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  1. Predator–prey interactions are a key feature of ecosystems and often chemically mediated, whereby individuals detect molecules in their environment that inform whether they should attack or defend. These molecules are largely unidentified, and their discovery is important for determining their ecological role in complex trophic systems. Homarine and trigonelline are two previously identified blue crab (Callinectes sapidus) urinary metabolites that cause mud crabs (Panopeus herbstii) to seek refuge, but it was unknown whether these molecules influence other species within this oyster reef system. In the current study, homarine, trigonelline, and blue crab urine were tested on juvenile oysters (Crassostrea virginica) to ascertain if the same molecules known to alter mud crab behavior also affect juvenile oyster morphology, thus mediating interactions between a generalist predator, a mesopredator, and a basal prey species. Oyster juveniles strengthened their shells in response to blue crab urine and when exposed to homarine and trigonelline in combination, especially at higher concentrations. This study builds upon previous work to pinpoint specific molecules from a generalist predator’s urine that induce defensive responses in two marine prey from different taxa and trophic levels, supporting the hypothesis that common fear molecules exist in ecological systems. 
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    Free, publicly-accessible full text available August 1, 2024
  2. Abstract

    The capacity of an apex predator to produce nonconsumptive effects (NCEs) in multiple prey trophic levels can create considerable complexity in nonconsumptive cascading interactions, but these effects are poorly studied. We examined such effects in a model food web where the apex predator (blue crabs) releases chemical cues in urine that affect both the intermediate consumer (mud crabs seek shelter) and the basal prey (oysters are induced to grow stronger shells). Shelter availability and predator presence were manipulated in a laboratory experiment to identify patterns in species interactions. Then, experimentally induced and uninduced oysters were planted across high‐quality and low‐quality habitats with varying levels of shelter availability and habitat heterogeneity to determine the consistency of these patterns in the field. Oyster shell thickening in response to blue crab chemical cues generally protected oysters from mud crab predation in both the laboratory and in field environments that differed in predation intensity, structural complexity, habitat heterogeneity, and predator composition. However, NCEs on the intermediate predator (greater use of refugia) opposed the NCEs on oyster prey in the interior of oyster reefs while still providing survival advantages to basal prey on reef edges and bare substrates. Thus, the combined effects of changing movement patterns of intermediate predators and morphological defenses of basal prey create complex, but predictable, patterns of NCEs across landscapes and ecotones that vary in structural complexity. Generalist predators that feed on multiple trophic levels are ubiquitous, and their potential effects on NCEs propagating simultaneously to different trophic levels must be quantified to understand the role of NCEs in food webs.

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  3. This innovative practice work in progress paper presents the Biologically Inspired Design for Engineering Education (BTRDEE) project, to create socially relevant, accessible, highly-contextualized biologically inspired design experiences that can be disseminated to high school audiences engineering audiences in Georgia and nationally. Curriculum units arc 6-10 weeks in duration and will meet many standards for high school engineering courses in Georgia. There will be three curriculum units (one for each engineering course in the 3-course pathway), each building skills in engineering design and specific skills for BID. Currently in its second year, BIRDEE has developed its first unit of curriculum and has hosted its first professional development with 4 pilot teachers in the summer of 2020. The BIRDEE curriculum situates challenges within socially relevant contexts and provides cutting-edge biological scenarios to ignite creative and humanistic engineering experiences to 1) drive greaterengagement in engineering, particularly among women, 2) improve student engineering skills, especially problem definition and ideation skills, and 3) increase students awareness of the connection and impacts between the engineered and living worlds. This paper describes the motivation for the BIRDEE project, the learning goals for the curriculum, and a description of the first unit. We provide reflections and feedback from teacher work and focus groups during our summer professional development and highlight the challenges associated with building BID competency across biology and engineering to equip teachers with the skills they need to teach the BIRDEE units. These lessons can be applied to teaching BID more broadly, as its multidisciplinary nature creates challenges (and opportunities) for teaching and learning engineering design. 
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  4. This innovative practice work in progress paper presents Biologically inspired design (BID) to transfer design principles identified in nature to human-centered design problems. The Biologically Inspired Design for Engineering Education (BIRDEE) program uses biologically inspired design to teach high school engineering in a way that uniquely engages students in the natural world. For high school students, identifying natural systems’ analogues for human design problems can be challenging. Furthermore, it is often the case that students focus on and transfer superficial structures, rather than underlying design principles. Based on the Structure-Behavior-Function (SBF) design ontology, we developed a modified cognitive scaffold called Structure- Function-Mechanism (SFM) to assist students and teachers with identifying functionally similar biological analogies and identifying and transferring design principles. In this paper we describe SFM and its importance in BID and our observations from teaching SFM to high school teachers during a multi-week professional development workshop in the summer of 2020. Based on teachers’ work artifacts, transcriptions of discussions, and focus groups, we highlight the challenges of teaching SFM and our plans to scaffold this important concept for students and teachers alike. 
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  5. Biologically inspired design has become increasingly common in graduate and undergraduate engineering programs, consistent with an expanding emphasis by professional engineering societies on cross-disciplinary critical thinking skills and adaptive and sustainable design. However, bio-inspired engineering is less common in K-12 education. In 2019, the NSF funded a K-12 project entitled Biologically Inspired Design for Engineering Education (BIRDEE), to create socially relevant, accessible, and highly contextualized high school engineering curricula focusing on bio-inspired design. Studies have shown that women and underrepresented minorities are drawn to curricula, courses, and instructional strategies that are integrated, emphasize systems thinking, and facilitate connection building across courses or disciplines. The BIRDEE project also seeks to interest high school girls in engineering by providing curricula that incorporate humanistic, bio-inspired engineering with a focus on sustainable and authentic design contexts. BIRDEE curricula integrate bio-inspired design into the engineering design process by leveraging design tools that facilitate the application of biological concepts to design challenges. This provides a conceptual framework enabling students to systematically define a design problem, resulting in better, more well-rounded problem specifications. The professional development (PD) for the participating teachers include six-week-long summer internships in university research laboratories focused on biology and bio-inspired design. The goal of these internships is to improve engineering teachers’ knowledge of bio-inspired design by partnering with cutting-edge engineers and scientists to study animal features and behaviors and their applications to engineering design. However, due to COVID-19 and research lab closures in the summer of 2020, the research team had to transfer the summer PD experience to an online setting. An asynchronous, quasi-facilitated online course was developed and delivered to teachers over six weeks. In this paper, we will discuss online pedagogical approaches to experiential learning, teaching bio-inspired design concepts, and the integration of these approaches in the engineering design process. Central to the online PD design and function of each course was the use of inquiry, experiential and highly-collaborative learning strategies. Preliminary results show that teachers appreciated the aspects of the summer PD that included exploration, such as during the “Found Object” activity, and the process of building a prototype. These activities represented experiential learning opportunities where teachers were able to learn by doing. It was noted throughout the focus group discussions that such opportunities were appreciated by participating teachers. Teachers indicated that the experiential learning components of the PD allowed them to do something outside of their comfort zone, inspired them to do research that they would not have done outside of this experience, and allowed them to “be in the student's seat and get hands-on application”. By participating in these experiential learning opportunities, teachers were also able to better understand how the BIRDEE curriculum may impact students’ learning in their classrooms 
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  6. Abstract

    Predators affect community structure by influencing prey density and traits, but the importance of these effects often is difficult to predict. We measured the strength of blue crab predator effects on mud crab prey consumption of juvenile oysters across a flow gradient that inflicts both physical and sensory stress to determine how the relative importance of top predator density‐mediated indirect effects (DMIEs) and trait‐mediated indirect effects (TMIEs) change within systems. Overall, TMIEs dominated in relatively benign flow conditions where blue crab predator cues increased oyster survivorship by reducing mud crab–oyster consumption. Blue crab DMIEs became more important in high sensory stress conditions, which impaired mud crab perception of blue crab chemical cues. At high physical stress, the environment benefitted oyster survival by physically constraining mud crabs. Thus, factors that structure communities may be predicted based on an understanding of how physical and sensory performances change across environmental stress gradients.

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  7. Abstract

    Sustainability of urban areas is paramount in the coming years as cities continue to grow in population and resource consumption. A number of methods to model cities have been developed, including material flow analysis and urban metabolism, but these accounting methods do not fully analyze the complex network dynamics present within cities. Ecological network analysis (ENA) provides a new perspective into these urban areas by using metrics designed for analysis of natural ecosystems. This study analyzes 29 urban–industrial ecosystems using ENA, comparing the networks to each other as well as comparing them to previously analyzed eco‐industrial parks and natural food webs. It is found that these systems perform similar to other human‐designed systems, which consistently lack in ecological performance when compared with the natural ecosystems. Additionally, the impact of specific actor types within these networks is shown indicating the importance of industry, agriculture, and the natural environment. Finally, the types of networks are determined to affect the ecological metrics, with the more linear‐based energy networks having the worst performance. This new dataset of ecologically analyzed networks provides a deeper understanding of urban networks and their infrastructure, while providing useful information on how to potentially improve their sustainability.

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