Ambient light alters temporal-updating behaviour during mate choice in a Neotropical frog

2010 ◽  
Vol 88 (5) ◽  
pp. 448-453 ◽  
Author(s):  
Alexander T. Baugh ◽  
Michael J. Ryan
Keyword(s):  
Decision Making ◽  
Mate Choice ◽  
Light Level ◽  
Ambient Light ◽  
Light Conditions ◽  
Predator Detection ◽  
Physalaemus Pustulosus ◽  
Light Levels ◽  
Risk Of Predation ◽  
Assessment Time

It is well known that animal decision-making can be influenced by environmental variables, such as the risk of predation. During the breeding season, nocturnal amphibians encounter a range of environmental conditions at breeding aggregations, including variable ambient light conditions. For nocturnal frogs, illumination is expected to minimize conspicuous movement that might increase predator detection. Previous work has shown that female Physalaemus pustulosus (Cope, 1864) (= Engystomops pustulosus (Cope, 1864)) are sensitive to variation in light levels during mate choice. Here we use an acoustic playback design in which stimuli are adjusted for intensity and complexity during female phonotaxis to show that choosiness is influenced by light level. Frogs were more likely to commit to an initial mate choice despite a dynamic reduction in mate attractiveness under dim light conditions compared with darkness. These results suggest that females are trading off the attractiveness of potential mates with the perceived costs of executing mate choice by committing to an initial decision and thereby reducing assessment time and movement. The dynamic playback design used here provides an approach that could be applied in other systems in which context-dependent decision-making is thought to be important.

scholarly journals Response time of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph

2019 ◽  
Vol 6 (8) ◽  
pp. 190677 ◽  
Author(s):  
Carina Nebel ◽  
Petra Sumasgutner ◽  
Adrien Pajot ◽  
Arjun Amar
Keyword(s):  
Response Time ◽  
Response Times ◽  
Bright Light ◽  
Light Level ◽  
White Background ◽  
Light Conditions ◽  
Dark Light ◽  
Light Levels ◽  
Columbia Livia ◽  
Colour Morphs

To avoid predation, many species rely on vision to detect predators and initiate an escape response. The ability to detect predators may be lower in darker light conditions or with darker backgrounds. For birds, however, this has never been experimentally tested. We test the hypothesis that the response time of avian prey (feral pigeon Columbia livia f. domestica ) to a simulated hawk attack (taxidermy mounted colour-polymorphic black sparrowhawk Accipiter melanoleucus ) will differ depending on light levels or background colour. We predict that response will be slower under darker conditions, which would translate into higher predation risk. The speed of response of prey in relation to light level or background colour may also interact with the colour of the predator, and this idea underpins a key hypothesis proposed for the maintenance of different colour morphs in polymorphic raptors. We therefore test whether the speed of reaction is influenced by the morph of the hawk (dark/light) in combination with light conditions (dull/bright), or background colours (black/white). We predict slowest responses to morphs under conditions that less contrast with the plumage of the hawk (e.g. light morph under bright light or white background). In support of our first hypothesis, pigeons reacted slower under duller light and with a black background. However, we found no support for the second hypothesis, with response times observed between the hawk-morphs being irrespective of light levels or background colour. Our findings experimentally confirm that birds detect avian predators less efficiently under darker conditions. These conditions, for example, might occur during early mornings or in dense forests, which could lead to changes in anti-predator behaviours. However, our results provide no support that different morphs may be maintained in a population due to differential selective advantages linked to improved hunting efficiencies in different conditions due to crypsis.

scholarly journals Plastic responses in the coral Pocillopora acuta to extreme low-light conditions with and without food provision

2021 ◽  
Vol 168 (7) ◽  
Author(s):  
Jenny Fong ◽  
Rosa Celia Poquita-Du ◽  
Peter A. Todd
Keyword(s):  
Species Differences ◽  
Light Level ◽  
Ambient Light ◽  
Light Conditions ◽  
Feeding Rates ◽  
Low Light ◽  
Reef Environment ◽  
Ambient Light Level ◽  
Related Stress ◽  
Plastic Responses

AbstractThis study examines phenotypically plastic responses in Pocillopora acuta collected from a highly urbanized reef environment to extreme low-light conditions. While among-species differences in how corals cope with low light are well documented, much less is known about within-species responses. It also remains unclear how extreme low light and provision of food may interact and influence coral physiology. Clonal fragments from six colonies (genotypes) of P. acuta were subjected to two light treatments with mean midday irradiances of 4 and 40 μmol photons m−2 s−1 photosynthetically active radiation (PAR), representing just 0.5 and 5% ambient light level, and were either fed with zooplankton or not fed for nine days. Corals maintained in 4 PAR had lower endosymbiont density but higher cellular chlorophyll a concentration than those in 40 PAR. Feeding rates were similar in both light treatments and had no significant effects on endosymbiont density and chlorophyll a concentrations. While genotypes varied in the level of phenotypic plasticity expressed for both photoacclimation and heterotrophy, most displayed similar directions in their responses, indicating photoacclimation in P. acuta is broadly predictable. Our study demonstrates that P. acuta from Singapore is able to acclimate to very low-light conditions by adjusting their photophysiology, providing additional evidence that this species is resilient to urbanization-related stress.

scholarly journals Visual Comfort of Tablet Devices under a Wide Range of Ambient Light Levels

2021 ◽  
Vol 11 (18) ◽  
pp. 8679
Author(s):  
Hsin-Pou Huang ◽  
Minchen Wei ◽  
Hung-Chung Li ◽  
Li-Chen Ou
Keyword(s):  
Evaluation Model ◽  
Light Level ◽  
White Background ◽  
Psychophysical Experiment ◽  
Visual Comfort ◽  
Ambient Light ◽  
Viewing Condition ◽  
Light Levels ◽  
Ambient Light Level ◽  
Wide Range

E-reading devices are becoming more and more common in our daily life, and they are used under a wide range of ambient light levels, from completely dark to extremely bright conditions. In this study, a psychophysical experiment is carried out to investigate how ambient light level affects the visual comfort of an e-reading device. Human observers compare the visual comfort of pairs of different text-background lightness combinations on a tablet device under three ambient light levels (i.e., 150, 1500, and 15,000 lx). With our previous work, the experimental results show that the trend of visual comfort interval scales below 1500 lx (i.e., Dark, 150, 300, and 1500 lx) are similar to each other but not for those under illuminance above the 1500 lx (i.e., 3000 and 15,000 lx). For the same lightness difference between text and background, the observers tend to read the text with a white background compared to a black background, especially for 3000 and 15,000 lx. Moreover, a black text on a light-gray background is the most comfortable combination under these two illuminance levels. An evaluation model is proposed based on ambient illuminance, screen parameters, and visual estimation to design an optimal viewing condition when reading on the tablet display.

scholarly journals Learning to feed in the dark: how light level influences feeding in the hawkmoth Manduca sexta

2021 ◽  
Vol 17 (9) ◽  
pp. 20210320
Author(s):  
Tanvi Deora ◽  
Mahad A. Ahmed ◽  
Bingni W. Brunton ◽  
Thomas L. Daniel
Keyword(s):  
Motor Control ◽  
Manduca Sexta ◽  
Three Dimensional ◽  
Light Level ◽  
Artificial Light ◽  
Motion Sensors ◽  
Light Conditions ◽  
Light At Night ◽  
Light Levels ◽  
Artificial Flowers

Nocturnal insects like moths are essential for pollination, providing resilience to the diurnal pollination networks. Moths use both vision and mechanosensation to locate the nectary opening in the flowers with their proboscis. However, increased light levels due to artificial light at night (ALAN) pose a serious threat to nocturnal insects. Here, we examined how light levels influence the efficacy by which the crepuscular hawkmoth Manduca sexta locates the nectary. We used three-dimensional-printed artificial flowers fitted with motion sensors in the nectary and machine vision to track the motion of hovering moths under two light levels: 0.1 lux (moonlight) and 50 lux (dawn/dusk). We found that moths in higher light conditions took significantly longer to find the nectary, even with repeated visits to the same flower. In addition to taking longer, moths in higher light conditions hovered further from the flower during feeding. Increased light levels adversely affect learning and motor control in these animals.

Mate choice decisions of female serrate-legged small treefrogs are affected by ambient light under natural, but not enhanced artificial nocturnal light conditions

2019 ◽  
Vol 169 ◽  
pp. 103997
Author(s):  
Ke Deng ◽  
Bi-Cheng Zhu ◽  
Ya Zhou ◽  
Qing-Hua Chen ◽  
Tong-Liang Wang ◽  
...  
Keyword(s):  
Mate Choice ◽  
Ambient Light ◽  
Light Conditions

scholarly journals Effects of Light, N and Defoliation on Biomass Allocation in Poa annua

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1783
Author(s):  
Louis John Irving ◽  
Sayuki Mori
Keyword(s):  
Biomass Allocation ◽  
Light Level ◽  
Poa Annua ◽  
Root Mass ◽  
Light Conditions ◽  
Low Light ◽  
Light Levels ◽  
Below Ground ◽  
Shoot Mass

Plants allocate biomass to above- and below-ground organs in response to environmental conditions. While the broad patterns are well-understood, the mechanisms by which plants allocate new growth remain unclear. Modeling approaches to biomass allocation broadly split into functional equilibrium type models and more mechanistically based transport resistance type models. We grew Poa annua plants in split root boxes under high and low light levels, high and low N supplies, with N supplied equally or unequally. Our data suggest that light level had the strongest effect on root mass, with N level being more important in controlling shoot mass. Allocation of growth within the root system was compatible with phloem partitioning models. The root mass fraction was affected by both light and N levels, although within light levels the changes were primarily due to changes in shoot growth, with root mass remaining relatively invariant. Under low light conditions, plants exhibited increased specific leaf area, presumably to compensate for low light levels. In a follow-up experiment, we showed that differential root growth could be suppressed by defoliation under low light conditions. Our data were more compatible with transport resistance type models.

SCUBA diver-operated low-light-level video system for use in underwater research and survey

1987 ◽  
Vol 67 (2) ◽  
pp. 299-306 ◽  
Author(s):  
G. W. Potts ◽  
J. W. Wood ◽  
J. M. Edwards
Keyword(s):  
High Resolution ◽  
Power Supply ◽  
Light Level ◽  
Natural Light ◽  
Scuba Diver ◽  
Ambient Light ◽  
Low Light ◽  
Marine Research ◽  
Light Levels ◽  
External Power

Television cameras and video equipment are well established as tools in many areas of marine research and have been reviewed by Barnes (1963), Myrberg (1973), Harris (1980), and Holme (1984, 1985). The TV camera is usually mounted on a remote sledge (Machan & Fedra, 1975; Holme & Barrett, 1977) or submersible, often with arrays of lights, and lacks the manoeuvrability that is necessary for many types of detailed survey and behavioural recording. Commercial and industrial uses also demand high-resolution equipment that is often contained in bulky underwater cases capable of operating at great depths and well below that possible by the conventional SCUBA diver. It is not unusual for the equipment to be used in conjunction with external lighting units where natural light levels are too low for the use of ambient light, and is dependent on an external power supply normally situated in the surface support vessel or within a submersible (Sisman, 1982).

Silence is sexy: soundscape complexity alters mate choice in túngara frogs

2020 ◽  
Author(s):  
Derek A Coss ◽  
Kimberly L Hunter ◽  
Ryan C Taylor
Keyword(s):  
Decision Making ◽  
Mate Choice ◽  
Animal Communication ◽  
Female Mate Choice ◽  
High Noise ◽  
Physalaemus Pustulosus ◽  
Duty Cycles ◽  
Noise Density ◽  
Different Types ◽  
Tungara Frogs

Abstract Many animals acoustically communicate in large aggregations, producing biotic soundscapes. In turn, these natural soundscapes can influence the efficacy of animal communication, yet little is known about how variation in soundscape interferes with animals that communicate acoustically. We quantified this variation by analyzing natural soundscapes with the mid-frequency cover index and by measuring the frequency ranges and call rates of the most common acoustically communicating species. We then tested female mate choice in the túngara frog (Physalaemus pustulosus) in varying types of background chorus noise. We broadcast two natural túngara frog calls as a stimulus and altered the densities (duty cycles) of natural calls from conspecifics and heterospecifics to form the different types of chorus noise. During both conspecific and heterospecific chorus noise treatments, females demonstrated similar preferences for advertisement calls at low and mid noise densities but failed to express a preference in the presence of high noise density. Our data also suggest that nights with high densities of chorus noise from conspecifics and heterospecifics are common in some breeding ponds, and on nights with high noise density, the soundscape plays an important role diminishing the accuracy of female decision-making.

A Comparison of the Light- Reduction Capacity of Commonly Used Incubator Covers

2005 ◽  
Vol 24 (2) ◽  
pp. 37-44 ◽  
Author(s):  
Yi-Hui Lee ◽  
Nima Malakooti ◽  
Marilyn Lotas
Keyword(s):  
Bright Light ◽  
Light Level ◽  
Outcome Variable ◽  
Ambient Light ◽  
Light Reduction ◽  
Light Levels ◽  
Ambient Light Level ◽  
Main Outcome Variable ◽  
Few Data ◽  
Incubator Covers

Purpose: The use of incubator covers to enhance preterm infants’ rest and recovery is common in the NICU. However, the kinds of covers used vary extensively among and within nurseries. Few data exist on the effectiveness of different types of covers in reducing light levels to the infant. This study compared several types of commonly used incubator covers as to efficacy of light reduction.Design: A descriptive, comparative design was used in this study.Sample: Twenty-three incubator covers were tested, including professional, receiving blanket, hand-crocheted, three-layer quilt, and flannel.Main Outcome Variable: The percentage of light level reduction of different incubator covers under various ambient light level settings.Results: The amount of light reduction provided by incubator covers varies depending on type of fabric as well as percentage of incubator surface shielded by the cover. Dark-colored covers provided greater light reduction than bright/light-colored covers when covers identical in fabric type were compared. The light-reduction efficiency of the covers varied depending on the level of ambient light. Covers provided less light reduction in higher ambient light levels.

scholarly journals Identification of multiple noise sources improves estimation of neural responses across stimulus conditions

2020 ◽  
Author(s):  
Alison I. Weber ◽  
Eric Shea-Brown ◽  
Fred Rieke
Keyword(s):  
Ganglion Cells ◽  
Light Level ◽  
Response Variability ◽  
Retinal Ganglion ◽  
Ambient Light ◽  
Neural Responses ◽  
Multiple Sources ◽  
Noise Sources ◽  
Modeling Framework ◽  
Light Levels

AbstractMost models of neural responses are constructed to capture the average response to inputs but poorly reproduce the observed response variability. The origins and structure of this variability have significant implications for how information is encoded and processed in the nervous system. Here, we present a new modeling framework that better captures observed features of neural response variability across stimulus conditions by incorporating multiple sources of noise. We use this model to fit responses of retinal ganglion cells at two different ambient light levels and demonstrate that it captures the full distribution of responses. The model reveals light level-dependent changes that could not be seen with previous models. It shows both large changes in rectification of nonlinear circuit elements and systematic differences in the contributions of different noise sources under different conditions. This modeling framework is general and can be applied to a variety of systems outside the retina.

Sign in / Sign up

Export Citation Format

Share Document