Browsing by Author "Moore, Janice, advisor"

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Open Access
Altered behavior and cost of manipulation: the acanthocephalan Leptorhyncoides thecatus in its amphipod host Hyalella azteca
(Colorado State University. Libraries, 2014) Stone, Charles F., author; Moore, Janice, advisor; Kondratieff, Boris, committee member; Ghalambor, Cameron, committee member; Naug, Dhruba, committee member
Behavioral manipulation occurs when a parasite causes changes in its host's behavior to the parasite's benefit. The parasite benefits from these behavioral changes by increased survival or transmission. It has been hypothesized that such manipulation carries a cost for the parasite because energy allocated to manipulation does not contribute to growth or reproduction. The acanthocephalan parasite Leptorhynchoides thecatus provides a system in which to test this concept. This parasite uses the amphipod Hyalella azteca as an intermediate host and fish as definitive hosts; it has not been previously shown to alter host behavior. This system is advantageous for testing costs of manipulation: the size of the larval cystacanth stage in the intermediate host provides an easily quantified measure of fitness. Larger cystacanths establish in the fish host more frequently than smaller cystacanths. If manipulation is costly, I predict that there should be a negative relationship between the strength of behavioral change and fitness measures (larval size). I compared geotaxis, phototaxis, photophilia, and activity responses of infected and uninfected H. azteca to determine whether L. thecatus modified behavior. I also measured the responses of infected and uninfected amphipods to alarm pheromones and predator kairomones. I then investigated whether these behavioral changes were correlated with larval size. I found that L. thecatus does indeed alter host behavior. Compared to uninfected amphipods, infected amphipods were found higher in the water column, spent greater time in lighted areas, and were more active. There was no difference in phototaxis; both groups of amphipods swam away from a direct light source. Infected amphipods also reduced anti-predator responses to alarm pheromones and predator kairomones. This is the first example of altered alarm pheromones behavior in parasitized amphipods. These findings strongly suggest that L. thecatus increases encounters between its intermediate host and definitive host predators and that the parasite increases its transmission rate through behavioral manipulation. None of these behavioral changes were correlated with a decrease in larval size as predicted by the manipulation cost hypothesis. In fact, larger cystacanths altered geotaxis and photophilia more than smaller cystacanths did. Finally, I compare L. thecatus host use data collected from Atkinson Reservoir, Nebraska, between 2008 and 2011 to published data from 1979-1980. Both data sets show that the Green Sunfish (Lepomis cyanellus) and Pumpkinseed Sunfish (Lepomis gibbosus) are the highest quality hosts for this population. However, the current data suggest a possible shift in secondary hosts from Largemouth Bass (Micropterus salmoides) to Bluegill Sunfish (Lepomis macrochirus). Understanding the cost associated with any trait sheds light on the evolution and maintenance of that trait. This dissertation uses a unique population of L. thecatus to add this parasite to the growing list of those that behaviorally manipulate their hosts, and to demonstrate that, contrary to predictions from the theoretical literature, behavioral manipulation is not necessarily costly.
Open Access
Description and distribution of Helminth parasites of White-bellied Grass mice (Akodon albiventer) and Andean Vesper mice (Calomys lepidus) of the altiplano region of Bolivia
(Colorado State University. Libraries, 2016) Griffin, Bretton Skyler, author; Moore, Janice, advisor; Black, William, committee member; Raines, Karen, committee member
Akodon and Calomys genera are among the most speciose of South American rodents. Within Bolivia, these genera inhabit multiple environments of varied geomorphology, elevation, vegetation and climates, including the Bolivian altiplano, which consists of complex ecosystems at elevations of 3,000 meters and above. A number of species like the White-Bellied Grass Mouse (Akodon albiventer) and Andean Vesper Mouse (Calomys lepidus) primarily reside at the high elevations of the altiplano. Because of their habitat location, relatively few studies have addressed A. albiventer and C. lepidus parasites, specifically their helminth parasites. To gain further knowledge about the parasite fauna infecting these rodents, a biodiversity survey was conducted. This biodiversity survey is the first that describes and reports the distribution of helminth parasites occurring in A. albiventer and C. lepidus collected from the altiplano region of Bolivia. Gardner and colleagues collected A. albiventer and C. lepidus hosts during expeditions in 1984-1993 from five departments in Bolivia: Oruro, Chuquisaca, Tarija, La Paz, and Cochabamba. From these collections, 27 A. albiventer and 11 C. lepidus were randomly chosen for parasite analysis, and yielded a total of 702 helminth parasite specimens, representing five helminth taxa. Oxyurids were the most common, followed by protospirurids, rictulariids, trichostrongylids, and cestodes. These are the first parasite records from A. albiventer and C. lepidus within the altiplano region of Bolivia. Many of the oxyurid parasites recovered from A. albiventer and C. lepidus were unidentifiable to species due to the overlap of morphological measurements and features. In order to evaluate the accuracy of manual identification techniques through the examination of morphological relationships between species, statistical analyses were performed on male and female oxyurid specimens (Syphacia spp.) separated into three species groups. The analyses indicated that two species groups from the host, A. albiventer, shared more morphological measurement similarities than the species group from C. lepidus. Though further analysis is necessary, it is possible that the species group derived from C. lepidus is a new Syphacia species.
Open Access
Dung beetles and their nematode parasites as ecosystem engineers and agents of disease
(Colorado State University. Libraries, 2012) Boze, Broox G. V., author; Moore, Janice, advisor; Naug, Dhruba, committee member; Lacy, Michael, committee member; Ubelaker, John, committee member
Dung beetles (Order Coleoptera, Subfamily Scarabaeoidea), are a magnificent group of insects noted for both their physical beauty and ecologically significant role in parasite suppression and agricultural management. These insects feed on feces in both their larval and adult forms and are classified into one of three groups based on the way they procure fecal resources to their young. Paracoprid dung beetles collect chunks of feces and bury them in tunnels/nests dug directly below the site of deposition, telocoprid beetles create carefully crafted balls of dung and roll them away from the pat before burying them in underground nests, and endocoprid beetles create nests in the feces without moving it from the original deposition site. Because dung beetles interact with feces on a regular basis, and because many parasites use feces as a medium for distributing their eggs, it is not uncommon for dung beetles to come in contact with parasite propagules at a rate higher than that seen in other animals. While the majority of parasite propagules cannot survive consumption by a dung beetle, several nematode species have found a way to use these insects as their intermediate hosts. After being consumed by a dung beetle, both Streptopharagus pigmentatus (found throughout East Asia) and Physocephalus sexalatus (found in the Southeastern United States) migrate from the dung beetle's digestive tract into the body cavity of the beetle where they wait to be consumed by their final host. Trophically transmitted parasites often change the behavior of their host and examples of behavioral modification have been found in most major host taxa. This study asks whether these two nematodes alter dung beetle behavior in ways that affect transmission dynamics and/or their role as ecosystem engineers. Indeed, when nematode infections are present, both paracoprid and telocoprid beetles reduce their feeding rate and interaction with feces. Paracoprid beetles (from the genus Onthophagus and Phaneaus) infected with nematodes consume only half of the feces consumed by uninfected beetles. Further studies on beetles from the genera Phaneaus indicate that these beetles also bury less feces and do so at a shallower depth. This is relevant because dung beetles are responsible for removing and processing the majority of fecal material in both agricultural areas and forest ecosystems. Feces serve as breeding grounds for many insect pests and carry nutrients that, when buried by dung beetles, are essential for plant health. I show that both S. pigmentatus and P. sexalatus, through alterations in their host's behavior, alter the availability of fecal resources to both plant and animal communities and should therefore be classified as an ecosystem engineers. Telocoprid beetles infected by the nematode parasite P. sexalatus also exhibit reduced feeding behavior and provide a unique opportunity to quantify the fecal resources provided to young. It is not uncommon for males and females of many host to respond to infection in different ways and indeed that is what we see in telocoprid beetles from the genus Canthon. Both C. pilularis and C. nigricornis females show reduced feeding whereas this difference in consumption is not present in male beetles. Male beetles of both C. pilularis and C. nigricornis consistently make smaller brood balls than beetles that are not infected. Because of the direct correlation between adult size and fecal resources available at emergence, this type of behavioral modification in adults is relevant to the outcome of competitive interactions seen in future offspring. Typical tests for predator avoidance (use of shelter, use of substrate, and activity level) did not indicate a change behavior based on infection for any of the species studied. The fact that activity, shelter use and substrate use are not altered is interesting given that a large number of parasites with complex lifecycles play an active role in increasing the probability of transmission. While this study asks if the most common forms of predator avoidance in dung beetles are changed by parasites, it is not exhaustive and it is possible that the parasite alters its host's predator avoidance behavior in some other way. Uninfected dung beetles are extremely beneficial and a variety of countries have actually imported exotic dung beetles because of the services they provide. Some of the most common and beneficial dung beetles in the United States (Onthophagus Taurus and O. gazelle) were introduced from Asia and Africa in the early 1980s and continue flourish throughout the country. These insects are so important in agricultural and disease management and are believed to save the American cattle industry $380 million per year. It is therefore imperative that we understand how the parasites transmitted by dung beetles alter host behavior, especially if the behavioral changes affect their role as ecosystem engineers.
Open Access
Invasive mosquitoes, larval competition, and potential implications for vector competence
(Colorado State University. Libraries, 2007) Bevins, Sarah, author; Moore, Janice, advisor
Aedes albopictus is an invasive mosquito species which established rapidly in the US. It is characterized as an aggressive biter, prolific breeder, and dominant larval resource competitor. Declines in resident mosquito species have followed its arrival, and species that persist often emerge from shared larval habitats as small, nutritionally deprived adults. Aedes albopictus is a competent disease vector in both its native range and in areas of recent establishment. It therefore has the potential to alter vector-borne disease transmission either directly, by creating a new pathogen association, or indirectly, via interactions with native mosquito vectors.
Open Access
Parasite communities of wild turkeys (Meleagris gallopavo) in Colorado
(Colorado State University. Libraries, 2014) Shilling Littman, Paige Willever, author; Moore, Janice, advisor; Ghalambor, Cameron, committee member; Pabilonia, Kristy, committee member
Wild turkeys (Meleagris gallopavo) are large galliform birds, are commonly hunted birds, and they are non-migratory. Wild turkeys were originally found over most of the United States. In the early 1900s they experienced widespread population declines which are thought to have been caused by overhunting and habitat loss. Due to many reintroduction efforts, the wild turkey is now found in its historical range and it has expanded its range even further. However, considering the popularity of wild turkeys as game birds, relatively few studies have addressed their parasites, and specifically the helminth parasites. Island Biogeography Theory has been applied to parasite and host relationships in which the host is considered an island. In particular, the Island Size hypothesis predicts that a larger island will allow for greater species diversity due to the increased area, and by extension, larger host species, in terms of body mass, will have more species of parasites. This study evaluates whether or not galliform birds support the Island Size Hypothesis in terms of their parasite communities. Birds in the order Galliformes have a wide range of sizes and are generally non-migratory; thus they will not pick up parasites from different locations. I reviewed twenty six studies of 19 species of galliform birds and recorded the number of helminth species reported in each host bird species. Based on these data, I show that there is a positive correlation (R2 = 0.212) between galliform host size and number of helminth parasite species. The model that best fits the data includes both the mean mass of the host species as well as the family of the host species. This is the first survey of helminth parasites in wild turkeys of Colorado. I collected 24 wild turkey intestines that were donated by hunters. These intestines were examined for helminth parasites, which were collected and identified. A total of 7 different species of helminth parasites were identified in these Colorado wild turkeys. Cestodes were the most commonly identified helminths, followed by acanthocephalans, trematodes, and nematodes. The Colorado data were then compared to a previous study of the helminths of wild turkeys in both Florida and New Zealand. A total of 14 helminth parasite species were reported from wild turkeys in Florida while 6 helminth species were reported in wild turkeys from New Zealand. These data suggest that there are differences in these parasite communities in terms of parasite species richness and prevalence of each helminth species. The fact that wild turkeys are not only a popular game bird, but also a common component of domestic poultry operations underscored the importance of understanding their parasites. This knowledge can help us to harvest wild turkeys safely when hunting as well as minimize the transfer of parasites between domestic and wild turkeys.