Lab Summary This lab has students constructing models of a species of butterfly that has seasonally dimorphic individuals that vary in their ability to thermoregulate, with early season individuals having more black on both the ventral base of the hind-wing and the dorsal base of the fore-wing.  These two areas are used for lateral and dorsal basking, respectively.  Late season individuals are significantly lighter in both of these wing locations. Lab teams develop alternative hypotheses regarding adaptations which influence thermoregulation in these butterflies.  Variables to consider will be 1) seasonal brood, 2) darkness of the ventral hind-wing, 3) darkness of the dorsal forewing, 4) basking position, and potentially 5) basking substrate.  After deciding on two alternative hypotheses to test, students will first collect control group data as a class. Then individual teams design and implement an experiment to distinguish between their alternative hypotheses.  For example, students may test if dorsal or lateral basking should be more important for early season (darker) butterflies.  Students then make models of appropriately colored butterflies (using pre-printed images of the butterflies) and conduct their experiment to compare the alternatives.  Teams decide on appropriate measurements, gather data, and run a statistical analysis. They will use these data and the analysis to evaluate their hypotheses and explain their finding in light of the evolution of thermoregulatory adaptations in butterflies.

Conceptual Learning Goals - Upon completion of this lab, students should be able to

• explain how morphological and behavioral differences among individuals can arise through selection; in this case how invertebrates can thermoregulate to control homeostasis, and why this may be adaptive.

Scientific Skills - In this lab students practice and receive feedback on

• developing alternative experimental hypotheses and predictions and design an experiment to test these alternative hypotheses.
• designing an experiment with appropriate positive and/or negative controls
• summarizing data with descriptive statistics & appropriate graphs in MS Excel
• using inferential statistics to analyze the data and draw conclusions regarding two alternative experimental hypotheses.
• applying general biological concepts and knowledge from a primary literature article to formulate hypotheses and inform experimental conclusions.

Teaching Theory & Pedagogy

In this exploration of behavioral thermoregulatory adaptations in butterflies, it is basic scientific research which sets the stage for the mainly student-driven investigation.   This lab begins with a journal article which summarizes the thermoregulatory adaptations from Kingsolver (1987), Kingsolver & Wiernasz (1991) and Stoehr & Goux (2008), among others.  This lab approach provides students with a scientific inquiry experience in which knowledge from primary literature provides the basis (or context) for a scientific investigation.    

Required Materials

• Vernier temperature sensors, data loggers
• Student team computer with MS Excel