Are Fat Squirrels Happy Squirrels?
Will Horner & Jules Weinstein
Current scientific knowledge of squirrel dietary behavior includes the high-tannin hypothesis, in which squirrels will store high-tannin foods for later, and observations of foraging and caching behaviors. However, there was little inquiry into the feeding behavior and food selectivity of squirrels as the temperature changes. Reed campus and various parks in the east Portland area were chosen for sampling. To test whether squirrels would begin to prefer food items with higher fat content as temperatures dropped, six foods of differing fat content were placed at the bases of trees that squirrels had climbed. After climbing down, the squirrels were allowed to choose among the foods and eat their fill. The amount of each food eaten was recorded, along with the temperature in Celsius. The results were tabulated and ANOVAs were run analyzing the significance of the type of food eaten vs. the temperature and also the type of food eaten vs. the day. There were no significant results at the 0.05 level, but the amount of corn eaten was shown to vary significantly with temperature at the 0.10 level (p=0.0739). Corn was eaten more frequently at higher temperatures than lower temperatures. Given that corn was one of the lowest fat-containing foods (2 grams fat/ 30 grams serving), this appears to support our hypothesis. However, since there were no other significant results and the only significance was at the 0.10 level, we could not disprove the null hypothesis.

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Stereotypy is Not Irrelephant!
Emily Agan, Christina Barrett, Ivy Hellickson
Zoo Asian elephants (Elephas maximus) live a very different life than they would in the wild. In their native Asian jungles, they would walk for long distances in large herds comprised of their family members, searching for food (Fernando, 2000). At the Oregon Zoo, the seven elephants are given much smaller spaces to roam. The males are isolated, and the females and calf are left to comprise a small herd of four. Under conditions such as these, it is not surprising that the elephants in the Oregon Zoo exhibit stereotypy. In elephants, rhythmic head movements, swaying or repetitive pacing are all examples of stereotypy (Rees, 2009). In our experiment, we observed individual elephants using focal animal sampling, examining the relationships between stereotypy and time elapsed, stereotypy and feeding, and stereotypy and proximity to other elephants. We found that there is a positive correlation between stereotypy and time elapsed, and a negative correlation between stereotypy and proximity and stereotypy and feeding. Our findings suggest that captive elephants' wellbeing can be enhanced by increased space and food-based-enrichment. These findings are consistent with previous findings by Rees that stereotypic behavior decreases with increased feeding and increases toward the end of the day (Rees, 2009).

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Risky business: boldness in crickets
Aashis Thapa, Gustavo Lopez, Marisol Lauffer
On the population level individuals can be classified into certain behavorial syndromes. These syndromes can be distinguished into two categories: shyness and boldness. The behavioral syndromes can differ based on external stimuli (Niemela et al 2012); the one being studied in this experiment is the presence of a predator. In this study, male house crickets, Acheta domestica,are placed in an arena that has a predator present, the Bombina orientalis. We tested the participation of risky behavior by measuring the latency to cross the arena with and without a predator. By adding external stimuli, food and female crickets, at the end of the arena, we could test whether engagement of risky behavior was affected. Our initial hypothesis stated that crickets would engage in less frequent risky behavior (i.e. crossing the arena) with a predator being present and that this risky behavior could be modulated by baiting the behavior with food and a female cricket. Based off of the two way ANOVA, the latency to cross the arena with a predator was not significantly greater than crossing without. Based off of the chi-square test we could not deduce an increase in risky behavior, but by looking further into the data we could infer that the condition alone (i.e. food and female) showed an increase in risky behavior.

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Unrequited Love, the Bride of Frankenstein, and Fish: The Effects of Lack of Reinforcement of the Relationship Between Behavior Lateralization and Color Lateralization in Guppies, Poecilia reticulata
Ryan Streur
Fluctuating asymmetry has been discussed in reference to male mating displays in guppies (Poecilia reticulata) (Gross 2007), but the ontogenic basis of this relationship is poorly understood. A group of guppies was placed in a) a tank with a live female and b) a tank with a nonresponsive plastic model of a female to see if the loss of positive reinforcement of behavior lateralization from the responsive female would result in a loss of the relationship between color and behavior lateralization. After two weeks, the guppies were observed in a separate observation tank, separated from females with a transparent plastic barrier. They were scored for mating displays to the left and the right. The guppies were then digitally photographed on both their right and left sides and the images were analyzed using ImageJ. Though guppies from the group housed with the nonresponsive female did show a statistically significant difference in the mean ratio of behavior lateralization to color lateralization, only two guppies were under study at the end of the experiment and these differences could be the result of idiosynchratic differences between the guppies and may not represent the more general trend in guppy reproductive behavior.

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Competitive Resource-Based Aggression in Betta splendens
Amanda Carnegie & Sarah Resnick
Male Siamese Fighting Fish, or Betta splendens, are commonly known to display aggressive behaviors when presented with conspecific males (Peeke et al., 1969). We presented 3 trial male betas with 3 conspecific alternating "opponent" fish in 3 resource- specific defense trials (total trials = 9): territory defense, food competition, and female courtship. This was done over the course of one month in order to test our hypothesis that betta fish will display more aggressive behaviors, such as gill flaring, charging, and dorsal fin flaring (Thompson et al., 1965), when more valuable resources are threatened due to competition from other fish. We presumed that the presence of a female would evoke the highest aggression, whereas territory would rank the lowest. Our data significantly support our initial hypothesis by assigning point values to the observed behaviors (ANOVA, p=0.0326); however, the aggression count ranked lowest for food defense, possibly due to a lack of energy in the subjects due to prior starvation (~24 hours). These results imply a hierarchy of resource importance in this species, and may suggest possible sources of aggression in Betta splendens. The data also suggest a potential cost/benefit model for displaying these behaviors in bettas, as the cost of exerting energy may more appropriate and worthwhile for obtaining certain resources but not necessarily others. Further research needs be done to confirm these implications.

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Are Growers Worse Showers?
Brendan Kohrn, Kata Martin, Ben Goggin
During the course of investigations on male guppy displays, it was observed that many guppies had white, globular growths on their bodies. At the time, it was decided to ignore the presence of the growths. However, questions arose about the effect of these growths on male guppy display behavior. Given that guppies judge potential mates based on visual cues, and that parasites, one potential source of the growths, have been shown to affect guppy displays, it seemed reasonable that the growths would affect male guppy display to females. In order to test this, male guppies were exposed to a female with growths and a female without growths, in a random order. The percent of the male's body covered by the growths was measured. No significant difference was found in male displays based on female condition (p=0.618) or male growth size (p=0.126); however, males with growths tended to display less than males without growths.

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I got my Palate from my Mother
Erin Appleby & Tess Myers
When it comes to food preference, there are many factors that contribute to decision making in adult flies, many of which are determined by genetic factors. Drosophila melanogaster, the aptly named common fruit fly, is known to seek out sugars as a source of simple carbohydrates. In the wild, this usually includes a variety of fruit, often in varying states of fermentation. To investigate the possible genetic factors that affect the food choice made by adult Drosophila, we allowed a wild population of flies to make a choice between fermenting wild plums, and fermenting fly media sweetened with table sugar. After counting the number of flies in each food source chamber, we bred the sorted populations based on their food choice, and repeated the sorting procedure for three generations, with the intention to selectively breed for the possible genetic factors that would dictate food choice. The food preference results in the F2 generation showed that lineage and food choice are independent factors. The food choice results from the F5 generation showed that lineage type is not independent from food preference, especially for the sweet food lineage which preferred sweet food. This supports the hypothesis that after selective breeding of a lineage for food preference as a trait, the lineage will influence the food that the flies choose due to a genetic factor.

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Crayfish Fight Club
Anna Fimmel
Crayfish are able to live in many different water temperatures.  Males establish dominance as soon as possible upon seeing other males, battling each other in fascinating but nonlethal ways and then continuing on with their lives, secure with their place in the crayfish dominance hierarchy.  Could previous experience living in a certain temperature affect how the crayfish fight in that temperature?  How about different temperatures?  Two groups of 14 male crayfish were put into 20 gallon tanks of deionized water—one tank was kept at a constant temperature of 16 degrees C, the other kept at 23 degrees C.  After five days of ‘experience,’ crayfish from one group were pitted against their counterparts from the other group, in a hot tank, then a cold tank, and then a neutral tank.  So that the previous fights wouldn’t influence them, the fights were done over the course of three days, one each night.  The data show that crayfish with experience in colder water do better in general—in both the control and the cold fight tank conditions, the cold-experience crayfish displayed more agonistic material.  The hot tank crayfish, though, displayed more agonistic behavior than the cold tank crayfish when they were fighting in the hot tank.  This suggests that there is a sort of trade-off—crayfish can live in a warm climate and risk losing fights that do not take place in a hot climate, or they can live in a cold climate, and risk losing fights that take place in hot climate.

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You are (Not) What You Eat Fruit Fly Food Preference
Matt Keeslar & Alexandra Mariani
Food preference in fruit flies has clear adaptive value as the animals seek to maximize energy intake while minimizing energy expenditure, but the literature is divided on how this crucial trait develops. Our study sought to identify the ontogeny of food preference in D. melanogaster. We questioned whether food preference was passed from parent to offspring or influenced by exposure during the larval stage of development. We took flies from a lab population that had fed for generations on fly medium. This original population was divided into three isolated stocks: one stock was raised exclusively on banana, one stock was raised exclusively on apple, and a control stock was raised exclusively on fly medium. On average, thirty-seven (37) flies from each stock were separated and put through a Y-maze. The maze had a releasing chamber without food connected by 10 cm drinking straws to two different fly bottles, each containing either banana or apple. The mazes were placed in an incubator for five hours, at the end of which, the flies in each chamber were counted. The three stocks were raised for four generations and each generation was tested for food preference. After four generations, we could find no significant correlation between food preference and either ancestral food source or exclusive food source available as larvae. Our results thus do not support the hypothesis that adult flies will prefer the food source available to them as larvae, nor do they show that food preference is a strongly heritable trait after four generations.

 

WEDNESDAY DECEMBER 4

Seeing the Light: Phototaxis through Buridan's Paradigm in Drosophila melanogaster.
Jacob Kraus & Wyatt Gormley
Vision remains an area of active research in many distinct academic fields. Within the context of animal behavior, an experimentally favored hypothesis forwarded fifty years ago suggests elementary motion detection is achieved through "spatially separated visual inputs implemented across neighboring retinotopic visual columbs," although many of the neural pathways involved in the computation of motion remain unknown. (Zhu Y. et al. 2009) Important to our research, neural computation of visual stimuli in Drosophila is believed to be lateralized in decisions related to phototaxic behavior. While laboratory-generated mutant Drosophila may be telling of genes necessary for the phenotypic expression of a behavioral, physiological, or morphological trait, they are less likely to yield information on the effects of functional variation at particular loci, and so we made use of a population of drosophila which were not in-bred, stock flies. We hypothesized that i) there exist phototaxic behavior in our sample population, and ii) that behavioral lateralization affects phototaxic behavior. Through collecting and breeding wild type Drosophila, Burdigan's paradigm was used to assess the phototaxic preferences of each generation. Additionally, a system of mazes was used, each with the light and dark paths randomized between left and right directions, to assess lateralization's effect on phototaxis. As a result of these experiments, no statistically significant phototaxic preference or change was observed on our set of generational flies, part of which we believe was a product of sample size. Another trial with a greater number of flies did see significant lateralized phototaxic preference for dark-right paths, supporting hypotheses i) and ii).

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Bottoms up! Maintain a Vigilant Eye
Sarah Johnson, Rhea Chawla, Pia Molina
Contrary to proposed assumptions that animals are unable to be vigilant while feeding, many studies have shown that feeding and foraging are not always mutually exclusive (Guillemain et al. 2001). The Mallard duck, Anas platyrhynchos, often feeds on bodies of water and obtains food by using a variety of feeding methods, which fall into two main categories with respect to visibility: 1) shallow foraging, where eyes are above substrate level, allowing head-down vigilance and 2) deep foraging, where eyes are underwater so vigilance and feeding are mutually exclusive (Nilsson et al. 1972). In this study, foraging behavior of Mallard ducks was recorded to test the hypothesis that feeding behavior will change on land versus in water to maximize vigilance. Behavioral sampling was conducted on 32 Mallard ducks in the Crystal Springs Rhododendron Garden using JWatcher software. Behavioral sampling was conducted in 5-minute intervals on a single randomly chosen duck. Ducks were observed during continuous feeding on land and on water in two separate locations within the Rhododendron Gardens. Ducks feeding in water, regardless of location, spent significantly more time not engaging in any feeding behavior (head up) as compared to ducks observed on land. We cannot conclude solely from our data that vigilance and foraging are not always mutually exclusive activities. Nevertheless, we can conclude that, regardless of location, sex, population size, or the number of Canadian geese present, Mallard ducks in water spend significantly more time not engaging in any feeding behavior (head up) as compared to ducks observed on land.

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Phototaxis in tardigrades
Daniel Dashevsky and Patrick Sadil
Tardigrades (phylum Tardigrada) are small animals with eight legs. They are well known for being able to survive incredibly harsh environmental conditions. This allows them to be found in most any habitat Despite extensive study of these physiological abilities, their behavior is not well documented. We investigated phototaxis in tardigrades. To do so, we collected and isolated local tardigrades from moss samples taken from the Reed College Physics Building. We placed tardigrades on sterile plates of nutrient agar and analyzed the resulting trails of bacteria. To test the hypothesis that tardigrades negatively phototax, we exposed plates to different lighting conditions. We found preliminary evidence to suggest that tardigrades are in fact negatively phototactic.

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Sexy Crayfish: Dominance or Size?
Female mate choice in crayfish: role of male size and social ranking
Anand Panchal, Kimmy Stanton & Emmeline Hill
Mate choice is an important force in the sexual evolution of a species. Female crayfish have been shown to prefer larger males. However, several papers have demonstrated that social ranking of males is also important to females. We tested the importance of male size and male social ranking in influencing female choice by giving the female a choice between small high-ranking males and large low-ranking males. Male ranks were determined by 10 minute fights in the presence of a female behind a transparent barrier. Female choice was measured by time spent near one of the two males separated by transparent barriers. Although we observed a general preference for higher-ranking small males over lower-ranking large males, the mean time spent by the female near a small male (310 sec) was not significantly greater than the mean time spent near a large male (144.7 sec). We conclude that social ranking is an important factor in female choice, but more trials are needed to determine if a male's social ranking is more important than his size for female mate choice.

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Hungry Hungry Squirrels: A Study of Reed Squirrel’s Feeding and Foraging Behavior
Claire Brumbaugh-Smith
In this project, we explored whether squirrels in different habitats (field and wooded) would have different feeding and foraging behaviors. This is an interesting question, as increased deforestation and urbanization are changing the natural habitat of squirrels. To quantify feeding and foraging, squirrel behavior was divided into eating acorns, eating maple seeds, foraging on the ground, and foraging in maple trees. Focal squirrels were then observed either in a wooded or field habitat, both of which contained maple and oak trees, and the time spent doing each feeding or foraging behavior was recorded. Though there was no significant difference in the time spent doing each behavior in the different habitats, there were differences in the efficiency of the squirrels’ acorn gathering. For squirrels in the wooded habitat , time spent foraging on the ground was correlated with time spent eating acorns. For squirrels in the field habitat, time spent foraging on the ground was negatively correlated with time spent eating acorns. This shows that squirrels in the wooded habitats spent less energy obtaining more acorns  than squirrels in field habitat. One explanation for this observed behavior is that squirrels in wooded habitats are more specialized in finding acorns on the ground than squirrels in the field habitat. It is possible that increased habitat destruction could cause squirrels to be less efficient at finding acorns to eat.

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Chilling new discovery: Heritability of cold-sensitivity in D. melanogaster
Celina Ortiz & Jason Swinderman
Fruit flies (D. melanogaster) are known to thrive in a variety of thermal environments in the wild (Morgan &McKay 2006). D. melanogaster have specific gene loci relating to thermo-tolerance that are phenotypically expressed as a resistance to high- and low-temperature extremes (Colinet & Hoffmann 2011). At freezing temperatures, D. melanogaster fall into a chill-coma state due to an inability to maintain muscle-resting potentials (Holser et al 200). The relative speed of recovery from a chill-coma is used as a behavioral measure of an individual's chill-tolerance. Inbreeding has also been shown to influence thermo-resistance and acclimation responses, causing acclimation to cold or hot temperatures to be passed from parent to child (Colinet & Hoffman 2011). To test the strength of hereditary of thermo-tolerance genes in D. melanogaster, two strains of flies, "cold-resistant" and "cold-sensitive", were selectively bred for three generations using a cold-bath assay to assess individual resistance to cold. The "cold-resistant" strain was created and maintained by independently housing the 15 flies that recovered quickest from an induced chill coma, while the "cold-sensitive" were bred from the 15 flies that recovered slowest. Results demonstrated that the cold-sensitive individuals became significantly more sensitive to the chill-coma assay over the three generations. On the other hand, there was no significant increase in cold-resistance for the cold-resistant strain. These results imply that sensitivity to cold can be more easily inherited, while resistance to cold is less heritable.

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Fearful Feeding Frenzy: Do predator cues affect the eating habits of Guppies?(Poecilia reticulata)
Chrissy Schmidt and Elizabeth Pekarskaya
T he major focus of this experimental was to determine whether visual and chemical predator cues would affect the eating behavior of guppies (Poecilia reitulata). According to Giaquinto and Hoffmann using Pseudoplatystoma corruscans fish have a visual and olfactory cue that helps them recognize predatory cues and food present in the water. The experiment was based on the idea that all fish can sense a chemical cue in the water when a predator is present. The presence of the predatory cue should therefore cause a change in behavior that would show up in a change in feeing behavior (Giaquinto & Hoffman 2010]. The feeding behavior was expected to be positively affected by a predatory cue, two cichlids (Astatotilapia burtoni). Feeding behavior was assessed by counting number of 'bite and let go' movements by the guppies at the food flakes within a 6-minute period. The number of bites was then divided by the number of fish in each tank. Results showed that we could not reject the null hypotheses and that guppy feeding behavior was not statistically significantly different between the control and experimental groups (p > 0.5). However, further review indicated a statistically significant relationship between salinity and guppy feeding behavior (p < 0.0001) which is of note for further study in the chemical changes that alter guppy feeding behavior.

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Down to Earth: Neuropeptide expression and geotactic behavior in Drosophila melangonaster
Melissa Ashbaugh and Robin Byron
The neuropeptide PDF has been found to be more highly expressed in strains of Drosophila melangonaster selected for negative geotactic behavior than in drosophila selected for positive geotactic behavior, leading to the hypothesis that PDF is causal for the behavior. We tested this hypothesis, asking whether the correlation between presence of PDF and differences in geotactic behavior holds in a wild strain of Drosophila. We hypothesized that presence of PDF would not significantly differ between flies which demonstrated geotactic behavior, choosing a downward path when offered a choice, and flies which did not demonstrate the behavior, choosing to move upward.
Flies between the ages of 2 and 6 days old were placed in a geotactic maze for 3 hours, after which time flies which had moved upward and flies which had moved downward were collected. Fly brains were isolated and fixed overnight in 4% paraformaldehyde solution. Immunohistochemistry was performed using a rabbit anti-BPH primary antibody and an anti-rabbit fluorescent secondary antibody. Brains were examined using fluorescent microscopy; the number of fluorescent cells were counted and scored for comparative brightness an analyzed by ANOVA in JMP. There was no statistically significant difference in either brightness or number of fluorescent cells between geotactically positive and negative Drosophila melanogaster.

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Magnetic Field Navigation in Ants
Yuan Xue. Soso; Erin McAllester; Tess Tumarkin
Evidence from several studies suggests (Banks and Srygley, 2003; Çamiltepe and Stradling, 1995) certain species of ants navigate by orienting to a magnetic field. Banks and Srygley's study (2003) suggested that, while leaf-cutter ants (Atta colombica) normally navigate by azimuthal, visual, and chemical cues, they oriented navigationally to an artificially generated magnetic field in the experiment when other cues were absent. Following the procedure of Çamlitepe and Stradling (1995), we generated an artificial magnetic field to which trained ants were subjected. We observed and quantified ant "choice" based on the changes in magnetic field navigational orientation. Two species of ants, Red Harvester ants (Pogonomyrmex occidentalis) and Carpenter ants (Camponotus pennsylvanicus), were tested for magnetic field orientation based on their food foraging and carcass disposal behaviors in the absence of visual and chemical cues. Consistent with previous studies, the ant subjects in our behavioral tests navigated towards a particular artificially generated coordinate (north, south, east or west). Our results do not suggest that Harvester ants utilize a magnetic field to navigate when deprived of other cues such as polarized sunlight, visual cues, or pheromone signals. Our results suggest there may be a correlation between Carpenter ants and dead placement relative to a magnetic field, according to our food assay results in which the ants placed their dead irrespective of food placement within the chambers.