scholarly journals Mazes to Study the Effects of Spatial Complexity, Predation and Population Density on Mate Finding

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 256
Author(s):  
Lloyd D. Stringer ◽  
Nicola J. Sullivan ◽  
Robyn White ◽  
Alfredo Jiménez-Pérez ◽  
Jess Furlong ◽  
...  
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Habitat Complexity ◽  
Spatial Separation ◽  
Generalist Predator ◽  
Mate Finding ◽  
Testing Hypotheses ◽  
Species Establishment ◽  
3D Printed ◽  
Population Maintenance

The difficulty to locate mates and overcome predation can hamper species establishment and population maintenance. The effects of sparseness between individuals or the effect of predators on the probability of population growth can be difficult to measure experimentally. For testing hypotheses about population density and predation, we contend that habitat complexity can be simulated using insect mazes of varying mathematical difficulty. To demonstrate the concept, we investigated whether the use of 3D printed mazes of varying complexity could be used to increase spatial separation between sexes of Drosophila simulans, and whether the presence of a generalist predator hampered mate-finding. We then examined how increasing D. simulans population density might overcome the artificially created effects of increasing the distance between mates and having a predator present. As expected, there was an increase in time taken to find a mate and a lower incidence of mating as habitat complexity increased. Increasing the density of flies reduced the searching time and increased mating success, and overcame the effect of the predator in the maze. Printable 3D mazes offer the opportunity to quickly assess the effects of spatial separation on insect population growth in the laboratory, without the need for large enclosed spaces. Mazes could be scaled up for larger insects and can be used for other applications such as learning.

scholarly journals Trends of forest area and population and the impact of population on forest area per hectare in Serbia without APS

2012 ◽  
pp. 183-196
Author(s):  
Nenad Rankovic
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Forest Cover ◽  
Forest Policy ◽  
Forest Area ◽  
Economic Changes ◽  
Policy Measures ◽  
Per Capita ◽  
The Impact

Socio-economic changes throughout history have shaped the attitude towards the forest and most significant ones are changes in terms of population. Over the centuries population and population density have had a significant impact on deforestation and the reduction of forest areas. Therefore, it is important to check what kind of trends are concerned and how population growth affects forest areas, forest cover and forest area per capita. These elements are important for assessing the direction, intensity of activity and the degree of success in the implementation of all forest policy measures in Serbia.

Aging in suburban Canada

2021 ◽  
pp. 81-88
Author(s):  
Maxwell Hartt ◽  
Natalie S. Channer ◽  
Samantha Biglieri
Keyword(s):  
Population Density ◽  
Built Environment ◽  
Population Growth ◽  
Home Ownership ◽  
Operational Definition ◽  
Single Family ◽  
Family Housing ◽  
Definition Of ◽  
Commuting Patterns ◽  
Suburban Landscape

This chapter talks about Canada's built environment and population growth that predominantly occurs on the urban fringe. It describes Canada as a suburban nation and its largest metropolitan areas, which include Vancouver, Montréal, and Toronto with the suburban residents that exceed 80 percent. It also distinguishes traditional forms of suburban locations that can be characterized by a variety of factors, such as the proportion of single-family housing, car-commuting patterns, population density, and home-ownership rates. The chapter recognizes that the modern suburban landscape is complex and diverse and that there is no single perfect operational definition of suburban. It examines suburban Canada's population that is relatively heterogeneous, compared to rural locations, but is still significantly less diverse than urban Canada.

Density-Dependent Population Growth

2020 ◽  
pp. 29-46
Author(s):  
Michael J. Fogarty ◽  
Jeremy S. Collie
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Density Dependence ◽  
Multiple Equilibria ◽  
Dynamical Behavior ◽  
Logistic Growth ◽  
Density Dependent ◽  
Per Capita ◽  
Discrete Time Models ◽  
Complex Dynamical Behavior

The observation that no population can grow indefinitely and that most populations persist on ecological timescales implies that mechanisms of population regulation exist. Feedback mechanisms include competition for limited resources, cannibalism, and predation rates that vary with density. Density dependence occurs when per capita birth or death rates depend on population density. Density dependence is compensatory when the population growth rate decreases with population density and depensatory when it increases. The logistic model incorporates density dependence as a simple linear function. A population exhibiting logistic growth will reach a stable population size. Non-linear density-dependent terms can give rise to multiple equilibria. With discrete time models or time delays in density-dependent regulation, the approach to equilibrium may not be smooth—complex dynamical behavior is possible. Density-dependent feedback processes can compensate, up to a point, for natural and anthropogenic disturbances; beyond this point a population will collapse.

The Role of Predators and Other Biotic Agents in Regulating the Population Density of Phytophagous Mites in Ontario Peach Orchards

1966 ◽  
Vol 98 (8) ◽  
pp. 808-820 ◽  
Author(s):  
W. L. Putman ◽  
D. H. C. Herne
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Tetranychus Urticae ◽  
Considerable Extent ◽  
Panonychus Ulmi ◽  
Apple Orchards ◽  
Rapid Population Growth ◽  
One Year ◽  
Heavy Mortality

AbstractMore than 40 species of insects and arachnids attack Panonychus ulmi (Koch), Tetranychus urticae Koch, T. canadensis (McGregor), Bryobia arborea Morgan and Anderson, or Aculus cornutus (Banks) in peach orchards of the Niagara Peninsula. The most effective predators attacking P. ulmi are Typhlodromus caudiglans Schuster, Haplothrips faurei Hood, Stethorus punctillum Weise, and Chrysopa spp. Peach orchards lack the predatory mirids characteristic of apple orchards. A condition, presumably disease, caused heavy mortality in one year. Endemic densities of P. ulmi are maintained in that state by predators, chiefly T. caudiglans, that subsist to a considerable extent on other sources of food, whereas epidemics of P. ulmi are reduced largely by other predators, chiefly H. faurei and S. punctillum, that increase in numbers by feeding on the mite during its period of rapid population growth but exert their greatest effect later in the season by destroying the winter eggs.

Model gospodarowania populacją jelenia europejskiego Cervus elaphus L. w Wolińskim Parku Narodowym i na Wyspie Wolin

2018 ◽  
Vol XI ◽  
pp. 81-90
Author(s):  
Adam Mohr ◽  
Antoni Przybylski ◽  
Małgorzata Zimnicka – Pluskota ◽  
Damian Spieczyński
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Cervus Elaphus ◽  
Environmental Conditions ◽  
Red Deer ◽  
Actual State ◽  
Model Population ◽  
Deer Population ◽  
Proposed Model ◽  
Age And Sex

The paper presents the current methods of management and environmental conditions of the functioning of red deer population on the Wolin Island. The inventory carried out in 2014 using the drive census method revealed the prevalence of stags in the population (0.86 hinds/1stag) and the population density of 225 individuals/1,000 hectares of the forest, whereas harvest conducted in this season showed merely 22 individuals/1,000 hectares. In the analysed seasons before the inventory, harvest was also low (about 10% of the probable actual state) and despite harvesting mainly hinds, it did not curb the population growth. In the years 2006 – 2014, the yearly harvest in the largest hunting district fluctuated within the range of 14.5 to 60.5, x̅=27.0 individuals/1,000 hectares (n=9), while in the remaining four smaller population management units, the average yearly harvest amounted to only 0.2 to 9.8 individuals/1,000 hectares (n=9). The realized rate of population growth determined by the method of summer deer observation in 2015 amounted to 42.2% of the hinds number. Applying the simulation of the model population meeting the parameters indicated in the inventory, the researchers calculated and proposed the optimal indicators of harvesting individual age and sex groups. The proposed model of hunting monitoring and management assumes optimization of environmental conditions, structure and size of the actual population within the next 10 years.

Spatial and dietary requirements of the chuditch (Dasyurus geoffroii) in a semiarid climatic zone

2012 ◽  
Vol 34 (1) ◽  
pp. 59 ◽  
Author(s):  
Kelly Rayner ◽  
Brian Chambers ◽  
Brent Johnson ◽  
Keith D. Morris ◽  
Harriet R. Mills
Keyword(s):  
Population Density ◽  
Home Range ◽  
Resource Availability ◽  
Climatic Zone ◽  
Generalist Predator ◽  
Home Ranges ◽  
Jarrah Forest ◽  
Semiarid Zone ◽  
Dietary Requirements ◽  
Management Regimes

Knowledge of the ecology of the chuditch (Dasyurus geoffroii) is largely restricted to its distribution in mesic jarrah forests. There is a need for information regarding its ecology in semiarid zones where rainfall and consequently productivity are lower than mesic forests. Given that spatial requirements are strongly influenced by resource availability, it was expected that the chuditch in the semiarid zone would be present at lower densities and would have larger core home ranges (defined by daytime refuges) than those in the jarrah forests. The diet was also investigated by examining the contents of scats. Chuditch at Forrestania were trapped and six individuals were radio-tracked. The population density was one-third that of the lowest estimate reported from the jarrah forest and core home-range estimates were substantially larger, particularly for males. The diet included mammals, birds, reptiles, invertebrates, plants and rubbish, which was consistent with it being a generalist predator. Chuditch did have greater spatial requirements than in the jarrah forest, therefore different management regimes may be needed for populations occurring in the semiarid zone.

Suicide in Wide-Open Spaces

1994 ◽  
Vol 79 (1) ◽  
pp. 650-650 ◽  
Author(s):  
David Lester
Keyword(s):  
Population Density ◽  
Population Growth ◽  
Open Spaces ◽  
Suicide Rates

As predicted, suicide rates were associated negatively with population density and positively with population growth for the continental states of America in 1980.

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