Date: 08/27/2022

Number: 1

In an entry for Monarch Egg Sighted 28 JUL 2022 at < https://journeynorth.org/sightings/query_result.html?record_id=1526592351 > we reported on the following behavior: “a monarch female fluttered about the back garden for 45 minutes. she sometimes nectared on bergamot, but mostly she visited single common milkweed plants. she checked individual leaves, and sometimes conducted an apparent selective behavior as she seemed to 'nectar' at the bit of sticky, dark moisture collected in the clustered whorl at the base of the smaller topmost leaves of a plant. then she either fluttered about and laid one or more eggs on a leaf of that plant or she rejected that plant as suitable for eggs. we had not previously observed this apparent selective behavior. we watched this female monarch lay perhaps as many as 15 eggs on 6 different plants. we will await larval hatching?”

During the next several days we found several eggs (though not 15) and only a single larva about 8 mm length. Since that time (now 27 AUG 2022) we have not found any more eggs or any larvae.

But we continue to observe that the sticky, dark coating on milkweed leaves covers the entire surface of most older leaves as well as collecting at the base of small new leaves at the tips of the 40 plants in this patch. We recall that on 28 JUL the sticky leaves were populated by many green bottle flies and medium sized dark brown ants (see photo attached to this entry). Thinking back to previous years of monarch observations at this location, we recall also the sticky leaf surfaces, the green-bottle flies, and the ants during late July and into mid or late August. Whenever the sticky leaves, flies, and ants were present, monarch larvae were not evident. Sticky leaves, flies, and ants mostly disappeared in late August. Then only later in the season were monarch larvae successful whether by captive rearing or by natural development in this patch.

Is the sticky black substance toxic to monarchs but not to flies? Do the flies eat or otherwise interfere with monarch eggs and larvae? Do ants eat or otherwise interfere with monarch eggs and larvae? Are similar circumstances known elsewhere? Unfortunately for 2022 we have not found many adult monarchs in this region. Neither have we yet found any caterpillars on other milkweed where neither sticky material, flies, nor ants are present. A quandary!

Any advice, other similar observations, or comments from other observers are welcome.

Waterville, ME

Latitude: 44.6 Longitude: -69.7

Observed by: mega
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