Matching Items (156)
Description
The spread of invasive species may be greatly affected by human responses to prior species spread, but models and estimation methods seldom explicitly consider human responses. I investigate the effects of management responses on estimates of invasive species spread rates. To do this, I create an agent-based simulation model of an insect invasion across a county-level citrus landscape. My model provides an approximation of a complex spatial environment while allowing the "truth" to be known. The modeled environment consists of citrus orchards with insect pests dispersing among them. Insects move across the simulation environment infesting orchards, while orchard managers respond by administering insecticide according to analyst-selected behavior profiles and management responses may depend on prior invasion states. Dispersal data is generated in each simulation and used to calculate spread rate via a set of estimators selected for their predominance in the empirical literature. Spread rate is a mechanistic, emergent phenomenon measured at the population level caused by a suite of latent biological, environmental, and anthropogenic. I test the effectiveness of orchard behavior profiles on invasion suppression and evaluate the robustness of the estimators given orchard responses. I find that allowing growers to use future expectations of spread in management decisions leads to reduced spread rates. Acting in a preventative manner by applying insecticide before insects are actually present, orchards are able to lower spread rates more than by reactive behavior alone. Spread rates are highly sensitive to spatial configuration. Spatial configuration is hardly a random process, consisting of many latent factors often not accounted for in spread rate estimation. Not considering these factors may lead to an omitted variables bias and skew estimation results. The ability of spread rate estimators to predict future spread varies considerably between estimators, and with spatial configuration, invader biological parameters, and orchard behavior profile. The model suggests that understanding the latent factors inherent to dispersal is important for selecting phenomenological models of spread and interpreting estimation results. This indicates a need for caution when evaluating spread. Although standard practice, current empirical estimators may both over- and underestimate spread rate in the simulation.
ContributorsShanafelt, David William (Author) / Fenichel, Eli P (Thesis advisor) / Richards, Timothy (Committee member) / Janssen, Marco (Committee member) / Arizona State University (Publisher)
Created2012
Description
Females are highly vulnerable to the effects of methamphetamine, and understanding the mechanisms of this is critical to addressing methamphetamine use as a public health issue. Hormones may play a role in methamphetamine sensitivity; thus, the fluctuation of various endogenous peptides during the postpartum experience is of interest. This honors thesis project explored the relation between anxiety-like behavior, as measured by activity in an open field, and conditioned place preference to methamphetamine in female versus male rats. The behavior of postpartum as well as virgin female rats was compared to that of male rats. There was not a significant difference between males and females in conditioned place preference to methamphetamine, yet females showed higher locomotor activity in response to the drug as well as increased anxiety-like behavior in open field testing as compared to males. Further study is vital to comprehending the complex mechanisms of sex differences in methamphetamine addiction.
ContributorsBaker, Allison Nicole (Author) / Olive, M. Foster (Thesis director) / Presson, Clark (Committee member) / Hansen, Whitney (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Collective decision making in social organism societies involves a large network of communication systems. Studying the processes behind the transmission of information allows for greater understanding of the decision making capabilities of a group. For Temnothorax rugatulus colonies, information is commonly spread in the form of tandem running, a linear recruitment pattern where a leading ant uses a short-ranged pheromone to direct a following ant to a target location (in tandem).The observed phenomenon of reverse tandem running (RTR), where a follower is lead from a target back to the home nest, has not been as extensively studied as forward tandem running and transportation recruitment activities. This study seeks to explain a potential reason for the presence of the RTR behavior; more specifically, the study explores the idea that reverse tandem run followers are being shown a specific route to the home nest by a highly experienced and efficient leading ant. Ten colonies had migrations induced experimentally in order to generate some reverse tandem running activity. Once an RTR has been observed, the follower and leader were studied for behavior and their pathways were analyzed. It was seen that while RTR paths were quite efficient (1.4x a straight line distance), followers did not experience a statistically significant improvement in their pathways between the home and target nests (based on total distance traveled) when compared to similar non-RTR ants. Further, RTR leading ants were no more efficient than other non-RTR ants. It was observed that some followers began recruiting after completion of an RTR, but the number than changed their behavior was not significant. Thus, the results of this experiment cannot conclusively show that RTR followers are utilizing reverse tandem runs to improve their routes between the home and target nests.
ContributorsColling, Blake David (Author) / Pratt, Stephen (Thesis director) / Liebig, Juergen (Committee member) / Sasaki, Takao (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-12
Description
Division of labor among task specialists is a key feature of the organization of insect societies. Foraging and emigration are two distinct colony tasks that nonetheless depend on very similar behaviors, including searching outside the nest, evaluating discoveries, and recruiting nestmates. These subtasks are crucial to collective decisions about forager allocation and nest site selection. It remains unclear, however, whether the same ants are responsible for similar behavior in both contexts, and to what degree they show finer specializations among common subtasks. We are investigating these issues in the ant Temnothorax rugatulus, by making detailed behavioral descriptions of individually marked colonies as they forage and emigrate. There exists considerable heterogeneity among nest-movers, with a small proportion consistently responsible for a large share of recruitment. We found a similar pattern of heterogeneity amongst ants retrieving food during foraging, but had inconclusive results when examining recruitment to the food. It also appears that the ants that complete tasks during foraging are different from the ants that complete similar tasks during emigrations. These findings will shed light on the organization of division of labor and how it contributes to collective decision-making.
ContributorsSchaper, Gage (Contributor) / Pratt, Stephen (Thesis director) / Fewell, Jennifer (Committee member) / Shaffer, Zachary (Committee member) / Barrett, The Honors College (Contributor)
Created2013-05
Description
Communication amongst eusocial insect is key to their success. Ants rely on signaling to mediate many different functions within a colony such as policing and nest mate recognition. Camponotus floridanus uses chemosensory signaling in the form of cuticular hydrocarbons to regulate these functions. Each cuticular hydrocarbon profile contains numerous hydrocarbons, however it is yet to be seen if Camponotus floridanus can discriminate between linear hydrocarbons of similar length. Individual specimens were conditioned in three different ways: 5 conditioning with high concentration of sugar water (1;1 ratio), 1 conditioning with high concentration of sugar water, and 5 conditioning with low concentration of sugar water (1;4). Two linear hydrocarbons were use, C23 and C24, with C23 always being the conditioned stimulus. Specimens who were conditioned 5 times with high concentration of sugar water were the only group to show a significant response to the conditioned stimulus with a p-value of .008 and exhibited discrimination behavior 46% of the time. When compared 5 conditioning with high concentration to the other two testing conditioning groups, 1 conditioning with high concentration produced an insignificant p-value of .13 was obtained whereas when comparing it with 5 conditioning low concentration of sugar a significant p-value of .0132 was obtained. This indiciates that Camponotus floridanus are capable of discrimination however must be conditioned with high concentration of sugar water, while number of conditioning is insignificant.
ContributorsDamari, Ben Aviv (Author) / Liebig, Juergen (Thesis director) / Ghaninia, Majid (Committee member) / Pratt, Stephen (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Evolutionary theory predicts that animal behavior is generally governed by decision rules (heuristics) which adhere to ecological rationality: the tendency to make decisions that maximize fitness in most situations the animal encounters. However, the particular heuristics used by ant colonies of the genus Temnothorax and their propensity towards ecological rationality are up for debate. These ants are adept at choosing a nest site, making a collective decision based on complex interactions between the many individual choices made by workers. Colonies will migrate between nests either upon the destruction of their current home or the discovery of a sufficiently superior nest. This study offers a descriptive analysis of the heuristics potentially used in nest-site decision-making. Colonies were offered a choice of nests characterized by the Ebbinghaus Illusion: a perceptual illusion which effectively causes the viewer to perceive a circle as larger when it is surrounded by small circles than when that same circle is surrounded by large circles. Colonies were separated into two conditions: in one, they were given the option to move to a high-quality nest surrounded by poor-quality nests, and in the other they were given the option to move to a high-quality nest surrounded by medium-quality nests. The colonies in the poor condition were found to be more likely to move to the good nest than were colonies in the medium condition at a statistically significant level. That is, they responded to the Ebbinghaus Effect in the way that is normally expected. This result was discussed in terms of its implications for the ecological rationality of the nest-site choice behavior of these ants.
ContributorsTalken, Lucas Warren (Author) / Pratt, Stephen (Thesis director) / Sasaki, Takao (Committee member) / Liebig, Juergen (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Department of Psychology (Contributor) / Economics Program in CLAS (Contributor)
Created2014-05
Description
Consumption of seafood poses a substantial threat to global biodiversity. Chemical contamination found in both wild-caught and farmed seafood also presents significant health risks to consumers. Flame retardants, used in upholstery, plastics, clothing, and other products to reduce fire danger, are of particular concern as they are commonly found in the marine environment and permeate the tissues of fish that are sold for consumption via multiple pathways. By summarizing various metrics of sustainability and the mercury content in consumed species of fish and shellfish, researchers have found that high levels of chemical contamination was linked with lesser fishery sustainability. I conducted a literature review of flame retardant content in seafood to further compare contamination and sustainability in addition to the initial analysis with mercury. My review suggests that the widespread issue of fishery collapse could be alleviated by demonstrating to stakeholders that many unsustainable fish stocks are mutually disadvantageous for both human consumers and the environment. Future research should address the need for the collection of data that better represent actual global contaminant concentrations in seafood.
ContributorsNoziglia, Andrea Joyce (Author) / Gerber, Leah (Thesis director) / Smith, Andrew (Committee member) / Pratt, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Herberger Institute for Design and the Arts (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Sports related concussions, or mild traumatic brain injuries (mTBI), have recently increased in prevalence, and thus gained a great deal of recognition from the public and the media. While the acute symptoms associated with concussions are well known, which include headaches, dizziness, vomiting, and fatigue, recent research has indicated that there can be severe chronic consequences of multiple conditions. Most notably, a disease called Chronic Traumatic Encephalopathy (CTE) has been linked to multiple mTBIs, which produces symptoms similar to Alzheimer's disease and dementia, in addition to personality changes, increased suicidality, and in some cases death. This knowledge has led the NFL to take steps to protect their players, and increase both the understanding and awareness of the problems associated with multiple concussions. This comes with many problems, however, as players and fans alike are quick to resist any type of change to the rules or policies present in football, in fear that it may damage the integrity of the game. The NFL is thus forced into a difficult position, and must balance public opinion and player safety. There are things that can be done, however, that do not threaten the game itself, such as investing in concussion research and safety equipment design that will more effectively protect the brain from concussions.
ContributorsAiello, Mimi Elizabeth (Author) / Olive, M. Foster (Thesis director) / Bimonte-Nelson, Heather (Committee member) / Camp, Bryan (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2013-05
Description
In large part, the great success of eusocial insects is due to efficient division of labor (Duarte et al. 2011; Dornhaus 2008). Within ant colonies, the process of dividing labor is not clearly defined, but it may be key to understanding the productivity and success of these colonies. This study analyzed data from an experiment that was conducted with the goal of examining how finely division of labor is organized in ant colonies. The experiment considered the actions of all ants from three Temnothorax rugatulus colonies. The colonies were each carefully recorded during five distinct emigrations per colony. The experiment produced such a large quantity of data that it was challenging to analyze the results, a major obstacle for many studies of collective behavior. Therefore, I designed a computer program that successfully sorted all of the data and prepared it for an initial statistical analysis that was performed in R. The preliminary results suggest that while most of the ants perform little to no work, there is an overall pattern of elitism; it seems that division of labor in ants is not more finely divided than previously shown. Future studies should provide further analysis of the data and will be useful in forming a more complete understanding of the division of labor within the emigrations of Temnothorax rugatulus colonies.
ContributorsJones, Samantha (Author) / Pratt, Stephen (Thesis director) / Jones, Donald (Committee member) / Shaffer, Zachary (Committee member) / Barrett, The Honors College (Contributor) / W. P. Carey School of Business (Contributor)
Created2012-12
Description
An introduction to neuroscientific thought aimed at an audience that is not educated in biology. Meant to be readable and easily understood by anyone with a high school education. The first section is completed in its entirety, with outlines for the proposed final sections to be completed over the next few years.
ContributorsNelson, Nicholas Alan (Author) / Olive, M. Foster (Thesis director) / Brewer, Gene (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2014-05