I did a milkweed survey over the course of two days (with help from my son): March 27th in the evening and March 28th in the morning. I looked at 201 individual milkweed plants (Asclepias viridis). On them I observed a total of 446 monarch eggs and 38 monarch larvae.
The specific numbers are as follows:
77 milkweed w/0 eggs
29 milkweed w/1 egg
30 milkweed w/2 eggs
22 milkweed w/3 eggs
10 milkweed w/4 eggs
9 milkweed w/5 eggs
9 milkweed w/6 eggs
4 milkweed w/7 eggs
3 milkweed w/8 eggs
2 milkweed w/9 eggs
1 milkweed w/10 eggs
1 milkweed w/11 eggs
3 milkweed w/12 eggs
1 milkweed w/25 eggs
There were 38 larvae found and they all were 1st instars. The larvae were on milkweed plants that also had eggs on them.
Some of the eggs on the milkweeds were darkening, looking like they were close to hatching, especially on the morning of March 28. I saw more new larvae when I checked a few milkweeds later in the day (not included in the survey).
One thing that really stands out in this survey is the large number of eggs on some of the milkweed plants. I would say most of these were the earliest laid, when milkweed was still emerging and scarce. Some monarchs laid multiple eggs because of the scarcity. In addition, other monarchs laid eggs on plants which already had eggs, due again to insufficient milkweed. Thankfully, the milkweed numbers started to catch up and the monarchs have gone back to a smaller number of eggs on each plant ~ their preferred egg-laying method.
This is a photo of a milkweed crown with multiple monarch eggs on it, including one or two that look close to hatching.
Latitude: 30.4 Longitude: -95.8
Observed by: Kathy
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