The Economics of Managing Wildlife Disease

The spread of infectious disease among and between wild and domesticated animals has become a major problem worldwide. Upon analyzing the dynamics of wildlife growth and infection when the diseased animals cannot be identified separately from healthy wildlife prior to the kill, we find that harvest-based strategies alone have no impact on disease transmission. Other controls that directly influence disease transmission and/or mortality are required. Next, we analyze the socially optimal management of infectious wildlife. The model is applied to the problem of bovine tuberculosis among Michigan white-tailed deer, with non-selective harvests and supplemental feeding being the control variables. Using a two-state linear control model, we find a two-dimensional singular path is optimal (as opposed to a more conventional bang-bang solution) as part of a cycle that results in the disease remaining endemic in the wildlife. This result follows from non-selective harvesting and intermittent wildlife productivity gains from supplemental feeding.

Essays on Industrial Organization and Environmental Economics

This dissertation studies environmental regulation issues in the hog production industry as well as forces behind the reorganization of the industry during the past two decades. Federal and State-level environmental regulations imposed on U.S. hog production during the year 2003 are examined in Chapter 1. Based on the number of regulations passed by the Federal government and states, the 2003 regulatory index is constructed. The regulatory stringency index suggests that state-level regulations vary across states and have increased over the years. In addition, state-level regulations are more stringent than federal regulations. Chapter 2 develops an empirically implementable theoretical model which allows us to investigate the long-run effects of environmental regulations on the U.S. hog industry. Hog feeding operations (HFOs) are divided into large feeding operations (LHFOs) and small feeding operations (SHFOs). The impact of the presence of a large number of LHFOs on the entry and exit of CHFOs is also examined. Results of this study suggest that: Increased state-level regulation stringency significantly lowers the output of SHFOs; increased state-level regulation stringency significantly lowers the output of LHFOs; increased state-level regulation stringency significantly lowers the number of SHFOs; SHFO output rises significantly in states that have a greater number of LHFOs; LHFO output rises significantly in states that have a greater number of LHFOs; the number of SHFOs significantly increases in states that have a greater numbers of LHFOs; regulation increases the average SHFO size; and regulation decreases the average LHFO size. Chapter 3 examines the importance of input availability, market attractiveness, agglomeration economies and environmental regulations on the reorganization of U.S. hog production for a panel of 22 U.S. hog producing states which include, Northern states, Southern states and Midwest states for the period 1994-2006. Results from this study suggest that: Hog production in a state is positively affected by hog production in a nearby state, confirming the presence of agglomeration economies; Environmental regulations and high corn price have negative effects on state-level U.S. hog production; High hog prices, and favorable labor cost, and land values attract hog production; and transportation cost has no effect on hog production. Advisors: Azzeddine Azzam and Karina Schoengold

The Economics of Threatened Species Conservation: A Review and Analysis

Stabilizing human population size and reducing human-caused impacts on the environment are keys to conserving threatened species (TS). Earth's human population is ~ 7 billion and increasing by ~ 76 million per year. This equates to a human birth-death ratio of 2.35 annually. The 2007 Red List prepared by the International Union for Conservation of Nature and Natural Resources (IUCN) categorized 16,306 species of vertebrates, invertebrates, plants, and other organisms (e.g., lichens, algae) as TS. This is ~ 1 percent of the 1,589,161 species described by IUCN or ~ 0.0033 percent of the believed 5,000,000 total species. Of the IUCN’s described species, vertebrates comprised relatively the most TS listings within respective taxonomic categories (5,742 of 59,811), while invertebrates (2,108 of 1,203,175), plants (8,447 of 297,326), and other species (9 of 28,849) accounted for minor class percentages. Conservation economics comprises microeconomic and macroeconomic principles involving interactions among ecological, environmental, and natural resource economics. A sustainable-growth (steady-state) economy has been posited as instrumental to preserving biological diversity and slowing extinctions in the wild, but few nations endorse this approach. Expanding growth principles characterize most nations' economic policies. To date, statutory fine, captive breeding cost, contingent valuation analysis, hedonic pricing, and travel cost methods are used to value TS in economic research and models. Improved valuation methods of TS are needed for benefit-cost analysis (BCA) of conservation plans. This Chapter provides a review and analysis of: (1) the IUCN status of species, (2) economic principles inherent to sustainable versus growth economies, and (3) methodological issues which hinder effective BCAs of TS conservation.

Agricultural Economics: The Year In Review

Undergraduate programs continue to be a mainstay for the Department of Agricultural Economics. In an ongoing effort to match our offerings with the market demands for our graduates, we have implemented four new options in the Natural Resources and Environmental Economics major. This, combined with the options in the Agribusiness and Agricultural Economics majors allows students to customize their program to meet particular career goals. As a result of diligent efforts by faculty and staff, student enrollment for fall semester 2008 increased by 13.2 percent over the 2007 fall semester. This increase was greater than the College average.

Using Economics Experiments to Understand Patent Licensing Behavior

To successfully compete in today’s globalized economy, agribusiness firms need to innovate. Innovation enables firms to produce new and/or differentiated products/services that satisfy specialized consumer demands, and enables firms to generate cost reducing processes to out-compete rivals in domestic and international food markets. Firms will engage in innovative activities if they are able to recoup research and development (R&D) costs and capture innovation rents, so it is critical that they are able to identify the optimal strategies of protecting and profiting from their innovations.

BEHAVIORAL RESPONSE OF CATTLE EGRETS TO POPULATION CONTROL MEASURES IN HAWAII

We monitored behavior of cattle egrets (Bubulcus ibis) during a population control program to reduce egret-aircraft strike hazards from a small heronry near the Hilo, Hawaii, airport. Results verified that attempts to move egrets from undesirable roost sites should be undertaken before nesting begins. Although possibly compounded by previous treatments, our observations also indicate that 1) egrets may abandon a new roost in response to a few dead egrets placed in clear view around the roost, and 2) shooting at egrets as they attempt to land at a traditional feeding site causes long-term avoidance of the area. Rapid repopulation after control indicates that techniques to move roosts and prevent congregations are more likely than population control to resolve problems.

Unifying Representations and Responses: Perseverative Biases Arise From a Single Behavioral System

A dominant account of perseverative errors in early development contends that such errors reflect a failure to inhibit a prepotent response. This study investigated whether perseveration might also arise from a failure to inhibit a prepotent representation. Children watched as a toy was hidden at an A location, waited during a delay, and then watched the experimenter find the toy. After six observation-only A trials, the toy was hidden at a B location, and children were allowed to search for the toy. Two- and 4-year-olds’ responses on the B trials were significantly biased toward A even though they had never overtly responded to this location. Thus, perseverative biases in early development can arise as a result of prepotent representations, demonstrating that the prepotent-response account is incomplete. We discuss three alternative interpretations of these results, including the possibility that representational and response-based biases reflect the operation of a single, integrated behavioral system.

Effects of pregabalin on behavioral alterations induced by ketamine in rats

Objective: The aim of this study is to investigate the effects of pregabalin on the behavior of rats under the influence of ketamine, an NMDA receptor antagonist that mimics the symptoms of schizophrenia. Methods: Rats were injected with saline or 25 mg/kg ketamine intraperitoneally. After that, behavior modifications were investigated by the evaluation of stereotypy and hyperlocomotion, after treating rats with pregabalin (at doses of 30 mg/kg or 100 mg/kg) or placebo (saline solution). Results: The administration of pregabalin reduced ketamine-induced hyperlocomotion. However, neither doses of pregabalin had a significant effect on ketamine-induced stereotypy. Conclusion: This is the first study to investigate the effects of pregabalin using an animal model of psychosis. Furthermore, our results indicate that behavioral changes induced by ketamine in rats can be reversed with the use of pregabalin, suggesting its potential to treat psychotic symptoms.

Intraspecific competition in Zabrotes subfasciatus: Physiological and behavioral adaptations to different amounts of host

The effects of competition on populations of the bean weevil Zabrotes subfasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaining the number of couples (6) and varying the amount of available host seeds: HC, high (limited availability of host: 1.35 g); IC, intermediate (intermediate availability of host: 6 g); and LC, low competition (abundance of host: 36 g). It was found that the distribution of the eggs laid on grains was different among treatments: in LC, for example, although females showed high fecundity (35.4 +/- 5.6 eggs/female) the number of eggs laid on each grain was small (1.2 +/- 0.4 eggs on each seed), thus avoiding larval competition of their offspring; whereas in HC treatment, females showed low fecundity (27.04 +/- 4.5 eggs/female) but laid many eggs on each grain (15.03 +/- 4.3 eggs). There were no changes in the ability to respond to different amounts of host via oviposition behavior (egg distribution) during 41 generations. However, HC females had more offspring than LC females under HC conditions. This suggests that HC insects evolved toward higher fitness in crowded conditions. In addition, after inverting the competition level, insects behaved independently of the treatment conditions they experienced through generations, thus showing that oviposition behavior is flexible. Taken together, our results show that Z. subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.

Biological and behavioral parameters of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae) are altered by the pathogen Nosema sp (Microsporidia: Nosematidae)

A major issue for mass rearing of insects concerns sanitary conditions and disease. Microsporidian infection (Nosema sp.) in laboratory colonies of Diatraea saccharalis (Fabr.) (Lepidoptera: Crambidae), used in producing the parasitoid. Cotesia flavipes Cameron (Hymenoptera: Braconidae), is representative of the problems faced by growers and industry. Although C. flavipes has been produced for several years in Brazil for biological control of D. saccharalis, we have only recently observed that the parasitoid becomes infected when developing inside hosts infected with Nosema sp. We assessed the effects of Nosema sp. on C. flavipes, including the ability to locate and select hosts, and evaluated pathogen transmission. Third instar larvae of D. saccharalis were inoculated with Nosema sp. spores at different concentrations and were parasitized when larvae reached fifth instar. Heavily infected D. saccharalis larvae did not support parasitism. Parasitoids that developed in infected D. saccharalis larvae exhibited increased duration of larval and pupal stages, decreased adult longevity and number of offspring, and reduced tibia size compared to parasitoids developing in uninfected D. saccharalis larvae. Infection by Nosema sp. reduced the ability of the C. flavipes parasitoid to distinguish between volatiles released by the sugarcane infested by healthy larvae and pure air. Uninfected parasitoids preferred plants infested with uninfected hosts. But infected C. flavipes did not differentiate between uninfected hosts and those infected with Nosema sp. The pathogen is transmitted from host to parasitoids and parasitoids to hosts. Pathogenic effects of the microsporidium in C. flavipes are sufficiently severe to justify disease management efforts, particularly considering the importance of C. flavipes as a biological control agent in sugarcane. (C) 2012 Elsevier Inc. All rights reserved.

Neural mobilization reverses behavioral and cellular changes that characterize neuropathic pain in rats

Background: The neural mobilization technique is a noninvasive method that has proved clinically effective in reducing pain sensitivity and consequently in improving quality of life after neuropathic pain. The present study examined the effects of neural mobilization (NM) on pain sensitivity induced by chronic constriction injury (CCI) in rats. The CCI was performed on adult male rats, submitted thereafter to 10 sessions of NM, each other day, starting 14 days after the CCI injury. Over the treatment period, animals were evaluated for nociception using behavioral tests, such as tests for allodynia and thermal and mechanical hyperalgesia. At the end of the sessions, the dorsal root ganglion (DRG) and spinal cord were analyzed using immunohistochemistry and Western blot assays for neural growth factor (NGF) and glial fibrillary acidic protein (GFAP). Results: The NM treatment induced an early reduction (from the second session) of the hyperalgesia and allodynia in CCI-injured rats, which persisted until the end of the treatment. On the other hand, only after the 4th session we observed a blockade of thermal sensitivity. Regarding cellular changes, we observed a decrease of GFAP and NGF expression after NM in the ipsilateral DRG (68% and 111%, respectively) and the decrease of only GFAP expression after NM in the lumbar spinal cord (L3-L6) (108%). Conclusions: These data provide evidence that NM treatment reverses pain symptoms in CCI-injured rats and suggest the involvement of glial cells and NGF in such an effect.

Maternal Depression, Behavioral Profile and School Performance in School-Age Children

The aim of this study was to compare behavioral profile and school performance of school-age children living with a mother who presents clinical history of recurrent depression, diagnosed according to CID-10 criteria in order to verify the influences of such adversity. Thirty-eight mother-child dyads were evaluated using tests, interviews and questionnaires. Approximately two-thirds of the children presented behavioral and school performance difficulties with predominance of emotional and relationship problems, and impairment in the three areas of school performance which were assessed (writing, arithmetic and reading). Such difficulties may be associated with the negative impact of maternal depression. One-third of the children did not present difficulties, which suggests the use of protective mechanisms. The study highlights the importance of considering differences in children's profiles for the planning of mental health practices.

Neuropathology and behavioral impairments after three types of global ischemia surgery in Meriones unguiculatus: Evidence in motor cortex, hippocampal CA1 region and the neostriatum

The effects of three types of global ischemia by occlusion of carotid artery on motor and exploratory behaviors of Gerbils were evaluated by the Activity Cage and Rota rod tests. Animals were divided based on two surgical criteria: unilateral (UNI) or bilateral (BIL) carotid occlusion, with (REP) or without (OCL) reperfusion; and their behavior was evaluated on the fourth (4) or sixth (6) day. There was reduction of cell number in striatum, motor cortex M1 area, and hippocampal CA1 area in all groups in comparison to control animals. For M1 area and striatum, the largest reduction was observed in UNI6, UNI4, and BIL4 groups. Neuronal loss was also observed in CA1 area of BIL4 rodents. There was a decrease in crossings and rearings in all groups in activity cage test, compared to control. Reperfusion, unilateral and bilateral occlusion groups showed decrease in crossings. Only the BIL4 showed a decrease of rearing. In the Rota rod test, except the UNIOCL6, the groups showed a decrease in the balance in comparison to control. Both groups with REP4 showed a major decrease in balance. These findings suggest that both unilateral and bilateral carotid occlusions with reperfusion produce impairments of motor and exploratory behavior. (C) 2011 Elsevier B.V. All rights reserved.