Can We Quantify If It's a CURE?

Course-based undergraduate research experiences (CUREs) rapidly have become more common in biology laboratory courses. The effort to implement CUREs has stimulated attempts to differentiate CUREs from other types of laboratory teaching. The Laboratory Course Assessment Survey (LCAS) was developed to measure students' perceptions of how frequently they participate in activities related to iteration, discovery, broader relevance, and collaboration in their laboratory courses. The LCAS has been proposed as an instrument that can be used to define whether a laboratory course fits the criteria for a CURE or not. However, the threshold LCAS scores needed to define a course as a CURE are unclear. As a result, we examined variation in published LCAS scores among different laboratory course types. In addition, we examined the distribution of LCAS scores for students enrolled in our research-for-credit course. Overall, we found substantial variation in scores among CUREs and broad overlap among course types in scores related to all three scales measured by the LCAS. Furthermore, the mean LCAS scores for all course types fell within the main part of the distribution of scores for our mentored research students. These results suggest that the LCAS cannot be used to easily quantify whether a course is a CURE or not. We propose that the biology education community needs to move beyond trying to quantitatively identify whether a course is a CURE. Instead, we should use tools like the LCAS to investigate what students are actually doing in their laboratory courses and how those activities impact student outcomes.

Developmental Trajectories of Student Self-Perception over a Yearlong Introductory Biology Sequence.

Student self-perception is related to persistence in science. Yet how self-perception develops over time is less clear. We examined student self-perception trajectories and their relationship with gender, persons excluded due to ethnicity or race (PEER) status, and first-generation college student (FGCS) status across a yearlong introductory biology sequence. While we found similar rates of change in self-efficacy and science identity for all groups, females and PEER students had lower initial scores that failed to "catch up" to male and non-PEER scores by the end of the year. Students grouped into either high and stable or lower and decreasing trajectories for scientific community values, with first-generation college students overrepresented in the latter group. Additionally, we found no evidence for intersectionality of subgroups. We did find evidence that the relationship between gender and PEER status and science identity is likely mediated via self-efficacy. Taken together, our results suggest that introductory biology students develop self-efficacy and science identity at similar rates regardless of gender, PEER status, or FGCS status and that interventions targeting scientific community values for all students and self-efficacy of female and PEER students may be fruitful areas to pursue to increase persistence of students in the sciences and to reduce score differences between groups.

Assessment of Course-Based Research Modules Based on Faculty Research in Introductory Biology.

Calls for early exposure of all undergraduates to research have led to the increased use and study of course-based research experiences (CREs). CREs have been shown to increase measures of persistence in the sciences, such as science identity, scientific self-efficacy, project ownership, scientific community values, and networking. However, implementing CREs can be challenging and resource-intensive. These barriers may be partly mitigated by the use of short-term CRE modules rather than semester- or year-long projects. One study has shown that a CRE module captures some of the known benefits of CREs as measured by the Persistence in the Sciences (PITS) survey. Here, we used this same survey to assess outcomes for introductory biology students who completed a semester of modular CREs based on faculty research at an R1 university. The results indicated levels of self-efficacy, science community values, and science identity similar to those previously reported for students in the Science Education Alliance-Phage Hunters Advancing Genomics and Evolutionary Science (SEA-PHAGES) full-semester CRE. Scores for project ownership (content) were between previously reported traditional lab and CRE scores, while project ownership (emotion) and networking were similar to those of traditional labs. Our results suggest that modular CREs can lead to significant gains in student affect measures that have been linked to persistence in the sciences in other studies. Although gains were not as great in all measures as with a semester-long CRE, implementation of modular CREs may be more feasible and offers the added benefits of exposing students to diverse research fields and lab techniques.

Symbiont Genomic Features and Localization in the Bean Beetle Callosobruchus maculatus.

A pervasive pest of stored leguminous products, the bean beetle Callosobruchus maculatus (Coleoptera: Chrysomelidae) associates with a simple bacterial community during adulthood. Despite its economic importance, little is known about the compositional stability, heritability, localization, and metabolic potential of the bacterial symbionts of C. maculatus. In this study, we applied community profiling using 16S rRNA gene sequencing to reveal a highly conserved bacterial assembly shared between larvae and adults. Dominated by Firmicutes and Proteobacteria, this community is localized extracellularly along the epithelial lining of the bean beetle's digestive tract. Our analysis revealed that only one species, Staphylococcus gallinarum (phylum Firmicutes), is shared across all developmental stages. Isolation and whole-genome sequencing of S. gallinarum from the beetle gut yielded a circular chromosome (2.8 Mb) and one plasmid (45 kb). The strain encodes complete biosynthetic pathways for the production of B vitamins and amino acids, including tyrosine, which is increasingly recognized as an important symbiont-supplemented precursor for cuticle biosynthesis in beetles. A carbohydrate-active enzyme search revealed that the genome codes for a number of digestive enzymes, reflecting the nutritional ecology of C. maculatus. The ontogenic conservation of the gut microbiota in the bean beetle, featuring a "core" community composed of S. gallinarum, may be indicative of an adaptive role for the host. In clarifying symbiont localization and metabolic potential, we further our understanding and study of a costly pest of stored products. IMPORTANCE From supplementing essential nutrients to detoxifying plant secondary metabolites and insecticides, bacterial symbionts are a key source of adaptations for herbivorous insect pests. Despite the pervasiveness and geographical range of the bean beetle Callosobruchus maculatus, the role of microbial symbioses in its natural history remains understudied. Here, we demonstrate that the bean beetle harbors a simple gut bacterial community that is stable throughout development. This community localizes along the insect's digestive tract and is largely dominated by Staphylococcus gallinarum. In elucidating symbiont metabolic potential, we highlight its possible adaptive significance for a widespread agricultural pest.

The Relationship between Perceptions of Instructional Practices and Student Self-Efficacy In Guided-Inquiry Laboratory Courses.

Science self-efficacy, a student's confidence in being able to perform scientific practices, interacts with science identity and outcomes expectations, leading to improved performance in science courses, persistence in science majors, and ultimately, the pursuit of advanced training in the sciences. Inquiry-based laboratory courses have been shown to improve undergraduate student self-efficacy, but the mechanisms involved and specific components of instructional practices that lead to improved self-efficacy are not clear. In the current study, we determined whether student and faculty perceptions of laboratory instructional practices (scientific synthesis, science process skills, and instructor-directed teaching) were related to postsemester self-efficacy across 19 guided-inquiry laboratory courses from 11 different institutions. Self-efficacy related to science literacy increased significantly from the beginning of the semester to the end of the semester. Variation in individual student perceptions of instructional practices within a course were significantly related to differences in student self-efficacy at the end of the semester, but not average student perceptions or faculty perceptions of their own practices across courses. The importance of individual student perceptions suggests that faculty should engage with students during curricular development. Furthermore, faculty need to use noncontent talk to reinforce the science practices students are engaging in during inquiry-based laboratory courses.

Advancing Undergraduate Laboratory Education Using Non-Model Insect Species.

Over the past decade, laboratory courses have made a fundamental shift to inquiry-based modules and authentic research experiences. In many cases, these research experiences emphasize addressing novel research questions. Insects are ideal for inquiry-based undergraduate laboratory courses because research on insects is not limited by regulatory, economic, and logistical constraints to the same degree as research on vertebrates. While novel research questions could be pursued with model insect species (e.g., Drosophila, Tribolium), the opportunities presented by non-model insects are much greater, as less is known about non-model species. We review the literature on the use of non-model insect species in laboratory education to provide a resource for faculty interested in developing new authentic inquiry-based laboratory modules using insects. Broader use of insects in undergraduate laboratory education will support the pedagogical goals of increased inquiry and resesarch experiences while at the same time fostering increased interest and research in entomology.

The Bean Beetle Microbiome Project: A Course-Based Undergraduate Research Experience in Microbiology.

Course-based undergraduate research experiences (CUREs) are an effective means of transforming the learning and teaching of science by involving students in the scientific process. The potential importance of the microbiome in shaping both environmental health and disease makes investigations of microbiomes an excellent teaching tool for undergraduate microbiology. Here, we present a CURE based on the microbiome of the bean beetle (Callosobruchus maculatus), a model system for undergraduate laboratory education. Despite the extensive research literature on bean beetles, little is known about their microbiome, making them an ideal system for a discovery-based CURE. In the CURE, students acquire microbiological technical skills by characterizing both culturable and unculturable members of the beetle gut-microbial community. Students plate beetle gut homogenates on different media, describe the colonies that are formed to estimate taxonomic diversity, extract DNA from colonies of interest, PCR amplify the16S rRNA gene for Sanger sequencing, and use the NCBI-nBLAST database to taxonomically classify sequences. Additionally, students extract total DNA from beetle gut homogenates for high-throughput paired-end sequencing and perform bioinformatic and statistical analyses of bacterial communities using a combination of open-access data processing software. Each activity allows students to engage with studies of microbiomes in a real-world context, to apply concepts and laboratory techniques to investigate either student or faculty-driven research questions, and to gain valuable experiences working with large high-throughput datasets. The CURE is designed such that it can be implemented over either 6-weeks (half semester) or 12-weeks (full semester), allowing for flexibility within the curriculum. Furthermore, student-generated data from the CURE (including bacterial colony phenotypic data, full-length 16S rRNA gene sequences from cultured isolates, and bacterial community sequences from gut homogenates) has been compiled in a continuously curated open-access database on the Bean Beetle Microbiome Project website, facilitating the generation of broader research questions across laboratory classrooms.

A Model for an Intensive Hands-On Faculty Development Workshop To Foster Change in Laboratory Teaching.

Faculty development workshops are frequently used to bring about change in faculty teaching. Yet, the characteristics of successful faculty professional development in the context of laboratory teaching are unclear. In this Perspective, we describe our approach to intensive hands-on faculty development workshops for fostering change in laboratory teaching and present evidence for the effectiveness of the approach. The outcomes from our workshops and feedback from past participants support the following recommendations: 1) faculty should attend workshops in teams from their institutions, 2) workshops should allow participants to develop curricula that can be implemented with relatively little additional work after the workshop, 3) workshops should allow faculty time to "work" on tangible products and should involve hands-on activities, 4) workshops should be of sufficient duration to allow for faculty to develop expertise and tangible products but short enough that faculty do not "burn out," and 5) a structure for ongoing and systematic follow-up with participants is essential.

Laboratory Courses with Guided-Inquiry Modules Improve Scientific Reasoning and Experimental Design Skills for the Least-Prepared Undergraduate Students.

Past studies on the differential effects of active learning based on students' prior preparation and knowledge have been mixed. The purpose of the present study was to ask whether students with different levels of prior preparation responded differently to laboratory courses in which a guided-inquiry module was implemented. In the first study, we assessed student scientific reasoning skills, and in the second we assessed student experimental design skills. In each course in which the studies were conducted, student gains were analyzed by pretest quartiles, a measure of their prior preparation. Overall, student scientific reasoning skills and experimental design skills did not improve pretest to posttest. However, when divided into quartiles based on pretest score within each course, students in the lowest quartile experienced significant gains in both studies. Despite the significant gains observed among students in the lowest quartile, significant posttest differences between lowest and highest quartiles were observed in both scientific reasoning skills and experimental design skills. Nonetheless, these findings suggest that courses with guided-inquiry laboratory activities can foster the development of basic scientific reasoning and experimental design skills for students who are least prepared across a range of course levels and institution types.

Multi-Institutional, Multidisciplinary Study of the Impact of Course-Based Research Experiences.

Numerous national reports have called for reforming laboratory courses so that all students experience the research process. In response, many course-based research experiences (CREs) have been developed and implemented. Research on the impact of these CREs suggests that student benefits can be similar to those of traditional apprentice-model research experiences. However, most assessments of CREs have been in individual courses at individual institutions or across institutions using the same CRE model. Furthermore, which structures and components of CREs result in the greatest student gains is unknown. We explored the impact of different CRE models in different contexts on student self-reported gains in understanding, skills, and professional development using the Classroom Undergraduate Research Experience (CURE) survey. Our analysis included 49 courses developed and taught at seven diverse institutions. Overall, students reported greater gains for all benefits when compared with the reported national means for the Survey of Undergraduate Research Experiences (SURE). Two aspects of these CREs were associated with greater student gains: 1) CREs that were the focus of the entire course or that more fully integrated modules within a traditional laboratory and 2) CREs that had a higher degree of student input and results that were unknown to both students and faculty.

Alternative Realities: Faculty and Student Perceptions of Instructional Practices in Laboratory Courses.

Curricular reform efforts depend on our ability to determine how courses are taught and how instructional practices affect student outcomes. In this study, we developed a 30-question survey on inquiry-based learning and assessment in undergraduate laboratory courses that was administered to 878 students in 54 courses (41 introductory level and 13 upper level) from 20 institutions (four community colleges, 11 liberal arts colleges, and five universities, of which four were minority-serving institutions). On the basis of an exploratory factor analysis, we defined five constructs: metacognition, feedback and assessment, scientific synthesis, science process skills, and instructor-directed teaching. Using our refined survey of 24 items, we compared student and faculty perceptions of instructional practices both across courses and across instructors. In general, faculty and student perceptions were not significantly related. Although mean perceptions were often similar, faculty perceptions were more variable than those of students, suggesting that faculty may have more nuanced views than students. In addition, student perceptions of some instructional practices were influenced by their previous experience in laboratory courses and their self-efficacy. As student outcomes, such as learning gains, are ultimately most important, future research should examine the degree to which faculty and student perceptions of instructional practices predict student outcomes in different contexts.

Redefining authentic research experiences in introductory biology laboratories and barriers to their implementation.

Incorporating authentic research experiences in introductory biology laboratory classes would greatly expand the number of students exposed to the excitement of discovery and the rigor of the scientific process. However, the essential components of an authentic research experience and the barriers to their implementation in laboratory classes are poorly defined. To guide future reform efforts in this area, we conducted a national survey of biology faculty members to determine 1) their definitions of authentic research experiences in laboratory classes, 2) the extent of authentic research experiences currently experienced in their laboratory classes, and 3) the barriers that prevent incorporation of authentic research experiences into these classes. Strikingly, the definitions of authentic research experiences differ among faculty members and tend to emphasize either the scientific process or the discovery of previously unknown data. The low level of authentic research experiences in introductory biology labs suggests that more development and support is needed to increase undergraduate exposure to research experiences. Faculty members did not cite several barriers commonly assumed to impair pedagogical reform; however, their responses suggest that expanded support for development of research experiences in laboratory classes could address the most common barrier.

Evolution of female preference for younger males.

Previous theoretical work has suggested that females should prefer to mate with older males, as older males should have higher fitness than the average fitness of the cohort into which they were born. However, studies in humans and model organisms have shown that as males age, they accumulate deleterious mutations in their germ-line at an ever-increasing rate, thereby reducing the quality of genes passed on to the next generation. Thus, older males may produce relatively poor-quality offspring. To better understand how male age influences female mate preference and offspring quality, we used a genetic algorithm model to study the effect of age-related increases in male genetic load on female mate preference. When we incorporate age-related increases in mutation load in males into our model, we find that females evolve a preference for younger males. Females in this model could determine a male's age, but not his inherited genotype nor his mutation load. Nevertheless, females evolved age-preferences that led them to mate with males that had low mutation loads, but showed no preference for males with respect to their somatic quality. These results suggest that germ-line quality, rather than somatic quality, should be the focus of female preference in good genes models.

Energetics of metamorphic climax in the southern toad (Bufo terrestris).

During metamorphic climax, anuran larvae must rely on stored energy because changes in oral and digestive morphology prevent foraging and efficient assimilation. Thus, the time required to store adequate energy for metamorphic climax may set a lower limit on age at which it can occur. Therefore, the amount and type of energy used during metamorphic climax must be determined. To quantify the energetic costs of metamorphic climax in Bufo terrestris, oxygen consumption during climax was measured. Wet mass, dry mass, and lipid mass for a group of individuals at the initiation of climax (forelimb emergence, FL) and for another group at the end of climax (complete tail resorption, TR) were also measured to determine whether lipids were used to fuel metamorphic climax. The total amount of energy used, maintenance costs, and development costs during metamorphic climax varied considerably among individuals. Variation in energy metabolism during climax was not related to differences in energy metabolism during larval development or body mass at initiation of climax. TR individuals were significantly lighter in terms of wet mass and had less body water than FL individuals. However, the two groups did not differ in dry mass or lipid mass. Therefore, lipid catabolism is not a major source of energy during metamorphic climax in B. terrestris. As a result, decreases in age at metamorphosis may not be constrained by the need to store energy in the form of lipids.

Effect of changes in resource level on age and size at metamorphosis in Hyla squirella.

Recent experiments suggest that timing of metamorphosis is fixed during development in some anurans, insects, and freshwater invertebrates. Yet, these experiments do not exclude a growth rate optimization model for the timing of metamorphosis. I manipulated food resources available to larvae of squirrel treefrogs (Hyla squirella) to determine if there is a loss of plasticity in duration of larval period during development and to critically test growth rate models for the timing of metamorphosis. Size-specific resource levels for individual tadpoles were switched from low to high or high to low at three developmental stages spaced throughout larval development. The effects of changes in resource availability on larval period and mass at metamorphosis were measured. Switching food levels after late limb bud development did not significantly affect larval period in comparison to constant food level treatments. Therefore, developmental rate in H. squirella is better described by a fixed developmental rate model, rather than a growth rate optimization model. The timing of fixation of developmental rate in H. squirella is similar to that found in other anuran species, suggesting a taxonomically widespread developmental constraint on the plasticity of larval period duration. Mass at metamorphosis was not significantly affected by the timing of changes in food levels; the amount of food available later in development determined the size at metamorphosis. Larval period and mass at metamorphosis were negatively correlated in only one of two experiments, which contrasts with the common assumption of a phenotypic trade-off between decreased larval period and increased mass at metamorphosis.