----- Original Message -----
Sent: Thursday, November 07, 2002 1:04 PM
Subject: RE: More on Nocturnal Color Vision
This is a note regarding the
implications of an
example I believe Nabokov
discussed. He was fascinated by the translucent "windows" in the wings of
the large Saturnid moths and in some other
"leaf mimics etc." and, in one case (where this window had a
venation line running through it) speculated that this kind of "detail" with
regard to what it appeared to look like to him, certainly could not have come
from directional (natural) selection alone. With the information now
available on nocturnal color vision (by starlight!) indicated in moths, the
following comments appear quite relevant to the situation of adaptive
(selectable) value in the translucent "windows" on wings of Saturnid , or other, moths. The
arguments can be
seen below:
Whereas,
l. As is well known in the scientific literature, insect sensory
receptors, and the patterns of behavior ("released patterns") they trigger,
usually work on an "all or none" basis. That is, a specific kind of
reception of sensory data is linked to specific kinds of patterns of
behavior that can be released/performed; and
2. The long and quite detailed paper (still unpublished) I gave at
the Harvard ALA meeting noted that scientific papers document that insects can
pick up [and thus "look for" regarding their behavioral patterns, recognition
patterns etc.] specific wavelengths, frequencies, and resonanace patterns of
direct and/or reflected light, most often in the UV spectrum; and
3. It
is well known in diurnal (day-flying) Lepidoptera (butterflies) that behavior
and recognition patterns relate to reflected UV from the wings that human beings
cannot see (Scientific papers demonstrating this use visible photographs of
these UV signals from the butterflies wing by using UV sensitive film.
These UV signals are seen as PATCHES and PATTERNS on the wings, just like what
we see on the wings are color or colored patterns etc. But most of
the UV patches ARE NOT in the same places on the wings as the visible light
patterns);
Thus,
If,
according to this new information, UV light from starlight creates a "visible"
spectrum for color vision by moths at night, it is quite possible that the
translucent "windows" on the wings of Saturnid , or other, moths function as a
differential channel for the conveying of that light (from the environment, i.e.
starlight) through the wing and "out" to other moths sensory systems (for
recognition or other purposes etc. as is common with sunlight and diurnal
Lepidoptera). The "windows" may therefore be one of the channels in the
wing involved with this light-related communication. In the
case of a vein running through the translucent "window", and sensitivity of
insect recognition to wing beat rate (well documented in the scientific
literature) the vein might function as a modality regarding the frequency of
light that is let through the translucent "window" etc. Thus, there
appears now to a possibly large range of actual adaptive (and thus selectable)
functions that the translucent "window" in the wings of Saturnid , or other, moths could be
performing.
best
Dr.
Kurt Johnson