Abstract
Organisms such as starlings and honeybees appear to forage based on the marginal value theorem. This experiment tested whether humans could forage in like manner. An equal number of students took long and short routes to the foraging patch and collected simulated food items in a way that simulated diminishing marginal returns. Data on travel time, foraging time, and number of food items collected were collected. The data differed significantly from the calculated optimal values. This may be a result of low number of trips between the foraging patch and the simulated dwelling.
Introduction
When animals forage, many factors become involved. They include the location of the food, its distance from the animals’ dwelling, and the quantity to be returned, among other things. Economic models, such as the marginal value theorem, can be used to predict the outcomes of many of these factors.
According to the marginal value theorem (Fig. 1), the food intake rate of the forager decreases with the time spent in the foraging patch (Charnov 1974).
Fig. 1. A graph of the marginal value theorem from Krebs (1993). The asymptotic curve represents food intake. The optimal number of food items to take is found by drawing a line from the travel time to the patch to the steepest point possible on the curve.
This model can be applied to a wide range of situations based on the factor to be maximized. Honeybees apparently maximize energetic efficiency, but other factors are possible (Schmid-Hempel et al. 1985). For example, the starling (Sturnus vulgaris) apparently maximizes feeding rate according to the marginal value theorem (Kacelnik 1984).
Our objective was to determine whether humans would optimize foraging behavio...
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...ee. Those numbers match ours more closely. However, Schmid-Hempel et al. found that honeybees maximize energy efficiency rather than number of food items per run. Repeating our experiment with a factor other then number of M & Ms to maximize may yield more interesting data about the ways in which the student sample would forage.
Works Cited
Charnov, E. L. 1974. Optimal Foraging, the Marginal Value Theorem. Theoretical Population Biology, 9, 129-136.
Kacelnik, A. 1984. Central Place Foraging in Starlings (Sturnus vulgaris). I. Patch Residence Time. Journal of Animal Ecology. 53, 283-299.
Krebs, J. R. & Davies, N. B. 1993. An Introduction to Behaviourial Ecology. Oxford: Blackwell.
Schmid-Hempel, P., Kacelnik, A., & Houston, A. I. 1985. Honeybees Maximize Efficiency by Not Filling Their Crop. Behavioral Ecology and Sociobiology, 17, 61-66.
In 1927, Charles Elton took niche theory a step further and included food. He defined the niche of an animal as its place in the biotic environment and its relations to food and enemies (Elton, 1927). Grinnell also wondered if food was a limiting factor to the California Thrasher’s niche, but since the bird is omnivorous, it could find food in other habitats such as a forest floor or a meadow. There had to be other factors that restricted the bird to the chaparral bushes (Grinnel, 1917). Elton believes that the niche of an animal can be defined by its size and its food habits. It is important to study niches because it enables ecologists to see how different animal communities may resemble each other in the essentials of organization (Elton, 1927). For example, in a forest there could be a niche of owls that feeds on small animals such as rats. This same carnivore niche is filled with kestrels in the open grasslands. This carnivore niche is then dependent on the small animals in the herbivore niche (Elton, 1927). Hutchinson also discusses niche theory in his “Concluding Remarks” paper. His theory seems to combine some of the ideas
Abstract: The house cricket, Acheta domesticus, was used to test whether food and potential mates drive aggressive behavior. Male crickets were randomly selected in pairs and place into a cage to observe aggressive behaviors in the presence of no food, food, and female. The cage provided a confine area for the crickets to fight one another while the variables of food and female were used in attempts of increasing aggressive interactions between the male crickets. There was no significance found through this experiment due to a lack of data. It was discovered that the experiment would have to be done at a larger scale to be able to see any significance in the two variables.
Gardner, Christopher. Notes from the Doc Talks. Stanford University. Web. April 10, 2014. Pollan, Michael. The Omnivore's Dilemma: A Natural History of Four Meals. New York:
Deborah L. Duffy, Yuying Hsu, James A. Serpell ,Applied Animal Behavior Science - 1 December 2008 (Vol. 114, Issue 3, Pages 441-460, DOI: 10.1016/j.applanim.2008.04.006)
...l; Retired, formerly apiculturist, U.S. Department of Agriculture. BEEKEEPING IN THE UNITED STATES; AGRICULTURE HANDBOOK NUMBER 335 Revised October 1980; Pages 2 – 9
Elizabeth Cashdan addresses the question of territoriality among human forager groups, specifically comparing four Bushman groups. She argues that territoriality should occur only in places where the benefits will outweigh the costs. Introducing the scientific definition of territoriality in animals, she first claims that animals tend to be the most territorial when they have adequate food and other resources. It is when there is a severe lack of or abundance of resources that animals are not territorial. With a lack of food, territoriality tends to waste too much energy. In the case of an abundance of food, it is not worth defending that which is plentiful for animals. She points out predictability as another environmental factor: if a resource is unpredictable, then it is not economical to defend it. It is only worthwhile to defend a territory if there is high probability that the resources will still be available when they are wanted. However, the costs and benefits of being territorial not only depend on the environment, but also on the species and its characteristics.
All animals employ a vast array of behaviors that contribute to their ability to find resources, increase their chances of utilizing them efficiently, and therefore increase their overall fitness. One of the behaviors observed extensively throughout the animal kingdom to accomplish these tasks is aggression. Agonist conflict and aggressive behavior occurs both between species and within species. Curiously, within-species agonism is common in many animals because it can manipulate social hierarchies which can affect the distribution of resources within a population (Moore 2007 and Wofford 2013). Evaluating agonistic behavior is therefore a valuable means by which to examine expenditure of energy for resources (Moore 2007 and Wofford 2013).
...nt”. So it is clear that catastrophic scenarios could very well ensue if CCD is not reversed to save the honeybee. The environment suffering greatly and collapsing will have a direct impact on our daily lives and forever change the way we eat.
Birds follow and clean up after herbivores. And so during their turn in the p...
All around the world honeybees are vanishing at an alarming rate, according to the documentary Vanishing of the Honeybees. This film features two commercial bee keepers and their fight to preserve their bee numbers. David Hackenburg was the first commercial bee keeper to go public the bee population was decreasing. Approximately two billions bees have vanished and nobody knows the reason why. Honeybees are used all across America to help pollinate monoculture crops like broccoli, watermelon, cherries, and other produce. Without the honeybees the price for fresh and local produce would be too much money. According, to this film commercial bee keeper’s help fifteen billion dollars of food get pollinated by commercial
What do you think when you think of bees? I think of honey, pollination, and soon, new life. According to Walt D. Osborne, “Bees are vital for the pollination of more than 90 fruit and vegetable crops worldwide, including almonds, peaches, soybeans, apples, pears, cherries, raspberries, blackberries, cranberries, watermelons, cantaloupes, cucumbers, and strawberries,” (Osborne 9-11) but each year a large percent of hives have vanished due to many different factors such as stress. Most people would declare that the average honey bee is insufficiently important to the world because bees are pests to home owners everywhere, but bees are extremely important to earths’ survival than any other pollinator in the world; they help pollinate most of the world’s agriculture; yet in the recent years bee populations have plummeted rapidly. I am writing this paper to create awareness that the agricultural society ought to stop or lessen the spraying of pesticides/ insecticides on crops, unnatural diets and overcrowding in the hives.
...his builds a relationship between the two causing the predator to consume its meat without looking away (Pollan 307). This causes that person to no want to know what they are eating because people are used to not knowing what they are eating.
“Marginal analysis involves changing the value(s) of the choice variable(s) by a small amount to see if the objective function can be further increased (in the case of maximization problems) or further decreased (in the case of minimization problems)” (Thomas & Maurice, 2012, pp. 91). Marginal analysis is known as “the central organizing principle of economic theory” for its importance and applicability to many aspects of our daily lives as well as our careers (Thomas & Maurice, 2012, pp. 94). The key concepts of marginal analysis include total benefit, total cost, marginal benefit, marginal cost and net benefit. These concepts all come together to play a significant role in the use of marginal analysis to reach the optimal desired outcome.
Honey bees look for a new nest site when a colony grows too large for their present nest. During this process, some of the colony stays, and the others leave to establish a new colony. Half of the workers in the colony along with the mother queen bee leave the nest to find a new one, while the rest of the workers and one of the daughter queen bees remains in the nest to continue the colony. The bees leave the nest in a swarm, and group at a nearby site, where some bees then go their separate ways and search for a new nest site. This process was originally studied by Martin Lindeur (1955).
off of just one host but very few predators can feed on the same prey(1973). In