Tag: Poster 61

Variability Selection Hypothesis, Weed Macaques, and Body Size Variance

Presenter: Harry Sullivan

Mentors: Andrea Eller and Frances White, Biology

Poster: 61

Major: Biology 

Variability Selection Hypothesis (VSH) proposes that early Homo gained adaptive benefit from being flexible in novel or unpredictable climates. Increased intra-taxon variation in body size and the expansion of geographic ranges in early Homo populations suggests greater phenotypic and developmental plasticity. Similar levels of ecological flexibility have been documented in some species of macaques, earning them the moniker of “weed species”. We compare body size variance between weed and non-weed macaques to determine whether intrataxon variation in body size positively correlates with ecological flexibility, as proposed by the VSH. We used two sources of body size data for all available taxa: original data on postcranial osteological body size estimators (seven species, n=49), and published body masses for nineteen species. Fourteen osteometric body size estimators on the humerus, radius, ulna, femur, and tibia were included. All estimators show a tight correlation with body mass: R2 values range from 0.79 to 0.95 with a mean of 0.9. Variance per estimator per species was calculated, as proxies for body mass variance. Averaged estimator variances in non-weed species range from 1.71-11.34, but only 2.26-4.36 within weed species. This data analysis indicates that weed macaques do not exhibit more intrataxon body size variance than non-weeds. Macaques are under-utilized ecological referents for human evolution, and this genus’ diversity is informative for understanding the role of adaptive flexibility in primate evolution generally.

High Fat Diet In Utero Exposure Disrupts Circadian Rhythms in Mice Offspring

Presenter: Mai’ana Feuerborn

Faculty Mentor: Carrie McCurdy, Byron Hetrick

Presentation Type: Poster 61

Primary Research Area: Science

Major: Human Physiology

Funding Source: University of Oregon Undergraduate Mini-grant, $1,000

Maternal obesity and excessive gestational weight are linked to increased risk of obesity in offspring, suggesting that in utero exposure programs an organism’s metabolism for life. Studies in mice have shown exposure to a high calorie environment in utero causes more weight gain in offspring fed a high fat diet (HFD). Circadian rhythms create an internal temporal clock that coordinates behavior and metabolism to daily cycles. Disruption of circadian cycles leads to increased weight gain, suggesting that metabolic dysregulation observed in offspring of obese mothers may be due to altered circadian cycles. We hypothesized that offspring exposed to a high fat environment in utero will be more sensitive to postnatal HFD, with dampened circadian cycles, than mice exposed to a lean maternal environment in utero. To study the effect of diet on fetal programming, mice were subjected to either a HFD or control diet during gestation. Post weaning, the offspring were fed a HFD or control diet. Insulin controlled tissues were then collected at different times of the day. We propose to measure the effect of maternal diet on offspring by measuring the expression levels of key circadian genes by quantitative PCR. Understanding the role of fetal programming in metabolic regulation of metabolism will better help us understand and combat obesity in western society, and potentially understand the diseases increasing incidence.

Unprecedented Long-term Survival of Saline Lake Cyanobacteria and Algae in Hyper-saline, Highly Alkaline, Dark, Anoxic Muds

Presenter(s): Maisie Bailey – Biology

Faculty Mentor(s): Richard Castenholz

Poster 61

Research Area: Natural science

The survival of photosynthetic microorganisms buried in muds of a saline lake over several years of a saline lake has been observed. This phenomenon was quite unexpected and unprecedented. Lake Abert is a large, closed basin, soda lake in eastern Oregon. It normally has a pH of ~10, a salinity of about 30-50 ppt, and annual temperatures of 4-25°C. Under these conditions the predominant phototrophs in the water were several species of cyanobacteria, diatoms, green algae, and micro-invertebrates. During 2013-2016, the lake water had shrunk in area, drying out almost completely due to evaporation exceeding input. Salinity reached over 200 ppt, with most of the sodium carbonates precipitated, NaCl remaining as the predominant salt in solution. Photosynthetic microorganisms were no longer present visibly nor culturable from this water. However, the former shores were bounded by moist muds (~50% water by weight), hyper-saline (>200 ppt), anoxic, with pH>10. Samples taken from this mud were collected and incubated in light at 24°C in liquid nutrient medium at a salinity of 30 ppt. Various cyanobacteria and diatoms grew as enrichments and were isolated and purified in culture. These results occurred after mud samples had been kept in the dark for over 12 months at 12°C. All of the cyanobacteria in culture also survived desiccation. Gene sequences of selected survivors will be obtained to ascertain if these strains are genetically unique. Survival under these severe conditions is unprecedented and results may apply to limits of photosynthetic microorganisms in other extreme environments.

Resolving conflict between oak conservation and organic hazelnut production

Presenter(s): Calvin Penkauskas

Faculty Mentor(s): Lauren Hallett & Alejandro Brambila

Poster 61

 Session: Sciences

Filbertworm (Cydia laiferreana) is a polyphagous moth that burrows into acorns of Oregon white oak (Quercus garryana) and hazelnuts (Corylus spp.). Filbertworm source populations in remnant oak habitat can lead to cyclical infestation in neighboring hazelnut stands. This makes these remaining oak stands, which are mostly on private agricultural land, a potential liability to hazelnut production in Oregon – which accounts for over 90 percent of the US production. Oregon white oak habitat is one of the most reduced habitats in Oregon and is of conservational concern. I’m testing a novel way to mitigate hazelnut filbertworm infestation through pig grazing in oak woodland and organic hazelnut understories. Removal of infested nuts interrupts the developmental stage in the filbertworm life cycle. I hypothesize that controlled grazing will reduce filbertworm populations, nut infestation rates, and herbaceous cover. During Spring and Summer of 2018 I conducted baseline filbertworm inventories via pheromone-lured sticky traps in the canopy and ground-based emergence traps in oak woodland and organic hazelnut orchard on My Brothers Farm in Creswell, Oregon. Grazed and ungrazed plots were established in the woodland and orchard. Domestic pigs (Sus domesticus) were rotated through two-acre pastures in late September/early October with four to five days in each. Understory vegetation was sampled along transects in each plot and acorn density/infestation rates were inventoried before and after treatment. Preliminary results display a reduction of infested acorns in the oak woodland and no effect on understory vegetation. Ongoing filbertworm, acorn, and vegetation monitoring will continue through Fall of 2019.