Life cycle of the Mealworm
They go through four
distinct stages during their life cycle.
A female beetle lays
as many as 500 Eggs in her brief lifetime of a
month or two.
The eggs are about the
size of the full-stop at the end of this
After a couple of
weeks the equally tiny larvae emerge from the
- The larvae are known
as Mealworms - altho they are not true worms.
The larvae seem to
have two purposes in life:
Any similarity to a
true worm is incidental
Mealworm larvae are
golden yellow and have 13 segments
Beetles at all stages + Pupa
a head, three
thoracic segments, and nine abdominal
Beetles start off pale>brown>Black
Mealworm larvae are
the counterpart of the Butterfly Caterpillar.
They pull themselves
around on six stubby legs
one pair on each
Mealworms are the
larval stage of Darkling (Tenebrio) Beetles.
Beetles, along with
other insects, are members of the phylum
a word meaning
Like all members of
their phylum, they have their skeleton on the
outside, like a suit of armour.
This is practical when
they are under attack but very inconvenient
when they are trying to grow.
Arthropods solved this
problem by moulting (shedding) this outer
shell-like cuticle periodically.
the moult, the soft white larva expands before
the new larger cuticle hardens.
For mealworms this
process repeats five times over a 2-month period
after which the
larva is about 3 cm
(just over 1") long.
- The final larval moult
reveals the next stage - the PUPA.
these are the
"Soft white, caterpillar-looking things"
You can see them in
the pictures at the top of the page
Click on the
Pictures to enlarge them and see the
Mealworms and Pupae more
Pupae don't eat and
they don't move except for a twitch when
Inside, however, the
mealworm is turning into a Beetle
much the same as a
caterpillar turns into a butterfly while
sequestered inside its chrysalis.
In 2 - 3 weeks the
Pupa splits open and out walks a beetle,
It's white at
first but soon turns brown and finally
black, after a day.
The Beetles mate and
lay eggs, and the cycle repeats itself.
Darkling Beetles are rarely seen in the wild
They are most often
found in barns, grain storage facilities and
food preparation areas.
Mealworms and Darkling
Beetles are small but not tiny
They don't bite,
smell, fly or jump and they are extremely
easy to care for.
HOW TO MAKE YOUR
You can keep & breed
Mealworms in a large, relatively flat
container with their food source
ideal start number is approx 1000 mealworms,
obviously less, if you start with the Beetles,
as they can lay up to 500 eggs each
Male & Female Beetles MUST be present
the picture below I am using a deeper smaller
tub, as I only had about a hundred Mealworms to
This will provide a constant source of "Live
Food" thru the winter months and into the Spring
and into the start of your Breeding Season, when
you need to up the Protein levels for your Birds
to bring them into Breeding condition.
Mealworms are a good, High Protein "Live Food"
for your Birds
foods Sources are :
Wheat Bran, Oat-Bran,
Rolled Oats, Breakfast Flakes/Muesli (If
NO sugar or salt added) or chick starter
The food must be kept
dry otherwise it can go mouldy.
- You've heard the
saying, "you are
what you eat"
well this applies to the mealworms when you use
them to feed to your birds.
What you have fed
them decides how nutritious they will be for
This also applies
to the fruit/veg you use as your "Water
as well as the
substrate you use as their basic "Food
Mealworms can go
through their complete life cycle without any
very efficient at extracting water from the
fruit/veg you add.
recommended that small bits of apple,
potato, carrot, lettuce, Banana etc., be added from
time to time as their "Water Source".
remove all stale fruit/veg. b4 it goes mouldy
and b4 you add new.
They seem to thrive
best when the colony of Mealworms has a large surface area.
Keep the bran or the
food source you have decided to use
about 2 or 3
cm (±1") deep in a basin, Cat-Litter Tray,
aquarium, or plastic shoe box etc.
If the container sides
are steep and smooth, it is not necessary to
keep the container covered.
I use an orange mesh
10kg carrot bag doubled over
keeps the container covered but allows
air - essential
NEVER PUT A solid LID
OVER YOUR CONTAINER - YOUR MEALWORMS MAY
can't climb the shiny plastic sides
of a container, so won't escape
Click on Picture to enlarge > >
Adults and larvae seem
to prefer hiding under bits of paper or light
I use cardboard
egg boxes which is ideal as it is
undulating and provides shaded areas
The Pupae give
no indication that they care either way - they
are in a kind of "Limbo"
The mealworm's preferred
Is very dry,
moderately warm and dark.
A bit of apple or
other fruit/veg provides extra moisture for the
mealworms and seems to stimulate rapid growth.
Keeping the container
on the top of a wardrobe in a warm room seems
and ideal environment.
As the temperature
increases, so does the rate at which mealworms
advance through their life cycle.
conditions, the complete life cycle can take
place in as little as 3 months
but more likely it
will take 4 months.
Cold slows the
process almost to the point of suspended
Mealworms can be
put into the refrigerator (not the freezer)
for periods of time to stop metamorphosis.
or if you are
storing them to feed to your birds and
don't want them to continue with their
Most people start out with Mealworms and go thru
all the stages up to eggs being laid and
Others buy them in as Beetles - to cut out a
lot of waiting
Keep them in the Bran or Oatmeal with a piece of
Fruit/veg as their water source.
Then when they've grown sufficiently and moulted
out of their skins for the final time
(they moult approx. 5 times as they grow out
of their skins and shed them)
You will see the shed skins like those
of a snake, littered in the Food source.
They then turn into the soft white pupa
They stay as fairly immobile Pupa for 10 -
this point a lot of people
remove the Pupa into a separate container
with similar Food source in the bottom
They then hatch out into "Darkling Beetles"
They are Pale coloured when they first hatch
but soon darken up into Black
these Beetles and keep them in a separate
Use the same Food and water source as for
They can fly but tend not to so keep the
container covered with something they cannot
penetrate but still allows air to circulate
The Beetles will lay their eggs 5 - 10 days
after they have morphed into Beetles
You will not see the eggs as they are minute
- as small as a full stop.
Eggs Hatch 7 - 14 days after they have been laid
You will not see the small mealworms until
they have grown up to about 1/8 - 1/4"
Smaller Finches consider them a delicacy
when they are young and soft at this
stage/size of their growth.
So, basically they are removed into separate
containers at each stage of their development.
If you order
Mealworms, Beetles/Pupa thru the Post to use in a
- What to do
when they arrive.
Mealworms &/or Beetles are
usually Posted out in a container with a
"breathing" cap to provide air.
Keep the Beetles in a
Warm room/area in low light.
At warmer room
temperatures, larvae will soon pupate.
Cover Beetles loosely with a
paper towel to provide crawling space.
Beetles can fly but
rarely seem to
a paper towel
should keep them enclosed where you want
or mesh Carrot bag
if they are in the mealworm/pupa stage.
THEY MUST HAVE
plenty of AIR CIRCULATING or they MAY DIE !
Add slices of potato
or carrot etc (see
above) for moisture and add a substrate of
bran/oats etc. for food.
necessary or if it becomes mouldy.
If you Order Mealworms
to Feed to your Birds, thru the Post
- Keep them in a cool environment i.e. Fridge (not for human
They need no special
care but should be used as soon as possible, as
they have a rather short life span.
Store in a cool place
at 45 to 65º F out of direct sunlight.
Keeping them cool
slows development, so they do not metamorphosise
Keep them in a feed
medium (see above) Bran etc.,
this keeps them
healthy and nourished until you are ready to
feed them to your Birds.
Don't forget to add a small piece
of Fruit/veg as their water source
: Maggots are also interesting
- Feeding them can be done in a number of ways :
- Fresh Maggots - put them into bran or sawdust until the black line
down their bodies disappears (usually a couple of days) you can then
feed then in the same way as mealworm
- Let them form a chrysalis - then feed them direct
- Some people then put the chrysalis into a box with small holes
in the top and as the flies hatch the birds get used to catching them
-but not all birds eat flies
- "Pinkies" are acceptable but many birds don't seem to eat Pink
- there's research going on about colour of feed at Glasgow
university at the moment for which I've supplied the birds - there
wont be any results on that for a couple of years
- Usual cheapest place for mealworm is Priory Pets in Cage Birds
- - they will happily keep somewhere cool for up to 6 weeks
- so buying in bulk is possible-
- if you do this have to keep them in trays so that you can
constantly add dry food otherwise they sweat and die.
- Alternatively look on Nettles, Beans, Cabbages, Roses etc., for
Aphids, Caterpillars etc.,
- just nip the infested shoots off and feed in a dish to the