[Taxacom] Trichoptera morphology

[John Grehan]

This email is directed to any trichopterists on this list who work on
Trichoptera morphology. I am writing a small note on an 'obscure'
(relatively speaking) structure in Lepidoptera where the sclerotized
posterio-lateral margin of the first abdominal tergite extends laterally
as a tergosternal bar posterior to the spiracle which hinges with the
anterior-lateral arms of the second abdominal sternite in the
'primitive' Lepidoptera (at least those few representatives where this
structure has been noted), whereas in the Ditrysia (in which most
butterfly and moth species occur) there is no direct connection. Even
though there may be a post-spiracular lateral extension in Dityrysia,
the sclerotization does not cross the pleural region to make contact
with sternite 2, and the anteriolateral arms of sternite 2 are in direct
contact with the thorax. 

 

These observations raised the question as to whether either arrangement
was derived relative to an outgroup so I thought I would look at
Trichoptera. I was surprised to find in my specimen (Limnephilus sp)
that there was not only no post-spiracular tergosternal bar for the
first abdominal segment, but that the anterior-lateral arms of sternite
2 were in contact with anterior-lateral arms of the second abdominal
tergite.

 

I could look into the literature, but this is just a side observation to
my principal projects, so I would be grateful if any trichopterist
morphologist on this list may be able to comment on whether the
arrangement I saw in the trichopteran is general for Trichoptera, or
whether the arrangement is far more variable. 

 

As this is a rather obscure subject I suggest any feedback come to me
off list. If any clarification is required for such individuals I can
send images.

 

Thanks,

 

John Grehan

Dr. John R. Grehan
Director of Science and Research
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, NY 14211-1193

email: jgrehan at sciencebuff.org
Phone: (716) 896-5200 ext 372
Fax: (716) 897-6723

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