Will this one fly to Mexico?

[skates4marty]

I am in Maryland. The folks I've brought into this hobby are always asking me around this time -- "Are the ones we are releasing now going to mate and lay eggs now, or are they going to fly to Mexico?"

I looked on the MonarchWatch website and still can't tell. What's the generally accepted cutoff date for changing from "still a summer butterfly" to "Buen viaje!"

[Mona Miller]

http://www.monarchwatch.org/tagmig/index.htm
Migration and Tagging

http://www.monarchwatch.org/tagmig/peak.html
Peak Migration

Find your latitude. During the peak migration is the time to tag.

I also use this to try to determine diapause. I'd say late August on for us, but if the butterfly is raised totally inside that may interfere with diapause. Diapause is triggered by light (day length), heat (temperature outside), and host plant quality.

Have you asked Denise Gibbs?

[Paul Cherubini]

I looked on the MonarchWatch website and still can't tell.

Right. In fact there aren't any websites available on the internet that provide accurate information about basic monarch biology such as the date of onset of diapause.

Annapolis is about 38.9 degrees North and at that latitude in California and the Midwest the butterflies emerging the first week in Sept. will be mostly in diapause. Some emerging the last week in August also will be. Only monarchs in reproductive diapause have any interest in flying to an overwintering site like those in central California and along the California coast.

[Mona Miller]

Paul,

Didn't I just say the last week of 'August on', which includes the rest of the season. And, this is the East Coast not the West Coast that she was asking about.

Go take care of your cat.

[Paul Cherubini]

Diapause is triggered by light (day length), heat (temperature outside), and host plant quality.

No one actually knows what triggers diapause. Diapause occurs the first week in August every year up at 48 degrees N and higher http://www.learner.org/cgi-bin/jnorth/j ... 1312776153
even though the daylength is still very long, both day and night temperatures have not declined and host plant quality is still good (many of the syriaca milkweeds are still flowering and their leaves have not yellowed yet).

[Mona Miller]

The day length is not as long now. It used to get dark at 9 PM and now it gets dark at 8 PM. Up North, the days are getting colder and with that the milkweed is senescing. Things are changing. And, the Monarchs notice these changes. These changes trigger reproductive diapause.

[Paul Cherubini]

Here are the July and first week of August temperatures for Thief River Falls, MN which is up at the 48 degree N latitude area where one sees diapausers by Aug 3-5 each year:
http://www.accuweather.com/us/mn/thief- ... =7-01-2011 As you can see, neither average or actual daytime highs nor overnight lows were declining between July 1 and the first week of August, yet the butterflies emerged in a state of diapause the first week of August. And up there on Aug. 4 the days were still very long; i.e. sunrise at about 6:03 am and sunset at about 9:03 pm = about 15 hours. And the milkweeds were still green and often flowering like this:

[Mona Miller]

But, daylight is declining. And, just cause you show one tiny patch of green milkweed that does not mean the rest is not green--this was probably an area where it was mowed. The grass in the area looks way too low. Just because one day is warmer does not account for the average temperature changes of day and night and the length of that day. Animals know these changes and respond to them.

Paul, you just like to argue. I think we all know that.

[Paul Cherubini]

And, just cause you show one tiny patch of green milkweed that does not mean the rest is not green--this was probably an area where it was mowed.

I took lots of photos of unmowed fields of milkweed too, like these that show the milkweed was still fully green, some still flowering and the oldest seed pods were real small

[skates4marty]

Ah, but what is "summer"? What is "fall"? Tourist industries would say summer is Memorial Day to Labor Day. College students might say May 15 to Aug 15. To high school students, perhaps Aug 27 is the start of "fall." Yet my calendar says fall starts on Sept 23. The there are the astronomers...

Anyway, thanks for the info. Seems like the one I release today will mate. Her little ones may make it to Mexico. Indeed, it appears we had a minor rush. It is quiet again, and I anticipate we will find a bunch starting in about a week.

[Mona Miller]

But, I said late August on, I didn't say Summer and I didn't say Fall.

We are starting to get an influx of gravid/faded females and some males setting up territory here in Northern Virginia.

[skates4marty]

MonarchWatch says "When the late summer and early fall Monarchs emerge from their pupae, or chrysalides ..."

In Maryland, when temps dip below 80 degrees, people start wearing sweaters and saying, "Feels like fall!"..

[4estry]

G'day... Thought I'd put my two cents in.

Here in Northern Ontario, Canada Monarch's still have sex on their mind. Just yesterday I observed two monarchs, the female I tagged several days ago, doing their flutter-chase around my yard. I will admit it isn't as vigorous as earlier in the summer, and the male did lose interest shortly after I observed them.

My observations from past years observations is that at my latitiude (~46.5 degrees) Monarchs begin their trek around now and are fully in the migration mode by next week. I never see a single Monarch after the end of August.

My thoughts are that if you are south of me...especially a lot south, I believe the Monarchs you raise now are not in diapause and are not thinking migration yet.

[Mona Miller]

The deal with the migration and I've read this in Dr. Urquhart's books. "The Monarch Butterfly, International Traveler" is incredible. There will be reproductive Monarchs that are pushed by the cold and will journey south with the ones in diapause. The ones in diapause can also be observed having sex. The ones truly in diapause will not lay eggs. The ones in diapause do not have mature ovaries. This is what the reproductive diapause does. They are stuck in the juvenile stage until mid-February to mid-March of the following year.

http://www.monarchwatch.org/tagmig/peak.html
Latitude, Midpoint, Peak in monarch abundance
49, 26 August, 18-30 August
47, 1 September, 24 August -5 September
45, 6 September, 29 August - 10 September

You are between 45-47 latitude. So, you see late August is the timeframe for diapause and migration.

[Mona Miller]

MonarchWatch says "When the late summer and early fall Monarchs emerge from their pupae, or chrysalides ..."
In Maryland, when temps dip below 80 degrees, people start wearing sweaters and saying, "Feels like fall!"..

This is your latitude and longtitude:
County: Anne Arundel County
Location: 38:58:18N 76:30:11W

This is the peak migration (see below). Eggs laid in late August would be part of this migration for you. Can you tell there is a difference in daylight and night time temperatures are getting lower? Also, gradually, the day temperatures are getting lower, too. Many of the milkweeds are setting seed and the leaves are yellowing. At least this is what is happening in my yard.

http://www.monarchwatch.org/tagmig/peak.html
Latitude, Midpoint, Peak in monarch abundance
39, 22 September, 14-26 September
37, 27 September, 19 September - 1 October

When do you usually start tagging? Isn't Denise Gibbs tagging on September 3 for Monarch Fiesta Day.

http://www.montgomeryparks.org/nature_c ... grams.shtm
Scroll down for a list of activities for Monarch Fiesta day at Black Hill Regional Park in Maryland.

[Paul Cherubini]

G'day... Here in Northern Ontario, Canada Monarch's still have sex on their mind.

At your latitude most of the newly emerged monarchs after Aug. 5 are in diapause and have no interest in sex and will begin migrating south. Like these 4 monarchs I saw in northwestern Minnesota on Aug. 5 one of which was a female:
http://www.learner.org/cgi-bin/jnorth/j ... 1312776153

Yes, there will still be older reproductive monarchs around, but the newly emerged butterflies will nearly all be in diapause. Diapausers are preoccupied with nectaring so to see them you need to find a field of attractive nectar plants like alfalfa, red clover, liatris (blazing star) or knapweed. Diapausers also have a noticably slower wing beat frequency and relaxed flight style as compared to the skittish, nervous flight style of reproductive butterflies.

As I've said before, the university scientists up to now have not acknowledged the existence of these first week of August diapausers, so there aren't any books or websites that talk about them. University scientists don't spend much time in the field so they miss out on alot of what's happening.

[Mona Miller]

They don't spend much time in the field? How about Nathan Miller and Tyler Flockhart? Both of these university students have spent loads of time in the field. Many other scientists spent lots of time in the field, too. Where in the world are you getting your information--from your cat?

[Paul Cherubini]

They don't spend much time in the field? Where in the world are you getting your information--from your cat?

Not enough time in the field to notice what citizen scientist's noticed 10 years ago:

Aug. 7 2001, a citizen scientist, Tom Mostrom reports 1,000 monarchs clustering at Grygla, Minnesota, which is proof they were diapausers: http://www.learner.org/cgi-bin/jnorth/j ... ?997216767. Tom also mentions the first cluster of 40-50 was noticed Aug. 1
http://www.learner.org/cgi-bin/jnorth/j ... ?997730200

Aug. 7. 2001: Citizen scientist Blane Klemek reports roosts at Warren, MN near the Canadian border
http://www.learner.org/cgi-bin/jnorth/j ... ?998445471

Aug. 5, 2007: Citizen scientist Paul Cherubini posts two photos of roosts at Grygla, Minnesota
http://www.learner.org/cgi-bin/jnorth/j ... 1187632066

Aug. 5. 2011 Citizen scientist Paul Cherubini posts a still photo and a video of gregarious nectaring at Brooks, Minnesota (northwestern Minnesota) which proves the butterflies were in diapause:
http://www.learner.org/cgi-bin/jnorth/j ... 1312776153

Aug. 5 = MID-summer, not late summer. And air temperatures have not begun to cool yet and the days
are still 15 hours long up near the Canadian border.

Meanwhile, university scientists continue to claim: "the late summer and early fall Monarchs emerge from their pupae, or chrysalides, they are biologically and behaviorally different from those emerging in the summer. The shorter days and cooler air of late summer trigger changes. In Minnesota this occurs around the end of August." http://www.monarchwatch.org/tagmig/index.htm