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Archive for October, 2012

Wasps Still Flying

The lingering warm weather and the few remaining flowers (such as the mustard in the photograph) have allowed worker wasps to extend their lives this fall longer than many years, for once several hard frosts hit, they will die. Unlike honeybees, the queen of social wasp colonies lives only about a year, but that is longer than the workers. In the late summer the (old) queen stops laying eggs and the colony soon begins to decline. In the fall, mated female offspring of the queen seek overwintering sites such as rotting logs. In these protected spots they tuck their wings and antennae under their bodies, and hunker down for the winter. The remainder of the colony does not survive the winter. If predators such as spiders don’t kill the new queens, and if they don’t emerge early due to a warm winter and starve due to lack of food, the young queens begin building nests and laying eggs in the spring.


American Hornbeam

American Hornbeam (Carpinus caroliniana) goes by many names, including Musclewood,  Bluebeech and Ironwood. Its smooth, gray bark that appears twisted and somewhat muscular is very distinctive. This member of the Birch family usually has several trunks, and is usually less than 30 feet tall. Its fruit is in the form of clusters of small nutlets, each attached to a papery bract. A good seed crop is produced every three to five years, at which time it benefits ruffed grouse, cardinals, evening grosbeaks and American goldfinches, all of whom prefer it over many other seeds.


Autumn Meadowhawks Mating

Meadowhawks are the only small red dragonflies seen in New England (most males are red, most females are brown).The latest species of dragonfly flying in the fall in this area is the Autumn Meadowhawk (Sympetrum vicinum), which doesn’t emerge until mid-summer. It seems a bit incongruous to observe these dragonflies not only flying, but mating and laying eggs in late October, but that is exactly when you can expect to see them. Until there have been several hard frosts, these winged masters of the air are able to keep active by basking in the sun and warming their flight muscles. The two pictured Autumn Meadowhawks are copulating in the typical “mating wheel” fashion, with the male grasping the female behind her head while the female places the tip of her abdomen at the spot on his abdomen (the seminal vesicle) where he stores his sperm. The female Autumn Meadowhawk lays her eggs in tandem with the male (his presence prevents other male meadowhawks from replacing his sperm with their own).


Piles of Snow Fleas

We tend to associate snow fleas, a type of springtail, with winter, as that is when we can easily see their tiny black bodies against the white snow.   However, these insects don’t magically appear when it snows – they are in the leaf litter and soil all year round.  Snow fleas are considered to be one of the most numerous land animals on earth, with several hundred thousand inhabiting a cubic yard. Even so, it was with amazement that I found several piles of snow fleas at the base of my garage door this morning – it’s the wrong time of year, and most of the individual snow fleas were not scattered apart from each other.  Several solid black patches of snow fleas, one patch measuring roughly 6” by 2 ½ ”, piled 1/8” high, had appeared overnight.  Something about the warm, humid air this morning may have caused them to leave the safety of the forest floor and for some unknown reason gather in piles on the cement.  Once the garage door was raised, the piles disappeared within five minutes, as each tiny snow flea catapulted itself several inches away and disappeared into fallen leaves.


Snail and Slug Eggs

Snails and slugs are very similar, except for a slug’s lack of a shell.  Both are hermaphroditic, possessing male and female reproductive organs.  In some species an individual may behave as a male for a while, then as a female. In a few species, self-fertilization occurs. Some species mate and lay eggs in the spring, some in the fall. Most snails and slugs that hatch in the spring can begin egg laying in the fall. The eggs of both snails and slugs are tiny, white or cream-colored, round and laid in roughly one-inch diameter clusters of 30 or so eggs. Look for these clusters under rotting logs, where they are protected from drying out as well as from freezing.  (Remember to place the log back exactly as you found it.)


Avian Digestion

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What happens to food after a bird swallows it? It may be stored in their crop, a pouch which is actually an enlarged part of its esophagus that some species of birds (and bees, fish and earthworms) have, or it may go directly to their stomach.  Birds have a two-chambered stomach.  The first chamber, the proventriculus, secretes acids that help break down food, including bones. A shrike’s well-developed first stomach chamber can digest an entire mouse in only three hours!  From the proventriculus the food goes into the second chamber, which is referred to as the gizzard, before entering the intestines.  The gizzard is a muscular organ which grinds up tough food, sometimes with the help of grit that some birds ingest.  The gizzard grinds the gravel and stones against the nuts and seeds, a process which smashes the food.  Wild turkeys can actually pulverize walnuts in their gizzards!  In some species, the gizzard remains small and insignificant during the summer when their diet consists of soft food such as flesh, insects, or fruit, but it grows more powerful during the winter when seeds are their main food.


Insects in Winter

What happens to insects this time of year?  A few remain active, such as snow fleas, and some, like monarch butterflies, migrate, but the vast majority of insects overwinter in New England.  The insects that stay here are susceptible to freezing due to the fact that they cannot control the temperature of their body.  Some insects, such as woolly bear caterpillars, can tolerate having ice form in their tissues, but most insects go into a state known as diapause.  When the days start getting shorter, these insects reduce the water content of their body, as water freezes at a high temperature compared to other liquids, and replace it with glycerol, which acts like antifreeze, protecting them from freezing. (Please excuse duplicate post.  I’m testing new posting process.)