(b) only the mean, and have students calculate the Rayleigh and
Watson tests separately for each scenario and compare the inferences
When discussing improvements to the experimental design, the
students suggested performing the experiment several times in different places throughout the room, standardizing the way in which
students placed the pill bugs in the center of the arena, and controlling for size differences between individuals. For collecting further
data, they suggested performing more trials per group, using multiple pill bugs per group, and swapping pill bugs between groups to
see if the same individual acted differently when tested by different
experimenters. Lastly, they discussed how increased understanding
of the magnetic sense may assist society in developing navigation
The results generated in this class did not provide conclusive evidence for the presence or absence of a magnetic sense in pill bugs.
Nonetheless, throughout the experiment the students were focused
on the given tasks and excited to be generating their own data. For
many students, this was their first opportunity to handle “bugs,”
and although initially concerned, they quickly became accustomed
to the handling procedure. When contributing anonymous feedback
for the course, half (8/16) of the students ranked the pill bug lab as
their favorite activity. Reasons for why it was their favorite activity
included descriptions based on its interdisciplinary nature, for
example, “It includes coding, using a compass, electric circuit making, and testing actual bugs, which was very novel and fun,” and “I
loved using R by ourselves to do the pill bug lab. It put what we
had learned to good use”; whereas others enjoyed the process of
discovery and lack of a predefined answer, such as “It’s the most serious lab and so exciting to do a lab where we didn’t know the result!”
and “Because we got to do a whole experiment from start to finish,
and it is really great to get our own results.”
Implications for STEM Curricula
Interdisciplinary and active-learning exercises that address a variety
of NGSS and AP concepts (see Tables 1 and 2), such as this pill
bug activity, are in increasing demand to promote the addition
and retention of undergraduate students in the science, technology, engineering, and mathematics (STEM) disciplines (PCAST
STEM Undergraduate Working Group, 2012; Freeman et al., 2014).
Furthermore, introductory-level activities in biophysics that apply
evidence-based inquiry spanning scientific disciplines are effective
tools for improving scientific literacy among non-STEM students
An important component of the pill bug activity is to introduce
students to new concepts in statistics, such as circular data analysis,
while reinforcing existing knowledge (e.g., statistical testing, means).
Although all calculations could be made by hand, the tutorials (see
Online Materials) include basic training in data analysis using the
free and open-source statistical software R (http://www.r-project.
org). Until recently, quantitative skills in the sciences, notably the life
sciences, had been deemphasized, thus resulting in the growing con-
cern among professional and academic organization for improved
training (Berlin & Lee, 2005; Feser et al., 2013). Evaluations from
students enrolled in the sensory biology course demonstrated their
enthusiasm for data analysis through such remarks as “. . . my
favorite thing: using R,” “This is the first time I learn [sic] about the
data analyzing software. It’s cool!” and “It was cool seeing how my
statistics background actually is being used.” As a result, the expo-
sure of undergraduate STEM students to basic computer program-
ming and statistical analysis (e.g., using R) through active-learning
exercises like the pill bug lab will greatly contribute to the improve-
ment of quantitative skills.
The pill bug lab presented here provides an excellent opportunity for students to integrate concepts from multiple disciplines into
an active-learning exercise. Furthermore, the materials required for
this lab are inexpensive and readily available online or in most laboratories. Depending on the instructor’s goals and the students’
background, the experiment can easily be modified to assess additional
species or individuals, to include more complex electrical concepts
(e.g., capacitance and micro-controlled circuits), and/or to examine
other cues aside from magnetic effects. The incorporation of interdisciplinary exercises like the pill bug activity will be a valuable contribution to any science curriculum and will further prepare students
for careers in the STEM fields.
A complete repository of information, tutorials, and full description
of procedures is available at GitHub ( https://github.com/rfitak/
Circular_Biology). These include the basis for calculating a statistical mean by hand ( https://github.com/rfitak/Circular_Biology/
blob/master/Circular_data_by_hand.pdf) and how to use the software
R ( https://github.com/rfitak/Circular_Biology/blob/master/Circular_
The pill bug orientation data presented here were collected during
two class periods of Duke University summer session course
Bio190S (Sensory Biology – Sight, Smell, Taste, Touch, Sound,
and Beyond) taught by E.M.C. (instructor of record) and R.R.F.
(guest lecturer). The Duke Office of Continuing Studies and Summer Session provided funding for materials. We also thank the student participants in the Bio190S course for their useful input on
improving the activity.
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Behaviour, 49, 227–267.
Batschelet, E. (1981). Circular Statistics in Biology. New York: Academic
Berlin, D.F. & Lee, H. (2005). Integrating science and mathematics
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spiny lobsters: implications for magnetoreception. Journal of
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Feser, J., Vasaly, H. & Herrera, J. (2013). On the edge of mathematics and
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