Last weekend I visited Cameron Parish in the southwest corner of Louisiana and I was shocked by my discoveries. This parish has the largest concentration of milkweed plants in state. (In Louisiana rather than counties the land is divided into parishes.) The most important milkweed species is "green" or "antelope horn" milkweed (Asclepias viridis). It is utilized heavily for the first spring generation of monarchs since it is the earliest milkweed to grow in our region.
Out of 150 plants I checked, I saw no monarch eggs on any of the plants! What's more, only 2 plants had any evidence of having been eaten by caterpillars. Normally caterpillars would have eaten from at least 75 % of the plants.
I know one of the two caterpillars didn't make it past a day or two because one of the leaves had just a tiny hole and no other damage. Predation is very high on caterpillars. Paper wasps usually get them; the wasps paralyze the monarchs and take them back to their nest to feed their own larvae. On the other plant, the leaves was practically denuded, so I assume that caterpillar probably made it. Since the two plants were side by side the two eggs were most likely laid by a single adult monarch.
In 2 days I saw only 2 adult monarchs. Normally at this time of year I would expect to see dozens and dozens--maybe even hundreds of monarchs.
Based on my observations, I assume virtually no first generation monarchs were produced this spring in this region. They usually begin to produce the first generation in March. However, I am presuming the host plants (milkweed) were not ready for the monarchs when they arrived this year. Similarly, since there were virtually no nectar plants blooming, I assume there was little food available for the adults.
As you might suspect, the milkweed plants are very healthy this year! Not only were the monarch larvae lacking, so were few other insects. I usually find huge crops of sap sucking insects such as aphids & milkweed bugs. But we just didn't see them either.
By the way, this spring is exceptionally dry. We have had virtually no rain in 3 months. This drought is affecting everything that lives here. All the marsh creatures are moving around in search of water and food. We saw alligators crossing the roads over the weekend looking for habitat. Crabs, otters, snakes...are all looking for water & food. Cameron Parish is the largest and wettest parish in the state. It is 80% water and marshland; only 20% is dry land.
 |
|
|---|
