Message From Mary Beth Prondzinksi

Patrick Foley patfoley at
Mon Oct 6 09:24:44 EDT 2003

Mary Beth,

Weak back-migrations of the Painted Lady (Vanessa cardui) have been 
observed. We have some discussion of this in the leps list archives.

In Northern California (near Sacramento, this year's northward migration 
was not inpressive. I was also in Anza Borrego (CA's little bit of 
Sonoran Desert) this spring, and the Painted Ladies were common but not 
very abundant, despite (or perhaps because of)the reasonable rainfall. 
Rainfall improved this year after a couple of SW drought years. Someone 
from the region should improve this vague description.

These are just haphazard observations, not careful, quantitative analyses.

Patrick Foley
patfoley at

Stanley A. Gorodenski wrote:

> Mary Beth wanted me to post the following message in Leps-L
> Mary Beth Prondzinski
> ----- Forwarded Message -----
> From: mbpi at
> Date: Sat, 4 Oct 2003 08:24:59 -0500
> Subject: Re:  Question on Vanessa cardui...
> MIME-Version: 1.0
> Content-Type: multipart/alternative; boundary=--__JNP_000_06be.5a48.3203
> Hello everyone!
> Remember me?!  It's been awhile since I was on this listserv, but
> something has come up that I would like your professional input on...
> Here in the Midwest, and more specifically the Chicago, Illinois area
> where I am, there was a HUGE irruption of Painted Ladies (Vanessa cardui)
> which was first observed on the 18th of September.  All the individuals
> observed were fresh and unblemished...indicating they were new emergents
> as opposed to "migrants."
> So here is my question:  Do Painted Ladies ever "reverse migrate"?  I
> never observed any directional movement in the massive numbers, but
> rather saw them flitting around from one nectar source to another without
> exhibiting any territorial behavior.  These large numbers seemed to be a
> phenomenon restricted to the middle regions of the US, including
> Minnesota, Wisconsin, Iowa, Illinois, Kansas, etc. at least from the
> variety of "sightings" that were reported.
> Most interestingly...there was no observable movement of massive numbers
> of Vanessas during the spring...rather, we had an unusually blustery,
> cold spring with predominating northeasterly winds, right up until June
> 21st, when BAM...summer quite suddenly convened (!)  Few butterflies were
> even seen until mid-summer, and even then numbers were modest, with the
> dominating species being Monarchs, and a good representation of Hackberry
> butterflies (including the rare-in-these-parts Snout butterfly).  But I
> digress...  The Vanessas were a small handful, at best.
> So what promoted this astounding irruption?!  The only clue I received
> was an email of a photo of a Vanessa cardui caterpillar munching on an
> unidentified Salix species.  Not much help considering the vast number of
> host plants that Painted Ladies lay their eggs on (!)
> Anyone of you experts want to posit a feasible conjecture on what
> happened and why?!  I would greatly appreciate some knowledgeable
> feedback, as I've been asked to write a "personal observation" on the
> irruption for Chicago Wilderness magazine, and from the inquiries I've
> made here in Chicago, there hasn't been one really GOOD explanation from
> any of the local entemologists.  Granted, there is a dirth of "butterfly
> experts" here, which is why I am enlisting your expertise! 
> I might also add that after one week of Painted Ladies in my hair and in
> my face...the temperatures dropped the point where the
> observed intrepid few appeared to be "shell shocked" from the abrupt
> wintery change.
> Thanks in advance for your much anticipated response!  Please cc: me if
> you respond on LEPS-L, as I am no longer subscribed...
> Mary Beth Prondzinski
> mbpi at
> ------------------------------------------------------------
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