The effects of the timing of exposure to cadmium on the oviposition behavior of Drosophila melanogaster.

Animals can greatly increase their fitness by choosing oviposition sites free from damaging substances such as the heavy metal cadmium (Cd). Previous research has shown that Drosophila melanogaster reared on uncontaminated media lay fewer eggs on substrates containing Cd. In this study, we examined the effects of prior exposure to Cd on oviposition site preference. We tested flies that had been exposed to Cd continuously from egg to adult, only during pre-adult stages, or for the 4 days of adulthood prior to testing. We found that flies avoid laying eggs on Cd-contaminated medium and also that flies exposed to Cd as adults laid significantly fewer eggs than controls never exposed to Cd. We did not observe consistent changes in oviposition as a result of pre-adult exposure alone. Our results suggest that the presence of cadmium in the environment, even at low doses and for short periods of time during adulthood, can harm the fitness of Drosophila melanogaster.

Three Steps to Adapt Case Studies for Synchronous and Asynchronous Online Learning.

Pandemic SARS-CoV-2 has ushered in a renewed interest in science along with rapid changes to educational modalities. While technology provides a variety of ways to convey learning resources, the incorporation of alternate modalities can be intimidating for those designing curricula. We propose strategies to permit rapid adaptation of curricula to achieve learning in synchronous, asynchronous, or hybrid learning environments. Case studies are a way to engage students in realistic scenarios that contextualize concepts and highlight applications in the life sciences. While case studies are commonly available and adaptable to course goals, the practical considerations of how to deliver and assess cases in online and blended environments can instill panic. Here we review existing resources and our collective experiences creating, adapting, and assessing case materials across different modalities. We discuss the benefits of using case studies and provide tips for implementation. Further, we describe functional examples of a three-step process to prepare cases with defined outcomes for individual student preparation, collaborative learning, and individual student synthesis to create an inclusive learning experience, whether in a traditional or remote learning environment.

Individual discrimination by odors in sibling prairie voles (Microtus ochrogaster).

The habituation-discrimination paradigm has been used widely to demonstrate that animals can detect individually distinctive odors of unfamiliar conspecifics. By using a modification of the habituation-discrimination technique, Todrank et al. (Anim Behav 55:377-386, 1998) found that golden hamsters discriminate between the individual odors of their own familiar brothers but cannot discriminate between the odors of two siblings that are unrelated and unfamiliar to the subject. This suggested that previous evidence showing that animals could discriminate between the odors of individuals actually may have demonstrated the ability to discriminate between genetically unrelated conspecifics (i.e., members of different families). To test this possibility, we conducted habituation-discrimination experiments with prairie voles, Microtus ochrogaster. Voles were tested under three conditions: subject and both targets were unrelated and unfamiliar; subject and both targets were brothers and familiar; subject was unrelated and unfamiliar to targets, but targets were brothers. In all cases, voles discriminated between the two individual odors. Thus, prairie voles can discriminate individual differences between the odors of brothers and they do not have to have previous experience with the conspecifics in order for discrimination to occur. The theoretical importance of these results is discussed.