) allowed the identification of lobsters' initial substrate choice, diel activity and key behaviors (peeking, shelter construction, exploration and hiding). To ensure independence, YOY lobsters in the intermolt stage were randomly selected and assigned to the experimental tanks and used only once. We provide the first evidence that stressors alone, and in combination, constrain YOY lobsters' initial substrate choice towards rocks. During nighttime, the joint effect of exposure to a constant low-frequency noise and predator presence decreased antipredator behavior (i.e., hiding) and increased exploration behavior. Noise may thus interfere with YOY lobsters' attention and decision-making processes. This outcome pinpoints that added tonal low-frequency noise in the environment have the potential to influence the behavior of early-life stages of European lobsters under predator pressure and highlights the importance of including key benthic invertebrates' community relationships in anthropogenic noise risk assessments. Among others, effects of noise must be taken into consideration in plans involving the multi-use of any offshore area for decapods' stock enhancement, aquaculture, and temporary no-take zones.


Assuntos
Nephropidae , Ruído , Animais , Aquicultura , Comportamento Exploratório , Humanos , Alimentos Marinhos
20.
PeerJ ; 9: e10684, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33585081

RESUMO

Invertebrates dominate the animal world in terms of abundance, diversity and biomass, and play critical roles in maintaining ecosystem function. Despite their obvious importance, disproportionate research attention remains focused on vertebrates, with knowledge and understanding of invertebrate ecology still lacking. Due to their inherent advantages, usage of camera traps in ecology has risen dramatically over the last three decades, especially for research on mammals. However, few studies have used cameras to reliably detect fauna such as invertebrates or used cameras to examine specific aspects of invertebrate ecology. Previous research investigating the interaction between wolf spiders (Lycosidae: Lycosa spp.) and the lesser hairy-footed dunnart (Sminthopsis youngsoni) found that camera traps provide a viable method for examining temporal activity patterns and interactions between these species. Here, we re-examine lycosid activity to determine whether these patterns vary with different environmental conditions, specifically between burned and unburned habitats and the crests and bases of sand dunes, and whether cameras are able to detect other invertebrate fauna. Twenty-four cameras were deployed over a 3-month period in an arid region in central Australia, capturing 2,356 confirmed images of seven invertebrate taxa, including 155 time-lapse images of lycosids. Overall, there was no clear difference in temporal activity with respect to dune position or fire history, but twice as many lycosids were detected in unburned compared to burned areas. Despite some limitations, camera traps appear to have considerable utility as a tool for determining the diel activity patterns and habitat use of larger arthropods such as wolf spiders, and we recommend greater uptake in their usage in future.

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