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Archive for July 7, 2011

Monarch Butterflies

The third and fourth generations of the monarchs that migrated from New England to central Mexico last fall are arriving in New England, mating and laying eggs.  The eggs are hatching, and some of the larvae, or caterpillars, are well on their way to adulthood.  This larval stage of their metamorphosis lasts about two weeks, and is the only stage during which monarchs have chewing mouth parts. The caterpillars take advantage of this by consuming both the leaves and flower buds (see photograph) of common milkweed practically non-stop, increasing their body mass up to 2,000 times.