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| Caterpillar |
Moth |
Egg mass |
Eastern tent
caterpillars are hairy, brownish black with a light stripe down the
back. Blue spots and brown yellow lines are found along the sides
of their bodies. The adult moths are usually a reddish-brown
colour, but can be yellow-brown as well.
The Eastern
and Forest tent caterpillar moths lay their eggs in late June or
early July, while the Western tent caterpillar moth appears later
and lays eggs in August. The eggs are laid in groups of 150 to 350
and encased in a frothy substance that hardens into a shiny
Styrofoam-like material, forming a dark brown or gray band that
straddles or encircles twigs of susceptible trees.
In the
spring, as soon as foliage opens, the eggs hatch into young
caterpillar larvae that make communal tent webs. The Eastern tent
is usually built in tree or branch forks while the Western tent may
enclose the tips of branches. The size of the tent increases as the
larvae grow. The caterpillars mature in four to six weeks, reaching
a length of about 2 to 3 cm.
In June or
July, the caterpillars enter the pupal stage of development,
covering themselves in cocoons. The cocoons may be found on tree
trunks, fences, debris and beneath sheltered areas such as raised
plant boxes. Approximately 10 days later, the adult moth will come
out of its cocoon and mate within 24 hours. The female immediately
begins to lay eggs for the next spring, producing only one
generation of tent caterpillars every year.
Caterpillars
feed on deciduous trees in most parts of southern Canada . The
Eastern tent caterpillar feeds mainly on cherry, apple and crab
apple trees. The Western tent caterpillar chooses willow, poplar,
apple, plum, cherry and oak, while Forest tent caterpillars seem to
prefer trembling aspen and poplars in Canada, but also feed on many
other trees like American beech, apple, basswood, cherry, white
ash, birch, mountain ash, sugar maple, red oak, white elm and
willow.
