When I was a kid, I found a HUGE green caterpillar in the backyard that looked like it had ladybugs growing out of its back. I used my insect book to identify it, and found that it was the larvae of the giant Cecropia moth. The species of silk moth will spend all winter in a cocoon and hatch in the spring, boasting a wingspan of 6 inches, give or take.
This Ible
focuses on the needs of Cecropia moths in particular, though the build will
also be relevant to other silk moths (Lunas are what I'd like to try next) and
the raising of your local butterflies. I'll be focusing on function as well as
optimal quality of life for the insects within.
Why raise
giant moths? My goal is to successfully breed caterpillars that can be given to
community members and classrooms for educational purposes, as well as obtain
adult specimens for entomological display.
Step 1: The
Plan
The Plan
My initial
sketch was for a different size than the final house, but the materials and
principles remained the same.
PVC pipe for
a lightweight frame structure that could be easily disassembled for transport
if needed.
2 screen
mesh walls for ample air and temperature circulation, easy cocoon attachment,
and footing for the adult moths.
2 all
weather tarp walls to provide shade and rain protection.
All weather
tarp roof panel to provide shade, rain protection, and to block the moths from
the view of predatory birds above.
The bottom
will remain open for easy cleaning and so potted host plants can be slid
underneath for inclusion in the habitat.
Wide tabs of
tarp will be attached to the base to serve as anchor points, weighted with
heavy garden objects.
Step 2: You
Will Need...
Host plant
--Either available in nature locally or purchased from a garden center. Avoid
gathering foliage from places where pesticides are likely to have ben sprayed,
such as golf courses.
1/2 inch PVC
Pipe Lengths -- These make up the frame of the moth house. You can make this
any size you like. For my balcony-friendly version, I went with (4) five foot
pieces and (8) 1 foot pieces. Most hardware stores will sell PVC in longer
lengths like 10ft. If you ask nicely, most places will take your purchase in
the back and cut it down to your preferred sizes for you, making it much easier
to cart home.
1/2 PVC
3-Way Elbows -- These will be the corner pieces that bring your frame together.
Try to find elbows that have "slip" ports on all three openings.
1/2 inch PVC
male adaptors-- If you can only find elbows that have a threaded port involved,
you may need "male adaptor" pieces to convert the offending side into
a slip. My elbows had 2 slip and 1 threaded, which ultimately meant my moth
house was slightly rectangular (function was not affected).
1 Roll
Fiberglass Window Screen -- Can be found in the doors and windows dept. at your
hardware store.
1 Weather
Resistant Tarp -- inexpensive and easily found at hardware stores. They come in
a variety of sizes, so find the smallest tarp that will accommodate your moth
house dimensions.
1 Roll
Velcro --regular or self adhesive
E-6000 or
other flexible permanent adhesive. I used Loc-Tite on my base anchor tabs since
I feel more confident in its ability to withstand moisture.
Tools:
Sewing
Machine
Rotary
Cutter and Self Healing Cutting Mat
Ideally
these would be found locally, in nature, or you can order from a reputable
supplier.
A
responsible seller will be aware of state law and any other limitations on
where they can ship. There are some non-native species of butterfly I can not
receive in California, due to the caterpillars being a pest concern. Suppliers
should be willing and able to address any questions you have that are not
already verbalized on their website.
**Order
Responsibly. Never take on more than you can properly feed or house. Never
release a non-native species of insect into the wild.
Step 3: Host
Plant
Host Plant
Before you
purchase or hunt for caterpillars, the responsible thing to do is make sure
you'll be able to meet their dietary needs. Research your caterpillar of choice
and find out what their preferred host plants are. Cecropia caterpillar feed on
maple, cherry, plum, apple, box elder, willow, lilac, and a few others.
If you live
in an area with plentiful trees, you may be able to identify a large,
continuous source of food for your caterpillar. When I was a kid we had a maple
tree, so I would gather fresh leaves every day and put them in the container
with the caterpillar. Always provide fresh foliage daily and err on the side of
providing extra. You don't want a very hungry caterpillar to run out of food
while you're at school/ work.
Since I now
live in urban Los Angeles and the Cecropia's host plants are not as easily
found, I decided to purchase a plant well in advance to give it time to grow
before any caterpillars would need it. I bought a climbing species of lilac
which, trained to a rod or tomato cage, will make a nice vertically formatted
plant to fit inside the moth house.
I have read
that caterpillars tend to choose one type of plant early on and then prefer to
eat that type of leaf the rest of their cycle. So, again, make sure you have
enough of one type of host plant to get caterpillars through. You might be able
to offer a variety of plants, but whichever one they tasted first is probably
going to be their go-to.
Step 4: PVC
Frame
Work somewhere
with plenty of space to lay out and manipulate your PVC. Normally I would have
gone outside but it was 90 something degrees that day and I opted for a stretch
of living room floor instead.
You'll begin
by building the base footprint of the structure.
Lay out your
3 way elbows, facing each other to map out a square. As mentioned previously,
threaded ports will require male adapter pieces to make the elbows work with
your PVC lengths. Adapters simply screw in place on the threading. You can see
in the 6th photo how the addition of adapters makes my base rectangular, which
is totally fine as long as your top mirrors this shape.
Connect the
elbows using (4) one foot pieces of PVC. Press the resulting shape flat to the
ground to ensure all connections are firm and squarely situated on the ground
plain.
Insert your
4 long pieces of PVC in the vertical ports of your elbow joints. This gives you
the ultimate height of your moth house. It is important that this habitat be
generous in size, allowing moths to flutter up and down without damaging their
wings on the structure.
Connect your
remaining elbows and one foot PVC lengths in the same manner you used to create
the base.
When
finished, you will install this upside down; fitting the top of your tall PVC
pipes into the vertical ports of the elbows. This caps off the structure,
giving you a lightweight but sturdy frame.
Step 5:
Screen Sides
2 sides of
the moth house will be screen. This will allow healthy fresh air flow,
temperature regulation, and provide the moths with a surface they can easily
climb.
Unroll your
fiberglass window screen and flatten on the ground.
Lay the PVC
frame on its side on top of the screen, lining up the edge and corner squarely.
Push the PVC frame in 1 inch from the edge to give yourself some seam
allowance.
Wrap the
screen up and over so that it covers a second side of the frame. Take care not
to let the frame shift positions while you work. I could not find a reliable
way of marking measurements on the screen, so keeping edges and corners lined
up was key.
Since I
could not make markings on the screen, I used a ruler to measure the excess
screen (the distance from the edge of the roll to the point on the frame I
wanted the screen to end) so I knew how much to trim away.
Place a
cutting mat underneath the end of your screen roll. Using a ruler and rotary
cutter, trim away the excess inches of screen you just identified.
Work
vertically, trimming all the way up the length of your frame.
When you
reach the top of your frame, scoot the cutting mat over and work horizontally.
Trim away all excess screen 1 inch above the top of your frame. Again, we're
leaving that extra inch for seam allowance. You can move the PVC frame out of
the way while you work, just make sure you keep cutting in a straight line and
don't veer up or down.
This will
leave you with a piece of screen that covers 2 sides of your moth house frame.
Place your
frame back on top of the screen piece, as it was when you first started. The
PVC will serve as guidelines so you can cut door flaps that are reasonably
centered.
DOOR
CUTTING: You will make 3 door flaps; 1 high, 1 low, and 1 in the middle. This
will ensure you can easily access any part of the moth house for maintenance
and care.
Slide your
cutting mat underneath the screen, near the top of the frame.
Find a
rectangular template to trace with your rotary cutter for easy, consistent door
making. We get a ton of junk mail from Omaha Steaks and this plastic card was a
great size. A good door flap will be large enough to comfortably fit your hand
through, as you will need to be able to access the inside of the house to
provide food and do cleaning.
Place the
template on your screen. Use the guidelines on the mat to situate it squarely.
Make 3 cuts:
Left side, Right Side, and Bottom. Leave the top edge attached!
Slide your
cutting mat down and repeat all door cutting steps toward the middle of your
screen side.
Slide down
again and repeat toward the bottom of the screen side.
Step 6: Tarp
Sides
Tarp Sides
Since you've
already determined how much material it takes to cover 2 sides of the frame,
making your tarp half is easy.
Spread your
weather proof tarp out flat on the ground.
Place your
finished screen piece on top, living up the corner and edges squarely.
Using stick
pins, pin the screen and tarp together just as you would fabric. This will keep
the screen in place and ensure you get a mirror image out of your tarp.
Do a quick
trace around the edge of the screen using a dark Sharpie.
Now, leaving
the screen pinned in place, stand your frame upright with the edge of the pipe
touching to top border of your tarp tracing. See 4th photo.
Trace around
the base of the frame. This addition to your tarp pattern will be the piece
that serves as your roof.
Remove your
frame and remove the pins from your screen. You can set these elements aside
for now.
Use scissors
to cut along the Sharpie lines on the tarp. LEAVE the roof piece ATTACHED to
the larger tarp tracing. You want to end up with something that looks like the
7th photo.
ANCHOR TABS:
Since this
structure is lightweight, I though it would be a good idea to install some
anchor points to keep to from being blown over in the wind or otherwise knocked
around. The simplest solution that would work on any surface was tabs of tarp
that could then be weighted down with cinder block, heavy potted plants, etc.
Cut a piece
out of your excess tarp that measures approx. 13 x 16 inches.
Fold in half
to form a long rectangle, then cut on that fold to divide the piece in 2.
Stand your
PVC frame upright.
Slide one
tarp tab underneath the base.
Fold up and
over the PVC until the 2 ends meet. This will be the final length of your
anchor tab. If you do not feel this is enough space to place an adequate weight
on, cut a longer piece of tarp from your scrap and try again.
When you
have a tab size you are satisfied with, use a waterproof adhesive like Loc-Tite
to secure the tab halves together. Draw lines of adhesive on one side and then
fold over and press. DO NOT apply adhesive to the PVC pipe itself. You want
these tabs to be able to slide up and down the pipe so you can adjust their
placement based on your installation environment.
Let the
adhesive dry for a minimum of 20 minutes. Thick tarp material may tend to curl
up if not pressed, so I suggest stacking some books on top while the bond
dries.
Step 7:
Pinning and Sewing
You'll sew
your screen and tarp pieces together just as you would any other sewing machine
project. My Janome machine had no trouble getting through these unusual
materials on a tension setting of 3, with a regular needle. If you're nervous
about what your machine can handle, you may consider swapping out for a heavy
duty needle.
Pin the edge
of the roof piece to the edge of the adjacent tarp side.
Run through
your sewing machine as normal, taking care to remove pins as you go and
avoiding any metal grommets that remain in your tarp.
Pin the
remaining roof piece edge to the neighboring screen edges. Sew again.
You'll see
your piece beginning to take shape now that the roof is attached and corners
have formed.
Now pin the
long, vertical sides of tarp/ screen together. Run through the machine, again
taking care to work around metal grommets that could damage your needle. This
part takes a while simply because of the area you have to cover. If the weight
of the screen/ tarp is making sewing difficult, consider pulling a side table
up along your work station to support the excess while you work.
Leave the
bottom (the end without the roof panel) OPEN.
Step 8: Assembly
Place the
open end on the top of the frame and slide it on like a sock. If you encounter
any resistance, check for tarp or screen that may be hung up on one of the
elbows. Work down the length of the frame carefully and deliberately to avoid
popping any seams or creating tears.
Since your
cover dimensions were based directly off the frame, plus a little seam
allowance, it should be a pretty good fit --not too tight, not too loose.
Step 9: Door
Flaps
Now that the
structure of the moth house is intact, it's time to finish off the door flaps
so that they are escape/ intruder proof.
Using your
handy door flap template again, measure and trace 3 rectangles that are 1 inch
bigger on each side and 1 inch taller than your original.
Cut out the
rectangles.
Next, apply
E-6000 or Loc-Tite to the outside of the screen doorflaps. Hit all the edges
and make diagonal lines through the middle to get good coverage.
Line up the
top edge of 1 tarp rectangle with the top attached edge of the door flap. Press
and adhere the two together. Allow adequate dry time before disturbing the door
flaps again.
The generous
overlap provided by the tarp pieces will help create a secure seal that keeps
moths and caterpillars inside, and pest or predatory insects, like wasps, out.
Velcro
closures will make these doors simple to use. I had heavy duty stuff laying
around, but you can use regular craft weight velcro if that's what you have
handy.
Take a
length of velcro and sandwich the soft and prickly sides together. Doing this
before you cut ensures you will always get equal and proper amounts of each.
Use your
door flap template to mark and cut velcro pieces for each side and the bottom
edge. Since my velcro was very wide, I was able to split my cuts in half to get
more pieces made.
Keep your
velcro pieces sandwiched as you attach your velcro pieces to the screen around
each door frame. This will ensure your velcro halves are properly aligned to
eachother in the end.
I recommend
attaching the prickly side to the screen. This way if your velcro ever gets
misaligned during use, only the soft side will touch your fiberglass screen and
no damage can possibly be done.
If you have
trustworthy self adhesive velcro, peel of the backing and stick in place.
Otherwise, apply a few lines of E-6000 to secure the velcro to the screen.
Allow
adequate dry time for this first side to bond.
When the
first round of velcro is dry, you can remove the backing or apply adhesive to
the remaining velcro backsides.
Press the
tarp door down on top of this velcro and allow to dry. I turned the moth house
on its side to encourage even, flat drying of the adhesive.
Use gentle
encouragement at the bottom edge to open door flaps, and gentle pressing to
close them. You never have to have a complete seal all the way around to
consider them "closed", just enough velcro contact on the 3 sides to
keep insects from passing through.
Step 10:
Sealing for Safety
If your tarp
sections have any metal grommets, spot patch the open ports with a small square
of duct tape. Again, we want to shut out predatory or problem insects like
wasps, and safely contain any caterpillars we may house in this later.
Step 11:
Outdoor Set Up
An ideal
outdoor location is one that will not be too windy, and one that can warm and
cool naturally throughout the day (not inside a shed or other situation where
heat can be trapped). Do not worry if the location gets cool at night. The
cocoons are made to withstand full midwestern winters and will not suffer if it
gets a little chilly. Out on my balcony, next to the wall so that our apartment
can block strong winds and western sun, was a location that met these needs and
made it easy to monitor the cocoons daily.
When
choosing a location, be aware of neighboring hazards. Another reason I chose
the balcony, instead of down in my garden, is that several of my neighbors let
their cats roam the complex courtyard. A fluttering moth would be an all too
tempting target for a cat, so the house needed to go somewhere the cats do not
have access. Consider nearby pets, foot traffic, playing children, etc. and opt
for somewhere least likely to be disturbed.
Position the
moth house at an angle so that the tarp sides shield the inhabitants from
direct, prolonged daylight. My tarp faces the east, to block strong morning
sun, and the building blocks the western afternoon light. The nocturnal moths
will prefer shade, though having a sense of daytime is important for their
internal clocks.
WEIGHTS
Keep in mind
that your anchor tabs can slide side to side on the base PVC to accommodate
your location. You could center them both, or, for even more stable footing,
slide one all the way left and one all the way right. Weighing down the
opposite corners will give you the most firm grounding if the breeze kicks up.
Using heavy
potted plants as your weight provides an attractive solution. Bricks or cinder
blocks will serve you well too, if that's what you have handy. For my rear
weight I used my iron plant stand, which hasn't budged even in the craziest
Santa Ana winds.
Step 12:
Hanging the Cocoons
My eBay
order of 3 cocoons arrived very carefully packaged and cushioned with cotton.
To provide the hatching moths with ample room to emerge, climb, and dry, I
attached the cocoons to the fiberglass screen.
Note that
this outer, semi-fuzzy cocoon you see is actually an extra, outer layer made of
dead leaves and silk. The true pupae (the developing insect) is smaller unit
INSIDE this leaf/ silk shell. If you pick up the cocoon gently (handle as
seldom as possible to avoid any mishaps), you may be able to feel the pupae
roll around in there. Sometimes the insect even wakes up a little and you can
feel a twitching. This is normal and nothing to worry about.
To Hang
Cocoons:
Hold the
cocoon vertically, from one of the tapered ends. The pupae inside will shift to
the bottom of the pod.
Carefully
insert a safety pin into the very tip top of the cocoon. Since the pupae is now
sitting at the bottom, you will not hurt it.
Entering the
moth house though one of your door flaps, carefully run the safety pin through
the adjacent screen wall.
Close the
pin to secure.
Repeat with
any remaining cocoons. If you have multiple cocoons, stagger the height at
which they are pinned so that 2 moths emerging at the same time won't be
bumping into each other.
* It is
recommended to lightly mist the cocoons every few days. While the supplier I
brought from did not explain why, I suspect it keeps the cocoon materials moist
and thus easier to break through when the right time comes, in addition to
mimicking the moisture a cocoon in the wild would encounter through the
seasons.
Step 13:
Home Decor
Home Decor
You have
several weeks before the cocoons will hatch, which gives you some time to
browse the neighborhood for suitable moth aviary decor.
Keep it
Minimalist. While your first inclination may be to provide a lush habitat,
there are 2 good reasons to keep things simple:
--You don't
want to ruin all that nice clear, flight space by clogging it up with branches.
While these moths are large, their wings are still delicate and prone to
chipping and tearing if they are working in a tight space.
--Should a
mating pair produce eggs, you want to be able to find them easily so they can
be moved to a nursery container. Having a ton of foliage to examine will be a
time sucker.
Providing
just a few bare branches gives the moths a place to rest without cluttering up
the space. Thinner, flexible branches like those from a climbing plant work
well because you can maneuver them into the enclosure without risk of tearing
the screen. Choose branches that are no more than half the height of your
aviary. Keeping the "furniture" low reduces the risk of wing damage.
I stuck my branches in a small succulent pot to keep the bases stable.
Some blogs I
read suggested hanging a small brown paper sack on one of the branches. A
female moth will opt to deposit her eggs on the paper surface, since it is the
most leaf like item in the enclosure. This makes for easy identification and
removal.
Step 14:
Hatching Moths!
My first
female hatched on St. Patrick's Day morning, a bit ahead of schedule. She has a
chip out of one wing and I am unsure whether that was damaged when emerging or
if it was a developmental defect. After several hours pumping her wings, she
was mobile. While I do not recommend "playing with" your moths, they
are very docile and their chubbiness makes them easy to handle. I snapped a
photo of her on my hand when I helped her back up from a tumble.
If you have
multiple cocoons, you may find yourself confused as to which one your moth came
from. All of them looked perfectly undisturbed, even though I knew one now had
to be empty. What I learned via some YouTube research is that the moth emerges
from a pretty small hole on one end of the cocoon. This hole is called the
"vent". When spinning the silk, the caterpillar makes this end a lot
looser so it can be squeezed through. The cocoon facade doesn't split open as
obviously as the chrysalis of a butterfly, which is usually left obviously
torn.
After
carefully handling each cocoon and guessing by weight which was vacant, I used
small nail scissors to cut open the silk. Since I was operating on my best
guess, but wasn't certain, I worked slowly and carefully. Fortunately, I was
correct. While the outer silk seemed very intact to the untrained eye, the
pupae casing was definitely split and empty. The dark shell you see inside is
the actual pupae casing in which the moth developed.
*Again, I do
not recommend excess handling of the cocoons or moths, but if for some reason
you are concerned the pupae may not be viable (maybe it's getting way late in
the spring and you still haven't had a hatch), you can trim open that outer
silk covering and take a look. As long as you do not pierce or crush the actual
pupae, the moth will be fine. After checking the pupae, you can lay the silk
back into place and re-hang. Being exposed to the open air will not hurt the
pupae.
ADULT MOTH
CARE The adult moth's only purpose is to mate and create the next generation.
You do not need to provide a food source because they do not eat. In fact, they
don't even possess a mouth or digestive system. They are born with a finite
amount of energy reserves meant to be used up. For me as an avid pet owner,
initially this felt very odd and somewhat cruel, but the fact of the matter is
that this is how they are built and they do not feel hunger or pain for lack of
food. All an adult moth requires is a safe space with good footing (your screen
and branches) and access to a mate so it can fulfill its evolutionary drive.
Cecropia moth adults are reported to live anywhere from 4 -14 days. The cycle
then begins anew with any eggs they have left you.
Monitor your
moths and cocoons daily. You shouldn't have to get in and out of the aviary
much. The only times worth putting your hands in are to remove eggs or to
correct fallen decor that might cause a problem.
After only
one day out, the female began laying eggs like crazy. She deposited them on the
brown paper sack, as expected, but also all over the tarp walls and one of the
other cocoons. Since the male isn't out yet and our local Cecropia population
is scarce (making it unlikely that she was visited by a wild suitor), my guess
is that these eggs are not viable. Still, it was very cool to see them and
study which surfaces a moth mom deems good for eggs.
Step 15: The
Waiting Game...
I am now at
a point where the other two cocoons should hatch any day. My hope is that their
life spans will overlap with this first moth so i have a group. Based on the
size and formations on the pupae, I believe I have a male and female. I will
keep this Ible up to date as they emerge, and then hope to document the mating and
caterpillar raising process. Stay tuned!