Message From Mary Beth Prondzinksi

Rob Thorn robthorn at
Mon Oct 6 16:57:42 EDT 2003

Here in central Ohio we've had rather heavy numbers of Painted Ladies since
around mid-September.  Where census transects might usually get 1-3 this
time of year, we are instead getting 10-30.  Now in October, with most of
the nectar sources frosted out, the remaining butterflies are crowding into
plantings, esp of Butterfly Bush.  I had 12-14 on a butterfly bush this
morning, while Dave Parshall had mentioned seeing 20+ on bushes at his
house for several days.  There appears to be no obvious directionality to
their movement, so it's difficult to say if they are migrating or just
irrupting.  I've not found any eggs, larva, or pupae in September or

Rob Thorn, Gahanna

> [Original Message]
> From: Stanley A. Gorodenski <stan_gorodenski at>
> To: <leps-l at>
 > Date: 10/6/2003 1:40:26 AM
> Subject: Message From Mary Beth Prondzinksi
> 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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--- Rob  Thorn
--- robthorn at
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