late Green Darner

Harold B. White, III halwhite@UDel.Edu
Fri, 07 Jan 2000 08:55:30 -0500

Odonata -

Bob, Thanks for the response. Although I didn't spend any time in the
field on the 2nd of January, I was quite aware of the strong steady wind
from the south and the very mild temperatures here. The temperature got
to 69F in Wilmington. Because I am not that far west of you, it seemed
most likely that the Anax junius you observed in southern New Jersey
would have come from the south. Your comments and observations of
butterflies seems to support that hypothesis. However, it is of interest
to know how much cold weather adult A. junius can survive and whether
emergence can occur during unseasonal warm spells. 

I have had a long standing discussion with Phil Corbet about how early
Anax junius can emerge in the north. On March 31, 1963, Rudy Raff and I
observed fully mature Anax junius in central PA at Ten Acre Pond only
two weeks after snow melt. [Harold B. White, III and Rudolf A. Raff,
"Early Spring Emergence of Anax junius (Odonata:  Aeschnidae) in Central
Pennsylvania,"  Can. Ent. 102, 498-499 (1970)]. But, we also observed
two exuviae in an area that would have been dry in the fall which thus
seemed to preclude the chance that the exuviae had over-wintered from a
fall emergence. Phil (and I) find the obvious conclusion hard to accept
that emergence occurred that early so far north. Other observations of
A. junius exuviae and emergence in the early spring (or late winter)
would help resolve this long-standing puzzle. 


Bob Barber wrote:
> Northeastern Odonates -
> Bob Barber wrote:
>  On January 2, 2000, with temperatures in the mid-60's, we had a one Anax
>  junius flying in southern NJ.
> At 8:36 AM -0500 01/05/2000, Harold B. White, III wrote:
> >Bob, That is amazing! Are you sure it was a "late" rather than an
> >"early" record?
> >Hal
> Hi All,
> Hal raises an interesting point, and Ken Soltesz is curious as well.  I
> once saw a small flight of Anax in mid-November, that I thought were
> reverse migrants, mainly because I had seen none in this particular year
> since early October.  This flight was seen after a warm front came through
> from the south.  We certainly know from banding records that hawks and
> passerine birds reverse migrate in fall.  The Anax that I had on 1/2/2000
> could have wandered in from the south.  We also had a Common Buckeye
> butterfly on the same day, which is a species that can't overwinter here,
> but re-colonizes from the south each year.  This could have come in on the
> same winds.  We also had some Angle Wings, that do overwinter as adults,
> and many Orange Sulphur butterflies, but this species does not have a
> diapause and emerges in any warm period through the winter.  I did have
> more than normal numbers of Anax into early December this year, and they
> certainly can stand sub-freezing temperatures, but I certainly can't say if
> they could survive the temperatures we had in late December.  I guess I'll
> have to call it an early/late Anax junius.
> Bob
> *******************************
> Bob Barber
> Histology/Pathology
> Institute of Marine and Coastal Sciences
> Rutgers University
> Haskin Shellfish Research Laboratory
> 6959 Miller Ave.  Port Norris, NJ 08349
> ***********************************
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