Copyright (c) 2013 California Polytechnic State University All rights reserved. http://digitalcommons.calpoly.edu/biosp Recent documents in Biological Sciences en-us Fri, 19 Apr 2013 01:31:47 PDT 3600 http://digitalcommons.calpoly.edu/biosp/21 http://digitalcommons.calpoly.edu/biosp/21 Wed, 17 Apr 2013 09:40:54 PDT I investigated the abundance and diversity of riparian and oak woodland birds in a section of the Los Padres National Forest in Coastal Central California. Point counts were conducted in Oak Woodland and Riparian habitats during the summer of 2012. Point counts were replicated in time (2x) and space (25 replicates). The data were analyzed using Program Distance to correct for differing detection probabilities between species and habitat types. The two habitat types showed no significant difference in species richness. For most species, there was no difference in density between riparian and oak woodland habitats. However, the two species with significantly different densities between the habitats showed higher densities in the oak woodland habitats. Other analysis showed that seasonal behavioral changes may affect the detection probability of some, but not all, bird species over the course of the breeding season. The lack of significant differences in the densities of most species between habitats may suggest that that habitat associations in the study area were not strong or that inland birds can survive equally well in either type of habitat. If this is the case, oak woodland habitats may serve as a reservoir to maintain avian diversity in the rapidly declining riparian habitats of California.

]]> Jacy Hyde http://digitalcommons.calpoly.edu/biosp/20 http://digitalcommons.calpoly.edu/biosp/20 Wed, 17 Apr 2013 09:40:48 PDT This study attempts to determine if a significant difference in relative ear length exists between two neighboring populations of Peromyscus maniculatus on the central coast of California. Data was collected from individuals trapped at two plots in the Guadalupe-Nipomo Dunes National Wildlife Refuge and two plots near Black Lake, under the supervision of Francis X. Villablanca, Ph. D. of California Polytechnic State University, San Luis Obispo. A total of 98 individuals were captured over the course of three nights of trapping. A regression analysis was performed comparing the ear lengths of each population relative to body size. The analysis of the data showed that there was no significant difference in ear length between the two populations.

]]> Joshua S. Willems http://digitalcommons.calpoly.edu/biosp/19 http://digitalcommons.calpoly.edu/biosp/19 Tue, 21 Aug 2012 16:41:02 PDT The pocket gopher (Thomomys bottae) and voles (Microtus spp.) cause significant economic damage to vineyards. In response, many growers have taken steps to attract Barn Owls (Tyto alba) to their properties to help keep these rodent populations in check. This research project investigated Barn Owl consumption of pocket gophers and voles in Central California vineyards in order to assess the efficiency of this integrated pest management strategy. I collected a total of 715 owl pellets from five vineyard locations in Templeton and Paso Robles, California over an eight-month period during nesting and post-fledging seasons. I identified seven prey species within in the owl pellets, allowing for comparative analysis between the two collection periods. Comparisons of the average number of individuals per species per pellet (AVG) and a paired t-test indicated seasonal diets of Barn Owls are statistically similar. Although there was slight variation in AVG values between seasons, this research did satisfy the expectation that the diets from each vineyard would contain similar percentages of gopher and vole species. Microtus was the most highly consumed prey genus and made up the majority of both the spring (AVG = 0.528) and summer diets (AVG = 0.599) with a p-value of 0.77. Seasonal consumption for gophers was statistically similar and Thomomys bottae was the second most highly consumed prey species behind Microtus californicus, with AVG values of 0.304 (spring) and 0.299 (summer) with a p-value of 0.80. It would be fair to conclude from this snapshot of seasonal consumption that Barn Owls consume important vineyard pests and have the potential to assist in regulating these rodent populations.

]]> Hannah Tillmann http://digitalcommons.calpoly.edu/biosp/18 http://digitalcommons.calpoly.edu/biosp/18 Thu, 21 Jun 2012 12:33:34 PDT Bonobos (Pan paniscus) tend to have low frequencies of aggression due to a suite of affiliative behaviors that are thought to relieve group tensions. A few of these possible behaviors are grooming, sociosexual activities, and strategic positioning in regards to proximity with other individuals at food sites, where most aggression occurs. This observational study sought to determine whether captive bonobos exhibit certain social behaviors at different rates, and have differing proximity preferences in regards to other individuals, when food was and was not available. Results show that when food was available, the apes were less affiliative with fewer counts of grooming, but with higher rates of sexual activity. In addition, animals were found to be in proximity with at least one group member less often when food was available. There were very few recorded aggression events throughout the study, and no significant difference in rates of aggression when food is and is not available.

]]> Alyssa Semerdjian http://digitalcommons.calpoly.edu/biosp/17 http://digitalcommons.calpoly.edu/biosp/17 Thu, 21 Jun 2012 09:17:41 PDT Our study investigated the spatial distribution and movement behavior of predatory dragonfly larvae (Anax) and of two prey types: mosquito larvae and amphipods. Predator-prey interactions have important consequences for the population dynamics of both predator and prey groups and these interactions can shape community structure. We measured behavior of each prey type in the presence of the Anax predator and the behavior of the predator in the presence of these alternative prey types. Observations were made in five-gallon aquaria where a grid pattern allowed us to track the number of moves made by individuals. We compiled data from ten, one hour trials for each predator-prey combination (Anax + amphipods and Anax + mosquito larvae). Prey species differed in their behavior. Mosquito larvae spent more time near the water’s surface, were more likely to utilize the artificial vegetation, and were more active than amphipods. On the other hand, amphipods utilized full range of the aquarium and had a greater number of moves than mosquito larvae. Anax behavior was significantly different in the two prey treatments. Anax spent more time in the top potion of the aquarium during the mosquito treatments, utilized the artificial vegetation more in the amphipod treatments, had a greater number of moves in the amphipod treatments, and ate more amphipods than mosquito larvae. Our results indicate that Anax change their behavior based on prey type.

]]> Shane Elizabeth Johnson et al. http://digitalcommons.calpoly.edu/biosp/16 http://digitalcommons.calpoly.edu/biosp/16 Thu, 24 May 2012 16:57:31 PDT The following study examines the use of ear length as a diagnostic field character for differentiating between species of Kangaroo rats in San Luis Obispo County. Data was taken from a study of Kangaroo rats in the Guadalupe-Nipomo Dunes National Wildlife Refuge, as well as various collections under the supervision of Francis X. Villablanca, Ph. D. and California Polytechnic State University, San Luis Obispo. An ANOVA was used to compare subspecies within Dipodomys heermanni and t-tests were used to compare ear lengths between Dipodomys heermanni and Dipodomys venustus. The analysis shows a statistically significant difference and supports the hypothesis that ear length can be used to differentiate species. Further testing was completed at the subspecies level within Dipodomys heermanni but did not prove to be significant. This experiment is evidence that confirms the identification of Dipodomys venustus outside of its known range.

]]> Daniel W. Ziebron http://digitalcommons.calpoly.edu/biosp/15 http://digitalcommons.calpoly.edu/biosp/15 Mon, 09 Jan 2012 17:23:03 PST Christie Yorke http://digitalcommons.calpoly.edu/biosp/14 http://digitalcommons.calpoly.edu/biosp/14 Tue, 27 Sep 2011 17:50:22 PDT Michael Dennis Dwyer Jr. http://digitalcommons.calpoly.edu/biosp/13 http://digitalcommons.calpoly.edu/biosp/13 Thu, 09 Jun 2011 15:18:28 PDT Jaclyn Mann http://digitalcommons.calpoly.edu/biosp/12 http://digitalcommons.calpoly.edu/biosp/12 Thu, 05 May 2011 16:05:22 PDT The guppy, Poecilia reticulata, is a common study organism for behavioral and other ecological experiments (Houde, 1997). As far as we know, no previous data have been compiled regarding hormones and condition index of guppies. In this experiment we examined the relationship between circulating levels of three hormones (testosterone, 11-ketotestosterone and cortisol) and condition index in males and also made comparisons among the hormone levels, for three guppy sites from the northern range of Trinidad – Aripo River, Marianne River and Small Crayfish River. Hormone samples were obtained using non-invasive water borne techniques and quantified by our collaborator. The condition index of guppies was calculated as the ratio of mass per length³. We predicted the following relationships: positive relationships between testosterone (T) and 11-ketotestosterone (11KT), condition index (CI) and 11KT, and CI and T; negative relationships between 11KT and cortisol (C), T and C, and CI and C. We found: a positive relationship between 11KT and C, 11KT and T, and C and T for the Small Crayfish River population. Aripo River and Marianne River populations displayed no significant relationship between 11KT and C, and 11KT and T. The Aripo River population showed a significant positive relationship between C and T, but the Marianne River did not show a significant relationship. Overall, there were no relationships between any of the hormones and CI for any site. Our findings indicate that there may be genetic differences among the populations indicated by the hormone differences. Further experimentation is necessary for more comprehensive understanding of the functions of these hormones in the guppies.

]]> Shelly Gupta et al. http://digitalcommons.calpoly.edu/biosp/11 http://digitalcommons.calpoly.edu/biosp/11 Tue, 19 Apr 2011 15:16:00 PDT This is a study on trap shyness and trap avoidance in the kangaroo rat species Dipodomys heermanni arenae. This species is being studied as a surrogate for the critically endangered Dipodomys heermanni morroensis. This is an ongoing study that has been continuing for the past three years, with four three-day sessions per year. The study is a specific look at the effects of the use of Sherman traps on kangaroo rat behavior between individual session days. Capture proportions for each of the three days of each session were calculated and compared through a t-test. The current results of this data set display no support for a significant effect of trap shyness and avoidance on this species of kangaroo rats.

]]> Natalie E. Folsom et al. http://digitalcommons.calpoly.edu/biosp/10 http://digitalcommons.calpoly.edu/biosp/10 Tue, 22 Mar 2011 15:58:19 PDT Lindsey Anne Peterson http://digitalcommons.calpoly.edu/biosp/9 http://digitalcommons.calpoly.edu/biosp/9 Mon, 14 Mar 2011 10:44:03 PDT Diversity in songbirds (Passeriformes) between riparian and oak woodland habitats has not been studied before in the Los Padres National Forest around the Hi Mountain Lookout in San Luis Obispo County. Surveys of avian populations were conducted by point counts on fifty variable circular plots; surveys were performed between July and August of 2010. Diversity was calculated using the Shannon-Weiner method, and then squared for normality. No significant results were found when comparing the diversity values between riparian and oak woodland habitat (F = 0.52, p = 0.472). Although the results showed no significance, the data are still important, as they are part of a long term ecological monitoring project conducted between Cal Poly and the US Forest Service.

]]> Trevor Pell http://digitalcommons.calpoly.edu/biosp/8 http://digitalcommons.calpoly.edu/biosp/8 Tue, 01 Mar 2011 09:51:14 PST The purpose of this document is to report the results of a botanical survey of a portion of the Tierra Redonda Mountain Area of Critical Environmental Concern. The survey was conducted for the Bureau of Land Management, and executed between October 2009 and June 2010. Tierra Redonda Mountain is the type locality for the Tierra Redonda formation, and has weathered to form steep slopes of exposed chaparral and protected woodlands. Four general community types were found; foothill woodland, chaparral, southern coastal scrub and dune scrub. Alliances determined by The Manual of California Vegetation (2nd ed.) were: Quercus douglasii Woodland, Quercus agrifolia Woodland, Pinus sabiniana Woodland, Adenostoma fasciculatum Shrubland, Adenostoma fasciculatum—Salvia mellifera Shrubland, Ceanothus leucodermis Shrubland, Eriogonum fasciculatum Shrubland, Arctostaphylos glauca Shrubland, Heteromeles arbutifolia Shrubland, Ericameria ericoides Shrubland and Achnatherum speciosum Herbaceous Alliances. A total of 242 species were identified in the survey area, most with a respective voucher specimen housed in the Robert F. Hoover Herbarium (OBI) on the Cal Poly, San Luis Obispo campus.

]]> Anthony Baniaga et al. http://digitalcommons.calpoly.edu/biosp/7 http://digitalcommons.calpoly.edu/biosp/7 Wed, 16 Jun 2010 14:31:34 PDT Heather L. Price http://digitalcommons.calpoly.edu/biosp/6 http://digitalcommons.calpoly.edu/biosp/6 Wed, 09 Jun 2010 16:18:08 PDT Guppies, Poecilia reticulata, are a model species for studies of female preference based on male courtship displays; however, males also display to each other in an aggressive context, and little attention has been paid to the role of male-male displays. The display involves a male positioning his body in front or to the side of another male, arching his body, and quivering with his dorsal fin splayed. To understand what behaviors elicit a male display, we assigned individual males a dominance status. We then examined the relationship between dominance status and the number of displays delivered and received. By knowing the status of a displaying individual, we can better understand whether the display is given more often by dominant or subordinate individuals. Our results showed no significant correlation between dominance status and display rate; however, we found a significant relationship between the number of displays received and the number of displays delivered. Additionally, we found that a display is most often followed by aggression (nips and chases) by the other male rather than aggression by the focal male. Our results suggest that the display is a subtle form of aggression that escalates agonistic interactions. It also may serve to convey information about male quality (e.g. by displaying color patterns) and aggressive intent.

]]> Rebecca Nuffer et al. http://digitalcommons.calpoly.edu/biosp/5 http://digitalcommons.calpoly.edu/biosp/5 Wed, 09 Jun 2010 16:18:08 PDT Sodium chloride has been scrutinized of late, not only for its liberal use as a food preservative but for its contribution to disease states. The causal role of habitual high salt intake in increasing blood pressure and exacerbating hypertension has been established. A growing body of evidence strongly suggests that hypertension contributes to other conditions such as cardiovascular disease, obesity, stroke, and type II diabetes. Rates of hypertension are significantly higher in obese individuals. These comorbidities have been positively associated with the modern Western diet. Worldwide, many government and health organizations have called for public policy measures to mandate sodium reductions in processed foods. The objective of this study is to assess the possible direct association between high salt intake and adipocyte hypertrophy and hyperplasia as it relates to obesity.

]]> May Yong http://digitalcommons.calpoly.edu/biosp/4 http://digitalcommons.calpoly.edu/biosp/4 Wed, 05 May 2010 16:35:26 PDT Emerita analoga, Pacific coast sand crabs, are an important biological component of the swash zone ecosystem. They have evolved the ability to burrow into sand, and burrowing speed is commonly used as an indicator of performance relevant for fitness in this species. Sand grain size varies among beaches, and crabs may be better adapted to to burrow in some sand types. We performed a completely crossed 3-factor experiment to determine how the sand grain size associated with beach-of-origin and rearing conditions influence burrowing in coarse and fine sand. Crabs from a fine sand beach and a coarse sand beach were housed in both fine and coarse sand. The burrowing speed of each crab was tested in fine and coarse sand five times over ten weeks. Crabs were housed individually during the ten weeks, in either coarse or fine sand. We found a significant difference in burrowing times throughout sessions. Crabs from both beaches, housed in both sand types, burrowed faster in coarse sand than in fine sand. However, neither beach-of-origin nor rearing sand type influenced burrowing speed. There was also no difference in mortality among treatments. These results indicate that, although the abiotic factor, sand grain size, influences burrowing speed, this effect is not altered with long term exposure to different sand types.

]]> Natalie A. Lee et al. http://digitalcommons.calpoly.edu/biosp/3 http://digitalcommons.calpoly.edu/biosp/3 Thu, 07 Jan 2010 12:34:24 PST Botrylloides violaceus is a colonial ascidian with the ability to undergo sexual and asexual reproduction as well as regeneration. The canonical pathway starts with the extracellular protein Wnt and ends with β-catenin, a transcription factor, which also functions in cell adhesion. The Wnt signaling pathway is involved in embryogenesis and regeneration in a variety of other species. In our studies we attempt to isolate and sequence both a Wnt gene and from Botrylloides via degenerate primer design and PCR. Using bioinformatic methods we aligned sequences from other organisms, as the Botrylloides genome has not yet been sequenced. Using mouse, Ciona, sea urchin, and anemone DNA we were able to design primers using areas of conservation in both genes. We have been optimizing DNA and RNA isolation procedures from Botrylloides and are now identifying optimal annealing temperatures for our primers. Obtaining sequence data from fragments of these genes will allow us to compare them to sequences from other species and provide us with information about evolutionary conservation.

]]> Manasa Chandra et al. http://digitalcommons.calpoly.edu/biosp/2 http://digitalcommons.calpoly.edu/biosp/2 Wed, 09 Dec 2009 09:29:46 PST Acanthocephalan worms infect two hosts to reach full development. Some species have been demonstrated to change their intermediate host’s behavior or coloration to increase the likelihood they will reach the final host. The pacific mole crab, Emerita analoga, is commonly parasitized by Profilicollis altmani along the Pacific coast of North and South America, but the impact of parasitism on the crab intermediate host is unclear. We investigated whether P. altmani alters the concentration of dietary carotenoids present in E. analoga tissues and if the parasite may also acquire pigments normally allocated to the host. Fifty eight gravid female crabs were collected and dissected during the summer of 2008 from Pismo Beach, California. Ovaries, eggs, esophagus, and carapace, as well as cystacanth stage acanthocephalans, were removed from each crab. The samples were weighed and extracted in HPLC grade acetone. Carotenoids extracted from each tissue type were analyzed by UV-vis spectrophotometry, with the maximum absorbance and maximum wavelength recorded for each sample. Results were compared to the wavelength and absorbencies of previously identified carotenoids in E. analoga. The carotenoid content of each tissue type with respect to parasite load group was compared. Host carotenoid profile patterns differed between tissues and some with respect to parasite loads. Carapace and ovary tissue had differences between some absorbance groups, but as the data were not normally spread due to uneven sample sizes, the results cannot be confirmed. Cystacanths found in infected crabs contained carotenoids, but their UV-vis profile appears to differ from that of host tissues. This suggests that the parasites may modify host-acquired carotenoids.

]]> Whitney Melroy