Friday, 29 April 2011

Oshawa 2nd Marsh -- April 27th, 2011 -- Post 2

I went through my images from the 27th a little slower today, culling and deleting and found a few more that I thought I'd add-- Post 2 for the 27th.

One of the channels that leads out of the marsh to the bay.

The Willows are showing their color. 

There are interpretive signs in the marsh. This is part of one of them-- since I had shots of Garter Snakes earlier.

Some plants look more complex to me in winter & spring when they're withered than when they're full of life. The intricacy  fascinates me.

These galls have a story far more interesting than I'd have thought. It often surprises me when I research what first appears to be a simple thing and discover the details. This gall is on a Goldenrod plant, caused by a Gall Fly as shown in the last image.

If you share my passion for nature, you'll find the following interesting. It includes references to ice fishermen, Downy Woodpeckers, anti-freeze, a larva that plans ahead (how can that be?) and an adult fly that doesn't eat. A link to the source of most of the text (edited) and the image of the Goldenrod Gall Fly is below the image of the gall.

This gall forms in late spring, caused by the Goldenrod Gall Fly that lays her egg on a Goldenrod stem. After the egg hatches the larva eats its way into the stem and forms a feeding/living chamber. This stimulates the Goldenrod to defend itself by creating the 'ball gall'.

When winter arrives, the fly larva slows its metabolism and replaces much of its internal water with glycerol, a compound that serves as antifreeze. In northern areas, ice fishermen collect Goldenrod galls, cut open the ball, and use the hibernating grubs for fish bait when snow-covered ground makes earthworms hard to come by.

Downy Woodpeckers peck open galls to get the grubs within. (That's my guess for the one I shot. Otherwise the hole would be more circular as many are in images I saw on the web.)

If a gall goes undisturbed by humans or gall-invading predators, the larva inside slumbers until spring when warm days stimulate it to eat a narrow passageway radiating from its feeding chamber.

The larva stops tunneling just short of the gall's outermost layer of cells and goes back to the main chamber to form a pupa, emerging in a few weeks as an adult fly able to pop through the thin-walled porthole on what has become a hard, brown, one-inch gall.

Adult Goldenrod Gall Flies do not eat and last only about ten days, living only to mate and produce a new generation of gall-causing young.


The Friends of Second Marsh web site... 

A direct link to a map of the paths/trails in the marsh...

A link to a page that has my past posts re the marsh, in one place rather than scattered throughout this blog...
- fini -



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