Abstract.  1. Predaceous insects may benefit from feeding on non‐prey foods, such as pollen, nectar, and honeydew, because they can provide nutrients that help maintain metabolism and enhance overall nutrient intake. Yet, the extent to which predaceous insects can assimilate non‐prey food and the importance of diet mixing during particular life history stages is poorly understood. In this study the relative contribution of an omnivorous diet to the growth and survivorship of a predaceous larva was tested in a hypothetical situation in which nutritionally optimal prey was not available. The study system comprised a predaceous larva (second‐ and third‐instar larvae of the green lacewing Chrysoperla carnea), nutritionally poor prey (larvae of Drosophila melanogaster), and non‐prey food (pollen suspension, a mixture of bee pollen and artificial nectar (1 M sucrose solution)). Chrysoperla carnea larvae in the mixed diet treatment were provided with both Drosophila larvae and pollen suspension, while those reared on the prey and non‐prey diet treatments received only Drosophila larvae or pollen suspension respectively. 2. The inclusion of pollen and sucrose in their diet enhanced the growth of C. carnea larvae. Second instars reared on the mixed diet developed significantly faster than their cohorts reared on the prey diet, however third instars reared on the mixed diet did not develop faster than their cohorts reared on the prey diet. Larvae reared on the mixed diet became larger adults than did those reared on either the prey or non‐prey diets. Third instars reared on the non‐prey diet completed their development while second instars in the non‐prey diet treatment failed to pupate. 3. Stable isotope analysis indicated that the larvae obtained most of their carbon (55–73%) and nitrogen (71–73%) from Drosophila but acquired only a minor amount of carbon (2–5%) and nitrogen (3–11%) from pollen. Larvae reared on the mixed and non‐prey diets acquired a relatively significant amount of carbon (23–51%) from sucrose. 4. A model, which included a novel fractionation factor to account for the isotopic effect of metamorphosis, was developed to explain the proportion of larval growth attributable to each diet item. It explained the adult δ13C values to within 0.2‰ and adult δ15N values to within 0.7‰ in all treatments. 5. Adults fed 15N‐labelled pollen as larvae retained the 15N signal of the pollen as adults. 6. The collective results of this study support the view that, despite their dependence on prey arthropods to obtain most of their dietary nitrogen, omnivorous lacewing larvae can enhance their growth and development by supplementing their diets with alternative non‐prey food resources. This finding is consistent with the notion that omnivory has evolved as a feeding strategy to acquire both additional nitrogen as well as trace nutrients.

BACKGROUNDOur goal is to improve student learning in foundation engineering courses.These courses are prerequisite to many higher-level courses and are comprised of critically needed concepts and skills. PURPOSE (HYPOTHESIS) We hypothesize that learning is improved by providing rapid feedback to stu dents on their understanding of key concepts and skills. Such feedback also provides students with insight into their strategies for learning. DESIGN/METHODIn two consecutive years, we conducted this study in t\'o'0 sections of a lower-level engineering mechanics course, Statics. One author taught both sections and a crossover design of experiment was used. In a crossover design, one section was randomly chosen to receive feedback with handheld computers (the "treatment" group) while the other received the "control," which was either a feedback sysrem using flashcards (in year 1) or no feedback (year 2). After a certain period, rhe t\'o'0 sections swapped the

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Our goal is to improve student learning in foundation engineering courses. Our hypothesis is that learning is improved by providing rapid feedback to students of their understanding of key concepts and skills. In the past two years, we conducted this study in two sections of a lower-level course, Statics. One author taught both sections and a crossover design of experiment was used. In a crossover study one section was randomly chosen to receive feedback with handheld computers (the 'treatment' group) while the other received the 'control,' which was either a feedback system using flashcards (in 2004) or no feedback (2005). After a certain period, the two sections swapped the treatment and control. Student performance on a quiz at the end of each treatment period provided the data for comparison using a general linear statistical model. Our findings from 2004 showed that there was no significant difference using either rapidfeedback method. In 2005 we found a significant and positive effect when students received feedback. This is a noteworthy finding that confirms the value of rapid feedback and the currently popular 'clickers' that many professors are employing to promote classroom interaction.

In this project our goal is to adapt the Concept Inventory for frequent classroom use, and to implement it in a system to provide rapid feedback to students of their understanding of key concepts being presented. The feedback system acts as the focal point and catalyst to encourage students, working in pairs, to assist each other in correcting misconceptions or deepening each other's understanding of the topic at hand. Furthermore, the system allows the professor to assess the students' level of comprehension (or misconception) in a just-in-time fashion, and thus guides his or her pacing and coverage of the material. The rapid feedback is enabled through wireless-networked handheld computers. In this first year of the study, we have implemented the system in a lowerlevel, core-engineering course (engineering mechanics: statics). This paper will focus on the motivation for and the design of this project; our presentation will describe results from the first implementation.