Effects of warming and drying on the survival and performance of giant salmonfly nymphs (Pteronarcys californica)

Rising temperatures and anthropogenic influences threaten to alter aquatic ecosystems as oxygen supply and demand is altered depending on temperature, flow, and water presence. In late November of 2021, a dam malfunction occurred on the Madison River in Montana that caused the river to dry rapidly downstream of the dam and reduced flow by 70% for 50 hours. My experiments were designed to determine the effects of this event by assessing how long giant salmonfly nymphs (Pteronarcys californica) can survive in still water and in air depending on temperature and relative humidity. In the laboratory, we exposed salmonfly nymphs to four temperatures (5, 12.5, 20, and 25 ℃) in still water. We measured survival, feeding, and growth, as well as time spent performing ‘push-ups’ – a common respiratory movement that ventilates gills and increases oxygen supply rates. My study demonstrates that increases in temperature significantly increase the rate of pushups performed and decrease the survival of salmonfly nymphs. Next, we exposed nymphs to air – representing extreme dewatering – at five temperatures (5, 12.5, 20, 25, and 35 ℃) and two relative humidities (75% and 100%) to measure their survival. Survival times declined at higher temperatures, particularly in lower humidity, with an average survival of less than a day. Notably, the most significant factor influencing salmonfly survival was the type of medium they were in, as most of the nymphs in still water were able to survive the duration of the two weeks, while all the nymphs in air died

Bear Smart UM: Creating a University Campus Safe for Bears and Students

Universities nestled in the mountains across the globe like the University of Montana may find themselves dealing with human-bear conflict while lacking the proper resources to approach management. At UM, there has been an increase in bear activity over the past five years and it is expected to increase. Developing a plan to prevent bear activity on campus can be costly, time-consuming, and tedious. Our student group’s solution includes two intertwining parts: A bear management plan and educational outreach surrounding bear safety. The recommendations in the bear management plan were created by consulting bear-conflict specialists from Missoula County, craftspeople who construct bear-proof enclosures, and hotspots for bear activity gathered by the UM Chapter of the Wildlife Society. The bear management plan includes recommendations related to waste management for different locations on campus, fruit trees and native plants that are bear attractants, and a corresponding budget. The educational outreach has involved creating informational PowerPoints and flyers and presenting them to classes at UM to educate students about bear-safe behavior and to encourage students to attend our bear spray safety demonstration by the Bear Aware Campaign on April 4, 2023. Both parts of our project are essential in providing useful solutions for UM as we move into yet another bear season and seek to reduce bear-human conflict

Bear Smart UM: Creating a University Campus Safe for Bears and Students

Bear Smart UM: Creating a University Campus Safe for Bears and Students Biological Sciences Universities nestled in the mountains across the globe like the University of Montana may find themselves dealing with human-bear conflict while lacking the proper resources to approach management. At UM, there has been an increase in bear activity over the past five years and it is expected to continue to increase. Developing a plan to prevent bear activity on campus is often costly, time-consuming, and tedious. Our student group’s solution includes two intertwining parts: A bear management plan and educational outreach surrounding bear safety. The recommendations in the bear management plan were created by consulting bear-conflict specialists from Missoula County, craftspeople who construct bear-proof enclosures, and hotspots for bear activity gathered by the UM Chapter of the Wildlife Society. The bear management plan includes recommendations related to waste management for different locations on campus, fruit trees and native plants that are bear attractants, and a corresponding budget. The educational outreach has involved creating informational PowerPoints and flyers and presenting them to classes at UM to educate students about bear-safe behavior and to encourage students to attend our bear spray safety demonstration by the Bear Aware Campaign on April 4, 2023. Both parts of our project are essential in providing solutions for the intriguing relationship UM has with bears and preventing any further conflict that can harm the UM community and the bear population

Nonuniform Cardiac Denervation Observed by 11C-meta-Hydroxyephedrine PET in 6-OHDA-Treated Monkeys

Parkinson's disease presents nonmotor complications such as autonomic dysfunction that do not respond to traditional anti-parkinsonian therapies. The lack of established preclinical monkey models of Parkinson's disease with cardiac dysfunction hampers development and testing of new treatments to alleviate or prevent this feature. This study aimed to assess the feasibility of developing a model of cardiac dysautonomia in nonhuman primates and preclinical evaluations tools. Five rhesus monkeys received intravenous injections of 6-hydroxydopamine (total dose: 50 mg/kg). The animals were evaluated before and after with a battery of tests, including positron emission tomography with the norepinephrine analog 11C-meta-hydroxyephedrine. Imaging 1 week after neurotoxin treatment revealed nearly complete loss of specific radioligand uptake. Partial progressive recovery of cardiac uptake found between 1 and 10 weeks remained stable between 10 and 14 weeks. In all five animals, examination of the pattern of uptake (using Logan plot analysis to create distribution volume maps) revealed a persistent region-specific significant loss in the inferior wall of the left ventricle at 10 (P<0.001) and 14 weeks (P<0.01) relative to the anterior wall. Blood levels of dopamine, norepinephrine (P<0.05), epinephrine, and 3,4-dihydroxyphenylacetic acid (P<0.01) were notably decreased after 6-hydroxydopamine at all time points. These results demonstrate that systemic injection of 6-hydroxydopamine in nonhuman primates creates a nonuniform but reproducible pattern of cardiac denervation as well as a persistent loss of circulating catecholamines, supporting the use of this method to further develop a monkey model of cardiac dysautonomia

Effects of warming and drying on the survival and performance of giant salmonfly nymphs (Pteronarcys californica)

This study examines how warming and drying affect the performance and survival of giant salmonfly nymphs (Pteronarcys californica), which are important economically, ecologically, and culturally throughout the mountain west. My experiments were motivated by a dam malfunction that occurred in late November 2021 on the Madison River in Montana that caused the river to dry rapidly downstream of the dam and reduced flow by 70% for 50 hours. The effects of such events on aquatic insects are unknown, and my experiments were designed to assess how long salmonfly nymphs could survive in still water as well as in air depending on temperature and relative humidity. For the first portion of my study, I exposed salmonfly nymphs in the laboratory to four temperatures (5, 12.5, 20, and 25 ℃) in still water. I then measured survival, feeding, and growth, as well as a behavior called ‘push-ups’ – a stereotypic respiratory movement that ventilates gills and increases oxygen supply rates. My study demonstrates that temperature has a significant effect on the rate of pushups performed and the survival of salmonfly nymphs. The results for feeding and growth were not significant. In the second part of my study, I exposed nymphs to dry conditions – representing extreme dewatering – at five temperatures (5, 12.5, 20, and 25 ℃) and two relative humidities (75% and 100%) and measured how long they survived. Temperature and humidity influenced survival; survival times declined at higher temperatures and were especially short in the lower humidity. Regardless no salmonfly survived outside of water longer than four days at either humidity. However, the most significant factor influencing salmonfly survival was the type of medium they were in, as most of the nymphs in still water were able to survive the duration of the two weeks, while all of the nymphs in air died

Systolic and diastolic blood pressure measurements during 6-OHDA administration.

<p>Blood pressure results from a representative animal (RH2318). A, Both pressures increase immediately after each 6-OHDA dosing (arrows). B, Change in systolic and diastolic blood pressure from peak of pressure following 6-OHDA until levels normalized at which time the next injection of 6-OHDA was administered. The amount of time to normalize paralleled the change in blood pressure. At the accumulated dose of 2.0 mg/kg, this animal required 61 minutes to regulate blood pressure. bp, blood pressure.</p

Distribution volume maps before and after systemic 6-OHDA dosing.

<p>Maps express regional capacity of the tissue for MHED uptake relative to whole blood, thus providing a measure of the density of nerve terminals. Each individual map consists of 8 sectors and 7 rings (apex of the heart at the center, base of the LV at the edge), totaling to 56 blocks of data per timepoint. MHED uptake significantly decreased at each timepoint after 6-OHDA compared to baseline (<i>P</i><0.001). Scales (mL whole blood/g tissue) are similar between animals and identical across time points for each individual. The compass rose indicates regions: A, anterior; S, septal; I, inferior; L, lateral.</p

Circulating plasma catecholamine levels (pg/mL) at baseline (0) and at 1, 4, 10, and 14 weeks after 6-OHDA in three animals.

<p>The values in parentheses are the natural logarithms of the concentration values and used to graph correlations in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035371#pone-0035371-g005" target="_blank">Figure 5</a>. For statistical analysis, non-detectable levels (nd) levels were considered as the lowest detection level with 1.5 pg/mL for norepinephrine and 3.0 pg/mL for epinephrine. Post hoc analysis with Bonferroni multiple comparisons detected significance at all timepoints compared to baseline for norepinephrine and DOPAC (*<i>P</i><0.05, ** <i>P</i><0.01).</p

Electrocardiogram (ECG) measurements at baseline, 1, 4, 10 and 14 weeks after 6-OHDA for each animal.

<p>QTc was calculated using the Bazett's formula as QT interval/sqrt (RR interval), where the RR interval was calculated 60/HR. ΔQTc was calculated as QTc of each time point minus baseline. No significant differences were found in PR, QRS and QTc intervals obtained in anesthetized animals. HR, heart rate. QTc, corrected QT interval.</p

Echocardiogram measurements at baseline, 10 and 14 weeks after 6-OHDA for each animal.

<p>FS is calculated as [(LVD_d – LVD_s)/LVD_d]×100. Three animals experienced large decreases in FS compared to baseline, but there was no significant change in left ventricle diameter or in anterior and posterior wall thickness. This suggests that the increased luminal dimensions of the left ventricle were not due to the loss of cardiac muscle. AWd, anterior wall thickness in diastole. AWs, anterior wall thickness in systole. PWd, posterior wall thickness in diastole. PWs, posterior wall thickness in systole. LVD_d, left ventricle diameter in diastole. LVD_s, left ventricle diameter in systole. FS, fractional shortening.</p