Matching Items (63)
Description
A notable feature of advanced eusocial insect groups is a division of labor within the sterile worker caste. However, the physiological aspects underlying the differentiation of behavioral phenotypes are poorly understood in one of the most successful social taxa, the ants. By starting to understand the foundations on which social behaviors are built, it also becomes possible to better evaluate hypothetical explanations regarding the mechanisms behind the evolution of insect eusociality, such as the argument that the reproductive regulatory infrastructure of solitary ancestors was co-opted and modified to produce distinct castes. This dissertation provides new information regarding the internal factors that could underlie the division of labor observed in both founding queens and workers of Pogonomyrmex californicus ants, and shows that changes in task performance are correlated with differences in reproductive physiology in both castes. In queens and workers, foraging behavior is linked to elevated levels of the reproductively-associated juvenile hormone (JH), and, in workers, this behavioral change is accompanied by depressed levels of ecdysteroid hormones. In both castes, the transition to foraging is also associated with reduced ovarian activity. Further investigation shows that queens remain behaviorally plastic, even after worker emergence, but the association between JH and behavioral bias remains the same, suggesting that this hormone is an important component of behavioral development in these ants. In addition to these reproductive factors, treatment with an inhibitor of the nutrient-sensing pathway Target of Rapamycin (TOR) also causes queens to become biased towards foraging, suggesting an additional sensory component that could play an important role in division of labor. Overall, this work provides novel identification of the possible regulators behind ant division of labor, and suggests how reproductive physiology could play an important role in the evolution and regulation of non-reproductive social behaviors.
ContributorsDolezal, Adam G (Author) / Amdam, Gro V (Thesis advisor) / Brent, Colin S. (Committee member) / Gadau, Juergen (Committee member) / Hoelldobler, Bert (Committee member) / Liebig, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
While exercising mammalian muscle increasingly relies on carbohydrates for fuel as aerobic exercise intensity rises above the moderate range, flying birds are extraordinary endurance athletes and fuel flight, a moderate-high intensity exercise, almost exclusively with lipid. In addition, Aves have long lifespans compared to weight-matched mammals. As skeletal muscle mitochondria account for the majority of oxygen consumption during aerobic exercise, the primary goal was to investigate differences in isolated muscle mitochondria between these species and to examine to what extent factors intrinsic to mitochondria may account for the behavior observed in the intact tissue and whole organism. First, maximal enzyme activities were assessed in sparrow and rat mitochondria. Citrate synthase and aspartate aminotransferase activity were higher in sparrow compared to rat mitochondria, while glutamate dehydrogenase activity was lower. Sparrow mitochondrial NAD-linked isocitrate dehydrogenase activity was dependent on phosphate, unlike the mammalian enzyme. Next, the rate of oxygen consumption (JO), electron transport chain (ETC) activity, and reactive oxygen species (ROS) production were assessed in intact mitochondria. Maximal rates of fat oxidation were lower than for carbohydrate in rat but not sparrow mitochondria. ETC activity was higher in sparrows, but no differences were found in ROS production between species. Finally, fuel selection and control of respiration at three rates between rest and maximum were assessed. Mitochondrial fuel oxidation and selection mirrored that of the whole body; in rat mitochondria the reliance on carbohydrate increased as the rate of oxygen consumption increased, whereas fat dominated under all conditions in the sparrow. These data indicate fuel selection, at least in part, can be modulated at the level of the mitochondrial matrix when multiple substrates are present at saturating levels. As an increase in matrix oxidation-reduction potential has been linked to a suppression of fat oxidation and high ROS production, the high ETC activity relative to dehydrogenase activity in avian compared to mammalian mitochondria may result in lower matrix oxidation-reduction potential, allowing fatty acid oxidation to proceed while also resulting in low ROS production in vivo.
ContributorsKuzmiak, Sarah (Author) / Willis, Wayne T (Thesis advisor) / Mandarino, Lawrence (Committee member) / Sweazea, Karen (Committee member) / Harrison, Jon (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Here I present a phylogeographic study of at least six reproductively isolated lineages of harvester ants within the Pogonomyrmex barbatus and P. rugosus species group. The genetic and geographic relationships within this clade are complex: four of the identified lineages are divided into two pairs, and each pair has evolved under a mutualistic system that necessitates sympatry. These paired lineages are dependent upon one another because interlineage matings within each pair are the sole source of hybrid F1 workers; these workers build and sustain the colonies, facilitating the production of the reproductive caste, which results solely from intralineage fertilizations. This system of genetic caste determination (GCD) maintains genetic isolation among these closely related lineages, while simultaneously requiring co-expansion and emigration as their distributions have changed over time. Previous studies have also demonstrated that three of the four lineages displaying this unique genetic caste determination phenotype are of hybrid origin. Thus, reconstructing the phylogenetic and geographic history of this group allows us to evaluate past insights and plan future inquiries in a more complete historical biogeographic context. Using mitochondrial DNA sequences sampled across most of the morphospecies' ranges in the U.S. and Mexico, I employed several methods of phylogenetic and DNA sequence analysis, along with comparisons to geological, biogeographic, and phylogeographic studies throughout the sampled regions. These analyses on Pogonomyrmex harvester ants reveal a complex pattern of vicariance and dispersal that is largely concordant with models of late Miocene, Pliocene, and Pleistocene range shifts among various arid-adapted taxa in North America.
ContributorsMott, Brendon (Author) / Gadau, Juergen (Thesis advisor) / Fewell, Jennifer (Committee member) / Anderson, Kirk (Committee member) / Arizona State University (Publisher)
Created2012
Description
In social insect colonies, as with individual animals, the rates of biological processes scale with body size. The remarkable explanatory power of metabolic allometry in ecology and evolutionary biology derives from the great diversity of life exhibiting a nonlinear scaling pattern in which metabolic rates are not proportional to mass, but rather exhibit a hypometric relationship with body size. While one theory suggests that the supply of energy is a major physiological constraint, an alternative theory is that the demand for energy is regulated by behavior. The central hypothesis of this dissertation research is that increases in colony size reduce the proportion of individuals actively engaged in colony labor with consequences for energetic scaling at the whole-colony level of biological organization. A combination of methods from comparative physiology and animal behavior were developed to investigate scaling relationships in laboratory-reared colonies of the seed-harvester ant, Pogonomyrmex californicus. To determine metabolic rates, flow-through respirometry made it possible to directly measure the carbon dioxide production and oxygen consumption of whole colonies. By recording video of colony behavior, for which ants were individually paint-marked for identification, it was possible to reconstruct the communication networks through which information is transmitted throughout the colony. Whole colonies of P. californicus were found to exhibit a robust hypometric allometry in which mass-specific metabolic rates decrease with increasing colony size. The distribution of walking speeds also scaled with colony size so that larger colonies were composed of relatively more inactive ants than smaller colonies. If colonies were broken into random collections of workers, metabolic rates scaled isometrically, but when entire colonies were reduced in size while retaining functionality (queens, juveniles, workers), they continued to exhibit a metabolic hypometry. The communication networks in P. californicus colonies contain a high frequency of feed-forward interaction patterns consistent with those of complex regulatory systems. Furthermore, the scaling of these communication pathways with size is a plausible mechanism for the regulation of whole-colony metabolic scaling. The continued development of a network theory approach to integrating behavior and metabolism will reveal insights into the evolution of collective animal behavior, ecological dynamics, and social cohesion.
ContributorsWaters, James S., 1983- (Author) / Harrison, Jon F. (Thesis advisor) / Quinlan, Michael C. (Committee member) / Pratt, Stephen C. (Committee member) / Fewell, Jennifer H. (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
When examining the medical doctrines of previous empires, they reveal the influence of religion, societal attitudes, and the historical context that influenced the scholars that penned them. The advancements during the Islamic Golden age can be seen in the field of medicine, which had the Greco-Roman medical corpus as their foundation and the source of the theory of the four humors and anatomical beliefs. This paper will analyze the effect of cultural, societal, and historical influences on the medical doctrines of Muslim medieval physicians in the Golden Age and the works of the Roman physician Galen, and demonstrate how these effects result in similarities and differences in medical practice and the understanding of disease and anatomy. Due to translation efforts that were supported by religious views on the accumulation of knowledge and the efforts of the Abbasid empire, resultant acceptance of the theory of the four humors and anatomical doctrines is observed in the treatment and perception of disease, which would consist of this paper's focus on surgery, diet therapy and associations with nature. However, with further analysis of the extent of this acceptance and the findings in the Islamic medical doctrines, the differences in experimental methods, religious interpretations, and cultural attitudes shows a deviation from the Galenic tradition, with the second set of the paper's focus being human dissection, cause of disease, and experimentation. The purpose of this research is to demonstrate the impact of religion, societal attitudes, culture and the accepted paradigm on the practice of medicine and the study of anatomy, and what would cause a challenge against the legacy of Galen.
ContributorsAlzuhairi, Fatemah Saad (Author) / Vélez-Ibáñez, Carlos (Thesis director) / Smith, Brian (Committee member) / Historical, Philosophical & Religious Studies (Contributor) / Historical, Philosophical & Religious Studies, Sch (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Honey bee (Apis mellifera) colonies have experienced substantial losses due to colony collapse disorder (CCD) since the first officially reported cases in 2006. Many factors have been implicated in CCD, including pests, pathogens, malnutrition, and pesticide use, but no correlation has been found between a single factor and the occurrence of CCD. Fungicides have received less research attention compared to insecticides, despite the fact that fungicide application coincides with bloom and the presence of bees. Pristine fungicide is widely used in agriculture and is commonly found as a residue in hives. Several studies have concluded that Pristine can be used without harming bees, but reports of brood loss following Pristine application continue to surface across the country. The primary objectives of this study were to determine whether Pristine causes an aversive gustatory response in bees and whether consumption of an acute dose affects responsiveness to sucrose. An awareness of how foragers interact with contaminated food is useful to understand the likelihood that Pristine is ingested and how that may affect bees' ability to evaluate floral resources. Our results indicated that Pristine has no significant effect on gustatory response or sucrose responsiveness. There was no significant difference between bee responses to Pristine contaminated sucrose and sucrose alone, and no significant effect of Pristine on sucrose responsiveness. These results indicate that honey bees do not have a gustatory aversion to Pristine. A lack of aversion means that honey bees will continue collecting contaminated resources and dispersing them throughout the colony where it can affect brood and clean food stores.
ContributorsMcHugh, Cora Elizabeth (Co-author) / Jernigan, Christopher (Co-author, Committee member) / Burden, Christina (Co-author) / DeGrandi-Hoffman, Gloria (Co-author) / Smith, Brian (Thesis director) / Fewell, Jennifer (Committee member) / Barrett, The Honors College (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / School of Life Sciences (Contributor) / School of Art (Contributor)
Created2015-05
Description
This study illustrates the abilities of the honeybee, Apis mellifera, to learn and differentiate between patterns solely off their spatial frequencies. Patterns were chosen based off of calculations derived from the measurements of the physical construction of the apposition compound eye, which led to predictions of what the bees could theoretically see. The hypothesis was then that bees would have a visual threshold where patterns with spatial frequencies that fall below this line should be easily distinguishable, and patterns above the threshold would have scores that mimic if the bees made choices randomly. There were 9 patterns tested, all with different spatial frequencies and in the colors of black, white, and gray. The bees were tested on their learning and pattern differentiation abilities with 10 pattern comparisons, with the lower frequency of the two being associated with an unscented sucrose solution reward. The results were surprising in that the previous studies pointing towards this visual threshold were inaccurate because of some of the patterns being learning in an intermediate ability. These intermediate scores suggest that the calculations predicting what the bees could see clearly were slightly wrong because it was more likely that the bees saw those images in more of a blur, which resulted in their intermediate score. Honeybees have served as a useful model organisms over the decades with studying learning involving visual information. This study lacked in its total numbers of trials and bees tested, which could have led to incomplete results, and this showing of an intermediate score and ability. Future studies should continue in order to advance this understanding of a perceptually and cognitively advance processing animal.
ContributorsBalsino, Brandon Bartholomew (Author) / Harrison, Jon (Thesis director) / Smith, Brian (Committee member) / Duell, Meghan (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
Selenium, a group 16 metalloid on the periodic table, is a necessary mineral for many organisms. Trace amounts of selenium are essential for normal development, antioxidant protein function, enzyme function, and hormone regulation (Burden et al., 2016). However, when selenium is found in toxic amounts in organisms, it has been found to substitute for sulfur in proteins, which can be toxic to these animals, and cause oxidative stress (Quinn et al., 2007). Using the previous research done with acute exposure to organic and inorganic selenium compounds, we hypothesized that the inorganic sodium selenate would significantly decrease learning and memory recall for both chronic and acute exposure. We also hypothesized that the consumption of organic methylseleno-L-cysteine by honey bees would decrease learning and memory recall for both the chronic and acute exposure. We further hypothesized that protein carbonyl content would be increased due to oxidative damage caused by selenium in both the sodium selenate and the methylseleno-L-cysteine treatment groups, but that the inorganic selenium compound would increase the carbonyl content more than the methylseleno-L-cysteine. To run the experiments, three tents outside had two colonies in each tent. One tent contained the sodium selenate group, another had the sucrose control, and one contained the methylseleno-L-cysteine group. The treatment groups were fed selenium in their sucrose feeders. The first part of the experiment was training the bees by using proboscis extension response (PER) to teach them to extend their proboscis to the rewarded odor and not to the unrewarded odor. This was done by pairing the rewarded odor with a sucrose reward and not pairing it with the unrewarded odor. Then their short-term and long-term memory recall was tested. The second part of the experiment was checking for oxidative damage by measuring the protein carbonyl content in the bees. Three boxes were set up with the same three treatment groups as used in the tents. The treatment group bees were exposed to selenium in the sucrose feeders and in the pollen patties. After one week, the living bees were removed and frozen. They were then homogenized to extract protein. The first assay run was the protein content assay to establish a standard protein concentration for samples. Then a protein carbonyl assay was run, to determine the protein carbonyl content. Overall, the experiment found that exposure to selenium negatively impacted honey bees learning and memory recall significantly. Chronic exposure to the inorganic selenate reduced the bees' long-term memory abilities to differentiate between odors. With methylseleno-L-cysteine, it had no significant effect for the chronic exposure, but for the acute exposure, it had a significant impairment on their abilities to distinguish between the rewarded and unrewarded odors during conditioning. Our results showed that from our experiment there appeared to be no significant effect of selenium exposure on the increase of carbonylation content in the different treatment groups. This is most likely due to the fact the carbonyl content was not detectable because the protein concentration was low in the samples (approximately 3.5 mg/mL).
ContributorsWinski, Alexandra (Co-author) / Winski, Brandon (Co-author) / Smith, Brian (Thesis director) / Harrison, Jon (Committee member) / Burden, Christina (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Cuticular hydrocarbons (CHCs) play a crucial role in social insect recognition systems. In this study we investigated mate choice in the red harvester ant, Pogonomyrmex barbatus. In Phoenix, this species has two lineages, J1 and J2, which look identical, but are genetically isolated. In the genetic caste determination (GCD) system workers and queens are determined by their genotype (i.e., workers develop from interlineage crosses, queens from intralineage crosses). As such, J1 and J2 lineages are dependent on each other in order for colonies to produce both workers and reproductive queens. Given their genetic isolation and interdependence, we hypothesized that the CHCs of alate males and queens are affected by lineage, and that differences in the CHC profile are used for mate recognition. We tested these hypotheses by analyzing the lineage distributions of actively mating pairs (n=65), and compared them with the overall distribution of male and female sexuals (n=180). We additionally analyzed the five most abundant CHC compounds for 20 of the actively mating P. barbatus alate male and queen pairs to determine how variable the two lineages are between each sex. We found that mating pair distributions did not significantly differ from those expected under a random mating system (�2= 1.4349, P= 0.6973), however, CHC profiles did differ between J1 and J2 lineages and sexes for the five most abundant CHC compounds. Our results show that random mating is taking place in this population, however given the differences observed in CHC profiles, mate recognition could be taking place.
ContributorsTula Del Moral Testai, Pedro Rafael (Co-author) / Cash, Elizabeth (Co-author) / Gadau, Juergen (Thesis director) / Liebig, Juergen (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
I tested the hypothesis that in mature colonies of the seed harvester Pogonomyrmex californicus ant species, paired pleometrotic queens would produce workers more efficiently after a massive removal of their work force than haplometrotic queens, paired pleometrotic with haplometrotic queens, and single pleometrotic queens. I suggested that the paired pleometrotic queens would have an advantage of cooperating together in reproducing more workers quicker than the other conditions to make up for the lost workers. This would demonstrate a benefit that pleometrosis has over haplometrosis for mature colonies, which would explain why pleometrosis continues for P.californicus after colony foundation. After removing all but twenty workers for every colony, I took pictures and counted the emerging brood for 52 days. Analyses showed that the paired pleometrotic queens and the haplometrotic queens both grew at an equally efficient rate and the paired pleometrotic and haplometrotic queens growing the least efficiently. However, the results were not significant and did not support the hypothesis that paired pleometrotic queens recover from worker loss more proficiently than other social systems.
ContributorsFernandez, Marisa Raquel (Author) / Fewell, Jennifer (Thesis director) / Gadau, Juergen (Committee member) / Haney, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / Department of Psychology (Contributor)
Created2014-05