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The ability to provision offspring with milk is a significant adaptive feature of mammals that allows for considerable maternal regulation of offspring beyond gestation, as milk provides complete nutrition for developing neonates. For mothers, lactation is a period of marked increases in energetic and nutritive demands to support milk synthesis; because of this considerable increase in demand imposed on multiple physiological systems, lactation is particularly susceptible to the effects of chronic stress. Here, we present work that explores the impact of chronic stress during lactation on maternal lactation performance (i.e., milk quality and quantity) and the expression of key milk synthesis genes in mammary tissue using a Sprague–Dawley rat model. We induced chronic stress using a well-established, ethologically relevant novel male intruder paradigm for 10 consecutive days during the postpartum period. We hypothesized that the increased energetic burden of mounting a chronic stress response during lactation would decrease lactation performance. Specifically, we predicted that chronic exposure to this social stressor would decrease either milk quality (i.e., composition of proximate components and energy density) or quantity. We also predicted that changes in proximate composition (i.e., lipid, lactose, and protein concentrations) would be associated with changes in gene expression levels of milk synthesis genes. Our results supported our hypothesis that chronic stress impairs lactation performance. Relative to the controls, chronically stressed rats had lower milk yields. We also found that milk quality was decreased; milk from chronically stressed mothers had lower lipid concentration and lower energy density, though protein and lactose concentrations were not different between treatment groups. Although there was a change in proximate composition, chronic stress did not impact mammary gland expression of key milk synthesis genes. Together, this work demonstrates that exposure to a chronic stressor impacts lactation performance, which in turn has the potential to impact offspring development via maternal effects.

 

Students’ perceptions of challenges in biology influence performance outcomes, experiences, and persistence in science. Identifying sources of student struggle can assist efforts to support students as they overcome challenges in their undergraduate educations. In this study, we characterized student experiences of struggle by 1) quantifying which external factors relate to perceptions of encountering and overcoming struggle in introductory biology and 2) identifying factors to which students attribute their struggle in biology. We found a significant effect of Course, Instructor, and Incoming Preparation on student struggle, in which students with lower Incoming Preparation were more likely to report struggle and the inability to overcome struggle. We also observed significant differences in performance outcomes between students who did and did not encounter struggle and between students who did and did not overcome their struggle. Using inductive coding, we categorized student responses outlining causes of struggle, and using axial coding, we further categorized these as internally or externally attributed factors. External sources (i.e., Prior Biology, COVID-19, External Resources, Classroom Factors) were more commonly cited as the reason(s) students did or did not struggle. We conclude with recommendations for instructors, highlighting equitable teaching strategies and practices. 

ABSTRACT Test anxiety is a common experience shared by college students and is typically investigated in the context of traditional, face-to-face courses. However, the onset of the COVID-19 pandemic resulted in the closure of universities, and many students had to rapidly shift to and balance the challenges of online learning. We investigated how the shift to online learning during the pandemic impacted trait (habitual) and state (momentary) test anxiety and whether there was variation across different demographic groups already vulnerable to performance gaps in science, technology, engineering, and mathematics (STEM) courses. Quantitative analyses revealed that trait and state test anxiety were lower in Spring 2020 (COVID semester) than in Spring 2019 and were higher overall in women than men. We did not find a difference in either trait or state anxiety in first-generation students or among persons excluded because of ethnicity or race. Qualitative analyses revealed that student priorities shifted away from coursework during Spring 2020. While students initially perceived the shift to online learning as beneficial, 1 month after the shift, students reported more difficulties studying and completing their coursework. Taken together, these results are the first to compare reports of test anxiety during a traditional, undisrupted semester to the semester where COVID-19 forced a sudden transition online.