Re-examination of the Effects of Food Abundance on Jaw Plasticity in Purple Sea Urchins

Morphological plasticity is a critical mechanism that animals use to cope with variations in resource availability. During periods of food scarcity, sea urchins demonstrate an increase in jaw length relative to test diameter. This trait is thought to be reversible and adaptive by yielding an increase in feeding efficiency. We directly test the hypotheses that (1) there are reversible shifts in jaw length to test diameter ratios with food abundance in individual urchins, and (2) these shifts alter feeding efficiency. Purple sea urchins, Strongylocentrotus purpuratus, were collected and placed in either high or low food treatments for 3 months, after which treatments were switched for two additional months between February and September, 2015 in La Jolla, CA (32.8674°N, 117.2530°W). Measurements of jaw length to test diameter ratios were significantly higher in low compared to high food urchins, but this was due to test growth in the high food treatments. Ratios of low food urchins did not change following a switch to high food conditions, indicating that this trait is not reversible within the time frame of this study. Relatively longer jaws were also not correlated with increased feeding efficiency. We argue that jaw length plasticity is not adaptive and is simply a consequence of exposure to high food availability, as both jaw and test growth halt when food is scarce

SNAPSHOT USA 2019 : a coordinated national camera trap survey of the United States

This article is protected by copyright. All rights reserved.With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August - 24 November of 2019). We sampled wildlife at 1509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the USA. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as well as future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.Publisher PDFPeer reviewe

Mammal responses to global changes in human activity vary by trophic group and landscape

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human–wildlife interactions along gradients of human influence.Peer reviewe

Morphology and stable isotope ecology of Pleuroncodes planipes adult life stages and their vulnerability to climate change stressors

Like many in Southern California during the 2015/16 El Niño event, I was struck by the presence of thousands of bright red tuna crabs (Pleuroncodes planipes) abundant at sea and washing ashore. Their sudden prevalence inspired me to learn more about these fascinating animals. Despite drawing so much attention, basic details related to their feeding behaviors and life history remain unknown. P. planipes have long been thought, but never confirmed, to experience a unique life history among crustaceans during which they undergo a sequential habitat shift from pelagic to benthic as adults. In this dissertation research, I applied contemporary methods of stable isotope ecology in combination with ecomorphology to examine aspects of their life history relevant to their pelagic and benthic life stages. We further assessed their vulnerability to the climate change stressors of ocean acidification and ocean warming through a long-term experiment. Through this work, we uncovered morphological differences and an ontogenetic diet shift between pelagic and benthic adult stages as well as significant impacts of temperature, but not pCO2/pH on molting and growth in pelagic adults. These results provide the first evidence in support of the hypothesis that P. planipes adult pelagic and benthic stages are distinct and yield important insight into how this transition could be impacted as the oceans continue to change

An Exploratory Study of Faculty Perspectives of the Challenges and Successes of Undergraduate International Students who are Learners of English as a Foreign Language

This paper reports on an exploratory research study conducted about faculty perspectives of the struggles international students who are learners of English as a foreign language encounter at a U.S. university and the factors leading to their success. Semi-structured interviews with faculty and advisors revealed linguistic, cultural, academic, social, and personal struggles. Factors of success identified mirrored student struggles. Faculty and advisors also reported on recommendations for additional support services for students and institutional changes that should be made

MacArthur Park

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Data from: Functional consequences of morphologically plastic jaws in juvenile purple sea urchins

Morphological plasticity is a critical mechanism that animals use to cope with variation in resource availability. During periods of food scarcity, sea urchins demonstrate an increase in jaw length relative to test diameter. This trait is thought to be reversible and adaptive by yielding an increase in feeding efficiency. We directly test the hypotheses that (1) there are reversible shifts in jaw length to test diameter ratios with food abundance in individual urchins, and (2) these shifts alter feeding efficiency. Purple sea urchins, Strongylocentrotus purpuratus, were placed in either high or low food treatments for 3 months, after which treatments were switched for 2 additional months. Measurements of jaw length to test diameter ratios were significantly higher in low compared to high food urchins, but this was due to test growth in the high food treatments. Ratios of low food urchins did not change following a switch to high food conditions, indicating that this trait is not reversible. Relatively longer jaws were also not correlated with increased feeding efficiency. We argue that jaw length plasticity is not adaptive and is simply a consequence of exposure to high food availability, as both jaw and test growth halt when food is scarce

Tracing copper-thiomolybdate complexes in a prospective treatment for Wilson's disease.

Wilson's disease is a human genetic disorder which results in copper accumulation in liver and brain. Treatments such as copper chelation therapy or dietary supplementation with zinc can ameliorate the effects of the disease, but if left untreated, it results in hepatitis, neurological complications, and death. Tetrathiomolybdate (TTM) is a promising new treatment for Wilson's disease which has been demonstrated both in an animal model and in clinical trials. X-ray absorption spectroscopy suggests that TTM acts as a novel copper chelator, forming a complex with accumulated copper in liver. We have used X-ray absorption spectroscopy and X-ray fluorescence imaging to trace the molecular form and distribution of the complex in liver and kidney of an animal model of human Wilson's disease. Our work allows new insights into metabolism of the metal complex in the diseased state