P. sennae (Cloudless Sulphur) outbreak

[Pavulaan at aol.com]

In a message dated 98-09-08 13:57:36 EDT, Ed Rucker wrote:

<< P. sennae are flying in great numbers on the Delaware shore as well.  They 
 travel singly or in pairs, often following the same routes and giving the
 appearance of a butterfly procession.  >>

Ed has also observed a remarkable phenomenon that has not yet been thoroughly
studied or documented.  Several years ago, also along the Delaware Shore
(Delaware Beach State Park), I also observed Phoebis sennae flying along the
same precise routes along the dunes and swale.  Some would appear to follow
others, some alone.  After a time, I observed several very precise aerial
PATHS that the butterflies would follow.  They would generally cross a dirt
trail at exactly the same one or two places, then fly past the same shrub, on
the same side, cross the parking lot over the same rows of cars.  We even
stood at the parking lot's edge, where the butterflies would emerge from
behind a clump of shrubs, then have them repeatedly fly over or past us at a
rate of about one every 10 seconds.

The P. sennae invasion is also occurring in the Virginia Piedmont from
Fredericksburg west to Culpeper.  On 9/6/98, I observed them as singletons
along roadways, every mile or two, but this is still a good flight for the
northern Virginia Piedmont.

Harry Pavulaan