Here in SE MN I noticed the same lack of Monarchs in mid-summer. We also had robust milkweeds with very few larvae. I heard from (entomologically oriented) folks in NE MN that in June they saw far more Monarchs than usual, but with their relatively low population of milkweeds the Monarch seemed to overload the larval food plant. Then in August the flight of Monarchs here in SE MN was the lowest I have every seen.
Joel Dunnette
On Tue, Nov 6, 2012 at 8:21 PM, Bruce And Georgeann wrote:
I have been following this topic and want to ask about another angle of the past summer's Monarch slump -at least it was in Nw Iowa.
The Monarch Butterflies, were a real concern here this year. We had quite good numbers showing up in early spring - in fact the dates were record early arrivals for us. And I witnessed egg laying in the pasture...even photographed eggs as they were so obvious. But the thing that really puzzled and concerned me was we had no egg hatches and no caterpillars all summer! I have never, in my life, "Not" seen a Caterpillar all spring, summer or fall!!!???!!! Why after finding eggs, I could later not find larva?
Then the summer was "scant" as far as Monarchs were concerned. Nearly none, just a handful all summer. This should not have been the case here, we had the largest crop of Asclepias (milkweeds) that I've ever seen here...we had A. tuberosa(Butterfly Milkweed) in record numbers...they were stunning all over the county...even the area farmers were asking me what that "orange plant" is showing up everywhere! We had way more A. syriaca (Common Milkweed) than I care to see here - the neighborhood is coated with seed parachutes from our pasture...not a real "good neighbor" relations maker with the local farmers. We also had a good share (but down slightly from past years) of A. verticillata (Whorled Milkweed) and a small compliment of A. incarnata (Swamp Milkweed) in the ditches out front.
I witnessed a lone Monarch laying eggs on some Common Milkweed outside the studio windows in late August and tried keeping an eye on them - they were gone after just 3 days!? I don't know of "egg" eaters in the insect world but maybe something is going on? I know of parasitic wasps in caterpillars - but saw NO CATERPILLARS all summer (as I said before). I haven't the foggiest idea what is going on?
This fall we had virtually no Monarch roosts here - we usually have 150-500 individuals roost here each fall. 13 was our high number in a roost this fall..."6" was the other high day..."high" used very sarcastically...
Some folks following this have raised issue with the drought hurting the mid section of the continent's Monarch survival...I'm sure that has some bearing. They also have raised issue with GMO crops. But it does nothing to explain a local phenomenon like we've been experiencing here...eggs laid but no hatching, no larva...with an abundance of food source for larva and adult stages. We do not spray insecticides here on the acreage, but I have no knowledge of GMO crops or spraying issues in the surrounding area, so I can't speak to that.
Am I imagining things or is there anyone else raising these kinds of observations or concerns? ...Bruce Morrison, SE O'Brien County
