Tuesday, February 23, 2010

Monarchs having a rough winter

Monarch butterflies resting on Texas tree on way to Mexican overwintering sites.  Photographer: Mike Merchant
It's not related to pest control, but for anyone interested in the science side of entomology, the plight of the monarch butterfly is making headlines in the insect science community.  Overwintering monarch butterflies are having a tough winter in the Sierra Chincua mountains, in the Monarch Butterfly Biosphere Reserve in Mexico. Record torrential rains (which have been devastating for people in the region as well) along with cold temperatures have not been kind to monarchs this winter.

If you are not familiar, nearly all monarch butterflies, Danaus plexippus, in eastern North America migrate each fall to the Sierra Chincua mountains to spend the winter in a site that has ideal overwintering conditions for butterfly survival. In one of the true migratory wonders of nature, each year these butterflies start a return trip north to recolonize areas with milkweed plants and build up their population numbers.

Monarch Watch is a non-profit group dedicated to Monarch Conservation. In the blog postings at Monarch Watch, observers have been following the weather in central Mexico closely. Reports so far are fragmentary but of concern to monarch watchers. According to a recent email sent by Chip Taylor of Monarch Watch, surviving monarchs may be down more than 90% following the storms. Researchers fear that it will take monarchs at least two, and perhaps more, years to recover from the effects of this year's winter weather.

Of course monarchs have survived bad weather for hundreds, thousands, perhaps tens of thousands of years.  What makes bad weather significant today is that monarch refuges are shrinking due to habitat loss caused by illegal forestry and development in the key butterfly preserves.  With the loss of each hectare of prime butterfly habitat the monarch's survival becomes a little more tenuous.

No one knows the monarch's ultimate fate, but by all accounts we will see far fewer monarchs on the wing this year.

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