Cannibalistic Monarchs / part II

MKJ jantsa at
Thu Aug 17 03:19:31 EDT 2000

In article <v01510102b5be27badfc0@[]>, lutzrun at AVALON.NET (Martha V. Lutz & Charles T. Lutz) says:
>Hi . . . me again.  My original note got this response:
>///> Can anyone confirm (or refute) for me that Monarch larvae will eat
>> conspecific eggs?  A few years ago while raising Monarchs I lost an egg.  I
>> thought I had miscounted eggs, or perhaps misplaced one, or maybe the kids
>> took it out and didn't put it back.  I thought about that disappearing egg
>> today--when it happened again.
>I know whereof you speak.
>There a number of other possibilities.  Lacewings (probably either adults or
>immatures) and coccinelids (ladybugs, also probably either adults or immatures)
>come to mind right off the bat.  I had a couple hours-old hatchling gulf
>fritillary caterpillars (and one less than an hour old) a couple years ago and
>lost both them an some eggs on host plant (pssion vine foliage).  On checking
>them the afternoon after I had captured them, I found one nice fat lacewing
>larva and no caterpillars or eggs.  I was not a happy camper.
>Pierre A Plauzoles
>sphinxangelorum at
>It's a great hypothesis!  But I should have mentioned (sorry I left this
>out) that the Monarchs were the only living things in the cage, so I can
>rule out predation other than by the one larva on the same leaf.  I have,
>in the past, lost various Saturniid larvae to spiders that rode in on the
>twigs I used to feed the caterpillars, but with these Monarchs I was using
>single leaves, and had looked them over pretty carefully first.
>Another possibility I thought of was that the egg was sterile and simply
>collapsed to the point of invisibility (although I did look for
>it--unsuccessfully--under a low-power magnifying glass).  Today I swiped
>the egg from a newly-hatched Monarch and took a good look at it . . . there
>was nothing I saw that looked like that eggshell after egg #1 vanished.
>I hesitate to simply conclude that there is cannibalism among Monarch
>larvae, but I can't rule it out at this point, either!
>Does anyone have any more information on this?
>Since Saturniids are not cannibalistic (not mine, anyway), it does raise
>some curious evolutionary ideas about Monarchs.  There are some interesting
>possibilities concerning the selection pressures that would produce this
>In Stride,
Point the video camera to the Monarch egg group. Record 1 pic/1-3 sec.
Watch every day the tape thru and by luck you will see it with your own eyes.
You can buy/rent/... a video cam and a suitable recorder. Its not expensive
method, and result is sure, perhaps time taking and sometimes boring. 
But Andy Warhol has made a movie about a sleeping man (2 hours) so why not a movie about 
"sleeping" Monarch eggs....      :o)




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