Thursday, August 28, 2014

The Milkweed Wait Is Rewarded

Back in May we finally got some Milkweed plants for the garden thanks to the Norfolk Botanical Garden plant sale to provide a place for Monarch butterflies to lay and for the caterpillars to feed. Well we have watched since then and seen...nothing at all.

To be fair Monarchs are usually a late summer visitor to our garden as feeders and will often be one to the last butterflies in the yard in the fall as they pass on their migration. But last Sunday I was sitting having coffee in the kitchen when I looked out big french doors and saw something fluttering around one of the plants. I dashed out with the camera but it (apparently she) didn't really stop for long enough to get a decent shot.  However when I looked the following morning I found what we had been hoping for, Monarch eggs. The Monarch clearly isn't a very abundant layer. Unlike the Black Swallowtail which will usually lay a dozen or more eggs on each paln she visits, the Monarch laid a grand total of 5 eggs on the plant. They were laid singly, dotted on leaves and flower buds. I suppose that this Milkweed species is a relatively small plant compared to the 4 foot  bushy Fennel that the Swallowtail gets to work with. Often a fennel will have 20 swallowtail caterpillars feeding and growing on it at one time. This is enough to decimate the plant in the short term. I imagine 4 or 5 caterpillars is all a Milkweed of this size can reasonably support. 

Egg shortly after laying at the weekend.

An egg photographed today, Thursday August 28th. Visibly developing, the dark area at the top is the developing head seen through the shell. It seems likely that hatching will be tomorrow .

All very exciting, although the timing could be better. We are out of here on vacation a week from Friday and so we wont be around to see the pupation or the emergence as we will be in the mountains of Maine. Ah well you can't win 'em all.

Banished Jr. returned to school this week and as his last day out he wanted to go back to Bennett's Creek park. There I found this Red Spotted Purple (Limenitis arthemis) 

This is an interesting one. The sub species here in the south eastern US is Limenitis arthemis astyanax.  The upper wings looks like this 

In the northeast the butterfly is called the White Admiral and the wings look this this

They are regarded as the same species but are distinct subspecies. 
Why the difference? Well here in the south the Red Spotted Purple looks a lot like the Pipevine Swallowtail (less the swallowtail tails). The latter feeds as a caterpillar on the Pipevine and is unpalatable or toxic to many predators. So its in the interest of the Red Spotted Purple, which is not toxic, to mimic it's nastier neighbor. But why the difference in the north? The Pinevine Swallowtail doesn't occur that far north and so there is no survival advantage in looking like one!
Don't you just love natural selection?

And lastly a couple of flies to ID when I get the chance.
This first is sort sort of Hoverfly I'm fairly sure but I need to look deeper.

And this one looks like a predatory Robberfly.

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