• Form a null and alternative hypothesis about the biodiversity of
species living inside the millipede intestine.
• Calculate Shannon’s diversity index and equitability.
• Calculate Simpson’s diversity index.
• Write a short laboratory report including the following headings: synopsis, results, data analysis, and conclusion.
Class Schedule to Complete Project
Two days are needed to complete this laboratory inquiry, with each
classroom period lasting 90–120 minutes. Approximately 2 hours
will be needed to complete the report, including data analysis, results,
The Next Generation Science Standards (NGSS) recommend that stu-
dents have the ability to ask questions; plan investigations; collate,
analyze, and interpret data; use mathematics to support scientific
claims; articulate explanations; and effectively communicate findings
to peers (NGSS Lead States, 2013). The National Research Council
(2012) recommends that K–12 students be introduced to the con-
cepts of a three-dimensional approach that focuses on scientific and
engineering practices, crosscutting concepts, and core ideas in specific
disciplines. Application and implementation of both NGSS and
National Research Council standards can be applied and supported
through this laboratory inquiry that focuses on millipedes as organ-
isms to demonstrate commensalism. Both NGSS and National
Research Council concepts are outlined in Table 1.
• Millipedes can be easily collected in areas where there is moist
soil and around streams and creeks, under rocks and logs, and
under bark. Larger millipedes are more active in late spring,
summer, and fall in areas where there is sufficient moisture.
In urban areas where there is little to no natural area, they
can be purchased from biological supply houses such as Carolina Biological Supply ( https://www.carolina.com/millipedes-and-centipedes/millipede/ FAM_143124.pr), Fisher Scientific
2/p-4655726#?keyword=millipedes), or through private dealers
• Gloves and goggles
• One large millipede per group of two to four students
• Ethyl acetate or chloroform (optional anesthetizing agents)
• Razor blade
• Distilled water, water bottle
• Forceps, minuten pins, dissecting probe, Syracuse watch glass
or small plastic Petri dish
• Bright-field dissecting microscope
Supervised Inquiry Activity
Activity class, Day 1 (90–120 minutes):
• Divide students into working groups of two to four.
• Understand keys to identify millipedes and nematodes.
• Discuss general millipede and nematode anatomy.
• Provide students with live specimens of large millipedes. Explain
handling techniques and defensive mechanisms of millipedes.
Allow students to handle millipedes prior to dissections (wear
gloves and goggles when handing live millipedes).
Activity class, Day 2 (90–120 minutes):
• Gather students into groups of two to four. Students must put on
gloves before handling millipedes, whose natural defense mechanism releases pungent chemicals from their defense-gland openings (ozopores) to deter predators; some of these chemicals have
the potential to stain and irritate human skin and eyes; however,
there has never been an instance of people being seriously harmed
by millipedes. If the millipede secretions do come into contact
with skin or eyes, use an eyewash station to rinse eyes, and soap
and water to clean exposed skin. Do not taste millipedes!
• Millipedes can be anesthetized using chloroform or ethyl acetate
prior to dissection, or they can be decapitated with a razor blade.
If using anesthesia, while under a fume hood, place two or three
drops of chloroform or ethyl acetate in an enclosed container
and place the millipede in the container for 5 minutes or until
Figure 2. Morphological characters used in the key: (A)
Coronostoma, (B) Rhigonema, (C) Heth, (D) Thelastoma, (E)
Stauratostoma, (F) Aoruroides, and (G) Aorurus.