scholarly journals Heliconiini butterflies can learn time-dependent reward associations

2020 ◽  
Author(s):  
M. Wyatt Toure ◽  
Fletcher J. Young ◽  
W. Owen McMillan ◽  
Stephen H. Montgomery
Keyword(s):  
Time Of Day ◽  
Time Dependent ◽  
Dietary Behaviour ◽  
Pollen Feeding ◽  
Foraging Preferences ◽  
Temporal Predictability ◽  
Colour Preferences ◽  
Order Of Presentation ◽  
Trap Line ◽  
Foraging Time

AbstractFor many pollinators, flowers provide predictable temporal schedules of resource availability, meaning an ability to learn time-dependent information could be widely beneficial. However, this ability has only been demonstrated in a handful of species. Observational studies of Heliconius butterflies suggest that they may have an ability to form time-dependent foraging preferences. Heliconius are unique among butterflies in actively collecting and digesting pollen, a dietary behaviour linked to spatiotemporally faithful ‘trap-line’ foraging. Time-dependency of foraging preferences is hypothesised to allow Heliconius to exploit temporal predictability in alternative pollen resources, as well as contributing to optimal use of learnt foraging routes. Here, we provide the first experimental evidence in support of this hypothesis, demonstrating that Heliconius hecale can learn opposing colour preferences in two time periods. This shift in preference is robust to the order of presentation, suggesting that preference is tied to the time of day and not due to ordinal learning. However, we also show that this ability is not limited to Heliconius, as previously hypothesised, but is also present in a related genus of non-pollen feeding butterflies. This demonstrates that time learning pre-dates the origin of pollen-feeding and may be prevalent across butterflies with less specialized foraging behaviours.

scholarly journals Heliconiini butterflies can learn time-dependent reward associations

2020 ◽  
Vol 16 (9) ◽  
pp. 20200424
Author(s):  
M. Wyatt Toure ◽  
Fletcher J. Young ◽  
W. Owen McMillan ◽  
Stephen H. Montgomery
Keyword(s):  
Time Of Day ◽  
Time Dependent ◽  
Dietary Behaviour ◽  
Pollen Feeding ◽  
Foraging Preferences ◽  
Temporal Predictability ◽  
Colour Preferences ◽  
Order Of Presentation ◽  
Trap Line ◽  
Foraging Time

For many pollinators, flowers provide predictable temporal schedules of resource availability, meaning an ability to learn time-dependent information could be widely beneficial. However, this ability has only been demonstrated in a handful of species. Observations of Heliconius butterflies suggest that they may have an ability to form time-dependent foraging preferences. Heliconius are unique among butterflies in actively collecting pollen, a dietary behaviour linked to spatio-temporally faithful ‘trap-line' foraging. Time dependency of foraging preferences is hypothesized to allow Heliconius to exploit temporal predictability in alternative pollen resources. Here, we provide the first experimental evidence in support of this hypothesis, demonstrating that Heliconius hecale can learn opposing colour preferences in two time periods. This shift in preference is robust to the order of presentation, suggesting that preference is tied to the time of day and not due to ordinal or interval learning. However, this ability is not limited to Heliconius , as previously hypothesized, but also present in a related genus of non-pollen feeding butterflies. This demonstrates time learning likely pre-dates the origin of pollen feeding and may be prevalent across butterflies with less specialized foraging behaviours.

scholarly journals Prey removal in cotton crops next to woodland reveals periodic diurnal and nocturnal invertebrate predation gradients from the crop edge by birds and bats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Heidi L. Kolkert ◽  
Rhiannon Smith ◽  
Romina Rader ◽  
Nick Reid
Keyword(s):  
Pest Control ◽  
Open Space ◽  
Optimal Foraging Theory ◽  
Time Of Day ◽  
Camera Traps ◽  
Generalist Predators ◽  
Crop Cover ◽  
Foraging Preferences ◽  
Experimental Feeding ◽  
Natural Pest Control

AbstractFactors influencing the efficacy of insectivorous vertebrates in providing natural pest control services inside crops at increasing distances from the crop edge are poorly understood. We investigated the identity of vertebrate predators (birds and bats) and removal of sentinel prey (mealworms and beetles) from experimental feeding trays in cotton crops using prey removal trials, camera traps and observations. More prey was removed during the day than at night, but prey removal was variable at the crop edge and dependent on the month (reflecting crop growth and cover) and time of day. Overall, the predation of mealworms and beetles was 1-times and 13-times greater during the day than night, respectively, with predation on mealworms 3–5 times greater during the day than night at the crop edge compared to 95 m inside the crop. Camera traps identified many insectivorous birds and bats over crops near the feeding trays, but there was no evidence of bats or small passerines removing experimental prey. A predation gradient from the crop edge was evident, but only in some months. This corresponded to the foraging preferences of open-space generalist predators (magpies) in low crop cover versus the shrubby habitat preferred by small passerines, likely facilitating foraging away from the crop edge later in the season. Our results are in line with Optimal Foraging Theory and suggest that predators trade-off foraging behaviour with predation risk at different distances from the crop edge and levels of crop cover. Understanding the optimal farm configuration to support insectivorous bird and bat populations can assist farmers to make informed decisions regarding in-crop natural pest control and maximise the predation services provided by farm biodiversity.

The effects of age, sex, reproductive status and temporal factors on the time-use of free-ranging red kangaroos

1993 ◽  
Vol 20 (6) ◽  
pp. 785 ◽  
Author(s):  
DM Watson ◽  
TJ Dawson
Keyword(s):  
Body Size ◽  
Group Size ◽  
Time Use ◽  
New South ◽  
New South Wales ◽  
Time Of Day ◽  
Adult Males ◽  
South Wales ◽  
Free Ranging ◽  
Foraging Time

The effects of temporal (time of day and season) factors and size, sex, female reproductive state and group size on the diel time-use of free-ranging red kangaroos (Macropus rufus) was examined. Particular emphasis was given to the effects on their foraging behaviour, with foraging divided into cropping, chewing and searching components. The study was conducted in semi-arid western New South Wales from July 1991 to March 1992, a time of deepening drought conditions in New South Wales. Group size had very little influence on the time-use of M. rufus. It was negatively but only weakly correlated with the proportion of foraging time spent chewing (chewing intensity). No significant differences in time-use were found between size classes of adult males (large and medium-sized males), females with or without pouch young, or females with different-sized pouch young (no visible young, small pouch young or large pouch young). Differences occurred between adult males, adult females and subadult kangaroos. These differences were mainly associated with their chewing and searching behaviour and were related to body size; as body size increased the proportion of time spent chewing and the intensity of chewing increased while the proportion of time searching and the proportion of foraging time spent searching (searching intensity) decreased. Neither the proportion of time spent cropping or foraging nor the proportion of foraging time spent cropping (cropping intensity) or the proportion of active time spent foraging (foraging intensity) differed between any size/sex/reproductive class. Temporal effects had a considerable influence on time-use. M. rufus were most active at night and in the few hours after sunrise and sunset. Seasonal changes in time-use were largely a result of changes in daytime behaviour. M. rufus foraged less and rested more during the day in winter than in spring or summer. There was no increase in the intensity or proportion of time spent foraging or cropping at night to compensate for the reduction in diurnal foraging. It is hypothesised that temporal variations in time-use were related to variations in weather and vegetation conditions.

scholarly journals Bee foraging preferences on three willow ( Salix ) species: Effects of species, plant sex, sampling day and time of day

2020 ◽  
Vol 177 (3) ◽  
pp. 333-345
Author(s):  
Alex Mosseler ◽  
John Major ◽  
Don Ostaff ◽  
John Ascher
Keyword(s):  
Time Of Day ◽  
Species Effects ◽  
Foraging Preferences ◽  
Bee Foraging ◽  
Plant Sex

Variation in dive behavior of Cuvier’s beaked whales with seafloor depth, time-of-day, and lunar illumination

2020 ◽  
Vol 644 ◽  
pp. 199-214 ◽  
Author(s):  
J Barlow ◽  
GS Schorr ◽  
EA Falcone ◽  
D Moretti
Keyword(s):  
Surface Waters ◽  
Predator Avoidance ◽  
Time Of Day ◽  
Maximum Depth ◽  
Near Surface ◽  
Beaked Whales ◽  
Energetic Constraints ◽  
The Mean ◽  
Ziphius Cavirostris ◽  
Foraging Time

Depth distributions were analyzed from a study of 19 Cuvier’s beaked whales Ziphius cavirostris that were tagged with satellite transmitting instruments off southern California, USA. Over 113000 depth measurements were made over the equivalent of ~200 sampling days. The mean foraging depth was 1182 m (SD = 305 m), and the mean of the maximum depth of all foraging dives was 1427 m (SD = 298 m). Mean foraging depths increased with seafloor depths up to a maximum of ~1300 m at a seafloor depth of 1900 m, but decreased slightly to a mean of ~1200 m at seafloor depths of 2000-4000 m. Near-bottom habitat appears to be important for foraging; whales spent ~30% of their foraging time within 200 m of the bottom at seafloor depths of 1000-2000 m. However, little foraging time was spent near the bottom at seafloor depths greater than 2000 m. The percentage of time spent at near-surface depths (<50 m) was more than twice as high at night (25%) than during the day (12%). Lunar light also appears to affect diving, with 28% of dark nights and only 17% of brightly moonlit nights spent at these near-surface depths. The apparent avoidance of surface waters during daytime and on brightly moonlit nights is consistent with avoidance of visual predators. A considerably greater fraction of time was spent foraging at night (24.8%) than during the day (15.7%), possibly due to energetic constraints imposed by predator avoidance during the day.

scholarly journals Daily Variations in Ceftriaxone Pharmacokinetics in Rats

2003 ◽  
Vol 47 (2) ◽  
pp. 809-812 ◽  
Author(s):  
M. Rebuelto ◽  
L. Ambros ◽  
M. Rubio
Keyword(s):  
Time Of Day ◽  
Time Dependent ◽  
Pharmacokinetic Parameters ◽  
Dark Phase ◽  
Sprague Dawley ◽  
Dark Cycle ◽  
Once Daily ◽  
Daily Variations ◽  
Sprague Dawley Rats ◽  
Pharmacokinetics In Rats

ABSTRACT The aim of this study was to determine whether the time of day ceftriaxone was administered modified its pharmacokinetics. Ceftriaxone was given intraperitoneally at either 0400, 1000, 1600, and 2200 h to Sprague-Dawley rats synchronized under a light-dark cycle of 12 h of light and 12 h of dark. Pharmacokinetic parameters were analyzed for the presence of a 24-h rhythm. Results showed significant daily variations (P < 0.05) in ceftriaxone clearance, with the highest values during the dark phase. It is concluded that time-dependent variations in ceftriaxone pharmacokinetics may affect the therapeutic efficacy of current once-daily dosing schedules.

Appointment Scheduling Under Time-Dependent Patient No-Show Behavior

2020 ◽  
Vol 66 (8) ◽  
pp. 3480-3500 ◽  
Author(s):  
Qingxia Kong ◽  
Shan Li ◽  
Nan Liu ◽  
Chung-Piaw Teo ◽  
Zhenzhen Yan
Keyword(s):  
Optimal Solution ◽  
Time Of Day ◽  
Time Dependent ◽  
Worst Case ◽  
Arrival Times ◽  
Functional Relationships ◽  
Robust Model ◽  
Distributionally Robust ◽  
The Right ◽  
Dependent Patient

This paper studies how to schedule medical appointments with time-dependent patient no-show behavior and random service times. The problem is motivated by our studies of independent datasets from countries in two continents that unanimously identify a significant time-of-day effect on patient show-up probabilities. We deploy a distributionally robust model, which minimizes the worst-case total expected costs of patient waiting and service provider’s idling and overtime, by optimizing the scheduled arrival times of patients. This model is challenging because evaluating the total cost for a given schedule involves a linear program with uncertainties present in both the objective function and the right-hand side of the constraints. In addition, the ambiguity set considered contains discrete uncertainties and complementary functional relationships among these uncertainties (namely, patient no-shows and service durations). We show that when patient no-shows are exogenous (i.e., time-independent), the problem can be reformulated as a copositive program and then be approximated by semidefinite programs. When patient no-shows are endogenous on time (and hence on the schedule), the problem becomes a bilinear copositive program. We construct a set of dual prices to guide the search for a good schedule and use the technique iteratively to obtain a near-optimal solution. Our computational studies reveal a significant reduction in total expected cost by taking into account the time-of-day variation in patient show-up probabilities as opposed to ignoring it. This paper was accepted by David Simchi-Levi, optimization.

Flies’ colour preferences depend on the time of day

Nature ◽  
2019 ◽  
Vol 574 (7776) ◽  
pp. 43-44
Author(s):  
Charlotte Helfrich-Förster
Keyword(s):  
Time Of Day ◽  
Colour Preferences

scholarly journals Sunsetting skim matrices: A trajectory-mining approach to derive travel time skim matrix in dynamic traffic assignment for activity-base model integration

2020 ◽  
Vol 13 (1) ◽  
pp. 413-428
Author(s):  
Ye Tian ◽  
Yi-Chang Chiu ◽  
Jian Sun ◽  
Chen Chai
Keyword(s):  
Travel Time ◽  
Dynamic Traffic Assignment ◽  
Time Of Day ◽  
Time Dependent ◽  
Travel Time Reliability ◽  
Trajectory Data ◽  
Forecasting Models ◽  
Trajectory Mining ◽  
Vehicle Trajectory ◽  
Travel Impedance

The travel impedance skim matrix is one of the most essential intermediate products within transportation forecasting models and is a fundamental input for activity-based transportation forecasting models. It reflects interzonal travel time, travel time reliability, travel costs, etc. by time of day. The traditional method to obtain skim matrices is to execute multiple times of time-dependent, shortest-path calculations. However, the computational and memory use burden can easily increase to an intractable level when dealing with mega-scale networks, such as those with thousands of traffic-analysis zones. This research proposes two new approaches to extract the interzonal travel impedance information from the already existing vehicle trajectory data. Vehicle trajectories store travel impedance information in a more compact format when compared to time-dependent link performance profiles. The numerical experiments highlight huge potential advantages of the proposed approaches in terms of saving both memory and CPU time.

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