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Archive for December, 2011

Stream Icicles

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While there has been a lack of snow so far this winter, there has been no shortage of icicles.  Because of the warm temperatures, streams that are normally frozen are still open, allowing icicles of all sizes and shapes to form along their banks.


Blackberry Knot Gall

12-28-10      Blackberry Knot Gall

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Winter is a good time to look for galls (abnormal plant growths caused by different agents, including insects, fungi, mites and bacteria) such as the blackberry knot gall, which is much more noticeable when there are no leaves to hide it. Whereas many galls are inhabited by a solitary insect, the blackberry knot gall contains many individual chambers, each containing the larva of the tiny wasp Diastrophus nebulosus. During the spring and summer months, this little wasp deposits eggs into the ridged stems of blackberry which stimulates the plant’s tissue into abnormal growth along the stem. This particular colonial gall can be six inches in length, although two or three inches is more typical (the more eggs that are laid, the larger the gall).  The eggs hatch and the larvae overwinter inside the gall. Adult wasps emerge in the spring and chew their way out of the gall, leaving tiny holes along the gall’s lumpy ridges. In the first photograph you can see where a hungry predator has worked its way into two of the larval chambers.  In the second, multiple chambers and larvae are exposed (sacrificed for the sake of knowledge, but popular food for chickadees on a very cold morning).

 


White-footed and Deer Mouse Tracks

It may be possible to tell the difference between white-footed and deer mouse tracks, but I certainly can’t.  The only clue that sometimes works is to note the habitat in which you see the tracks– they are somewhat more likely to be those of a deer mouse if they are in a coniferous forest, but not always!  White-footed and deer mice often travel on top of the snow.  They are bounders, leaving tracks that resemble those of a miniature rabbit, with the larger back feet landing in front of the smaller front feet.  There is often a tail mark, but not always, as they can and do hold their tails vertically at times.


…and a Happy and Healthy New Year!

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Snow Worm & Snow Flea

With two new inches of fresh snow on the ground, my hopes were high for discovering some tracks this morning, but something even more unusual met my eyes – worms crawling on top of the snow!  Not our familiar earthworms, but skinny and relatively short worms ( one to two inches in length when not moving). There are such things as “ice worms,” but they are found only on glaciers.  Our “snow worms” are in the class Oligochaetes, and in the family of  Enchytraeidae, just like earthworms, so are members of Annelida, or segmented worms, but that’s about as far as I can go with their identification.  According to worm specialist Professor Crawford at the University of Wasington, members of Oligochaetes can’t be identified based on appearance alone. Whatever species they are, if our snow worms are like ice worms, they live off of snow algae and are most active at night.  These worms are studied by scientists interested in seeing if their proteins exhibit the right characteristics to be of use in transplant surgeries where keeping an organ cold without freezing is key.  I welcome any additional information on these creatures that anyone chooses to post! (Snow flea was included in photo for size reference.)


Christmas fern

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Christmas fern (Polystichum achrostichoides), a native, perennial fern, is very common throughout the woods of the Northeast. The association with Christmas is an old one, for the evergreen fronds were once harvested by the ton, baled into bundles and sold to florists for wreath making.  One easy way to confirm the identification of this fern is to examine an individual pinna (leaflet). If you use your imagination, each pinna looks like a Christmas stocking!  This year’s fronds will die next spring as the new fiddleheads unfurl, revealing the coming year’s fronds.


Mud Dauber Wasp Nest

There are many species of mud dauber wasps in New England that use mud to make cells for their eggs, developing larvae and pupae.  One of them is Pison koreense, a small, black wasp with a wingspread of less than half an inch.  This particular wasp is native to Korea, China and Japan, and was accidentally introduced in the United States after World War II.  Like other mud daubers, this wasp constructs one cell at a time with her mandibles; there can be anywhere from 1 to 12 mud cells (each roughly ¼” long) in a nest, which is often located in a crevice or behind bark.  She then hunts for spiders, stinging and paralyzing them before carrying them back to the cell, into which she stuffs them.  After collecting 20 – 30 spiders, she lays a tiny white egg on the last (and often largest) spider to be placed in the cell.  She then flies off and collects mud with which she seals the cell.   The egg hatches, the wasp larva consumes the live spiders and then pupates, spending the winter inside a cocoon inside the mud cell.  In the spring the adult wasp emerges from the cocoon and chews her way out of the cell, leaving a circular exit hole.