Saturday, 24 April 2010

Alderflies

Alderflies Sialis spp, with wings patterned like smoked leaded glass, emerge as adults at this time of year. They've spent the past two or three years as predatory larvae at the bottom of an étang (small man-made lake) and come out now to transform into their adult body and mate. They do not eat as adults, but survive for about 3 weeks after a synchronised emergence which ensures other adult alderflies are around to engage in the main business of adulthood.

They are not a true fly at all, but a much more primitive type of insect, in a family of their own, but related to Scorpionflies.

Susan

7 comments:

chm said...

Very interesting post. Nature is such a marvel.

Spending two to three years at the bottom of a pond with probably no oxygen, in complete darkness, eating all you can eat, and then emerge as an adult for three weeks of frolicking with lovely Alderflies, lay eggs, and then die happy!

This reminds me of the thirteen- and seventeen-year Cicadas here in the States. Millions of them, literally, emerge from deep in the ground, almost all at once, go to their very noisy business and then die! Wow!

chm said...

Sorry about that. Here, with dial-up, it is so slow you think your comment hasn't been recorded and click again for that result!

Susan said...

And here, I was so quick I'd deleted your repeat comment before you could post the apology ! :-)

Jean said...

I am always surprised how pretty some insects are, close up. So long as they don't bite, of course.

Susan said...

Jean: Some of the biting ones are the most beautiful. I'm a big fan of horseflies. It probably helps that I rarely get bitten.

Emm said...

Your small instructions on flies and other fauna are wonderfully informative, thank you. I truly enjoy these little learning moments.

Simon said...

Emm. I probably learn as much as you do!