Wednesday, August 23, 2017

Opportunists

I love pearly everlastings. Every summer, I collect a fresh handful to dry for winter flowers; they last all winter, and on into the next year, as white and delicate as they were the day they were picked.

Western pearly everlasting, Anaphalis margaritacea

The plant is another of the asters; the "flower" is a cluster of tiny, yellow flowers, in a showy head of papery bracts. The flowers fade, but the bracts persist until next year's crop pushes them aside.

Each flower head is about 1/4 inch across.

I made a mistake this year. I always hang the fresh plants stem up in a dry place until the yellow flowers and the leaves are dry. Last week, I was in a rush, and plopped the whole handful into a vase where a broken hollyhock stem was being cared for. Then I forgot all about it.

When I looked at them again yesterday, the sap was still running. And the stems were covered in fat, dark aphids.

Where did they come from? I'm sure there were none when I brought them home.

When host plant quality becomes poor or conditions become crowded, some aphid species produce winged offspring, "alates", that can disperse to other food sources. (Wikipedia)

Oh. So they may have flown in. Or ...

From KULeuven

(Text: "Did you know? In one season, just one aphid could produce over 600 billion descendants. During their asexual reproduction, the aphids give birth to live young instead of laying eggs. These young already contain their own young, meaning that an aphid gives not only birth to their children, but also their grandchildren.")

They were born here. And they're just getting started!

One aphid, showing off her siphunculi.

Most aphids have a pair of cornicles (or "siphunculi"), abdominal tubes through which they exude droplets of a quick-hardening defensive fluid containing triacylglycerols, called cornicle wax. (Wikipedia, again.)

These aphids are probably in the genus Uroleucon.


1 comment:

  1. They attacked my dill plant. One day it was doing well and the next had the life sucked out of it. I pulled it all and washed the little buggers off in the lake before cutting the plants up for the compost pile. Probably won't prevent more infestations but made me feel I was making it a bit harder. So far my other plants are free. - Margy

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