ZADBI Curriculum: Estimate fly biodiversity at your site
Suggested age: 11 to adult. But this curriculum can be modified for younger ages by reducing the
number of traps, and identifying flies to simple, sub-groups based on antennae morphology.
Summary: Classes will estimate local fly biodiversity by following the same protocols used by ZADBI
scientists to estimate Costa Rican fly biodiversity. The strategy is to select a restricted sampling site and
utilize varied collecting methods to catch different types of flies. Another important approach is to
include as many scientists (the students) as possible to collaborate and make the project sustainable.
Students will use the same collecting, sorting and identification procedures as entomologists. Students
will learn the unique physical characteristics of flies and different fly groups. Results will be analyzed to
assess fly biodiversity and consider the ecological role and behavior of collected specimens; which flies
occur in the sampling site and what are they doing there? Results can be shared with other participants
on the ZADBI website or the Encyclopedia of Life (www.eol.org).
Goals:
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Position students as scientists by 1) replicating ZADBI collecting, sorting, and identification
protocols 2) using the same methods as ZADBI scientists to analyze data 3) publishing results for
benefit of the larger scientific community.
Expand fly knowledge and amend common misconceptions by recognizing the 1) high
biodiversity of flies as a group, including great variation in their appearance and behavior 2) the
critical ecological roles that flies perform.
Duration: Modifiable. Recommended duration is at least 1 week.
Day 1: Introduction. Why study flies? (60-90 minutes).
Day 2: Sampling site selection and trap set-up (120 minutes)
* Skip at least a few days to accumulate specimens
Day 3: Collecting (60 minutes)
Day 4: Sorting and identifying (120 minutes)
Day 5: Data analysis and wrap-up (60-120 minutes)
Day 6 (optional): Publish! Upload results on the ZADBI website and/or EOL
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Background
The Diptera, or true flies, already include more than 160,000 species worldwide, far more than
the well-known mammals, birds, fish, reptiles, and amphibians combined. They are just as vulnerable to
extinction and habitat loss as these larger animals. However, research on flies is far less advanced
because flies are small and very diverse in their habits. Aside from the obvious pests and disease
carriers, like house flies and some mosquitoes, most flies are actually beneficial, as decomposers,
pollinators, predators, and much more. An estimate of their true species diversity, with many thousands
new to science, will allow us to better understand the importance they play in ecosystems, as well as
gauge the impact of habitat change and loss affecting life everywhere.
Scientists from the Entomology Department at the Natural History Museum of Los Angeles
County (LACM) and world-wide collaborators are currently working on a project called the “Zurqui All
Diptera Biology Inventory” (or ZADBI). Scientists often conduct biological inventories, or record how
many different kinds of organisms they find in a specific and identify new species in order to measure
biodiversity and create a baseline of organisms for future comparisons. ZADBI is the first effort to
comprehensively survey all species of a large, mega-diverse group of invertebrates (flies) of a tropical
forest location; it is potentially a landmark research project in tropical biology and will make a very
important contribution to understanding the species diversity of a highly diverse but restricted tropical
fauna.
The main sampling site is Zurqui de Moravia, a tropical cloud forest in the foothills in eastern
Costa Rica. Previous research has shown that middle elevation sites, like this one, is the most diverse in
the world and has the most potential for high diversity and number of species new to science. Currently,
no one really knows how many species are actually present in a single location, anywhere in the tropics,
which has been a huge gap in our understanding of biodiversity and how best to study and manage
terrestrial ecosystems.
ZADBI is unique among recent inventories, as it will sample only a small area in Costa Rica. This
is because the number of species presently unknown to science is overwhelming. Most previous
inventories for complete surveys got mired by trying to do too much and resulting in a backlog of
unidentified specimens, whereas ZADBI is restricted to a small site that, with the help of many experts,
will give us a complete list of species.
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Materials
Many of the following materials can be found online from Bioquip, Carolina Biological Supply, VWR, or
Ward’s.
Background
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PowerPoint presentation
Collecting
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Aspirators
Pan traps: Yellow plastic pans.
Tree trunk traps: Empty liter-sized plastic bottles, exacta knife or scissors to cut, string, holepuncher.
Blacklight traps: ¼ inch metal, screen mesh, blacklight, extension cord, large plastic tub.
Sweeping: Insect nets
Honey spray: spray bottles, honey.
Bait traps: Insect net (without handle), string, bait (rotten fruit, rotten meat, and other creative
ideas).
Ethanol
Water
Liquid dish soap
Sturdy zip-lock bags that can be labeled
Sharpie pens
Blue, screw-top vials
Fine-mesh, aquarium dip nets
Sorting materials
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Alcohol squeeze bottle (optimal, but optional)
Forceps
Ethanol
Large petri dishes
Hand magnifiers, or (optimally) dissecting scopes
Identification and data analysis materials (from the ZADBI website or EOL):
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Online fly guide/key
Sample Data Sheets (for each trap)
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Procedure
Day 1: Introduction to flies
Fly journaling (30 minutes)
Before delving into the project, first record students’ understandings and perceptions of flies to reexplore later. Ask students:
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What do you know about flies? What are they? How would you describe them physically? What
do you think makes flies from other animals?
Do you think flies are good or bad…or both? How do flies make you feel?
What do flies do? Where can they be found?
How many kinds of flies do you think there are? How many types of flies can you name? What
do you think fly biodiversity is compared to other animal groups?
*For younger students, the 3rd question of bullet #4 might be eliminated. Students need to
understand the concept of 'biodiversity' before the unit/activities begin. Or the term can be
introduced within the unit/activities once students understand the idea.
Background: ZADBI Intro PowerPoint (30 minutes)
A visiting member of the ZADBI team will offer a 30-minute PowerPoint presentation on why scientists
study flies, the ZADBI project, and how it can be replicated at the school. More specifically, the ZADBI
team member will discuss the purposes of biological inventories such as ZADBI and describe the
particular strategy to use different collecting methods within a limited sampling site, and how that can
be replicated from cloudforests to city environments. If a ZADBI team member is not available, the
PowerPoint presentation is designed so that the teacher can lead the same presentation.
Day 2: Sampling site selection and trap set-up (60-120 minutes)
Select and document sampling site (60 minutes)
Sampling sites like Zurqui yield fly biodiversity because they have habitat diversity. What is the most
comparable site within your school grounds? As a group, discuss and select an optimal area to set up
traps. What kinds of flies have students observed around your school? Take a quick walk around to see
where students observe the most kinds of flies. Habitat diversity will attract different kinds of flies:
Where is an area around your school with the most plants and microhabitats (e.g. tree trunks, grass,
shrubs, flowers, logs, lichens, mushrooms, decomposing material, etc.)? Explain that the designated area
for collecting the data is called a “sample site”.
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Ask students: How would you characterize our sample site overall; what do you think we can use to
attract flies? Do you expect to collect a low or high quantity of flies? Will the site yield low or high
biodiversity? Why? (For younger students, eliminate the next question). What resources are necessary
to support high biomass and high biodiversity? Have students record their thoughts for future
discussions.
How can you document your sampling site? Can you record your locality with a GPS, Google Earth,
measurement of the perimeter or take photos?
Set-up traps (60 minutes)
Follow the instructions below to set up as many of the following traps as is manageable. Where do
students think the best places are to set up different traps and why? Record students’ predictions and
reasoning. Just like the ZADBI team, you may need to readjusts the location of traps if they aren’t
working well. Traps may not work in bad weather, and sometimes they don’t work the same way in
different locations, so be patient and enjoy the experimental aspects! “Experiment-in-progress” signage
will perk interest in, and also protect your sampling site.
Bait trap
Bait traps: Bait traps attract decomposers and flies
searching for carbohydrates (on rotting fruit). Place rotten
fruit, carrion, dried old meat, or anything else that students
think may attract flies under an insect net, tip pointed up
and secured with string. Use sticks pushed in the ground or
some other method to keep the mouth of the net open and
expanded over the bait.
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Pan trap
Plastic pan traps: Pan traps resemble shafts of light in the
landscape, which serve as markers for flies searching for
mates. Place pans in various locations, such as near different
kinds of vegetation, and decomposing material, logs, water,
hidden dark spots, etc. Fill pans with water and a few drops of
detergent soap. Make small perforations are along their
upper rim to avoid flooding due to heavy rainfall.
Tree trunk trap
Tree trunk traps: These traps often attract flies that run up and down tree trunks searching for prey. Cut
up cleaned, plastic litre bottles. Cut through about 6 inches from the top of the bottle. Space two hole
punches about two inches down from the cut and two inches apart. Weave a long and sturdy piece of
string through. Make sure that the string is long enough to wrap around a tree a few times. Keep the
side of the bottle with the holes against the tree. Fill with water mixed with a drop or two of detergent.
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Blacklight trap
Blacklight trap: Nocturnal flies are attracted to light which they use navigate at night. Place a long UV
light over pan with a homemade ¼ wire mesh lid and fill the tub with water and a few drops of liquid
detergent soap.
***The soap in the above traps keeps flies from escaping out of the water.
DAY 3: Collecting (60 minutes)
Flies collected from each trap will be put in a separate ethanol-filled zip-lock bag and labeled with the
date, collection method, and (micro)habitat. Flies collected from same-day collecting methods will be
collected in blue-screw cap vials and also labeled with the date, collection method, and habitat. Discuss
this procedure: What is the purpose of recording this data (how do they serve as variables)?
**The ethanol allows us to prepare and preserve the flies so that we can collect data for our research.
Same-day collecting methods:
You may need to re-explain any terms used support student understanding of what is being done or
expected.
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Net sweeping
Net sweeping: Use nets to sweep vegetation (especially when it is sunny and vegetation is dry). Sweep
as many habitats as possible, such as: grass, flowers, shrubs, tree trunks (briskly up and down), twigs
and logs, any still or moving water and over ripe fruit, fungi, etc., Flies may need to be aspirated from
inside of nets. Pop collected flies into ethanol-filled, blue screw-top vials.
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Aspirating
on plants
Aspirating
flies caught
in nets
Aspirators: Suck up tiny flies caught in nets, in bait traps and on vegetation through mesh-filtered,
rubber tube and into a clear vial. Pop collected flies into ethanol-filled, blue screw-top vials.
Honey spray
Honey Spray: This sweet substance attracts nectar and honeydew-feeders. Fill a spray bottle with 2
tablespoons of honey mixed with water and spray on vegetation before collecting with nets and/or
aspirators. Spray collecting is most effective at sunny times and over plants, especially flowers. Pop
collected flies into ethanol-filled, blue screw-top vials.
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For the other traps:
Gently scoop out flies from soapy water with a fine-mesh dip net and place them into zip-lock bag. Fill
the bag with ethanol and use squeeze ethanol-squirt bottles to nudge any remaining flies off the dip net
and into the bag. Label the bag with trap, habitat and date.
Day 4: Sorting and identifying (120 minutes)
Students can work in either in small groups, pairs to sort, identify, and fill out data sheets. Before
beginning this activity, hold a discussion with students about the importance of thinking and working
like scientists as they continue to collect the data. This includes the careful and respectful handling of
specimens. Demonstrate to your class how the specimens are to be handled, before students are given
the materials.
Sort and identify flies (at least 60 minutes)
Pick a sample and fill out the first section of the sample data sheet (trap, date, location, habitat,
collection method, etc.). Pour out samples for each trap into ethanol-filled petri dishes where insects
can be viewed on top of a white background (place a piece of white paper under the dish if necessary)
and there is enough room to move them around under a hand magnifier, or preferable a dissecting
scope. Pour out one trap sample at a time for each student(s) so that samples don’t get mixed up.
1) Pull out the non-flies with forceps and discard them (or, better yet, use them for another
project).
2) Pull out and separate the larger flies into a different ethanol-filled dish. Use forceps to move the
bigger flies by gently grasping more than one of their legs. Or try to move flies by gentle
grasping their thoraces or abdomens—avoid grasping delicate parts like wings or antennae,
which will break off.
3) Sort the other flies by using the key to identify antennae; keep the nematocerans in the original
dish and pull out and separate the other flies (orthorrhappharans and cyclorrhapharans).
4) Identify one dish at a time; the smallest flies are most likely nematocerans, medium and larger
flies are most likely orthorrhapharans and cyclorrhapharans.
5) Use the online fly keys, starting with the fly antennae to identify to family-level if possible. This
can be hard, so just do the best you can. It takes time to learn a mega-diverse group like flies!
6) As each fly is identified, remove it from the dish and place it back in the zip-lock bag.
*You can always sort to the three main sub-groups based on antennae morphology, and explore fly
biodiversity in other ways; for example, students can describe or draw differences in fly morphology.
Then use the ZADBI website or EOL to look up different kinds of flies.
*As another alternative to identifying many flies, students can limit their identifications to five different
flies within each sub-group.
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Take a break halfway through identifying and regroup to share how identification process is progressing.
What have students been able to identify? What are the challenges? Can students offer tips to help each
other out? It may be beneficial for the class to go over a few identifications as a group.
When students are finished identifying, pour any remaining insects back into the zip-lock bag. Use extra
ethanol in squeeze bottles as necessary to wash specimens back in.
Record insects identified in the Sample Data Sheet. Start with the types of flies and the total. Afterward,
fill out the ecological role(s) (pollinator, predator/parasite, decomposer) of any flies that are identified
to family-level. You can find information on their ecological roles on the ZADBI website or EOL.
Fly
Example:
Calliphoridae
Total
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Pollinator
Predators/parasite
x
Decomposer
x
Extension: What Else Can You Find Out About Flies? (45-60 minutes)
Older students can be encouraged to go beyond and find out additional info about fly families. (Younger
students can stay focused on the observable characteristics, and their extended learning opportunities
might include identifying additional characteristics to compare.) Extend individual learning by directing
students to resources on flies on the ZADB and EOL websites. Students can explore information on the
flies that they have identified, or small groups can focus on certain families, or certan ecological roles
(pollinator, decomposers, predators, etc.).
DAY 5: Data Analysis and Wrap-Up Discussion
Data Analysis (45 minutes)
Go back to sample data sheets to analyze and compare results:
Were specific kinds of flies caught in particular types of traps? For instance, were more syrphid or flower
flies collected with sprayed honey water, than in tree trunk traps? Which traps were most effective?
Which collecting methods captured the most biodiversity…the least? What would happen if the class
only used one type of collecting method for this project? Which flies would not be trapped? How do
different types of traps offer a more accurate estimate of the fly biodiversity within the sampling site or
locality?
ZADBI scientists are aware that different traps attract different kinds of flies---for the most part. The
effectiveness of traps for particular flies is still being studied and refined.
Wrap-Up Discussion (30 minutes)
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Return to the original journal entries on students’ perceptions of flies. Are they the same/ have they
changed; if so, why?
Ask the student: How would you describe the overall quantity and biodiversity of flies found at our
school? Which factors affect biodiversity; what resources are available and what abiotic (nonliving
factors of the environment such as light, temperature, and atmospheric gases) exist? Refer to students’
previous recordings and observations of the sampling site.
ZADBI would not successfully inventory a comprehensive list of fly species as possible without various
collecting methods. Because flies are so incredibly diverse in where they live, how they behave, what
they eat, where they lay eggs, etc., it takes many types of traps to attract them. ZADBI would also not be
sustainable or successful without the participation of a large team. The participation and teamwork of
the whole class made your survey possible!
Congratulate students for following standard protocols used by entomologists and the ZADBI team.
DAY 6: Share or publish your work
Publish your research online!
ZADBI is more valuable if it is shared with a larger community of scientists and other interested groups.
This is a critical understanding for students at all grade levels -- scientists share their work and results in
order to gain knowledge and ask further questions! How do ZADBI’s results compare to fly surveys from
other geographical regions? How the populations of flies at Zurqui change over long periods of time? If
we don’t share ZADBI results though publications, websites and presentations than we won’t be able to
make comparison and track changes in fly populations. Because so many flies are vital for healthy
ecosystems, we really want to know more about them so we can better conserve them. What is the
value of research if it isn’t shared with other scientists?
Your class’ research can be uploaded onto the ZADBI website or EOL to share with other science classes,
diperists, and other fly fanatics. How does your class’ baseline survey of flies compare to schools in
other neighborhoods! The participation of enough schools can offer insight to the biodiversity of flies in
the Greater Los Angeles area; a collaborative study that has never been done before.
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