Studies of cooperation remain an important aspect in understanding the evolution of social cues and interactions. One example of cooperation is pleometrosis, an associative behavior of forming a colony with two unrelated, fertile queens. However, most ant species display haplometrosis, the founding of a colony by a single queen. In these associations, the queen typically rejects cooperation. In populations of Pogonomyrmex californicus, both pleometrosis and haplometrosis exists. It is not clear how associative -metrosis became a practiced behavior since haplometrotic queens tend to fight. However, as fighting in pleometrotic queens became less frequent, this induces benefit, in terms of cost savings, in having associative behaviors. The hypothesis tested was nest excavation of pleometrotic queens show sociality, while haplometrotic queens show association independence. Isolated pleometrotic queens (P) showed low excavation rate at 2.72cm2/day, compared to the rate when the task was shared in (PP) nests, 4.57cm2/day. Nest area of the (P) queens were also affected during days 3 and 4 of the experiment, where there was presence of nest area decrease. Furthermore, the excavation session of (P) was the only one determined as significant between all other nests. Although the (P) queens have low values, they eventually reach a similar point as the other nests by day 6. However, the lack of haste in excavation leads to longer exposure to the elements, substituting the risk of losing cuticles in excavation for the risk of predation. For the haplometrotic queens, nests of (H) and (HH) displayed no significant difference in excavation values, leading to having social effect in their association.

Abstract:
Given the incredible variety in ant nest architecture, this experiment sought to evaluate how the nest architecture of Harpegnathos saltator differs from other species’ nests. To achieve the ability to evaluate the structure of H. saltator nest, we created experimental colonies varying in size from 20, 40, 60, 80 workers of Harpegnathos saltator in five-gallon buckets of sand and then allowing the colonies to grow for four months and twelve days. To create the nest casts, we developed a charcoal kiln out of a galvanized trash can and used a ceramic crucible to hold the aluminum being melted. Using molten aluminum to create nest casts of each colony produced, we obtained three poorly developed nests and one decent nest. The decent nest cast, the 80 worker H. saltator nest, was lacking key features of H. saltator nests that have been excavated in the field. However, they do share many of the same structures such as the shaping of the chambers. The ability of the experimental colonies to excavate the soil provided in the buckets to them was likely halted by poor penetration of water into superficial layers of the soil, thus making the soil too difficult to excavate and form the structures that are key elements of the species nest architecture. Despite these key challenges which the colonies faced, the 80-worker colony showed extensive vertical development and did display features associated with natural H. saltator colonies. Thus, given the display of some key features associated with characteristics of the H. saltator nests excavated in the field, it can be said that with some modification to technique that this is a viable avenue for future study of nest architecture and colony structure.

Temnothorax rugatulus ants are known to recruit via the use of tandem running, a typically two ant interaction in which a leader ant guides a follower ant to a particular location with the intent of teaching the follower ant the knowledge required to navigate to said location independently. In general, the purposes of tandem runs are fairly clear. There are tandem runs towards food in order to recruit gatherers, and there are tandem runs towards potential new nest sites to allow the colony to assess site quality. However, a group of tandem runs known as “reverse tandem runs” are a subject of mystery at this time. Reverse tandem runs are a type of tandem run found mainly during specific spans of Temnothorax colony migration. They typically arise during the period of migration when brood are being transported into a new nest site. The carriers of the brood, when returning to the old nest site to gather more brood, occasionally start tandem runs running backwards towards the old nest. In this study, the effect of navigational and physical obstacles encountered during migrations on the number of reverse tandem runs was tested. The hypothesis being that such a disturbance would cause an increase in reverse tandem runs as a method of overcoming the obstacle. This study was completed over the course of two experiments. This first experiment showed no indication of the ants having any trouble with the applied disturbance, and a second experiment with a larger challenge for the migrating ants was performed. The results of this second experiment showed that a migration obstacle will lead to an increase in migration time as well as an increase in the number of failed reverse tandem runs (reverse tandem runs that started but never reached the old nest). However, it was shown that the number of complete reverse tandem runs (reverse tandem runs that reached the old nest) remained the same whether the obstacle was introduced or not.

Human-inhabited or -disturbed areas pose many unique challenges for wildlife, including increased human exposure, novel challenges, such as finding food or nesting sites in novel structures, anthropogenic noises, and novel predators. Animals inhabiting these environments must adapt to such changes by learning to exploit new resources and avoid danger. To my knowledge no study has comprehensively assessed behavioral reactions of urban and rural populations to numerous novel environmental stimuli. I tested behavioral responses of urban, suburban, and rural house finches (Haemorhous mexicanus) to novel stimuli (e.g. objects, noises, food), to presentation of a native predator model (Accipiter striatus) and a human, and to two problem-solving challenges (escaping confinement and food-finding). Although I found few population-level differences in behavioral responses to novel objects, environment, and food, I found compelling differences in how finches from different sites responded to novel noise. When played a novel sound (whale call or ship horn), urban and suburban house finches approached their food source more quickly and spent more time on it than rural birds, and urban and suburban birds were more active during the whale-noise presentation. In addition, while there were no differences in response to the native predator, rural birds showed higher levels of stress behaviors when presented with a human. When I replicated this study in juveniles, I found that exposure to humans during development more accurately predicted behavioral differences than capture site. Finally, I found that urban birds were better at solving an escape problem, whereas rural birds were better at solving a food-finding challenge. These results indicate that not all anthropogenic changes affect animal populations equally and that determining the aversive natural-history conditions and challenges of taxa may help urban ecologists better understand the direction and degree to which animals respond to human-induced rapid environmental alterations.

I examined how competition affects the way animals use thermal resources to control their body temperature. Currently, biologists use a cost benefit analysis to predict how animals should regulate their body temperature. This current theory of thermoregulation does not adequately predict how animals thermoregulate in the wild. While the model works well for animals in low cost habitats, it does not work as well for animals in high cost habitats. For example, animals that are in habitats of low thermal quality thermoregulate more precisely than predicted by the current model. One reason these predictions may be wrong is that they do not account for interactions between animals. By including these interactions in future predictions, a more accurate model of thermoregulatory behavior can be created.

Before developing a theory for all animals, a model needs to be developed for a single model animal, such as fruit flies, that can be used to empirically examine how organisms thermoregulate under competition. My work examines how flies behave around other flies and develops a game theory model predicting how they should optimally behave. More specifically, my research accounts for competition among larvae by using game theory to predict how mothers should select sites when laying eggs. Although flies prefer to lay their eggs in places that will offer suitable temperatures for the development of their larvae, these sites become less suitable when crowded. Therefore, at some density of eggs, cooler sites should become equally beneficial to larvae when considering both temperature and competition. Given this tradeoff, an evolutionarily stable strategy (ESS) emerges where some flies should lay eggs in cooler sites while other flies should lay eggs at the warmer temperature. By looking at the fitness of genotypes in habitats of differing quality (competition, temperature, food quality, space), I modeled the ESS for flies laying eggs in a heterogeneous environment. I then tested these predictions by observing how flies compete for patches with different temperatures.

Persistent cooperation between unrelated conspecifics rarely occurs in mature eusocial insect societies. In this dissertation, I present evidence of non-kin cooperation in the Nearctic honey ant Myrmecocystus mendax. Using microsatellite markers, I show that mature colonies in the Sierra Ancha Mountain of central Arizona contain multiple unrelated matrilines, an observation that is consistent with primary polygyny. In contrast, similar analyses suggest that colonies in the Chiricahua Mountains of southeastern Arizona are primarily monogynous. These interpretations are consistent with field and laboratory observations. Whereas cooperative colony founding was observed frequently among groups of Sierra Ancha foundresses, founding in the Chiricahua population was restricted to individual foundresses. Furthermore, Sierra Ancha foundresses successfully established incipient laboratory colonies without undergoing queen culling following emergence of the first workers. Multi-queen laboratory Sierra Ancha colonies also produced more workers and repletes than haplometrotic colonies, and when brood raiding was induced between colonies, queens of those with more workers had a higher survival probability.

Microsatellite analyses of additional locations within the M. mendax range suggest that polygyny is also present in some other populations, especially in central-northern Arizona, albeit at lower frequencies than that in the Sierra Anchas. In addition, analyses of multiple types of genetic data, including microsatellites, the mitochondrial barcoding region, and over 2000 nuclear ultra-conserved elements indicate that M. mendax populations within the southwestern U.S. and northwestern Mexico are geographically structured, with strong support for the existence of two or more divergent clades as well as isolation-by-distance within clades. This structure is further shown to correlate with variation in queen number and hair length, a diagnostic taxonomic feature used to distinguish honey ant species.

Together, these findings suggest that regional ecological pressures (e.g. colony density , climate) may have acted on colony founding and social strategy to select for increasing workforce size and, along with genetic drift, have driven geographically isolated M. mendax populations to differentiate genetically and morphologically. The presence of colony fusion in the laboratory and life history traits in honey ant that are influenced by colony size, including repletism, brood raiding, and tournament, support this evolutionary scenario.

The ability to detect and appropriately respond to chemical stimuli is important for many organisms, ranging from bacteria to multicellular animals. Responses to these stimuli can be plastic over multiple time scales. In the short-term, the synaptic strengths of neurons embedded in neural circuits can be modified and result in various forms of learning. In the long-term, the overall developmental trajectory of the olfactory network can be altered and synaptic strengths can be modified on a broad scale as a direct result of long-term (chronic) stimulus experience. Over evolutionary time the olfactory system can impose selection pressures that affect the odorants used in communication networks. On short time scales, I measured the effects of repeated alarm pheromone exposure on the colony-level defense behaviors in a social bee. I found that the responses to the alarm pheromone were plastic. This suggests that there may be mechanisms that affect individual plasticity to pheromones and regulate how these individuals act in groups to coordinate nest defense. On longer time scales, I measured the behavioral and neural affects of bees given a single chronic odor experience versus bees that had a natural, more diverse olfactory experience. The central brains of bees with a deprived odor experience responded more similarly to odorants in imaging studies, and did not develop a fully mature olfactory network. Additionally, these immature networks showed behavioral deficits when recalling odor mixture components. Over evolutionary time, signals need to engage the attention of and be easily recognized by bees. I measured responses of bees to a floral mixture and its constituent monomolecular components. I found that natural floral mixtures engage the orientation of bees’ antennae more strongly than single-component odorants and also provide more consistent central brain responses between stimulations. Together, these studies highlight the importance of olfactory experience on different scales and how the nervous system might impose pressures to select the stimuli used as signals in communication networks.

Among the most ornate animal traits in nature are the angle-dependent (i.e. iridescent) structural colors of many birds, beetles, and butterflies. Though we now have a solid understanding of the mechanisms, function, and evolution of these features in several groups, less attention has been paid to the potential for angle-dependent reflectance in otherwise matte-appearing (i.e. not thought to be structurally colored) tissues. Here for the first time we describe non-iridescent angle-dependent coloration from the tail and wing feathers of several parrot species (Psittaciformes). We employed a novel approach \u2014 by calculating chromatic and achromatic contrasts (in just noticeable differences, JNDs) of straight and angled measurements of the same feather patch \u2014 to test for perceptually relevant angle-dependent changes in coloration on dorsal and ventral feather surfaces. We found, among the 15 parrot species studied, significant angle dependence for nearly all parameters (except chromatic JNDs on the ventral side of wing feathers). We then measured microstructural features on each side of feathers, including size and color of barbs and barbules, to attempt to predict interspecific variation in degree of angle-dependent reflectance. We found that hue, saturation, and brightness of feather barbs, barbule saturation, and barb:barbule coverage ratio were the strongest predictors of angle-dependent coloration. Interestingly, there was significant phylogenetic signal in only one of the seven angle-dependence models tested. These findings deepen our views on the importance of microscopic feather features in the production of directional animal coloration, especially in tissues that appear to be statically colored.

Social insect colonies adeptly make consensus decisions that emerge from distributed interactions among colony members. How consensus is accomplished when a split decision requires resolution is poorly understood. I studied colony reunification during emigrations of the crevice-dwelling ant Temnothorax rugatulus. Colonies can choose the most preferred of several alternative nest cavities, but the colony sometimes initially splits between sites and achieves consensus later via secondary emigrations. I explored the decision rules and the individual-level dynamics that govern reunification using artificially split colonies. When monogynous colonies were evenly divided between identical sites, the location of the queen played a decisive role, with 14 of the 16 colonies reuniting at the site that held the queen. This suggests a group-level strategy for minimizing risk to the queen by avoiding unnecessary moves. When the queen was placed in the less preferred of two sites, all 14 colonies that reunited did so at preferred nest, despite having to move the queen. These results show that colonies balance multiple factors when reaching consensus, and that preferences for physical features of environment can outweigh the queen's influence. I also found that tandem recruitment during reunification is overwhelmingly directed from the preferred nest to the other nest. Furthermore, the followers of these tandem runs had a very low probability (5.7%) of also subsequently conducting transports.

Current conservation practices are substantially biased towards large, charismatic animals and are influenced by public perceptions of different animals. Therefore, it is important to understand how these perceptions are formed and what factors influence them in order to promote equitable conservation for all species. This study examines the effect of attending a park education program on public values, knowledge of, and attitudes towards a noncharismatic species. Data was collected from May through October 2016 at the Usery Mountain Regional Park "All About Scorpions" program. A four page, onsite, self-administered pre- and post-program survey was given to program attendees. An identical survey was given to hiking park visitors who had never attended the program as the control sample. Survey statements addressed participant's demographics, value of bugs, knowledge about scorpions, and attitudes toward scorpions. Data analysis was completed using paired t-tests to analyze any statistically significant changes in values, knowledge, and attitudes between pre- and post-participants. Independent sample t-tests were used to analyze the same between the control and pre-participants. The results showed no difference in the value of bugs for any of the survey participants. However, the program attendees had more positive attitudes and greater knowledge of scorpions than general park visitors, and attending the program further increased positive attitudes and knowledge. Contributions of the study are twofold: First, the results provide Usery with information regarding the influence of their public programs, along with how these programs can be improved to make a greater impact. Second, findings serve to extend the literature on what alters public perceptions and how educational programs can be used to change the current conservation mindset.