Foraging ecology of the night-active bull ant Myrmecia pyriformis

2013 ◽  
Vol 61 (2) ◽  
pp. 170 ◽  
Author(s):  
Samuel F. Reid ◽  
Ajay Narendra ◽  
Robert W. Taylor ◽  
Jochen Zeil
Keyword(s):  
Visual System ◽  
Foraging Ecology ◽  
Activity Patterns ◽  
Colony Founding ◽  
Liquid Food ◽  
Mating Season ◽  
Wild Populations ◽  
Ecological Information ◽  
Light Levels ◽  
Nest Activity

Here we report on the nocturnal bull ant Myrmecia pyriformis, a species whose activity to and from the nest is mainly restricted to the dawn and dusk twilight respectively. Recent research on M. pyriformis has focussed on its visual system, the timing of activity patterns, and the navigational strategies employed by individuals while foraging. There is, however, a lack of basic ecological information about this species. The present study describes the behaviour and foraging ecology of wild populations of M. pyriformis. We find that most foragers make only one foraging journey per night, leaving the nest at dusk twilight and returning during dawn twilight. Individuals who make multiple trips typically return with prey. We provide evidence that foragers imbibe liquid food while abroad and likely share these resources via trophallaxis once within the nest. Activity during the night varies with moon illumination, and we postulate that this is due to changes in light levels, which influence navigation to and from the nest. This hypothesis is supported by observations of activity during overcast conditions. Finally, we also describe some aspects of colony founding, colony demise and the behaviour of reproductive individuals during the mating season.

Preference of pigs for illuminance

2003 ◽  
Vol 2003 ◽  
pp. 38-38
Author(s):  
N.R. Taylor ◽  
G. Perry ◽  
M. Potter ◽  
N.B. Prescott ◽  
C.M. Wathes
Keyword(s):  
Visual System ◽  
Wild Boar ◽  
Activity Patterns ◽  
Artificial Lighting ◽  
Light Levels ◽  
Wide Range

Pigs housed under artificial lighting currently experience a wide range of illuminances and photoperiods, which may be more appropriate to the visual capabilities and needs of stockpersons rather than pigs. Pigs and wild boar can show nocturnal, diurnal and crepuscular activity patterns, suggesting that their visual system may function well under a wide range of light levels, unlike humans. Inappropriate lighting affects many aspects of an animal’s physiology, anatomy and behaviour and may compromise welfare. This experiment was designed to investigate the preference of juvenile pigs to occupy and conduct certain behaviours in different illuminances, and gain some indication of their preferred photoperiod.

The sleep maths: A strong correlation between more daytime light and better night-time sleep

2021 ◽  
Vol 53 (5) ◽  
pp. 423-435
Author(s):  
MG Figueiro ◽  
C Jarboe ◽  
L Sahin
Keyword(s):  
Sleep Quality ◽  
Visual System ◽  
Psychological Health ◽  
Strong Correlation ◽  
Emotional Health ◽  
Circadian System ◽  
The Self ◽  
Night Time ◽  
Online Surveys ◽  
Light Levels

Lighting for workplaces and schools is typically specified to meet the needs of the visual system without sufficient regard to the lighting characteristics that are required by the human circadian system. In 2020, many workers and students were compelled by the COVID-19 pandemic to work and study from home, where light levels are typically even lower than those found in most schools and workplaces. Using online surveys, this study sought to quantify potential changes in daytime light exposures resulting from teleworking or self-isolating at home and how those changes might have affected self-reported sleep quality, psychological health and emotional health. The first survey was administered in early May 2020, and the second survey was administered in September 2020. In broad terms, our analysis indicates that the greater the amount of light one is exposed to during the day (either in the home or outdoors), the better the self-reported sleep outcomes. Stress and mood were also correlated with greater self-reported daytime light exposures. The results suggest that spending one to two hours outdoors or staying in a bright to very bright room indoors may improve night-time sleep. These results have important implications for daytime lighting in homes, offices and schools.

scholarly journals Transformation from independent to integrative coding of multi-object arrangements in human visual cortex

2017 ◽  
Author(s):  
Daniel Kaiser ◽  
Marius V. Peelen
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Activity Patterns ◽  
Spatial Arrangement ◽  
Living Room ◽  
Natural Scenes ◽  
Response Patterns ◽  
Object Representations ◽  
Individual Object ◽  
Object Coding

AbstractTo optimize processing, the human visual system utilizes regularities present in naturalistic visual input. One of these regularities is the relative position of objects in a scene (e.g., a sofa in front of a television), with behavioral research showing that regularly positioned objects are easier to perceive and to remember. Here we use fMRI to test how positional regularities are encoded in the visual system. Participants viewed pairs of objects that formed minimalistic two-object scenes (e.g., a “living room” consisting of a sofa and television) presented in their regularly experienced spatial arrangement or in an irregular arrangement (with interchanged positions). Additionally, single objects were presented centrally and in isolation. Multi-voxel activity patterns evoked by the object pairs were modeled as the average of the response patterns evoked by the two single objects forming the pair. In two experiments, this approximation in object-selective cortex was significantly less accurate for the regularly than the irregularly positioned pairs, indicating integration of individual object representations. More detailed analysis revealed a transition from independent to integrative coding along the posterior-anterior axis of the visual cortex, with the independent component (but not the integrative component) being almost perfectly predicted by object selectivity across the visual hierarchy. These results reveal a transitional stage between individual object and multi-object coding in visual cortex, providing a possible neural correlate of efficient processing of regularly positioned objects in natural scenes.

Demography and foraging ecology of Chelonia mydas on tropical shallow reefs in Bahia, Brazil

2015 ◽  
Vol 96 (6) ◽  
pp. 1295-1304 ◽  
Author(s):  
Adriana Jardim ◽  
Milagros López-Mendilaharsu ◽  
Francisco Barros
Keyword(s):  
Red Algae ◽  
Foraging Ecology ◽  
Activity Patterns ◽  
Somatic Growth ◽  
Growth Dynamics ◽  
Chelonia Mydas ◽  
Annual Growth Rate ◽  
Life Stages ◽  
Green Turtles ◽  
Spatial Use

Long-term tagging studies, particularly those that target life stages away from nesting beaches can provide important insights in key life history traits, which are essential for the effective management of endangered species. The coast of Bahia hosts important green turtle foraging areas, but information on demography, spatial use and foraging ecology in this region is lacking. Here, we (1) examined the size-class structure of green turtles in Bahia, (2) compared the size distribution from Bahia to other foraging aggregations in Brazil, and (3) studied the somatic growth dynamics. Additionally, we investigated the (4) diet, (5) habitat use and (6) activity patterns of green turtles along shallow reefs in Bahia. From 2009 to 2013, 322 green turtles were captured and 44 were recaptured between 7 and 1218 days after initial tagging. Curved carapace length varied from 32.9 to 122.5 cm. Mean annual growth rate was 3.03 ± 1.18 cm year−1. The diet of the turtles was mainly composed of red algae of the family Gelidiaceae, Gelidiellaceae and Cystocloniaceae. There was a positive relationship between the abundance of red algae and the number of turtle sightings, with a significant increase in foraging activity during late afternoon. This study highlights the importance of this area as a mixed foraging aggregation of juvenile and adult green turtles, and reveals that foraging grounds for this species in Brazil exhibit southern immature-dominated assemblages and northern mixed aggregations. Areas with high aggregation of green turtles comprising individuals from different life stages must be targeted for conservation management.

scholarly journals Latitudinal variation in light levels drives human visual system size

2011 ◽  
Vol 8 (1) ◽  
pp. 90-93 ◽  
Author(s):  
Eiluned Pearce ◽  
Robin Dunbar
Keyword(s):  
Visual System ◽  
Human Population ◽  
Positive Relationship ◽  
System Size ◽  
Day Length ◽  
Ambient Light ◽  
Light Levels ◽  
System Components ◽  
Visual Cortices ◽  
Selection For

Ambient light levels influence visual system size in birds and primates. Here, we argue that the same is true for humans. Light levels, in terms of both the amount of light hitting the Earth's surface and day length, decrease with increasing latitude. We demonstrate a significant positive relationship between absolute latitude and human orbital volume, an index of eyeball size. Owing to tight scaling between visual system components, this will translate into enlarged visual cortices at higher latitudes. We also show that visual acuity measured under full-daylight conditions is constant across latitudes, indicating that selection for larger visual systems has mitigated the effect of reduced ambient light levels. This provides, to our knowledge, the first support that light levels drive intraspecific variation in visual system size in the human population.

scholarly journals Visual Experience-Dependent Maturation of Correlated Neuronal Activity Patterns in a Developing Visual System

2011 ◽  
Vol 31 (22) ◽  
pp. 8025-8036 ◽  
Author(s):  
H. Xu ◽  
A. S. Khakhalin ◽  
A. V. Nurmikko ◽  
C. D. Aizenman
Keyword(s):  
Visual System ◽  
Neuronal Activity ◽  
Visual Experience ◽  
Activity Patterns

Harpy Eagle Harpia harpyja nest activity patterns: Potential ecotourism and conservation opportunities in the Amazon Forest

2021 ◽  
pp. 1-15
Author(s):  
EVERTON B. P. MIRANDA ◽  
CAIO F. KENUP ◽  
CHARLES A. MUNN ◽  
NIKI HUIZINGA ◽  
NICKOLAS LORMAND ◽  
...  
Keyword(s):  
Wildlife Conservation ◽  
Activity Patterns ◽  
Daily Basis ◽  
Local Communities ◽  
Camera Traps ◽  
Amazon Forest ◽  
Apex Predators ◽  
Nest Activity ◽  
Harpia Harpyja ◽  
Potential Tool

Summary Tourism can be a powerful tool for wildlife conservation if well controlled and responsibly managed. Apex predators constitute particularly attractive subjects for tourism, but simultaneously they may generate conflict with local communities. Harpy Eagles Harpia harpyja are the largest eagle species and are highly sought-after by ecotourists. The last stronghold of the Harpy Eagle is the Amazon Forest, which is being deforested for cattle ranching. We tested methods for developing Harpy Eagle ecotourism as a potential tool to harmonize these issues. Using camera traps, we collected data on timing of Harpy Eagle visits to their nests, as well as on probabilities of viewing an eagle. Harpy Eagles can only be seen predictably during the first 12 of the 30–36 month nest cycle. In nests with nestlings (up to 5–7 months), adults are visible on a daily basis, and this period lasts 16.6% of the nesting cycle, demanding a minimum of 13, 17, and 26 nests to have at least one nest with a nestling on 90%, 95% and 99% of the days. After this 5–7 month window, we found that two and 4.16 days spent at nests afforded high probabilities of sighting a fledgling or adult eagle, respectively. Harpy Eagles were mainly active at the beginning and the end of the day. Activity core lasted 6.5 decimal hours for adults, peaking at 10h00, and 7.45 decimal hours for fledged eagles, peaking at 15h00. Our results demonstrate that Harpy Eagles fit several criteria for a viable wildlife attraction: predictable in activity and location, viewable, and diurnal, even though at the same time they are considered a rarity. In a broader perspective, Harpy Eagle tourism shows every indication of being a significant tool for more robust rainforest conservation.

Nest-Activity Patterns and Food-Provisioning Rates by Great Egrets (Ardea alba)

Waterbirds ◽  
2010 ◽  
Vol 33 (4) ◽  
pp. 504-510 ◽  
Author(s):  
Alan D. Maccarone ◽  
John N. Brzorad ◽  
Heather M. Stone
Keyword(s):  
Activity Patterns ◽  
Food Provisioning ◽  
Ardea Alba ◽  
Nest Activity

Social status of male Iberian rock lizards (Lacerta monticola) influences their activity patterns during the mating season

2000 ◽  
Vol 78 (7) ◽  
pp. 1105-1109 ◽  
Author(s):  
José Martín ◽  
Pilar López
Keyword(s):  
Social Status ◽  
Body Mass ◽  
Activity Patterns ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Individual Variability ◽  
Activity Levels ◽  
Mating Season ◽  
The Social ◽  
Body Mass Changes

Not all individual lizards in a population are simultaneously active even when thermal conditions are suitable for activity. We examined inter-individual variability in activity levels of male Iberian rock lizards (Lacerta monticola) in a seminatural enclosure during the mating season, and analyzed whether social status affects their activity levels, time budgets, and body-mass changes. Activity levels of lizards varied significantly with time of day. However, activity levels of individual males were significantly correlated with their rank in the social hierarchy. When the males were active, their status did not influence the time spent basking, resting, or moving, but males with a higher status spent more time in social activities. Higher activity levels were costly, causing males to lose more body mass, although this could have been mainly due to the costs of maintaining a higher social status. We conclude that because attaining a higher status may require a male to be more active and more involved in agonistic encounters, subordinate individuals decrease their activity in order to decrease the costs of social behavior.

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