[TN-Butterflies] Re: Common Buckeye - linea and rosa

MessageI simplified too much in my earlier description of the seasonal Buckeye 
morphs.

The rosa/linea difference is a continuum rather than a dichotomy.  Smith's 
study used a scoring system of five intervals to describe the degree of rosa 
expression:

0    Linea
1    Light intermediate
2    Dark intermediate
3    Rosa
4    Extreme Rosa

(see Table 1, p. 227 for more detailed descriptions of these categories)
http://lepidopteraresearchfoundation.org/pdf/pdf30/30-225.pdf

And the summer/fall timing is a continuum, too.  Smith's study showed that the 
fraction of individuals eclosed with at least some amount of rosa expression 
(meaning a non-zero score on the scale above) increased continuously from about 
14% under mid-summer conditions to 97-100% under lower-temperature or short-day 
conditions.

Smith's study doesn't discuss variations on the dorsal side, but his article 
references an earlier author (Mather) who does.  Mather provides detailed 
observations on the seasonal variations in the size ratios among the various 
eyespots, as well as in forewing lengths.  Again, conveniently, that article is 
available online:

http://research.yale.edu/peabody/jls/pdfs/1960s/1967/1967-21%281%2959-Mather.pdf

Mather, M.  1967.  Variation in Junonia coenia in Mississippi (Nymphalidae).  
Journal of the Lepidopterists' Society.   21(1):59-70.

Doug Bruce
Oak Ridge
Anderson Co., TN
  ----- Original Message ----- 
  From: Michael Lee Bierly 
  To: Tennessee Butterflies 
  Sent: Tuesday, November 17, 2009 9:45 PM
  Subject: [TN-Butterflies] Re: Common Buckeye - linea and rosa


  First, thanks to Harold for starting the "rosa" thread and others who have 
commented especially Doug who put everything in perspective. This is what this 
listserve should be (not counting counties). I first became aware of something 
in the air at Lowe's on November 4, when the wind folded the wings of a feeding 
Common Buckeye I was photographing and was rather shocked to see all the rose 
coloration and NO SPOTS. You have to work at seeing the ventral side as the 
species usually (from my limited experience) only partially folds its wings as 
it feeds and usually has them flat when landing on grass or rocks. I had 
wondered at the time if this was a fall thing, the only difference I was aware 
was a "regular" form and a "dark" form, something I still am sorting out. Now 
admittedly I have not had time to read the article Doug referenced, but from 
individuals that I have seen this fall, both morphs can be seen at the same 
time in the fall. Note from the images attached, that "rosa" was seen on 
November 4 at Lowe's and November 7 at the Manor; and "linea" was seen November 
8 at the Manor, the last time the species was seen for the season so far at the 
Manor.  Comments on the two forms at the same time would be appreciated. I 
don't know how long an individual lives or the "date-break" for "seasonal 
polyphenism".  I assume the dorsal side is the same in all morphs.? Thanks to 
all.

  Michael Lee Bierly, Nashville, Davidson County, TN

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