b-fly releases at events

Mark Berman bugman at bugs.org
Sun Sep 26 20:59:26 EDT 1999


Well, conspiracy theories aside, it doesn't seem as if these data support
your statement that "genetic programming" was unaffected by the displaced
releases presented below (**note comments below). My understanding of the
Monarch migration (which I obtained in the late 80's, and so is perhaps
somewhat outdated) is that individuals _east_ of the Rocky Mountains head
toward the (dwindling) overwintering sites in Mexico. But the butterflies
_west_ of the Rockies populate the coastal California sites. And that there
are a few non-migratory populations in Florida and Louisiana (and maybe
other places) that show some seasonal movement, but nothing dramatic.

If this is still the prevailing belief, I don't think the release data below
refute genetic control. I am also led to believe the mechanisms of this
migratory behavior are little understood. That suggests that it could be a
combination of environmental factors (angle of UV sunlight, day length,
average temp/humidity...) acting upon genetic templates may control their
migratory direction.

If that is indeed the case (and I'll be happy to have my understanding
updated it if needs it) then it seems possible that regardless of their
birthplace, Monarchs finding themselves in Nevada at migrating time will
head toward California. This would be true of those released in BC as well.
But butterflies released in North Dakota would head for the border. And it
seems in any case, these "experiments" (was that the purpose of these
releases?) did not actually test the geographical influence on migratory

It would have been more appropriate, to release portions of the same Toronto
population just to the east and just to the west of the Rockies at the same
north/south latitude and catalogue recaptures. A swell compliment to this
would be to release to the same sites butterflies raised in California or
someplace west. And just for the heck of it, release some in Florida, too.
In this scenario it would be reasonable to hypothesize those released to
east would end up toward the direction of Mexico, and those to west toward
coastal CA. Florida releases should pretty much stay put. This would suggest
a genetically controlled behavior influenced by environmental conditions.

I do not understand the design of the release experiments described below.

However, a further note on this topic: Empirically, it seems as if the
numbers of Monarchs flying in the New England area have declined in recent
years. I admittedly do not have hard data to back this up. It's just
something I pay attention to and have noticed. I am NOT suggesting this has
to do with anything that has come up in this (interesting) debate. There are
many potential causes for disruption of this sophisticated behavior. To
suggest (as I think you might have) that it is not under genetic control is
a little simplistic. I think "fixed behavior patterns" fall under genetic

Paul Cherubini <paulcher at CONCENTRIC.NET> wrote in message
news:37EE1CF7.5485 at concentric.net...

> > I have wondered, ever since hearing a fascinating paper in Ottawa in
> > whether the migration tracks of Monarchs might actually have nothing to
> > do with genetic variation, but rather merely reflect the effect of the
> > starting point on some fixed behavior pattern.
> Ken, available evidence suggests your latter hypothesis is correct.
> In 1964, 800 monarchs from Toronto, Canada were tagged and shipped to
Reno, Nevada
> for release in September. Three were recaptured along the California coast
in October and
> November in the vicinity of California monarch overwintering sites - these
eastern monarchs
> obviously did head in the direction of Mexico as one would expect if, in
fact, eastern
> monarchs are genetically programmed to do so.

** It seems like these headed to the California overwintering sites - that's
where they were captured? How do these data aim them toward the Mexican
sites - other than the fact they went southward to the California sites?
Releases west of the Rockies would expect recaptures in California.

> In 1972, Donald Davis, (who is subscribed to this list) shipped over 1000
> monarchs to Vancouver, British Columbia.in August and September. I
recaptured two of
> them, alive and clustering with our California monarchs, at overwintering
roosts near San
> Francisco, California in October and November - again demonstrating
genetics is not
> involved much, if at all, in the control of migration tracks.

How does this demonstrate "genetics is not involved much in the control of
migration tracks"?

Based on *my* understanding of the behavior, this makes perfect sense. West
of Rockies=>coastal California. If anything, it strongly supports the theory
which I had heard explains this phenomenon. (I'll admit, I'm not 100% sure I
could cite it - it might have been Urqhardt. My research in Monarchs was
focused on a localized color polymorphism, so it would take some effort to
put my hands on migration literature.)

> In Sept. 1973 I shipped hundreds of tagged California monarchs to North
Dakota for
> release. Three were recaptured - at Omaha, Nebraska, Pratt, Kansas and
Dwight, Kansas -
> exactly the "path" eastern monarchs take to Mexico.

Why? And how does this outcome refute genetic control? Do you think that
they would have had to go to the California sites (being California
butterflies) to support genetic control?

North Dakota.... east of Rockies... I would expect these to head to Mexico.

If you're suggesting that there is only one possible result of "genetic
programming," that they go to Mexico or California regardless of the
conditions when they initiate migrating behavior, there are many examples of
"flexible" "programmed" behaviors. Many studies have clearly demonstrated
insects "choosing" particular optional behaviors based on current
conditions. Some wasps can "intentionally" control the gender of their
offspring depending on the ambient temperature. Another wasp can "choose" to
abandon a nest she is digging (and already has considerable investment in)
if she is pestered enough. Honeybees which would probably rather be out
getting nectar will remain at the entrance and "air condition" the nest when
it becomes too warm. I can probably think of many, many others, but you get
the idea.

I suspect the only thing that might save the North American Monarch
population is that they can be flexible in their responses to prevailing
conditions. Because whether or not we effect their gene pool in some
unnatural way, they'll head down to the "old winter home" one year - and it
will be gone! Unlike the Painted-Ladies-in-schools issue, other humans
unconcerned about the ecological state of the Earth could take care of the
Monarch-migration-problem. And we'll all be off the hook!

Mark Berman
BUGMAN Educational Entoprises

> This is all published information in science journals - BUT, Jeff
Glassberg, Bob Pyle, Paul
> Opler and Tuttle obviously chose to ignore it when they wrote:
> Paul Cherubini, Placerville, California

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