Thursday, September 27, 2018

Snout Nose Butterflies Out Again

Snout butterflies are on the loose again in Texas.  If you've been out driving, you have certainly killed one or one hundred, unfortunately. 
American Snout Butterfly, topside of wings.

American Snout Butterflies get their name from elongated mouthparts called palps that extend from the head.  They are small to medium sized butterflies (much smaller than a Monarch, also a bit smaller than a painted lady) and have orange and brown markings.  They blend in perfectly on bark and even flying can appear to be a leaf fluttering in the wind.

American Snout Butterfly underside of wings.
Each year, these guys have several generations and population peaks, but their numbers are directly correlated with rainfall and moisture.  This year we had rain at the right times to help their population.  What the rain does is increase the leaves their host plant makes - the spiny hackberry.  With more food, the females lay more eggs in the summer and those eggs hatch and the caterpillars eat the new growth.  The caterpillars can really only eat new growth from the spiny hackberry because its tender enough for them to chew on.

This population explosion we are seeing is a result of those babies (caterpillars) that fed on the tender hackberry leaves that our rains produced.  The caterpillars become pupa and emerging..

I suspect that the small cool snap we had this past weekend also triggered the adults to emerge from the pupa case.... changes in temperature like that often encourages pupa to emerge (a cool trick if you are raising butterflies from pupa and don't have much patience).

I imagine once we get rain this weekend the Snouts will probably get washed away, so they may not stick around for very long.  If we keep a mild fall, you may even see another generation.

Also keep an eye out for Monarchs as they make their way through Texas to Mexico for their annual migration.  We're seeing a few here and there, but right now the Snouts are taking all our attention.

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