scholarly journals Extrinsic and intrinsic factors influencing the emergence and return of Asian particolored bats Vespertilio sinensis

2021 ◽  
Author(s):  
Lei Feng ◽  
Hexuan Qin ◽  
Jingjing Li ◽  
Xin Li ◽  
Jiang Feng ◽  
...  
Keyword(s):  
Light Intensity ◽  
Predation Risk ◽  
Environmental Changes ◽  
Return Time ◽  
Reproductive Status ◽  
Lactation Period ◽  
Emergence Time ◽  
Extrinsic Factors ◽  
Activity Rhythms ◽  
Return Times

The circadian rhythm is an adaptive biological process, allows organisms to anticipate daily environmental changes and implement appropriate strategies. Circadian rhythms play a crucial role in the health and survival of organisms. However, little is known concerning how intrinsic and extrinsic factors affect animal daily rhythms in the field, especially in nocturnal animals. Here, we investigated the emergence and return times of Vesperilio sinensis, and also integrated environmental conditions (temperature, humidity and light intensity) and biotic factors (reproductive status and predation risk) to determine causes of variation in the activity rhythms of the bats. We found that variation in the first emergence time, the mid-emergence time, and the final return time were distinct. The results demonstrated that the emergence and return times of bats were affected by light intensity, reproductive status, and predation risk in a relatively complex pattern. Light intensity had the greatest contribution to activity rhythms. Moreover, we first investigated the effects of actual predators on the activity rhythms of bats; the results showed that the mid-emergence time of bats was earlier as predators were hunting, but the final return time was later when predators were present. This challenges the traditional view that high predation risk leads to later emergence and earlier return. Finally, our results also highlighted the importance of higher energy demands during the lactation period in bats to variation in activity rhythms. These results improve our understanding of the patterns and causes of variation in activity rhythms in bats and other nocturnal animals.

Timing of the evening emergence of Hilgendorf’s tube-nosed bat (Murina hilgendorfi) in relation to roost type and season

2020 ◽  
pp. 1-11
Author(s):  
Hayato Takada
Keyword(s):  
Predation Risk ◽  
Vegetation Cover ◽  
Growth Stage ◽  
Outer Wall ◽  
First Record ◽  
Foraging Strategy ◽  
Late Spring ◽  
Reproductive Status ◽  
Central Japan ◽  
Behavioral Aspect

Abstract Like for many species, the timing of evening emergence of bats is an important behavioral aspect that affects their fitness and has been studied in various bat species. However, little is known about emergence timing of solitary bats that frequently switch day roosts, because they are difficult to observe. In this study, I examined the emergence timing of Hilgendorf’s tube-nosed bats (Murina hilgendorfi), which are solitary and frequently switch roosts, in relation to roost type and season over six years in Hayakawa, central Japan. The results show that the bats emerged after dusk when the light was weak. Later emergence may be related to the habits of this species, such as their solitary lifestyle, slow flight speed, and gleaning foraging strategy, which may enhance predation risk. Individuals roosting in dead foliage and on the outer wall of a building situated in closed forests emerged significantly earlier than those roosting in an old mine and tunnel located in open environments, suggesting that vegetation cover and/or lower predictability of roost location provide security for bats. Bats emerged progressively earlier from late spring (preparturition) to early autumn (late lactation or post-lactation), suggesting that the reproductive status of females or the growth stage of pups may influence emergence timing. To my knowledge, this study provides the first record of the emergence timing of Hilgendorf’s tube-nosed bat, and suggests that predation risk may impact the bats’ emergence behavior.

scholarly journals Temperature alters the physiological response of spiny lobsters under predation risk

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Felipe A Briceño ◽  
Quinn P Fitzgibbon ◽  
Elias T Polymeropoulos ◽  
Iván A Hinojosa ◽  
Gretta T Pecl
Keyword(s):  
Climate Change ◽  
Predation Risk ◽  
Environmental Changes ◽  
Environmental Drivers ◽  
Climate Change Scenarios ◽  
Metabolic Rates ◽  
Energetic Costs ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Spiny Lobsters

Abstract Predation risk can strongly shape prey ecological traits, with specific anti-predator responses displayed to reduce encounters with predators. Key environmental drivers, such as temperature, can profoundly modulate prey energetic costs in ectotherms, although we currently lack knowledge of how both temperature and predation risk can challenge prey physiology and ecology. Such uncertainties in predator–prey interactions are particularly relevant for marine regions experiencing rapid environmental changes due to climate change. Using the octopus (Octopus maorum)–spiny lobster (Jasus edwardsii) interaction as a predator–prey model, we examined different metabolic traits of sub adult spiny lobsters under predation risk in combination with two thermal scenarios: ‘current’ (20°C) and ‘warming’ (23°C), based on projections of sea-surface temperature under climate change. We examined lobster standard metabolic rates to define the energetic requirements at specific temperatures. Routine metabolic rates (RMRs) within a respirometer were used as a proxy of lobster activity during night and day time, and active metabolic rates, aerobic scope and excess post-exercise oxygen consumption were used to assess the energetic costs associated with escape responses (i.e. tail-flipping) in both thermal scenarios. Lobster standard metabolic rate increased at 23°C, suggesting an elevated energetic requirement (39%) compared to 20°C. Unthreatened lobsters displayed a strong circadian pattern in RMR with higher rates during the night compared with the day, which were strongly magnified at 23°C. Once exposed to predation risk, lobsters at 20°C quickly reduced their RMR by ~29%, suggesting an immobility or ‘freezing’ response to avoid predators. Conversely, lobsters acclimated to 23°C did not display such an anti-predator response. These findings suggest that warmer temperatures may induce a change to the typical immobility predation risk response of lobsters. It is hypothesized that heightened energetic maintenance requirements at higher temperatures may act to override the normal predator-risk responses under climate-change scenarios.

scholarly journals Ritme aktivitas penerbangan harian Tetragonula laeviceps (Smith) (Hymenoptera: Apidae) di Bogor

2018 ◽  
Vol 14 (3) ◽  
pp. 117
Author(s):  
Indah Putri Januar Yustia ◽  
Aunu Rauf ◽  
Nina Maryana
Keyword(s):  
Relative Humidity ◽  
Light Intensity ◽  
Stingless Bees ◽  
Common Species ◽  
Flight Activity ◽  
Activity Rhythms

<p><em>Tetragonula laeviceps</em> (Smith) is one of the most common species of stingless bees in Indonesia. However, only few publications available on the flight activity rhythms of the species. Research was conducted with the objectives to determine flight activity of <em>T. laeviceps</em> in relation to daily times and various weather elements. Three colonies of <em>T. laeviceps</em> were observed hourly for 5 minutes beginning at 06.00 a.m. until 06.00 p.m. Number of bees entering with pollen or resin, as well as exiting with waste were counted. Flight activity was significantly different (P &lt; 0.001) among times of day. The preferential times (acrophases) of flight activities occurred at afternoon (11 a.m. to 12 a.m.). Number of entrance and exit flights positively correlated (moderate) with temperature and light intensity, while negatively correlated (moderate) with relative humidity. </p>

scholarly journals Rejuvenating stem cells to restore muscle regeneration in aging

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 76 ◽  
Author(s):  
Eyal Bengal ◽  
Eusebio Perdiguero ◽  
Antonio L. Serrano ◽  
Pura Muñoz-Cánoves
Keyword(s):  
Stem Cells ◽  
Satellite Cell ◽  
Satellite Cells ◽  
Environmental Changes ◽  
Local Environment ◽  
The Elderly ◽  
Muscle Repair ◽  
Extrinsic Factors ◽  
Repair Capacity ◽  
Cell Dysfunction

Adult muscle stem cells, originally called satellite cells, are essential for muscle repair and regeneration throughout life. Besides a gradual loss of mass and function, muscle aging is characterized by a decline in the repair capacity, which blunts muscle recovery after injury in elderly individuals. A major effort has been dedicated in recent years to deciphering the causes of satellite cell dysfunction in aging animals, with the ultimate goal of rejuvenating old satellite cells and improving muscle function in elderly people. This review focuses on the recently identified network of cell-intrinsic and -extrinsic factors and processes contributing to the decline of satellite cells in old animals. Some studies suggest that aging-related satellite-cell decay is mostly caused by age-associated extrinsic environmental changes that could be reversed by a “youthful environment”. Others propose a central role for cell-intrinsic mechanisms, some of which are not reversed by environmental changes. We believe that these proposals, far from being antagonistic, are complementary and that both extrinsic and intrinsic factors contribute to muscle stem cell dysfunction during aging-related regenerative decline. The low regenerative potential of old satellite cells may reflect the accumulation of deleterious changes during the life of the cell; some of these changes may be inherent (intrinsic) while others result from the systemic and local environment (extrinsic). The present challenge is to rejuvenate aged satellite cells that have undergone reversible changes to provide a possible approach to improving muscle repair in the elderly.

Habitat choice and vigilance behaviour of brush-tailed rock-wallabies (Petrogale penicillata) within their nocturnal foraging ranges

2003 ◽  
Vol 30 (4) ◽  
pp. 355 ◽  
Author(s):  
Kerryn Carter ◽  
Anne W. Goldizen
Keyword(s):  
Light Intensity ◽  
Predation Risk ◽  
Habitat Choice ◽  
Night Vision ◽  
Energy Requirements ◽  
Vigilance Behaviour ◽  
Nocturnal Foraging ◽  
Limited Food ◽  
High Winds ◽  
Foraging Ranges

Habitat choice by brush-tailed rock-wallabies (Petrogale penicillata) in south-east Queensland was investigated by comparing the attributes of the nocturnal foraging locations that they selected with those of random locations within a radius of 50 m. Brush-tailed rock-wallabies were shown to select foraging locations on the basis of forage quality and/or their ability to see predators, rather than protection from predators amongst vegetation that could conceal them. Habitat choice may have been affected by limited food availability, as this study was conducted in the winter dry season. The attributes of foraging locations that brush-tailed rock-wallabies perceived as increasing their predation risk were assessed by recording the proportion of time that brush-tailed rock-wallabies spent vigilant while foraging. To measure vigilance, focal animals were observed with a night-vision scope for two minutes and the proportions of time spent vigilant and feeding were recorded. No measured feature of foraging locations was related to higher vigilance levels, suggesting that brush-tailed rock-wallabies did not alter their vigilance whether sheltered amongst grass tussocks or in open habitat, or whether feeding on good quality or poorer quality vegetation. Vigilance levels significantly declined as overnight temperatures decreased, which may have resulted from higher energy requirements of brush-tailed rock-wallabies during winter. The only factors that were found to significantly increase vigilance levels were high winds and moonlit nights. On bright nights, brush-tailed rock-wallabies were very unsettled and during high winds they often did not emerge to feed. More information is needed about how macropods detect predators at night before the effects of wind and light intensity upon vigilance can be fully understood.

Influence of Light Intensity on Plasma Melatonin and Locomotor Activity Rhythms in Tench

2005 ◽  
Vol 22 (1) ◽  
pp. 67-78 ◽  
Author(s):  
L. M. Vera ◽  
J. F. López‐Olmeda ◽  
M. J. Bayarri ◽  
J. A. Madrid ◽  
F. J. Sánchez‐Vázquez
Keyword(s):  
Locomotor Activity ◽  
Light Intensity ◽  
Activity Rhythms ◽  
Plasma Melatonin

Return times in nearly-completely decomposable stochastic processes

1978 ◽  
Vol 15 (02) ◽  
pp. 251-267 ◽  
Author(s):  
G. Latouche ◽  
G. Louchard
Keyword(s):  
Markov Chain ◽  
Stochastic Processes ◽  
Stochastic Matrix ◽  
Return Time ◽  
Second Order ◽  
Return Times ◽  
Second Moments

Consider a finite irreducible aperiodic Markov chain with nearly-completely decomposable stochastic matrix: i.e. a Markov chain for which the states can be grouped into disjoint aggregates, in such a way that the probabilities of transition between states of the same aggregate are large compared to the probabilities of transition between states belonging to different aggregates. Let Ω be a subset of one of the aggregates. Second-order approximations are determined for the first and second moments of the time to reach Ω and the return time to Ω.

scholarly journals Large scale debris-flow hazard assessment: a geotechnical approach and GIS modelling

2003 ◽  
Vol 3 (5) ◽  
pp. 443-455 ◽  
Author(s):  
G. Delmonaco ◽  
G. Leoni ◽  
C. Margottini ◽  
C. Puglisi ◽  
D. Spizzichino
Keyword(s):  
Debris Flow ◽  
Large Scale ◽  
Hazard Analysis ◽  
Slope Angle ◽  
Return Time ◽  
Distributed Model ◽  
Test Analysis ◽  
Soil Thickness ◽  
Return Times ◽  
Debris Flow Hazard

Abstract. A deterministic distributed model has been developed for large-scale debris-flow hazard analysis in the basin of River Vezza (Tuscany Region – Italy). This area (51.6 km 2 ) was affected by over 250 landslides. These were classified as debris/earth flow mainly involving the metamorphic geological formations outcropping in the area, triggered by the pluviometric event of 19 June 1996. In the last decades landslide hazard and risk analysis have been favoured by the development of GIS techniques permitting the generalisation, synthesis and modelling of stability conditions on a large scale investigation (>1:10 000). In this work, the main results derived by the application of a geotechnical model coupled with a hydrological model for the assessment of debris flows hazard analysis, are reported. This analysis has been developed starting by the following steps: landslide inventory map derived by aerial photo interpretation, direct field survey, generation of a database and digital maps, elaboration of a DTM and derived themes (i.e. slope angle map), definition of a superficial soil thickness map, geotechnical soil characterisation through implementation of a backanalysis on test slopes, laboratory test analysis, inference of the influence of precipitation, for distinct return times, on ponding time and pore pressure generation, implementation of a slope stability model (infinite slope model) and generalisation of the safety factor for estimated rainfall events with different return times. Such an approach has allowed the identification of potential source areas of debris flow triggering. This is used to detected precipitation events with estimated return time of 10, 50, 75 and 100 years. The model shows a dramatic decrease of safety conditions for the simulation when is related to a 75 years return time rainfall event. It corresponds to an estimated cumulated daily intensity of 280–330 mm. This value can be considered the hydrological triggering threshold for the whole Vezza basin.

scholarly journals Long-term temporal stability of Northeast Arctic cod (Gadus morhua) otolith morphology

2020 ◽  
Vol 77 (3) ◽  
pp. 1043-1054 ◽  
Author(s):  
Côme Denechaud ◽  
Szymon Smoliński ◽  
Audrey J Geffen ◽  
Jane A Godiksen
Keyword(s):  
Gadus Morhua ◽  
Environmental Changes ◽  
Temporal Stability ◽  
Individual Variability ◽  
Fish Growth ◽  
Environmental Drivers ◽  
Extrinsic Factors ◽  
Otolith Shape ◽  
Otolith Morphology ◽  
Biological Interpretation

Abstract Otolith shape analysis provides a robust tool for the discrimination of many fish stocks in the context of fisheries management. However, there has been little research to examine within-stock temporal stability of otolith morphology in relation to changes in the environment and stock conditions. This study investigated the variability of Northeast Arctic (NEA) cod (Gadus morhua) otolith shape between 1933 and 2015, using elliptical Fourier descriptors extracted from archived material of 2968 mature fish. Series of hierarchical multivariate models were developed to relate shape to the identified optimal windows of some environmental drivers. Differences between years accounted for &lt;3% of the observed variation and no significant differences were found between the average cohort shapes. The models not only confirmed that fish growth was the strongest driver of shape differences, but also highlighted effects of temperature and biomass-related variables at different life stages. Extrinsic factors described only a small fraction of the observed variance, which indicates that environmental changes over time likely account for less than the natural inter-individual variability in otolith shape. These results suggest that overall shape remains relatively stable through time within NEA cod, which further contributes towards a consensus on the biological interpretation of shape differences.

scholarly journals A Central Limit Theorem for Non-Overlapping Return Times

2006 ◽  
Vol 43 (1) ◽  
pp. 32-47
Author(s):  
Oliver Johnson
Keyword(s):  
Central Limit Theorem ◽  
Limit Theorem ◽  
Random Process ◽  
Central Limit ◽  
Return Time ◽  
Negative Association ◽  
Return Times ◽  
Entropy Estimation

Define the non-overlapping return time of a block of a random process to be the number of blocks that pass by before the block in question reappears. We prove a central limit theorem based on these return times. This result has applications to entropy estimation, and to the problem of determining if digits have come from an independent, equidistributed sequence. In the case of an equidistributed sequence, we use an argument based on negative association to prove convergence under conditions weaker than those required in the general case.

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