11th Annual EEB Undergraduate Poster Session
Join us virtually beginning April 28, 2021, to recognize the amazing research being done by undergraduates in Ecology and Evolutionary Biology.
Students have worked incredibly hard to adapt to this challenging time; we are so grateful to still be able to display their work while social distancing.
We would like to thank everyone who helped make the poster fair happen this year! To all of our students, their PIs, the grad students, and supportive family members and mentors: Thank you!
Please note that some presentations may need to be downloaded in order to play the audio.
Winners
Our presenters fell into two categories: Advanced and Emerging
Characterization of Umbilical Cord via Flow Cytometry for Quantification and Immunophenoptic Identification
Dr. David Harris, Health Sciences
Category: Advanced
Biobanks have become incredibly important in the field of medical research. Because of their ability to store a large number of samples, they have dramatically increased the efficiency of the research process since everything is in one place. There is evidence to support the fact that stem cells from umbilical cord blood can serve as a viable option for cell therapy in the treatment of patients suffering from certain disorders. They offer many benefits over bone marrow stem cells, especially considering the fact that retrieving umbilical cord blood stem cells is not invasive like the extraction for bone marrow stem cells. Stem cells from umbilical cord blood have varying characteristics when taking into account factors such as gestational age, size of the placenta, and age of the mother as well as many other factors. Using a Cellometer, immune cell counts and total nucleated cells were obtained. Though the use of flow cytometry, umbilical cord blood stem cells can be further characterized to look at certain markers such as CD3, CD4, CD8, and CD45.
Identifying the Change in Metabolite Profile during Thermal Bleaching
Dr. Jeremiah Hackett, Ecology & Evolutionary Biology
Category: Advanced
Coral reefs are home to 25% of marine biodiversity while protecting our coastlines and homes from tropical storms. The basis of these reefs is a symbiotic partnership between the coral host and algal symbiont where they exchange nutrients and protection benefits in order to thrive. However, this essential relationship is threatened when the corals are put under stress, including thermal stress. This project works to understand these stress response pathways with different, more heat-tolerant symbionts by tracking the metabolite profiles of each partner during periods of thermal stress.
Identifying the Change in Metabolite Profile during Thermal Bleaching
Larval Melanism and Thermoregulation in White-lined Sphinx Moth (Hyles lineata)
Dr. Goggy Davidowitz, Entomology
Category: Emerging
Hyles lineata larvae vary in how melanized (dark) they are. In this species, melanism is plastic in response to certain environmental conditions experienced during development. This project aimed to determine if the functional consequence of this variation could be explained by the thermal melanin hypothesis, which states ectothermic animals that are more melanized will be more efficient thermoregulators. Based on this hypothesis, we predicted when exposed to a radiant heat source, more melanized caterpillars would have a faster heating rate, and would grow and develop more quickly. These predictions were tested using a thermal imaging camera to record change in body temperature over a period of time, and comparing this heating rate among individuals of varying percent melanin. We also measured growth and development of caterpillars of different melanin levels in their final larval stage. Contrary to the thermal melanin hypothesis, thermoregulatory ability was influenced by weight, but not by percent melanin. There was no relationship between growth rate or development time and percent melanin. However, individuals that had an intermediate percent of melanin had a higher maximum larval weight and a higher pupal weight. This suggests that there is an optimal degree of melanism in terms of body size, but the adaptive function of melanism remains to be explained in this species.
Larval Melanism and Thermoregulation in White-lined Sphinx Moth (Hyles lineata)
Predator, prey, and a plant: Do carpenter bees (Xylocopa californica) position their nests within sotol (Dasylirion wheeleri) leaf rosettes to maximize protection from woodpeckers?
Dr. Judith Bronstein, Ecology & Evolutionary Biology
Category: Advanced
Native bees face a range of environmental pressures that drive evolution of adaptive behaviors, including interactions with predators. We examined a predator-prey interaction between developing carpenter bees and their woodpecker predators. In southeastern Arizona, carpenter bees (Xylocopa californica) build their nests in the dried inflorescence stalks (1.5 – 5m) of plants in the family Asparagaceae, including sotol (Dasylirion wheeleri), Agave, and Yucca (Gerling etal., 1989). Woodpeckers prey upon carpenter bee larvae developing inside the stalks. Sotol has a dense rosette of barbed leaves at the base of the stalk. We asked whether these leaves protect carpenter bee larvae from woodpeckers, and whether predators bypass carpenter bee nests built within sotol leaf rosettes. We hypothesized that nests surrounded by the leaf rosette would be more difficult for bird predators to reach, and therefore would exhibit less evidence of predation. To test this hypothesis, we recorded carpenter bee nest entrance height, the locations of bird predation marks, and the height of the tallest point of each leaf rosette, of sotol stalks containing nests. Carpenter bee entrance holes were observed most often within the basal rosette of sotol leaves rather than above it (X-squared = 127.04, df = 1, p-value < 2.2e-16). The peck marks were also observed significantly more often within rather than above the height of the leaves (X-squared = 74.691, df = 1, p-value < 2.2e-16). This could be due to birds pecking where nests are present. Indeed, a disproportionate 16.04% of peck marks were centered within 10 cm of the maximum leaf height, a region constituting only 5.35% of the range of peck heights. The median carpenter bee nest entrance is 3.49 cm deeper within sotol rosette height than is the median peck, indicating that carpenter bees commonly place nests lower on stalks than woodpeckers peck. When we compared the heights of nest entrances that were pecked to those that escaped predation, we found that the two distributions were significantly different (Mann-Whitney U Test, W = 3294, p <0.00581). Bees’ nest placement choices may be driven by the risk of woodpecker predation.
Testing for Changes in Plant-soil Feedbacks with the Soil Microbial Community During a Plant Invasion
Dr. Katrina Dlugosch, Ecology & Evolutionary Biology
Category: Advanced
Microbial communities associated with plants are responsible for disease but also enhancing plant nutrient uptake as well as defense against other pathogens. Interactions with microbes could determine the success of invading plant species. Yellow starthistle (Centaurea solstitialis; ‘YST’) is a plant native to Eurasia, but introduced and invasive in other locations such as California. The purpose of this study was to analyze the plant-soil feedbacks (PSF) between YST and its microbes by comparing soil microbial communities from inside vs. outside of YST patches. We predicted that PSF interactions would be stronger in the native range due to the buildup of native pathogens on YST, such that microbial communities would be more different inside and outside of YST patches in the native range. Soil samples were collected from the invaded range, California in the United states, and in the native range in western Europe, Spain and France. DNA from the v4 region of the 16S rDNA was amplified for identification of bacteria in the microbial community of both ranges. Sequencing of the DNA showed variation present between microbial communities inside vs. outside of YST patches at three different sites.
B2 Ocean, Coral, and Microbial Ecology
Dr. Jeremiah Hackett, Ecology & Evolutionary Biology
Category: Emerging
This semester our work entailed characterizing the microbial community in the B2 ocean before the introduction of corals in order to examine how coral influences microbial community structure, and identifying which organisms fill functional roles in the B2 ocean and how that compares to natural ecosystems. Due to COVID restrictions, we were unable to obtain such data in time for the poster fair, instead the poster describes some predictions and highlights DMS-DMSP cycling in marine ecosystems, which likely plays an important role in coral-microbial interactions.
What Regulates Cell Growth and Homeostasis in Proliferating Animal Cells?
Dr. Alex Badyaev, Ecology & Evolutionary Biology
Category: Advanced
Cells vary widely in size, type, and characteristics throughout organisms. However, cell sizes within tissues remain extremely similar across almost all tissue types. The mechanisms by which cells maintain homeostatic cell sizes remains poorly understood. Many factors may play a role in regulating cell size throughout tissues. Using a wide array of samples from house finch embryos, we are able to analyze the possible contributors to cell size homeostasis across development and genetically unique populations. Here, I will present the framework for analyzing these complex systems and describe work being performed in the near future to better understand this important process.
What Regulates Cell Growth and Homeostasis in Proliferating Animal Cells?
Microbial Symbionts of an Invasive Grass Differ Between Natural and Urban Environments
Dr. A. Elizabeth Arnold, School of Plant Sciences
Category: Advanced
Buffelgrass (Cenchrus ciliaris) is a widespread, invasive plant in the Sonoran Desert. It establishes readily, weathers drought, alters fire regimes, and is costly and labor-intensive to eradicate. Investigating microbial symbionts of buffelgrass may identify factors that promote its establishment and spread. We examined fungal microbiomes associated with buffelgrass in urban areas (alleyways with poor soil and limited plant cover) and ex-urban areas (sites with natural soil and vegetation) in and near Tucson, AZ. We isolated fungal endophytes from healthy roots and shoots and characterized them via DNA barcoding. We found that endophytes of buffelgrass were more abundant in urban areas, but more diverse in ex-urban areas. Endophyte communities differed between urban and ex-urban sites. Our data suggest context-specific symbioses in which buffelgrass recruits distinctive microbiomes under different environmental conditions. In future research, we will identify plant-microbe interactions that influence the fitness, germination, and stress tolerance of buffelgrass as an invasive plant.
Microbial Symbionts of an Invasive Grass Differ Between Natural and Urban Environments
How Placement of Carpenter Bee (Xylocopa californica) Larvae in Sotol (Dasylirion wheeleri) Nests Reflects Reproductive Strategies
Dr. Judith Bronstein, Ecology & Evolutionary Biology
Category: Emerging
Xylocopa californica (carpenter bees) are a species in southern Arizona that creates nests in the dead stalks of Dasylirion wheeleri (sotol plants). Specific behaviors when larvae are laid in these nests may reflect possible strategies to help survival of offspring. Direction of placement in the nests either upward or downward from the entrance hole was studied to see if a greater amount of initial offspring were placed in a specific direction. We analyzed 17 nests that fit the proper criteria and determined that we could not reject that placement of larvae was indifferent in terms of more larvae upwards or downwards in nests. There were 10 nests of the 17 with offspring placed upward first and with a greater sample size this trend may have had statistical significance. Factors such as increased predation or fluctuations in external temperature may be driving bee behavior and how they place their first larvae. Further analysis into carpenter bee behavior while placing larvae is presented in this poster.
Does mammalian disturbance of biological soil crusts threaten an endangered cactus, Echinocactus horizonthalonius var. nicholii?
Dr. A. Elizabeth Arnold, School of Plant Sciences
Category: Advanced
Echinocactus horizonthalonius var. nicholii (ECHO) is a rare, threatened cactus endemic to the Sonoran Desert. In the Waterman Mountains in southeastern Arizona, ECHO abundance has declined drastically since 1995. The decline corresponds to an increase in the local abundance of desert bighorn sheep (Ovis canadensis) after establishment of a water tank in the area in 2007. In this area, well-developed biological soil crusts often are observed in proximity to ECHO. Crusts provide ecosystem services related to vascular plant survival and are useful indicators of disturbance, as they are sensitive to trampling by mammals such as sheep. We evaluated whether ECHO are threatened due to damage of biological soil crusts by sheep. We measured biocrust coverage around ECHO individuals in six long-term study plots, and in adjacent plots without known ECHO occurrence. We quantified pawing and scat near focal individuals and across plots as a whole and recorded the number of flowers produced by each individual over the growing season. Biocrusts were more common and robust in areas ECHO occurs relative to adjacent areas without ECHO. Sheep were detected only in upland plots where ECHO numbers have declined most dramatically, but in these areas crusts were similarly robust relative to lowland plots without sheep. We suspect that direct damage by bighorn sheep via herbivory poses a greater threat to ECHO than indirect impacts caused by disturbing biocrusts. However, crusts may be important to the establishment and growth of this rare cactus when sheep are not highly abundant.
Bumblebee Multimodal Learning in a Pollen-Foraging Context
Dr. Daniel Papaj, Ecology & Evolutionary Biology
Category: Emerging
Bees collect both nectar and pollen to raise the young and support their colony. When foraging, bees are capable of learning certain foraging cues and associating these cues with a reward. The majority of bee learning studies focus on nectar-foraging with nectar reward or sucrose substitute. Likewise, multimodal learning—learning via a combination of two or more modalities (visual, auditory, olfactory, etc)—has been intensively studied for ‘nectar foraging’. This project investigates the ability of Bombus impatiens (the Common Eastern Bumblebee) to learn foraging cues in multiple modalities for a pollen reward.
Parent Nutrient and Pollination Treatment Effects on Datura wrightii Seed Germination
Dr. Judith Bronstein, Ecology & Evolutionary Biology
Category: Emerging
Datura wrightii (Solanaceae) produces large and presumably costly white flowers that generate large amounts of nectar to attract the hawkmoth Manduca sexta (Bronstein et al. 2009). These large flowers open for a single night. Larger flowers in other systems attract more pollinators and have higher pollinator visitation rates (Majetic et al., 2017), though this has not yet been shown in this system. The main question of this study asks, “Are there costs to self-pollination in D. wrightii? Specifically, does it affect the germination rate of the seeds?” In this study we look at how pollination and parent plant nutrient treatment affect germination time of D. wrightii seeds. To test this, seeds obtained from outcrossed and self-pollinated flowers produced by plants grown in either high or low nutrient environments were examined. Seeds were planted haphazardly in fresh soil in flats in a greenhouse and were watered daily to keep the soil moist. Once a seed germinated, the number of days it took to germinate was recorded. The days to germination was analyzed using a linear model with parent nutrient treatment, pollination treatment, and plant ID as factors. The results from an ANOVA test show that nutrient treatment (p=0.7029), pollination treatment (p=0.4415), nor plant ID (p=0.3859) affected how quickly the seeds germinated. The results showed that cross-pollination versus self-pollination has no effect on how fast the seeds germinated, so why would D. wrightii produce such large and costly flowers if there is no advantage in cross-pollination?
Parent Nutrient and Pollination Treatment Effects on Datura wrightii Seed Germination
Synesthesia and Creativity: An Analysis of Human Perception
Dr. Jessica Andrews-Hanna, Psychology
Category: Advanced
Synesthesia is a neurological condition in which the stimulation of one sensory or cognitive pathway leads to the automatic stimulation of a second pathway. Synesthesia can create a new form of perception that heightens the senses. One hypothesis that has received empirical support is that synesthesia enhances creativity, likely attributed to heightened mental images. Due to the barriers of COVID-19, we focused our efforts on re-analyzing an existing data set. In this Think Aloud Task, participants voiced aloud their thoughts under two conditions: an unprompted condition meant to capture spontaneous thought and one answering a creativity prompt. Following both tasks, participants self-rated their mental imagery and raters provided each with an overall creativity score. Importantly, one participant in the study is synesthetic and was analyzed as a case study. We found that participants’ visual imagery scores were predictive of overall creativity when prompted to think creatively. However there appeared to be no correlation between visual imagery and creativity with spontaneous thought. The synesthetic participant had heightened levels of mental imagery for both spontaneous and creative thinking, as well as one of the highest creativity scores. The overall results suggest that creative individuals may not habitually use mental imagery, while the synesthetic participant case study utilized high levels of mental imagery across both tasks. Overall, in understanding the inner workings of synesthesia and its link to creativity, we can broaden our understanding of human perception.
Effective Population Size (Ne) of Meda fulgida: Genome Sequencing & Depletion Sampling
Dr. Peter Reinthal, Ecology & Evolutionary Biology
Category: Emerging
Population estimates are valuable components in determining conservation and management practices. However, such estimates are difficult to establish, and using genome sequencing, effective population sizes (Ne) of the endangered fish species, Meda fulgida (spikedace) in the last natural Arizona population in Aravaipa Creek can be determined. In this study, we attempt to determine census population sizes based on three pass depletion and compare them to Ne estimates. Such data is essential for the management and conservation of the species, but also allows us to examine the importance of genetic drift and selection in fragmented populations.
Effective Population Size (Ne) of Meda fulgida: Genome Sequencing & Depletion Sampling
Urbanization and Leafcutter Bee Nesting Success
Dr. Daniel Papaj, Ecology & Evolutionary Biology
Extreme drought in the Tucson area reduces floral resources in naturalized areas much more than in residential areas with irrigation. Cities may thus act as a refuge for native bee species during times of drought. This study aims to investigate the two possibly contrasting effects of impervious surface coverage and vegetation density in order to address how urbanization influences megachilid bee nesting success. These potentially contrasting effects have generated 2 competing hypotheses; (1) High levels of impervious cover in the urbanized areas will reduce bee abundance and diversity, compared to naturalized areas, and (2) High levels of floral abundance and diversity in urbanized areas will increase bee abundance and diversity, compared to naturalized areas. To evaluate these hypotheses, megachilid bee abundance and diversity will be estimated using wooden nest boxes installed in urbanized and naturalized sites. GIS will be used to measure each site's impervious coverage percentage and vegetation density. Nest boxes from each site will then be visually inspected for occupancy in order to assess abundance, and samples of emerging adults will be collected and identified in order to assess diversity. Both abundance and diversity of megachilid nests will be compared between urban and naturalized sites.
Honeybees Amplify Threats Against Native Bees
Dr. Daniel Papaj, Ecology & Evolutionary Biology
Category: Advanced
Both native bee species and managed honeybees are being threatened by overlapping causes such as changes to their environments and habitats, as well as increased usage of pesticides and other stressors. The increase in honeybee transport for agricultural pollination has been causing an increase in honeybee death due to a combination of factors that ultimately lead to CCD. The U.S. Fish & Wildlife service shows eight species of native bees listed as endangered, including the rusty patched bumble bee, Bombus affinis, and seven yellow faced bee species, Hylaeus sp. However, native bees may face additional harm from the presence of honeybees as well, even to the point of extinction. Conflict can arise when trying to protect both native species and honeybees due to the additional threats that honeybees, both managed and feral, can pose. This review summarizes the threats to bee populations, how honeybees amplify these threats towards native species, and why native bee species are critical to protect. In order to better manage all threats, there needs to be reform in agricultural practices towards protecting and supporting the pollinators that crops rely on, as well as analysis of the consequences of different protection efforts. This review also demonstrates the importance of critical analysis of protection efforts due to the possibility of further harm to native bee populations.
How do Ants Care for the Next Generation? Colony Personality in Brood Care.
Dr. Anna Dornhaus, Ecology & Evolutionary Biology
Category: Advanced
Personality is an inherent part of organism phenotype and is acted upon by evolutionary selection where there are differences in individual organism fitness strategies. In social insects, where colony acts as the unit of evolutionary selection, the colony group itself acts as the individual and personality becomes a function of the group level. We study the possibility of parental care investment displayed as a personality trait in colonies of Temnothorax rugatulus. By observing changes in the ratio of nurses to brood before and after adding additional brood to each colony we found that colonies differ in approach to brood care with variation in the nurse to brood ratios, however variation is not consistent within colonies. Our data suggests that nurse to brood ratios are driven by factors other than an inherent colony personality and while there may be a positive trend between nurses and brood number, low sample size prevents an accurate analysis. Studying colony personality in social insects enables a better understanding of how evolutionary selection acts on colony units where individual member response is a key factor in colony fitness.
How do Ants Care for the Next Generation? Colony Personality in Brood Care.
Manipulation of the Gut Microbiome with Oligofructose to Ameliorate Menopause-related Metabolic Pathologies
Dr. John Konhilas, Physiology
Category: Advanced
Menopause, the cessation of estrogen production from ovaries, affects all women. Typically, women will spend 40% of their life in menopause. During menopause, women are more likely to suffer from several inflammatory pathologies such as obesity, inflammation, increased risk for cardiovascular disease (CVD), and hypertension. We hypothesize that OFS treatment will reverse obesity in menopausal mice and improve glucose tolerance. Within this study, we aim to elucidate metabolic phenotypes in 4-vinylcyclohexene diepoxide (VCD)-induced menopausal C57Bl/6J mice fed a 45% high fat diet (HFD) , and determine the ability of Oligofructose (OFS) to manipulate the gut microbiome to reverse menopause-related metabolic pathologies including obesity and glucose regulation. To address these aims, VCD was delivered via intraperitoneal injections for 20 days following 8 days post HFD to induce menopause through triggering primary and primordial ovarian follicles atrophy. We used OFS, a prebiotic insoluble fiber subunit of Inulin, to manipulate the gut microbiome to mitigate menopause-associated metabolic pathologies. OFS was introduced to the HFD food available ad libitum for 3 weeks after 40 days post VCD injection. We observed that menopausal mice had an increase in AUC of weight gain, and OFS treatment reversed the AUC weight gain compared to pre-menopausal mice fed OFS+ HFD and control pre-menopausal mice fed only HFD.