protozoan parasite

[murph372]

Today is 8-28-05 and I have many monarchs nectaring in my fields, but I also noticed several pupa with the signs of Ophryocystis elektroscirrha (Oe) on them. I don't usually look too hard for the pupal stage, but today I went looking under a farm wagon I had parked by some milkweed and under my porch. What I found were many pupa and more than half of them appeared to be infected with Oe. There is so much of it that the insides turn into a brown liquid. Also noticed several larva that had attempted to turn to pupa but apparently were so infected with Oe they died. I hope this is just localized to my area. I still have many hundreds of monarchs nectaring. I'm going to catch a few and see if they have Oe.
Is anyone else seeing much more Oe in their wild monarchs than they have observed in the past.?

[Teresa]

This is my first year doing this on a larger scale but so far I haven't seen any signs of it. I don't know that much about it but from what i've read I don't think i've seen it. My biggest problem has been the trachinid fly

[Pat]

Emory University has a research site devoted to OE with many good photos and information:

http://www.envs.emory.edu/altizerlab/monarchparasites/

[murph372]

Pat,
Thanks for your reply and the link to the OE site. It's very informative. I have now looked at 11 females and only one had OE. At the OE site they mention other possibilites as bacteria or virus? What I have starts to show itself just a few days after the pupa forms. And the contents turn a light brown only occasionally with spots like OE. What ever it is it is all over my 40 acres. I am seeing some healthy pupa and seeing some emplty cases where it appears all went well, but also seeing a disturbing number of failures. I'm going to continue to examine for OE. I'd like to get my technique down so I can do it faster. I may even send a card of the samples into the OE site as they suggest.
Thanks again
Tom

[Paul Cherubini]

According to the research of Dr's Sonia Altizer & Karen Oberhauser, only about 2% of Minnesota monarchs have high levels of OE. There are also other protozoan diseases besides OE, plus viral and bacterial diseases that even an insect pathologist may have difficulty identifying. In any case, there certainly isn't a shortage of monarchs in Minnesota right now:

http://www.saber.net/~monarch/gayf.jpg
http://i5.photobucket.com/albums/y189/m ... h/trua.jpg

[murph372]

Paul,
Fantastic photos! I see you're from CA. Did you come to MN for the monarch migration? I have many monarchs like that, but it is very difficult to get a photo that conveys the beauty and wonder of seeing so many monarchs. You've done an excellent job of capturing that. On the 2nd picture where they are flying, were they just coming off the roosts in the AM?

I'm now leaning toward my problem being a baterial something. It doesn't look like the viral "black death" as described on the Monarch Lab site.

Tom

[Paul Cherubini]

Tom, yeah I come out to the Midwest frequently in the late summer and fall for both business and monarch watching reasons. The second photo happened largely by accident - I walked up to the trees with the clusters in the morning and figured all the clusters were way up high where my presence wouldn't disturb them. Then suddenly masses of monarch took off because some clusters were actually located low in the trees and I inadvertently disturbed them. So then I took a picture of the spectacle.

Tom, are you the person from Cannon Falls who did alot of tagging in 2001 and had numerous tag recoveries from Mexico? If so, how do you think the size of the migratory population in Cannon Falls this year compares to Aug 2001 and 2003? Smaller? Bigger? About the same? So far I'm tending to think it's smaller than 2001, but bigger than 2003.

Paul

[murph372]

Yes, I'm the Cannon Falls guy.

As far as the numbers of monarchs, only speaking about my farm and this area, I'd tend to agree with you. It is certainly a good year and a wonderful recovery from last. In 2001 we had two days when I estimate we had 10,000 but it only lasted two days. This year it has been a steady 2,000 to 5,000 for 10 straight days (from 8-22 to 8-31). Today 8-31 there was a fall off in numbers and we had between 500 and 1000. And yes the numbers here are definetly bigger than 03.

I'm a teacher, and school is now starting, so I went out and collected 20 or so larva of various instars. I collected them from outer areas of my farm hoping to avoid my problem. Well, now that I have captive larva I realize I have seen this problem before. It usually happens very late in the year, late September, in a warm year early Oct. What happens is the larva eat very little, don't grow much, are lethargic, don't respond to sharp noises, etc. In other words clearly sick. I believe (just guessing) it is a bacteria that is on the milkweed. I would assume it is naturally occuring and multiplies with favorable environmental conditions and perhaps aided by large numbers of monarchs. The behavior of the larva are what bt is supposed to do to larva of various garden pests in their larval stages. I will continue to investigate and experiment. Anyone else seen this in their larva?