Biology 342 Animal Behavior 2007
Independent Project Presentations
Does size matter? The
fight characteristics and probability of winning as predicted by relative
size differences between opponents during agonistic encounters in female
R. Ian Moore and Kelsey J. Wood.
Orange is IN this season: Artificial
coloration and sexual selection in the common guppy.
Marjorie Nicholson and Natalie Morgenstern
Hungry Hungry Ducks
Jenny Eng and Austen Brown
Does size matter? The fight characteristics and probability of winning
as predicted by relative size differences between opponents during agonistic
encounters in female crayfish.
R. Ian Moore and Kelsey J. Wood. Previous studies on crayfish agonistic behavior and social dominance formation have typically paired crayfish by weight in order to minimize the effect that size differences might have on fight outcomes and characteristics. Other studies have used large weight differences to attempt to create winners and losers. Both these kinds of studies rely on the assumption that size differences between fighting crayfish influence the outcome and that weight is the best way to measure size differences. Females of the crayfish species Procambarus Clarkii were measured in terms of mass, length, and claw length. Fights were staged between pairs of crayfish either 1) mismatched by weight but matched by claw size, 2) mismatched by claw size but matched by weight, or 3) matched by weight and claw size. Behaviors during the agonistic encounters were scored such that avoidance behaviors were given negative values and aggressive behaviors were given positive values. The more aggressive behavior displayed by the winner and the more avoidance behavior displayed by the loser, the less time crayfish spent fighting. There is evidence to suggest that this may be modulated by the size of the difference in length between opponents, but not necessarily weight or claw size differences. A larger sample size is necessary to reveal the effects of weight and claw size if such effects exist. Even slight size differences between opponents had an effect on outcome and characteristics, indicating that crayfish are able to detect small differences in size or that small differences in size are correlated with other things important to fighting such as chemical production or maturity.
We Be Jammin’: Induced Jamming Avoidance
Response in Eigemennia
Aurelia Moran, Claire Matturro & Matt Lehet
The ability of electric fish to navigate, hunt (Babineau, 2007), interact socially (Tallarovic, 2002), aggressively (Metzner, 1999), and sexually (Kramer, 1987) using their electric pulse has been extensively studied. As in all perception and communication systems, the electric sense is requires the ability to discern a specific signal from other environmental noise .Electric fish (specifically Eigenmannia virescens) produce an electric signal from an organ in their tail. These electric organ discharges (EODs) interact with the world and the resulting changes in the electric field provides information to the fish. This information can be distorted though a phenomenon called jamming, in which the fish’s own signal is matched by an outside source, causing disorientation if not corrected. Eigenmannia have evolved the ability to avoid jamming by conspecifics (Tan, 2005). The jamming avoidance response (JAR) is for the fish with the higher frequency to increase its frequency and the fish with the lower frequency to decrease its frequency (Watanabe, 1963). In this study we attempted to cause JARs in four individual fish through playback of there own unique frequency, at the same rate emitted as well as with minor alterations in rate by +/- 15%. Our work would help quantify the amount of similarity of frequency necessary to induce jamming avoidance response. Results were inconclusive due to a small sample size and the crude method of recording and quantifying EODs.
Egr1 Expression as a Product of Social Opportunity in Astatotilapia
Emmeline Chuu and My Linh Nguyen
Burmeister et al., 2005 demonstrated immediate early gene expression in the pre-optic region of the hypothalamus as a consequence of “social opportunity” in male Astatotilapia burtoni during ascension to dominance. The “perception of social opportunity” is defined as the elevated expression of the immediate early gene egr1 in the hypothalamus. This experiment aimed to study whether subordinate males can recognize the “social opportunity” when a territory is made available due the removal of the dominant male and whether egr1 is expressed when this occurs. It is expected that subordinate fish that is larger in size or is healthier will express higher egr1 when ascending to dominance. Fish were allowed to acclimate for 2 weeks before any experimentation. Daily quantification of fish behaviors determined the social hierarchy of the fish community. There were six tanks total, each tank contained three males (large, medium, and small) and two females. There were three fish treatment groups: Control, Group X, and Acclimation. The control groups were groups where the dominant male was not removed from the social community. Group X was the treatment group in which the dominant male was removed in the dark and subordinate males were allowed to ascend to dominance. Once dominance was established, the ascending male and subordinate male were sacrificed. The acclimation groups differed from Group X in that after the removal of the dominant male, subordinate fish and ascending fish were allowed to acclimate for one week. Experimentation began after the removal of the dominant male in Group X. Behaviors were quantified and physical attributes were observed in subordinate A. burtoni to determine dominance between two subordinate males. Once dominance was established, the ascending fish and the subordinate fish were sacrificed. The hypothalamus was removed and RNA was extracted to look at the expression of egr1 using Q-PCR analysis. Behavioral data showed significant differences in the number of chases and flees between the large, medium, and small cichlids. Large, dominant A. burtoni significantly chased frequently than the medium and small cichlids, and the small and medium cichlids fled more often. Large A. burtoni were significantly greater in length, body mass, and gonad mass than the medium size and small size fish. Although, the medium and the small fish significantly differed in length and body mass, they did not differ in gonad mass or the number of chases and flees. Q-PCR analysis shows no difference in egr1 expression levels between three treatment groups of fish. This may be attributed to the crude extraction of the hypothalamus. Future directions encompass better, precise techniques of sampling tissues of the pre-optic region of the hypothalamus.
Intruder Defense Response
Alice Runkle, Laura Mulshine, and Ben Kessler
Western Harvester ants (Pogonomyrmex occidentalis) have highly complex forms of communication that involve both behavior and pheromone cues to warn the colony of an intruder. Two types of intruder responses have previously been reported for harvester ants, a panic response where an individual tries to “save himself” and an aggressive response where the individual either attacks the intruder or leaves a sent trail to recruit others to the area (Wilson and Regnier 1971). We first attempted to find the number of intruders (crickets) that would elicit either a panic or aggressive response in scouting ants. Our investigation then focused on the effects of oleic acid, a chemical released during decomposition of dead insects, on intruder responses. We tested foreign ants, spiders and crickets as both oleic acid scented and non-oleic acid intruders to see if intruder response would decrease as a result of the ants “smelling death” on an active intruder. Due to the lack of overall intruder response in the colony studied, we were unable to conclude the relationship between number of intruders and response, or characterize the effects of oleic acid on intruder response.
House Wren Brooding and Feeding Behavior
Laurel Brehm & Josie Griffin
House wrens, Troglodytes aedon, are pair-bonded passerine birds that commonly build nests in man-made nesting boxes. Females incubate a clutch of anywhere from 3 to 6 eggs and are responsible for the brooding, while both parents are in charge of feeding the nestlings. Using nests equipped with cameras, we examined brooding and feeding behavior across nests with clutches of varying size. Previously it had been conjectured that the number of eggs would be equivalent to the pairs’ ability to support and feed all the nestlings equally, and we investigated the validity of this claim. We scored incidence of feeding, amount of time spent brooding, and amount of time spent in nest performing other duties such as nest maintenance. We used t-tests to analyze whether there were significant differences in behavior for clutches ranging from 1 to 4 nestlings. We found that despite brood size, the amount of time the parents spent in the nest, both brooding and non-brooding, was approximately equal. Most of the in-nest time was consumed with brooding. Additionally, though feeding rate increased as there were more nestlings, it did not increase proportionally. There was a significant difference, by t-test, between the groups with 1 or 2 nestlings and the groups with 3 or 4 nestlings.
Snakes sex/species scent selections: conspecific and gender pheromone
preference in neonate red-sided garter snakes (Thamnophis
Past studies have firmly established snakes’ ability to sense conspecific odors, and snakes prefer areas soiled by conspecific snakes versus neutral areas. Presumably, this enables snakes to locate conspecifics during the cold winter months, which is vital to initiate aggregation for shared warmth among this cold-blooded species. Also, scent detection is utilized for location of the opposite sex, and mating is promoted upon meeting. Neonate conspecific odor trailing has been shown in other species of snakes, but not T. sirtalis infernalis. Furthermore, sex discrimination mediated through pheromone cues is shown in adult T. sirtalis infernali, but not neonates. This study investigates the preference of red-sided gartner snakes for conspecific pheromones versus no pheromones, through a free-range area preference test, with side preference measured through time and tongue flick activity. This establishes a novel ability of neonate T. sirtalis infernalis. Also, the same behavior test is used to determine the sex discrimination ability of neonates, which is previously uninvestigated for snakes in general. Results show a clear preference for conspecific soiled areas over neutral areas, but there is no significant preference for same-sex or opposite-sex soiled areas.
Drosophila Mate Choice
Valerie Conrad and Hannah Smith
Natural variations of the for gene yield two strains of Drosophila with different food-search strategies, rovers and sitters. The strains have been found to display differences in areas other than food-search, such as olfactory response, but no studies have been preformed exploring the effect of strain on courtship and mating behaviors. We used female and male mate choice paradigms in an effort to determine if strain affects mate choice and if the strains practice self-assortative mating. Females were placed in individual food bottles with a male of each strain, and the offspring genotyped using electrophoresis in order to identify the strain of the father. Males were placed in individual tubes with a female and observed for 30 minutes while scoring for courtship behaviors. Courtship vigor, defined as the number of wing songs and abdomen curls preformed by the male within the 30 minute period, was assumed to indicate male mate preference. Due to technical difficulties extracting DNA for PCR, the female mate choice experiment failed to yield any data. A shortage of male Drosophila due to high mortality rates resulted in a small sample size for the male mate choice paradigm, resulting in insignificant data. Because of these difficulties, we were unable to accept or reject the effect of strain on courtship behavior, as we found no evidence for or against the presence of self-assortative mating.
Orange is IN this season: Artificial coloration and sexual selection
in the common guppy.
Marjorie Nicholson and Natalie Morgenstern
The common guppy Poecilia reticulata, found in the Carribean and certain parts of South America, displays sexual dimorphic characteristics. The males of this species display an attractive orange coloring, while females in contrast look dull and grey. Orangeness is adaptive in that it makes males more attractive to females, but maladaptive because it makes males more visible to predators. Naturally, a balance between visibility and sexual attractiveness is reached in the wild. However, if researchers increase the amount of orange in a male guppy to the point of total susceptibility to predation, will females find him more attractive or will they see how this puts their male progeny at risk? Experimenters subcutaneously injected male guppies with orange dye using .27 gage needles, and then measured attractiveness to females by determining her preference between a normal male and an artificially colored male. Based on results, most females preferred the naturally colored male. However, two strategies were uncovered, as when 1/3 of the data was separated, that subset of the population showed preference for artificially colored males. This follows the speciation model, as different preferences within a population are known to lead to reproductive isolation.
Drosophila Smoke American Spirits: Nicotine and Starvation
Nicotine is an alkaloid found in the Nightshade family of plants, and it is often used as a natural insecticide. Nonetheless, humans choose to intake this toxic chemical on a regular basis to the obvious detriment of their health. Working with Drosophila melanogaster, as it is easy to work quickly with large numbers of individuals, we investigated the power of addiction to drive individuals towards choices contrary to their health and well-being. An experimental group of flies was divided by sex and the repeatedly exposed to tobacco smoke for 5 days. Each time that the smoke was administered, it was preceded by the introduction of raw tobacco into the environment so as to train the flies to associate the smell with the coming smoke. After the training period the flies were then starved for variable amounts of time before being given the choice between a chamber containing raw tobacco and one containing food. After 45 seconds the number of flies in each chamber was recorded. The data was then contrasted with data obtain from a control group that had not been exposed to smoke, yet had been starved and given the test in the same manner. As expected, addicted flies chose the tobacco over food until a certain period (~7hrs) of starvation is reached, at which point they choose food instead. Further investigation into the mechanism of this choice could help lead to a better understanding of nicotine addiction, and how individuals (humans especially) can make choices contrary to their well being.
Sex Differentiation and Growth Rate in Haplochromis burtoni
Candice Kam and Xeno Acharya
Many different reptiles show the characteristic of having temperature dependent sex-determination. Turtles, Lizards, and some crocodiles are examples of animals that have this trait, and we were interested in whether Haplochromis burtoni exhibits this trait as well. In this experiment, we wanted to see if there were differences in sex ratios of Haplochromis burtoni which were raised immediately after spawning in two different temperatures. Although we were unable to determine the sex of the Haplochromis Burtoni, we were able to see a significant difference in growth rate between the two rearing temperatures. There have also been studies that have shown that there is a difference in growth rate when Haplochromis burtoni are raised either in group or isolated environments. The previous studies found that group-housed Haplochromis burtoni grew at a faster rate than the isolated fish. However, the results from our experiment show a different trend because the individually housed fish had a significantly larger growth rate than the group-housed fish. One reason why our results may have suggested an opposing conclusion is because the individually housed fish had a larger tank area than the group-housed fish if measured by area per fish. Overall, the data shows that there are many different factors that influence the growth rate of Haplochromis burtoni. Because growth rates show dependency on different factors, the sex determination of these fish may be affected by these variables as well since size and sex are directly correlated. Further experimentation must be conducted in order to see if this is in fact true.
Differences in Visual Learning Between Rover & Sitter
The for allele in drosophila melanogaster encodes a cGMP-dependent protein kinase(PKG). Mercy and others (2007) found that this gene affects olfactory learning in Drosophila melanogaster. The PKG encoding genotype forr creates the rover phenotype, which has been observed to move more between feeding patches, the other genotype fors creates a sitter phenotype, which results in less movement. Mercy and others have suggested for may mediate an evolutionary tradeoff between a short-term memory rover and long-term memory sitter. Here we tested this hypothesis using a modified visual learning protocol from Gerber (2003) to test in differences between long-term associative learning. Larvae were exposed to ten training sessions of alternation between dark/sweet and light/plain environments. Flies were then tested twenty-four hours later for a preference between light and dark quadrants. We found no difference in behavior between rover and sitter groups and no difference in behavior between trained and untrained groups, thus we cannot show any differences between rover and sitter groups because the training was ineffective. However there was a difference in random distribution between light and dark, flies spent more time in the dark quadrants than light ones.
Affect of Age on Learning in Bombina orientalis (fire-bellied
Kristy Gonyer and Karla Schultz
It has previously been shown that Bombina orientalis are capable of learning to successfully navigate through a maze. Other studies have shown that aging decreases the ability to learn in the least shrew (Cryptotis parva) and in rats. Our study investigates whether B. orientalis shows a similar effect of age on learning. We obtained two groups of frogs. One group consisted of offspring bred from wild caught B. orinetalis from 2003, while the other group consisted of offspring from a 2006 breeding. Subjects were placed in a complicated maze and presented with aversive stimuli in the form of lamps placed over the maze. The frogs’ exploration of the maze was scored according to right and wrong decisions made in the maze until they reached the end of the maze where the subjects were rewarded with rest in cool damp conditions. If the subjects were unsuccessful in completing the maze within 20 minutes they were transferred to the end of the maze to avoid excessive stress. The subjects were each tested in up to 14 trials over 2 weeks. We found an overall trend in learning, however we did not find a difference in learning between the older and younger groups.
The Guppy Learning Curve
Clare Parker and Helen Magee
Female guppies choose their mates based in part on the amount of orange color the male has. If a male is colored more on one side than the other, he will preferentially display his more colorful side when courting females. Males learn what their good side is based on female response. We were interested in testing guppies’ memory and learning ability. Can males learn or remember what their good side is? We first tested whether males can improve their asymmetric display when exposed to females repeatedly. Males were placed in a tank with a female, separated by a clear divider, and their display recorded with JWatcher. They were then re-exposed to females at set intervals and their display recorded. Our second experiment tested whether males are able to remember their good side if female response is negated. In this test, the males were first exposed to a responsive female to teach the males their good side. They were then exposed at set intervals to a female that was anaesthetized with clove oil to eliminate her influence on his display. Male displays were again recorded with JWatcher. Our results indicate that guppies cannot learn, but can remember their good side. However, our analysis also reveals that the two groups we tested were not initially equal, which would make our results unreliable.
vocal responses (EVR) to urban and natural noise in a colony of Rock
Catie Uram and Jonathan Sweeney
Previous studies have shown that animals can regulate their vocalization is response to environmental sounds, often modulating amplitude, emission rate, and durations of vocalizations to communicate in the presence of noise. We examined a whether colony of 20 Rock Pigeons (Columba livia) exhibited different evoked vocal responses (EVR) to natural and synthetic noises. We tested street, wind, and pigeon call noises on the EVR of the colony. After analysis of 21 trials for number of cage rattles, warble frequency, duration, and amplitude, we found that habituation has a significant effect on EVR. This habituation could be to the noises used in playback or to presence of the experimenters. Further, we found that pigeons respond similarly to natural and synthetic noises. This study leads us to ask about the ontogeny of EVR, specifically, how it varies between urban pigeons and pigeons raised away from the city.
Glacial profiling: stereotypies between Ursus
maritimus and Ursus
americanus at the Oregon Zoo
Stereotypic behavior is defined as repetitive locomotor behavior that does not serve a purpose or function and is found in many captive animals such as canaries, primates, and elephants. While members of the genus Ursus share evolutionary roots, polar bears are the only species that exhibit stereotypic behavior in captivity. Here, I observed the behavior of polar bears and American black bears at the Oregon Zoo to better understand the frequency of stereotypy between the two species. I learned that stereotypic behavior occurs rarely in black bears compared to polar bears. I hypothesized that polar bears may show more frequent stereotypies due to unusual daylight conditions compared to their natural habitats. In the Arctic, daylight hours are distributed seasonally such that the summer includes nonstop daylight whereas in the winter there is no daylight altogether. To answer this question, I observed the difference in the frequency of stereotypy between a sunny day and an overcast day at the zoo. I determined that the relationship between stereotypic behavior and presence of sunlight is statistically significant in the case of polar bears, but not black bears based on the data I compiled over the course of six hours of observation.
Hungry Hungry Ducks
Jenny Eng and Austen Brown
The feeding behavior of Mallards (Anas platyrhynchos) was observed at two Portland area ponds, the urban Westmoreland Park, and the more naturalistic Oaks Bottom Wildlife Refuge. Concurrently, we observed feeding behavior of Northern Shovelers (A. clypeata) at Oaks Bottom. Mallards at Oaks Bottom spent significantly more time foraging than those at Westmoreland, and more time feeding with their heads underwater. Time spent foraging has been directly correlated with aquatic invertebrate abundance, a possible explanation for the difference in time budgets (3). As underwater feeding prevents ducks from seeing predators, a higher threat of predation at Westmoreland could explain the difference in specific foraging behaviors (2). Shovelers and mallards at Oaks Bottom showed no significant difference in frequencies of foraging behaviors. Increased intraspecies competition is demonstrated to increase species niche adherence, thus the lack of niche distinctions could indicate low competition and relative food abundance (1). Due to beaks specialized for straining, Shovelers have shown preference for ponds where surface feeding is the dominant foraging behavior. However, Shovelers at Oaks Bottom engaged primarily in deeper foraging (ft), a less-favored foraging behavior shown to increase as surface invertebrate populations decline during the winter (2). Thus Oaks Bottom is probably not an ideal Shoveler habitat, although it appears to be better than Westmoreland, as suggested by the complete absence of Shovelers at that location. As specialist feeders, Shovelers are a good indicator of protein-rich aquatic invertebrates, as opposed to more generalist Mallards who feed on seeds and vegetation as well as invertebrates. A greater abundance of invertebrates at Oaks Bottom could explain not only the presence of Shovelers but also our observation of higher frequencies of females at Oaks Bottom; females rely primarily on aquatic invertebrates as a protein source for egg production (3).