Tuesday, June 12, 2012

Syrphid flies on Sweet Alyssum

Where's Waldo?
I’ve been spending a little quality time with ‘Blushing Princess’ and ‘Silver Stream’ recently. Just to see for myself. Does Sweet Alyssum (Lobularia maritima) really attract more syrphid flies than other flowers, as researchers have written?

You’ve seen them, those miniature yellow jacket lookalikes that are always hovering about your flowers. Some call them sweat bees, but the fact is, there is an actual bee (family Halictidae) that claims that name. Hoverfly is a more apt nickname for the tiny fly (family Syrphidae). Beating its wings at a furious pace it hangs in the air above favored flowers and, alighting on a blossom, sucks nectar, tail bobbing slowly up and down. The hover fly is not interested in your sweat.

All that hovering about serves the female well when it comes to providing for her unborn offspring. She scouts the landscape for plants that host promising colonies of aphids, and deposits her eggs, one by one, nearby. And this is the good part: a single syrphid fly larva will eat hundreds of aphids.

And yet, as intimate as I am with aphids (we have similar tastes in lettuce) I have never seen a syrphid fly larva. At about 1 cm long they’re certainly visible. And they are undoubtedly populous, judging by the number of adults hovering around. So I have to conclude that I am not terribly observant. This is a good reminder that, no matter how much we might think we know and how observant we think we are, most of the action goes on unseen, under our noses. 

One thing I know is true: the answer is yes. A few syrphid flies visit catmint in passing, and one or two seek out arugula flowers. Coreopsis holds minor appeal and spiraea is fairly popular. But the winner, hands down, is Lobularia maritima ‘Silver Stream.’ 

Go syrphid fly larvae, Go!

1 comment:

  1. Thank you, Happy Naturalist. If you like to identify and draw insects you should check out my new blog, Artofnaturejournaling.com, and my facebook group by the same name.