Friday, August 29, 2008
Sunday, August 24, 2008
Tuesday, August 19, 2008
Thursday, August 7, 2008
Chrysalis minutes old
Often a new chrysalis will appear lumpy, lopsided or an unexpected color. This picture shows the normal appearance of a new chrysalis for the first couple hours of development. Note the yellow and white stripes resembling the caterpillar's skin. These will disappear and the chrysalis hardens.
Video: attempting to disconnect the shedded skin
The chrysalis is formed and the pupa is attempting to disconnect the shedded skin from to top of the chrysalis. If the pupa is unsuccessful, try gently teasing the skin away with a thin paint brush. This is the final step before the new chrysalis will hang still to dry and harden in preparation for 10-14 days of creation. The average time in our home for each chrysalis has been 11.5 days before a new monarch emerges.
Another sign of change
This is a wonderful example of the twisted antennae of the monarch larva shortly before 
metamorphosis. Notice how the body segments are clearly defined and puffy. Often the caterpillar will have a greenish hue. The caterpillar is in the "J" formation. This "J" is uncurling, another sign of change. Moments before the transformation begins, the three sets of front legs will be tucked in toward the skin and the "J" will open with an aparent muscle contraction. The back of the skin will splits open as the transformation begins. Metamorphasis from larva to pupa takes about 6 minutes, with an additional 30 - 60 seconds of twisting to detach the shedded skin.
(Note: The chrysalis behind the "J" is only minutes old.)
metamorphosis. Notice how the body segments are clearly defined and puffy. Often the caterpillar will have a greenish hue. The caterpillar is in the "J" formation. This "J" is uncurling, another sign of change. Moments before the transformation begins, the three sets of front legs will be tucked in toward the skin and the "J" will open with an aparent muscle contraction. The back of the skin will splits open as the transformation begins. Metamorphasis from larva to pupa takes about 6 minutes, with an additional 30 - 60 seconds of twisting to detach the shedded skin.(Note: The chrysalis behind the "J" is only minutes old.)
Research in Duluth, MN
Recently the changes in the monarch population in Duluth, MN were studied. The research, entitled "The Rise and Fall of Danaus plexippus in Duluth, MN", was conducted from 2000-2005. The researchers proposed the following hypotheses (taken directly from the link below):
The conclusions varied from the original hypotheses (again, taken directly from the link below):
This chart can be found at:
http://www.monarchlab.org/research/strom1poster.pdf
- H1:The ratio of monarchs to milkweed will
decrease year to year. - H2: Monarch eggs will always be in more
abundance than the larvae. - H3: In six years the overall numbers of
monarchs have decreased. - Null: The ratio of monarchs to milkweed will not
change from year to year.
The conclusions varied from the original hypotheses (again, taken directly from the link below):
- Every other year, the ratio of monarchs to
milkweed increased or decreased; H1 was
not supported. - H2 was correct: eggs were always more
abundant than larvae. - In six years of monitoring, overall monarch
numbers declined, supporting H3. - Ratios of monarchs to milkweed change
annually, therefore rejecting the null
hypothesis.
This chart can be found at:
http://www.monarchlab.org/research/strom1poster.pdf
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