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Gardening Articles for week
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26th JANUARY 2008
Written by Wally Richards.
MONARCH BUTTERFLIES
The monarch butterfly is a great fascination for gardeners,
we just love seeing them flitting around our gardens during
the summer months. Some become very worried when they don't
have these butterflies arrive in their gardens, at the expected
time each year with no caterpillars on any of the many swan
plants, they have specially planted out for them.
There is even a Monarch Butterfly web site in New Zealand
at http://www.monarch.org.nz/monarch/ where people can log
into and participate in sightings and many other activities.
The Monarch butterfly (Danaus plexippus) is an interesting
creature that is poisonous to birds and predictors because
of its diet on the milkweed plant we commonly call the swan
plant. (Gomphocarpus fruticosus) The caterpillars, having
a diet of this plant, helps to keep them safe from predictors
and the same applies to the adult butterfly. If by chance
a predictor was to eat either the caterpillar or butterfly
it would become sick and then remember in the future to leave
them alone.
Large amounts of caterpillars on even a large swan plant will
soon decimate the plant to the point where the plant has no
foliage left and it dies. My recommendation to prevent this
is to place a small clear plastic bag over a small portion
of the foliage at the end of one branch. Tied in such a manner
so that no caterpillars can get to eat the foliage inside
the bag. Punch very small holes in the bag so that the foliage
can breath and moisture can escape. By doing this it will
save the plant and once the caterpillars have finished for
the season the swan plant can regenerate for next summer.
(Remove the bag when caterpillars are finished for the season)
In the mean time you can, once the caterpillars have eaten
all the other foliage, either purchase more swan plants to
enable them to reach the stage of pupating (forming their
cocoon) or you can take the caterpillars off the plant and
feed them on pieces of pumpkin or cucumber till they reach
their final stage.
Another problem that gardeners can have is insect pests such
as aphids or mealy bug attacking the swan plant while there
are caterpillars present.
There is no chemical or safe sprays that can be used to control
the pests without also killing the caterpillars. Generally
speaking you need to control the pest insects by squashing
them till such time as the caterpillars have all pupated and
then if there are no further eggs on the swan plant you can
safely spray Neem Tree Oil for control. Also do not place
any Neem Tree Granules anywhere near the root zone of the
swan plant while the caterpillars and eggs are present.
If mites attack the swan plant you an safely spray with Liquid
Sulphur without harming the caterpillars.
I looked up the Internet and found some interesting facts
on Monarch Butterflies which I will share with you:
How do you tell the male monarch from the female?. Males have
a small spot on the inside surface of their hind wings that
is not present in females. The ends of their abdomens also
look different. Females tend to look slightly darker than
males, and have slightly wider wing veins.
How come only male monarchs have a big black spot on their
wings? These dots are made of specialized scales that, in
some butterflies, emit a chemical used in courtship. Even
though this chemical does not appear to be important in monarch
courtship, the males still have the spots. The spots are much
larger on close relatives of monarchs.
. How many times do their wings flap in a minute? . About
5 to 12 times a second, so about 300 to 720 times a minute.
(This is actually quite slow compared to many other butterflies.)
How do monarchs breathe? Monarchs breathe through tiny openings
on the sides of their bodies called spiracles. (The spiracles
are in their cuticle, like our skin). The holes open into
a system of tubes in their body (called trachea) that carry
the oxygen all over their bodies. They don't have lungs.
Do monarch butterflies have brains? Yes, they do. All insects
have brains. Just like our brains, their brains receive messages
from the rest of the body, and send messages to the muscles
and other organs in the body. They are relatively smaller
than our brains, though. ( Likely there are some exceptions
to this as I noted through my lifetime, my comment)
Can butterflies overheat if it gets too hot? . Yes! Butterflies
of many species need to avoid extreme heat, and have many
strategies for doing so. Monarchs retreat to shady places
when it's very hot.
Is it true that monarchs can only see one color? . No, butterflies
have the broadest visual spectrum of any known animals, and
can see more colors that you can! They can see UV light, which
humans can't.
Are butterflies nocturnal or diurnal? Diurnal.
Where do they go and what do they do at night? They remain
still at night, probably on vegetation like bushes and trees.
The life span of the adult Monarch varies, depending on the
season in which it emerged from the pupa and whether or not
it belongs to a migratory group of Monarchs. Adults that emerged
in early summer have the shortest life spans and live for
about two to five weeks. Those that emerged in late summer
survive over the winter months. The migratory Monarchs, which
emerge from the pupa in late summer and then migrate south,
(America) live a much longer life, about 8-9 months.
I hope that has given you a better insight to our much loved
Monarch Butterflies.
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Any Problems ring me at 0800 466464 (Palmerston
North 3570606)
Email wallyjr@gardenews.co.nz
Web site www.gardenews.co.nz
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