scholarly journals Prey-Driven Behavioral Habitat Use in a Low-Energy Ambush Predator

2020 ◽  
Author(s):  
Annalee M. Tutterow ◽  
Andrew S. Hoffman ◽  
John L. Buffington ◽  
Zachary T. Truelock ◽  
William E. Peterman
Keyword(s):  
Spatial Distribution ◽  
Habitat Selection ◽  
Small Mammal ◽  
Optimal Foraging ◽  
Prey Availability ◽  
Low Energy ◽  
List Type ◽  
Fine Scale ◽  
Timber Rattlesnake ◽  
Ambush Predator

AbstractFood acquisition is an important modulator of animal behavior and habitat selection that can affect fitness. Optimal foraging theory predicts that predators should select habitat patches to maximize their foraging success and net energy gain, which predators can achieve by targeting spaces with high prey availability. However, it is debated whether prey availability drives fine-scale habitat selection for predators.We assessed whether an ambush predator, the timber rattlesnake (Crotalus horridus), exhibits optimal foraging site selection based on the spatial distribution and availability of prey.We evaluated the spatial concordance of radio-telemetered timber rattlesnake foraging locations and passive infrared game camera trap detections of potential small mammal prey (Peromyscus spp., Tamias striatus, and Sciurus spp.) in a mixed-use forest in southeastern Ohio from 2016–2019. We replicated a characteristic timber rattlesnake ambush position by focusing cameras over logs and modeled small mammal encounters across the landscape in relation to remotely-sensed forest and landscape structural features. To determine whether snakes selectively forage in areas with higher prey availability, we projected the estimated prey spatial relationships across the landscape and modeled their overlap of occurrence with observed timber rattlesnake foraging locations.We broadly predicted that prey availability was greatest in mature deciduous forests, but T. striatus and Sciurus spp. exhibited greater spatial heterogeneity compared to Peromyscus spp. We also combined predicted species encounter rates to encompass a body size gradient in potential prey. The spatial distribution of cumulative small mammal encounters (i.e. overall prey availability), rather than the distribution of any one species, was highly predictive of snake foraging.Timber rattlesnakes appear to select foraging locations where the probability of encountering prey is greatest. Our study provides evidence for fine-scale optimal foraging in a low-energy, ambush predator and offers new insights into drivers of snake foraging and habitat selection.

A test of hypotheses based on optimal foraging considerations for a diving mammal using a novel experimental approach

2003 ◽  
Vol 81 (11) ◽  
pp. 1799-1807 ◽  
Author(s):  
Leslie A Cornick ◽  
Markus Horning
Keyword(s):  
Optimal Foraging ◽  
Prey Availability ◽  
Foraging Efficiency ◽  
Encounter Rate ◽  
Behavioural Plasticity ◽  
Fine Scale ◽  
Apex Predators ◽  
Encounter Rates ◽  
Marine Predators ◽  
Test Of Hypotheses

The response of marine predators to changes in fine-scale prey distribution is poorly understood. Precipitous declines in marine apex predators necessitate a better understanding of the magnitude of fluctuations in prey availability that are within the compensatory behavioural plasticity of predators. We experimentally manipulated the fine-scale prey field for a marine carnivore in a controlled, captive setting and examined changes in behaviour and efficiency with changes in prey encounter rate. We hypothesized (i) a minimum prey encounter rate below which the cost of foraging always exceeds the benefit, (ii) foraging effort should increase with increasing prey encounter rates, and (iii) a maximum threshold prey encounter rate at which foraging efficiency is optimized. Dive duration, foraging time, and dive and foraging efficiency increased significantly with increasing prey encounter rate up to an asymptote of ~13 fish per dive cycle, supporting two of the three hypotheses. The results also support predicted responses to changing prey encounter rates derived from an optimal foraging model for diving animals and are the first experimental validation of optimal foraging model predictions in a marine mammal. We believe that these results provide new insight and suggest new experimental techniques for examining the foraging ecology of large marine predators.

scholarly journals Spatio-temporal distribution patterns of Plutella xylostella (Lepidoptera: Plutellidae) in a fine-scale agricultural landscape based on geostatistical analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian-Yu Li ◽  
Yan-Ting Chen ◽  
Meng-Zhu Shi ◽  
Jian-Wei Li ◽  
Rui-Bin Xu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Plutella Xylostella ◽  
Agricultural Landscape ◽  
Seasonal Pattern ◽  
Distribution Patterns ◽  
Geostatistical Analysis ◽  
Distribution Model ◽  
Detailed Knowledge ◽  
Fine Scale ◽  
Spatio Temporal

AbstractA detailed knowledge on the spatial distribution of pests is crucial for predicting population outbreaks or developing control strategies and sustainable management plans. The diamondback moth, Plutella xylostella, is one of the most destructive pests of cruciferous crops worldwide. Despite the abundant research on the species’s ecology, little is known about the spatio-temporal pattern of P. xylostella in an agricultural landscape. Therefore, in this study, the spatial distribution of P. xylostella was characterized to assess the effect of landscape elements in a fine-scale agricultural landscape by geostatistical analysis. The P. xylostella adults captured by pheromone-baited traps showed a seasonal pattern of population fluctuation from October 2015 to September 2017, with a marked peak in spring, suggesting that mild temperatures, 15–25 °C, are favorable for P. xylostella. Geostatistics (GS) correlograms fitted with spherical and Gaussian models showed an aggregated distribution in 21 of the 47 cases interpolation contour maps. This result highlighted that spatial distribution of P. xylostella was not limited to the Brassica vegetable field, but presence was the highest there. Nevertheless, population aggregations also showed a seasonal variation associated with the growing stage of host plants. GS model analysis showed higher abundances in cruciferous fields than in any other patches of the landscape, indicating a strong host plant dependency. We demonstrate that Brassica vegetables distribution and growth stage, have dominant impacts on the spatial distribution of P. xylostella in a fine-scale landscape. This work clarified the spatio-temporal dynamic and distribution patterns of P. xylostella in an agricultural landscape, and the distribution model developed by geostatistical analysis can provide a scientific basis for precise targeting and localized control of P. xylostella.

Fine-scale habitat selection of American marten at the southern fringe of the boreal forest

Ecoscience ◽  
2010 ◽  
Vol 17 (2) ◽  
pp. 175-185 ◽  
Author(s):  
Guillaume Godbout ◽  
Jean-Pierre Ouellet
Keyword(s):  
Habitat Selection ◽  
Boreal Forest ◽  
Fine Scale ◽  
American Marten ◽  
Southern Fringe ◽  
Selection Of

Shelter selection by a small mammal community in the wet-dry tropics of Australia.

1989 ◽  
Vol 12 (2) ◽  
pp. 55
Author(s):  
R.W. Braithwaite
Keyword(s):  
Habitat Selection ◽  
Small Mammal ◽  
Tree Species ◽  
Average Distance ◽  
Small Species ◽  
Dry Tropics ◽  
Open Forest ◽  
Shelter Selection ◽  
Small Mammal Community ◽  
The Mean

The location of shelter used by nine species of small mammals released after capture during a mark-recapture study in tropical woodland and open forest was recorded whenever possible. A quantitative profile of such post-release behaviour by different species permits its incorporation into analyses of habitat selection. Characteristics of post-release behaviour also provide clues about the nature of predation pressure on various species. Arboreal species tended to select tree species with boles having camouflage potential. Small species used small holes. Scansorial species used the greatest range of sheltering sites. Average distance moved to shelter was inversely related to the mean density of a species.

Chemical Concentration and Spatial Uniformity of a Premixing In-Line Injection System Attached to a Variable-Rate Orchard Sprayer

2021 ◽  
Vol 64 (6) ◽  
pp. 1977-1987
Author(s):  
Zhihong Zhang ◽  
Heping Zhu ◽  
Zhiming Wei ◽  
Ramon Salcedo
Keyword(s):  
Spatial Distribution ◽  
Duty Cycle ◽  
Spray Deposition ◽  
Injection System ◽  
List Type ◽  
Variable Rate ◽  
Chemical Concentration ◽  
Fluorescent Tracer ◽  
Distribution Uniformity ◽  
The Mean

HighlightsA newly developed premixing in-line injection system attached to a variable-rate orchard sprayer was evaluated.Tests were conducted to verify the in-line injection system performance using a vertical spray patternator.Concentration accuracy and spatial distribution uniformity were determined with a fluorescent tracer.Uniform spray mixtures were obtained for different spray viscosities and duty cycle combinations.Abstract. Pesticide spray application efficiency is highly dependent on the chemical concentration accuracy and spatial distribution uniformity. In this study, the performance of a newly developed premixing in-line injection system was evaluated when it was attached to a laser-guided, pulse width modulated (PWM), variable-rate orchard sprayer. The chemical concentration accuracy was determined with respect to spray deposition with a fluorescent tracer, and the spatial distribution uniformity was determined with spray deposits at different heights on a vertical spray patternator. Outdoor tests were conducted with 27 combinations of target chemical concentration (1.0%, 1.5%, and 2.0%), viscosity of the simulated pesticide (1.0, 12.0, and 24.0 mPa·s), and various spray outputs manipulated with PWM duty cycles. For each injection loop, the amounts of the chemical concentrate and water discharged into the mixing line were measured separately in response to preset target concentrations. The results showed that the measured concentrations were consistent across the patternator heights, spray viscosities, and duty cycle combinations. For all treatments, the mean absolute percentage error (MAPE) of the measured concentration was 6.96%, indicating that the concentration accuracy of the system was acceptable. The mean coefficient of variation was 3.35%, indicating that the spatial distribution uniformity of the system was in the desirable range. In addition, there was little variation in chemical concentration for spray mixtures collected at different heights on the patternator. Thus, the premixing in-line injection system could adequately dispense chemical concentrate and water to produce accurate concentrations and uniform spray mixtures for variable-rate nozzles to discharge to targets. Keywords: Environment protection, Precision pesticide application, Laser-guided sprayer, Tank mixture disposal, Specialty crop.

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