Subject: Re: First grader's questions - round 2

From: "Boyce A. Drummond" <[email-masked]>
Date: Mon, 29 Apr 1996 23:32:11 EDT

Responding to my statement:

"3. Butterfly adults do not have chewing mouthparts and thus are incapable of
eating meat.  However, several species imbibe liquid secretions of carrion,
attracted by the amino acids and the salts available from rotting flesh."

Julian O'Dea wrote:

>It is not really "meat", but aren't there also some butterflies which feed on
tears (at the eyes of bovids if I >remember correctly) and, I think, some which
feed on blood?

Julian is apparently  referring to a group of noctuid moths (Noctuidae) that
frequent the eyes of several species of large animals (elephants, horses,
buffalo, antelope, deer, and pigs) to dine on the eye discharges, which contain
various proteins such as globulin, albumen, and others in the leucocytes and
epithelial cells in tears.  This unique group of "eye-frequenting Lepidoptera"
was reported on by Hans Banziger (a Swiss entomologist) in the journal Fauna and
elsewhere in the late 1960s and early 1970s, based on his observations in
southeast Asia.  Banziger even used himself as bait, allowing a small species
(_Lobocraspis griseifusa_) to feed at his own eye.  He wrote: "The lachrymal
secretion was very much stimulated by the activity of the moth.  After 30 min.
my eye was so irritated that I was forced to interrupt the experiment."

And in the rainforests of Malaya, Banziger studied several species of noctuids
that are opportunistic blood-drinkers --- known to lick at the open wounds of
large animals, and especially to follow after mosquitos, whose sloppy dining
habits often leave behind enough spilt blood to provide a serendipitous meal for
the tag-a-long moth.  Noting the peculiar stance of one such moth (_Calyptra
eustrigata_) on a water buffalo, Banziger experimented some more.  In his words:
" I had become suspicious of this insect species because of a photograph taken a
few days before while it was feeding on a Malay tapir.  The photograph showed
something very strange about the moth's proboscis.  Now with a live specimen I
intended to study its feeding behavior on myself.  That night was to become
especially exciting!  Having incised my finger with a scalpel to draw fresh
blood, I offered my finger to the caged moth.  The moth climbed onto my finger
and did in fact plunge its proboscis into the blood, but it appeared to imbibe
none.  Instead it stuck its straight, lancelike proboscis into the wound and,
without any regard for the donor, penetrated the flesh.  The pain I felt caused
me to utter a cry of --- joy!"   Such are the ecstasies of science in the
tropics...

Most Lepidoptera have a proboscis that coils up under the head.   The ability to
penetrate skin and flesh with such a flexible instrument represents a
considerable adaptation.  Banziger speculates that his" vampire moth" evolved
>from  fruit-piercing relatives, moths whose stiffer probosces allow them to
penetrate the skin of fruits (even oranges).  Perhaps in a habitat where fruit
was available only seasonally, its ancestors turned to a more reliable,
year-round food source ---- large juicy mammals, substituting animal hide for
fruit skin and blood for juice.

So, Julian, moths get the credit for these unique feeding innovations, not
butterflies.  And when those first graders next pierce a box of fruit  juice
with a straw, I hope they will realize that what they are doing mimics the
behavior of some unusual tropical moths, reminding us all of how much we can
learn from the natural world.

Boyce Drummond, Director
Pikes Peak Research Station
P.O. Box 167
Florissant, Colorado 80816
[email-masked]