<p>Animals utilize information about their environments in order to adaptively modify behaviour. Such information may come from individual experience or from social sources, both of which have costs and benefits to the animal. Here I first show benefits of individual learning with respect to foraging performance, a good proxy of fitness, in bumblebees in a naturalistic setting. Second, I show that despite fitness costs associated with learning, fruit flies do not modify their investment in learning ability due to environmental complexity of larval foraging environment. Third, I show that fruit fly larvae utilize social information in their foraging decisions, including social learning, despite increased competition costs. Fourth, I show that adult fruit flies also use the presence of larvae as a source of social information to find suitable food patches. Finally, I show that larvae spontaneously form small foraging aggregations, one benefit of which may be an improved ability to dig and burrow into the surface of the food. I discuss the costs and benefits of both individual and social learning, as well as the potential for insect model systems in future studies of sociality and learning.</p> / Doctor of Philosophy (PhD)

<p>For my doctoral research I examined social decision-making in a cooperatively breeding cichlid fish, <em>Neolamprologus pulcher</em> with a focus on affiliation and aggression. I investigated the role that the nonapeptide hormone, isotocin, plays in modulating social decisions in these contexts. I show that <em>N. pulcher</em> males prefer to join larger groups regardless of the rank at which they will join, whereas females prefer larger groups only when they can join a group in a high rank (Chapter 2). I examined decision-making during resource contests in<em> </em>(Chapter 3) and found that <em>N. pulcher</em> are sensitive to the size of their opponents, making fighting decisions depending on their opponents’ body size. I also found that smaller <em>N. pulcher</em> are more motivated to persist within contests, showing a shorter latency to resume fighting following interruption (Chapter 4). In Chapters 5 and 6, I explored the role of isotocin (the teleost fish homologue of oxytocin) in regulating social behaviour. I discovered that an increase in isotocin increased responsiveness to social information. Fish treated with isotocin were more sensitive to their opponent’s size in contests and were more submissive to dominant individuals within their social group (Chapter 5). Unexpectedly, I found that exogenous isotocin reduced sociality in <em>N. pulcher, </em>and that an isotocin receptor antagonist increased it (Chapter 6). These results suggest that the relationship between isotocin and social behaviour is both complex and context specific. In my final data chapter, I used social network analysis to explore the role of dominance interactions in determining the structure of <em>N. pulcher</em> social groups. I found that <em>N. pulcher</em> dominance hierarchies are highly linear, but that dominance interactions are not predicted by sex or body size asymmetry (Chapter 7). I found that conflict within <em>N. pulcher</em> social groups is greatest at the top of the dominance hierarchy. Taken together the results of my thesis helps to elucidate the behavioural and hormonal basis of social decision-making in a cooperatively breeding vertebrate and help to illuminate the evolution of social behaviour.</p> / Doctor of Philosophy (PhD)

<p>I studied acoustic and visual communication in the Smooth-billed Ani, a joint-nesting, cooperatively breeding cuckoo. I describe vocal repertoire of this species using both qualitative and quantitative methods. In this first, formal description of the species’ repertoire, I provide verbal descriptions of each call type, the contexts in which each call is produced, spectrograms, and acoustic measurements for each call type. I used multivariate statistics to show that call types can be correctly classified based on acoustic measurements alone. Smooth-billed Anis are capable of complex communication, including the use of functionally referential alarms and signals of aggression that reliably predict attack. Functionally referential signals are produced in response to a specific set of stimuli and elicit predictable, appropriate responses in signal receivers, even in the absence of any other cues. I show that anis produce two distinct signal types, <em>chlurps</em> and <em>ahnee</em> <em>alarms</em>, in response to two different predator classes, aerial and terrestrial, respectively. I also show that receiver responses to playback of these alarm signals are distinct and appropriate to evade predation from aerial and terrestrial attackers. Aggressive signals should increase in aggressive contexts, predict subsequent aggression and elicit responses from signal receivers. I show that <em>hoots</em>, an acoustic signal, and throat inflation, a visual signal, both increase in aggressive contexts and reliably predict aggressive escalation in the form of direct attacks on a mount. The receiver response to <em>hoots</em> and throat inflation remains to be tested. In the synthesis, I provide suggestions for future research.</p> / Master of Science (MSc)

Anolis carolinensis has been a model organism for ecology and evolutionary biology since the seventies, yet there are still understudied aspects of their ecology. A five-year study has provided microsatellite genotypes to be used in building a pedigree and assess relatedness, enabling us to evaluate the spatial distribution of an urban population of A. carolinensis. Results indicate no correlation between a male’s size and the distance others keep from it; however, males belonging in the heavyweight morph are dictating the spatial distribution in this population. In addition, juvenile dispersal of male offspring and partial philopatry of female offspring are key in this dynamic, where a single heavyweight male will actively defend a small area that contains multiple females, some of which are be daughters, and multiple unrelated males, most likely sneaker males.

When ovipositing, prey organisms avoid habitat patches containing predator cues because predators consume, and negatively affect the fitness of their prey. Richness of predator species often enhances the strength of consumptive predator effects, but little is known about how multiple predators combined affect prey non-consumptively. We quantified dipteran colonization in aquatic mesocosms in response to varied predator richness. Multiple predator species combined reduced oviposition by Culex mosquitoes, chironomid midges, and the general colonizing dipteran community more than predicted by the effects of the independent predator species. Previous research which quantifies effects of multiple predators on prey as prey abundance, but does not measure consumption by predators, may be underestimating or overestimating the strength of effect by assuming equal colonization. Our findings enhance understanding of the ways predators influence abundances and distributions of their prey, and yields insight into the ways predators may non-consumptively affect prey by changing prey behavior.

Marine mammals are in a precarious conservation position because of anthropogenic impacts and historic perceptions that they are a consumable commodity. In light of changing abiotic conditions, further evaluation is needed on the habitat use, behavior, and interactions among marine mammals. Conservation legislation has helped protect species, but the greatest ground swelling may be the advent of the commercial whale watching industry. The feeding grounds in Alaskan waters have made this area a prime tourism location, and these nutrient-rich waters have resulted in a confluence of marine mammal species, including the appealing and abundant humpback whale (Megaptera novaeangliae) that may associate with three ecotypes of killer whales (Orcinus orca). These species are interesting because they may travel together to feed on prey or be adversaries in a predator-prey relationship. Using whale watching as a platform, this study evaluated the effects of the presence of these two species separately and together, and of the type of interaction between them, on human perception. Data were collected via opportunistic observations and a retrospective pre- and post-survey instrument. Differences in humpback whale distribution and group size patterns were found relative to killer whale occurrence, although humpback whale behavioral states were unchanged. Changes in passenger conservation attitudes could not be attributed to species and behaviors but they were important determinates to whale watching satisfaction. Overall, more positive conservation attitudes and an increase in knowledge about marine mammals were reported after whale watching. These tours provide an opportunity for collecting meaningful scientific data and providing more in-depth education such as enhancing the appreciation for ecosystem services provided by marine mammals.

Roadways are a pervasive feature of northeastern landscapes and can be a significant source of mortality for turtles. Until recently, little has been known about the design requirements for successful under-road passages for turtles and other wildlife to move safely between bisected habitat patches. At outdoor laboratories, using a factorial experimental design, we examined movements in response to varying light levels, and barrier opacity for painted turtles (Chrysemys picta, n=833), Blanding’s turtles (Emydoidea blandingii, n=49), and spotted turtles (Clemmys guttata, n=49). Additionally, we examined tunnel size, tunnel entrance design, and artificial lighting for painted turtles only. All three species responded poorly to a 0% available light treatment. As the amount of natural light transmitted through the tops of tunnels increased, successful completion of the trials increased. Furthermore, turtles generally moved at a slower rate when traveling along a translucent barrier, compared to an opaque one. Our results indicate the importance of designing road passage structures for freshwater turtles that provide adequate tunnel lighting in combination with specific entrance designs that meet the goals of the project.

Whereas circadian rhythms in humans and many other organisms are closely linked to the solar day and even slight deviations could cause significant health problems, several spider species thrive despite extremely shortened or extended circadian clocks. These naturally occurring clocks influence a variety of behaviors, which may help spiders maintain a precarious balance between their conflicting roles as predator and prey. The southern black widow, Latrodectus mactans, is primarily nocturnal in its locomotor activity, but this activity appears only loosely regulated by its circadian clock. This study attempts to determine how internal circadian oscillators affect other aspects of black widow behavior, since preliminary data suggest that they also possess potentially irregular circadian patterns. The behavioral patterns of twenty female black widows were recorded over a span of several weeks. Approximately 3,400 hours of footage in standard (12-hour light-dark cycles) and constant conditions (complete darkness) were analyzed and specific behaviors were recorded using the software BORIS. This study focused on three specific sets of behavior: foraging versus retreat patterns, general activity levels throughout a 24-hr period, and waste disposal. Predation stimuli were also introduced during each cycle set to determine how the widows’ responses were affected by their internal circadian oscillators. Free-run behaviors (behavior no longer entrained to the standard 24hr cycle) observed during the dark-dark cycles differed from the behavior observed during light-dark cycles in both frequency and duration of actions, particularly those related to foraging or web work. Likewise, certain behaviors and prey avoidance techniques observed during light-cycle periods were not observed during constant conditions. This experiment examines several previously unstudied black widow behaviors for generating a better understanding on how they act in natural conditions and to determine how their actions may be influenced by their highly unusual circadian rhythms. Ultimately, this experiment will contribute to a larger, ongoing study investigating circadian-controlled behaviors and rhythms in spiders.

Behavior may be dramatically influenced by changing environments, and differences in light intensity environments may have important behavioral consequences. One approach to understanding changes in behavior is by studying behavioral syndromes, suites of correlated behaviors reflecting between individual consistencies in behavior expressed within a behavioral situation (e.g., correlations between antipredator behaviors in different habitats), or across behavioral contexts (e.g., correlations among feeding, antipredator, or mating behavior) (Sih et al. 2004a). Guppies (Poecilia reticulata) provide a great model system to study behavior. Guppies are small, freshwater tropical fish that inhabit still pools in swift-flowing streams, and the backwaters of small rivers in mountain forest areas of Trinidad (Houde 1997; Magurran 2005). In this study I attempted to answer the following questions using three low predation populations of guppies : 1) Do guppies display a behavioral syndrome for aggression and/or courtship across light situations?; 2) Are there mean level changes in aggression or courtship across light situations?; 3) Are mean level changes influenced by differing social environments that include or lack sexually receptive females?; 4) Are there correlations between behavior and the androgen hormones testosterone and 11-ketotestosterone?; 5) Are there correlations between behavior and the stress hormone cortisol?; 6) Are there mean level changes in hormone release rates across light environments?; and 7) Is flexibility in hormone release rates influenced by social environments that include or lack sexually receptive females? Guppies exhibit behavioral syndromes for both aggression and courtship. Furthermore, guppies exhibit behavioral flexibility for both aggression and courtship, but only in social environments that include sexually receptive females. I found no correlations between behavior and androgen hormones. I also did not find any correlations between behavior and the stress hormone cortisol. Furthermore, I did not find any mean level changes in hormone release rates across light environments. Interestingly, cortisol levels were higher in social environments in which sexually receptive females were absent. Many studies have looked at how the environment influences courtship behavior in guppies, especially employing high predation populations, but few studies have examined aggressive behavior or behavior in general with low predation populations. Furthermore, few studies have determined the role social environments play, and how hormones may interact with behavior. This study is important because it helps illuminate how low predation populations deal with changes in light intensity environments, and adds to what we understand about guppy behavior in general.

Parasites often have profound effects on the survival and evolution of their hosts, and hence on the structure and health of entire ecosystems. Yet basic questions, such as the degree of virulence of a given parasite on its host, and factors influencing which hosts in a population are at the greatest risk of infection, are vexingly difficult to resolve. The western blacklegged tick-western fence lizard (Ixodes pacificus-Sceloporus occidentalis) system is important, primarily because I. pacificus, a vector of the Lyme disease spirochete Borrelia burgdorferi, is dependent on S. occidentalis for blood meals in its subadult stages, and this lizard possesses an innate immune response that removes the Lyme disease pathogen from attached ticks. My study focused on two aspects of the I. pacificus-S. occidentalis interaction. In Chapter 1, I investigated factors correlating with the intensity of I. pacificus infestations on S. occidentalis. Infection intensity (parasites per host) is often highly variable within a host population, though certain individuals, such as males, tend to be more heavily infected. Previous work in the I. pacificus-S. occidentalis system suggests that differences in behavior, such as the frequency of territorial patrols, may contribute to variation in tick intensity among lizards. I therefore hypothesized that lizard traits that correlate with dominance would also correlate with infestation intensity. Specifically, I predicted that larger and more colorful males would have higher infestation intensities than less impressive animals. In this chapter, I also focused on site selection by ticks infesting S. occidentalis. Skin folds on the necks of these lizards (nuchal pockets) may function to divert ectoparasites away from eyes, ears, and other potentially vulnerable structures. I therefore also looked for factors correlating with tick attachment in these pockets. I sampled ticks on adult male S. occidentalis in the spring and summer, which is the seasonal peak for both S. occidentalis territorial behavior and subadult I. pacificus abundance. After determining the site of infestation and intensity of ticks on these lizards, I re-infested lizards with laboratory-reared I. pacificus larvae, and again quantified tick intensity and attachment location. Contrary to expectation, no host traits correlated with tick intensity among ticks naturally infesting lizards, and lab-reared larval intensity was negatively correlated with lizard body size. As expected, ticks acquired by lizards naturally concentrated inside nuchal pockets, and I also observed this site preference among ticks in lab-based experimental infestations. Although the general pattern, lab-reared ticks were more varied in the sites on which they fed. There was a negative correlation between infestation intensity and the proportion of ticks attached in nuchal pockets. Unsurprisingly, the most reliable predictor of tick intensity and site selection was the season. In Chapter 2, I explored how tick attachment affects male S. occidentalis contest behavior. I. pacificus infestation has been shown to have negative physiological impacts on S. occidentalis, but mechanisms linking physiological changes to ultimate fitness consequences have been largely underexplored. I hypothesized that tick infestation reduces male S. occidentalis fighting ability by reducing O2 carrying ­­capacity­, or by obstructing or damaging vulnerable structures on their hosts. I held fifty half-hour trials between pairs of size- and ventral badge-matched male S. occidentalis, with one male in each pair infested with lab-reared I. pacificus larvae. I found that tick infestation negatively correlated with aggressive behavior in these staged contests. In support of reduced O2 capacity as the mechanism of reduced aggression, my ecologically relevant infestation intensities seemed to cause significant declines in hematocrit among experimentally infested lizards relative to controls. However, the site at which ticks attached did not significantly correlate with the aggressiveness of their lizard hosts. This is one of only a handful of studies to address the direct effect of I. pacificus on S. occidentalis. My study demonstrates that tick infestation can be detrimental to the fitness of their lizard hosts even without the transmission of pathogens. This insight may prove informative in future work on the ecology of I. pacificus-borne diseases in the western United States. This study is also one of only a few to use parasite infection to induce an asymmetry in fighting ability in intrasexual contests.