Sunday, September 25, 2011

How to Tell a Garter Snake from a Ribbon Snake

Garter snake (Thamnophis sirtalis), Photo by Brad Sylvester
Growing up in New England, I saw many garter snakes up close. I don't recall ever seeing a ribbon snake. That's likely because they look almost identical and it never occurred to me that the snakes I saw and caught from time to time might be anything other than garter snakes. Now, of course, I know better, but it can still be hard to identify the species if all I see is a snake speeding away in the grass.

If I manage to get a closer look, or a photograph that I can enlarge later, then it gets easier to determine whether the snake happens to be a garter snake or a ribbon snake.I found one in my yard today (the first reptile detailed in this blog!) and managed to take a number of photos.
 The garter snake is completely harmless. Although it will try to bite if attacked, it has no fangs and no poison. Its bite cannot even break the skin or deliver enough pressure to hurt or cause any damage at all to people. The snake's biggest defense is its musky smell. When scared or threatened in exudes a strong unpleasant odor. It's not overpowering or anything, but I can imagine that if I were a predator looking for a meal, it would be unpleasant enough to make me hesitate to want to taste any animal that smelled like that. It doesn't seem to dissuade free-range chickens from killing and eating snakes, however.

Garter snakes have a fairly varied diet compared to some other snakes. They eat insect, earthworms, small frogs and toads, and pretty much anything small enough for them to fit into their mouth. The garter snake can open its mouth quite wide on its loosely hinged jaws, but it is a myth that snakes dislocate their jaws to swallow prey.

I most often see garter snakes hunting on my lawn or basking in the morning sunshine. As cold-blooded animals, they rely on warmth absorbed from their environment to power their metabolism and provide them with energy.

Garter snakes give birth to live young. They babies are fully formed and independent as soon as they are born. One of the oddest sites you might run across is what is called a breeding ball of garter snakes. Although they will mate in pairs, if multiple males come across a female during the breeding season, they will all entwine their bodies around her in a writhing ball of snakes.


Quick Facts about garter snakes (Thamnophis sirtalis):
Diet: Garter snakes eat insects, frogs, toads, earthworms, fish, bird eggs, carrion, slugs, and just about anything that moves that is small enough to swallow.
Where do garter snakes live? Garter snakes live in a wide variety of habitats from forests to to swamps to the front lawn of suburban homes from Alaska to Florida and everywhere in between including every U.S. state except Hawaii and most of Canada.
Where do  garter snakes go in the winter? garter snakes hibernate in the winter. They will seek shelter in houses, in burrows made by other animals, under rocks, or in other natural crevices that protect them from the snow. They often hibernate in large groups, but may also be found hibernating alone.
What is the lifespan of garter snakes? They can live about ten years in the wild.
Notes: Another defense used by garter snakes is a detachable tail. If caught by the tail, it breaks off and wriggle while the snake escapes. It will grow back over time.
Garter Snake Taxonomy:
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Sepentes
Family: Colubridae
Subfamily: Natricinae
Genus: Thamnophis
Species: Thamnophis sitralis

Thursday, September 15, 2011

Fork-tailed Bush Katydid (Scudderia furcata)

Fork-tailed Bush Katydid (Scudderia furcata)
Photo by Brad Sylvester. Copyright 2011. Do not copy.
I found this katydid in a window box on my back deck. It's color matched the green of the strawberry plant leaves upon which it sat very closely, as you can see from the picture to the left. katydids belong to the same animal Order as grasshoppers and crickets, Orthoptera. The physical similarities between them are obvious.

Katydids often prefer woodland trees and shrubs to the grasses usually sought by grasshoppers. Their loud calls can be heard from the tree line along country roads throughout New England. The Fork-tailed Bush Katydid (Scudderia furcata) is present throughout North America, pretty much anywhere from Mexico and north to wherever there are deciduous trees say the Audubon Field Guide. This species measures up to 2 inches long.

Quick Facts about the Fork-tailed Bush katydid (Scudderia furcata):

Diet: Herbivore. This species of katydid eats the leaves of trees and bushes.

When is it here? The fork-tailed bush katydid lives here all year round, overwintering as eggs.

Lifespan: Just over a year, including time in the egg.

Lifecycle: The eggs are laid in the fall and do not hatch until spring. The adults die off with freezing temperatures as winter approaches.

Fork-tailed Bush Katydid (Scudderia furcata)
Photo by Brad Sylvester. Copyright 2011. Do not copy.
Status: Common and widespread

Wednesday, September 14, 2011

Polyphemus: the Myth, The Moth, The Caterpillar (Antheraea polyphemus)


Staring into the face of the Polyphemus monster itself
Polyphemus moth caterpillar (Antheraea polyphemus)
Photo by Brad Sylvester. Copyright 2011. Do not copy.
 I had some old pictures of the polyphemus moth (Antheraea polyphemus) so I was quite pleased to find a polyphemus moth caterpillar as I went to check the mail. Because caterpillars and the moth or butterfly look so completely different,I particularly enjoy having images of both forms of an insect to post. It's absolutely fascinating to look at a caterpillar and see the similarities and differences between it and its adult form.

I also enjoy it when the first person to scientifically describe an insect is creative with the naming. This polyphemus moth caterpillar find is therefore particularly satisfying. Polyphemus, of course, is a name derived from Greek mythology. It is the name of the son of mythical Greek gods Poseidon and Thoosa. Students of the classics will recall that this was the same Polyphemus that was encountered by Odysseus (or Ulysses) in Homer's Odyssey. According to the legends Polyphemus was a cyclops, a one-eyed giant. The word cyclops is often thought o mean one eye, but it actually means round eye. Which brings us back to our moth.

In nature, eyes come in handy for two reasons: to find food or to spot predators before you become food. With many, many exceptions, those looking to spot predators have generally evolved to have very wide fields of vision so they can see predators coming from any direction. This means they often have eyes on the sides of their heads so they can see to the front and both sides all at once. Predators, on the other hand, generally have forward facing eyes that let them focus directly on their next meal.
As a predator then, if you see another animal that is staring back at you with two eyes both facing in your direction, there's a good chance that you're in for a fight. Thus, predators tend not to attack such creatures. When random spots and markings on a moth or butterfly's wings look like two big eyes staring back at an overhead attacker, overhead attackers think twice and leave those butterflies or moths alone. This means that the individuals with that sort of spot arrangement survive to reproduce and pass down their genes to offspring that look like their parents. Finally, the entire species may be descendants of those individuals whose spots just happened to look like eyes enough to fool its predators into thinking the moth or butterfly was staring right back at them with evil intent. Moth predators include toads, snakes, birds, bats and many small omnivorous mammals such as skunks and raccoons.

Polyphemus moth (Antheraea polyphemus)
Photo by Brad Sylvester. Copyright 2009. Do not copy.
The polyphemus moth is likely one such species. As you can see from the pictures here and in the linked slide show of photos, It has a distinct eye-spot on both the fore-wing and hind-wing. When the wings are swept back int he normal resting position, the eye-spots are staring straight up any would-be attacker. It is from these eye-spots that the polyphemus moth gets its name. Whether the discoverer named the moth after a cyclops because it had one-eye per wing, or because he knew that the word actually meant round eye and described the circular eye-spots of Antheraea polyphemus, I don't know.

Anyway, the polyphemus caterpillar shows no signs of the eye-spots that will as it undergoes metamorphosis in its cocoon. It does however, show signs that the rows of little black feet are different from the first six near its head. These first six feet, unlike the others, are pointed and brown. It is these that will become the adult moth's legs. The rest of the caterpillar's feet will be absorbed into the polyphemus moth's body in the cocoon.

Quick facts about the polyphemus moth (Antheraea polyphemus):

Diet: The caterpillar eats the leaves of many common deciduous trees such as beech, maple, birch and a number of others. Adults of this species do not eat at all.

Range: All across the United States and most of Canada.

When is it here? The polyphemus moth is here year round, overwintering in its cocoon.

Life Cycle: Adult polyphemus moths can be found from May to July in the North according to bugguide.net, however, I photographed the one shown above in mid-August. Caterpillars can be found from May until November. After that they will be in their cocoons for the winter. Since the adults don't eat at all, they exist only to mate and lay eggs. In warmer Southern states, two broods of Antheraea polyphemus may be raised each year.

Lifespan: The Polyphemus moth has a lifespan of approximately 12-13 months in the North.

Status: Common.

NOTES: The polyphemus moth caterpillar population is generally not dense enough to do any significant damage to forests or individual trees.

Tuesday, September 13, 2011

Greater Fritillary Butterflies (Speyeria spp.) and Nocturnal Caterpillars

Great Spangled Fritillary Butterfly (Speyeria cybele) --probably
Photo by Brad Sylvester. Copyright 2011. Do not copy.
I often see swallowtails and monarch butterflies (though not as many as I did years ago), but I had never really noticed the greater fritillaries. The greater fritillary genus (Speyeria) consists of about 15 species (give or take one depending upon which system is used) in North America, the largest of which measure out at just under a four inch wing-span. They belong to the same family, brushfooted butterflies (Nymphalidae) as the more well-known monarch, but receive much less attention.

In my yard, the greater fritillary butterflies prefer cone flowers, blazing stars (liatris spicata), and red clover. The caterpillars, however, are another matter altogether. According to the National Audubon Society Field Guide to North American Insects and Spiders, the great spangled fritillary caterpillar eats only the leaves of violets. furthermore, it will not be found on violets during the daytime as it leaves its food source to hide when it is light outside. At night, it returns to the violets and feeds. I looked for the caterpillars at night, but although there was damage to some of the violet leaves in my yard, I could not find them. They are fuzzy and black and have six rows of orange and red spikes.

Greater Fritillary Butterfly (Speyeria spp.) drinking nectar from a Cone Flower

The adult butterflies, however, don't try to hide. They happily flit about from flower to flower drinking nectar. It is difficult to identify some of the species of the greater fritillary genus (Speyeria spp.) because the visual differences are small. The one pictured on this blog entry and in the attached slide show is most likely a great spangled fritillary, but I can't be 100% sure of that identification so this is another one that gets an asterisk.

Quick facts about the Great Spangled Fritillary (Speyeria cybele):

Diet: Adult butterflies eat nectar. Caterpillars eat violet leaves.

Range: Although many species of greater fritillary butterfly have very specific ranges, the great spangled fritillary can be found over much of the United States except the southernmost part of the country.

When is it here? Unlike Monarch butterflies which migrate all the way to Mexico for the winter, greater fritillaries overwinter right here! The Audubon Guide says they can be found in flight (adult form) from May to October. This suggests that hard frost kills the butterfly itself, however, the caterpillars, says bugguide.net, after hatching in late summer or fall, don't eat and instead they overwinter as tiny caterpillars unchanged from from their hatching size until the following spring when the violets begin putting out new growth.

Lifespan: Not found, but likely about 13-15 months.

IUCN Redlist Status: Not listed. Common

NOTE: Butterflies will sometimes drink from hummingbird feeders, try the feeder kit shown below from Perky Pet one of the companies that helps sponsor this blog. At the time of this posting, they are a having a big sale on hummingbird feeders!
Perky Pet Antique Hummingbird Feeder Set With Free Nectar

Monday, September 12, 2011

Western Conifer Seed Bug Nymph (Leptoglossus occidentalis), A True Stink Bug


Western conifer seed bug nymph (Leptoglossus occidentalis)
Photo by Brad Sylvester. Copyright 2011. Do not copy.
When is a bug not a true bug? When it doesn't belong to the suborder Heteroptera (True Bugs). To qualify as a true bug, there are eleven basic criteria according to bugguide.net. (Nine really, with two more that apply only to some groups of true bugs.)

  1. True bugs do not pupate. They change into adult stage gradually with successive molts.
  2. Nymphs may have different coloration and much smaller wings, but otherwise look pretty much like adults of the same species. The wings often get larger with each instar stage.
  3. True bugs often have a flattened body
  4. Wings are beetle-like, but fore-wings may be partly thickened and partly membranous.
  5. Hind-wings are membranous and used for flight (as in beetles which are NOT true bugs).
  6. When folded at rest, wing-tips overlap or cross.
  7. True bugs (and some beetles) have a prominent scutellum (triangle-shaped part of the thorax between the wings).
  8. Mouth is beak-like and made for sucking.
  9. Antennae have 4-5 segments.
  10. *Some true bugs have simple eyes (as opposed to compound eyes)
  11. *Some true bugs (including the western conifer seed bug) have defensive scent glands.
Adult Western Conifer Seed Bug: note the overlapping wings,
four antenna segments, and prominent scutellum that are
indicators of a true bug. Also note the leaf-shaped extensions
on the rear legs that make this a leaf-footed bug.
Photo by Brad Sylvester. Copyright 2012
As you can see, true bugs share some traits with beetles and many somewhat resemble beetles. If you are trying to identify an insect that you think is a beetle, but it doesn't match any that you can find, consider that it might be a true bug (Heteroptera) instead.

All of which brings us to today's find: the western conifer seed bug. This true bug was particularly difficult to identify (for me), because most guides use only pictures of the adult form and while this immature specimen is similar to the adult, the differences are enough to cause problems and, of course, I started out with beetles instead of true bugs.

Finally, I figured out that this was a nymphal form of a true bug, and from there arrived at a juvenile western conifer seed bug (Leptoglossus occidentalis). Notice that it has full wings (lacking in my specimen) and a longer, narrower body, but is otherwise quite similar. Once I had arrived at this species, I could confirm the species' presence in my yard by the adult's typical behavior and my previous observations. (Note: I added the adult photo which I took in my yard on October 20, 2012). You see, the western conifer seed bug likes to spend the winter indoors, in human houses. It doesn't breed, burrow, or eat in the house, but just likes to be indoors to stay warm in the winter. In the winter it isn't unusual for an adult specimen of the western conifer seed bug to buzz down from the rafters of my house.

Quick facts about the western conifer seed bug:

Leptoglossus occidentalis, an invasive species in New England
Photo by Brad Sylvester. Copyright 2011. Do not copy.

Range: The range of the western conifer seed bug, according to the Connecticut State Agricultural Experiment Station website, has expanded to the northeast United States only as of the mid-1980's making it an invasive species, but one that migrated here naturally over time from the West.

When is it here? The western conifer seed bug resides here year-round, over-wintering in the adult form. However, it prefers to overwinter inside human houses for protection from the winter cold. This insect may be a case of an invasive species whose continued existence here relies on human help. Although it is possible that it might be able to survive the cold under pine bark.

Diet: Leptoglossus occidentalis sucks plant juices from many species of evergreen seeds, green cones and, less often, needles.

Habitat: Pine forests.

Lifecycle: Eggs are laid in spring on pine needles. Once hatched, Leptoglossus occidentalis molts through five instar stages before reaching adulthood around August.

Lifespan: Unknown

Other facts: As mentioned above, the western conifer seed bug is one of the true bugs that has scent glands for defense. If you crush these bugs in the home, they may give off an unpleasant odor. They are sometimes called "stink bugs."

Taxonomy of the Western conifer seed bug:

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Coreidae
Genus: Leptoglossus
Species: Leptoglossus occidentalis

 

Wednesday, September 7, 2011

Reader Question: Mystery Creature's Night Sounds


I recently received a question about a mystery creature in the comment section of one of the earlier posts on this blog and I wanted to share it and my reply with everyone:

Question:
"I hear a sound out of my 200 year old oak tree at night that sounds like clipping scissors. am suspecting it to be a squirrel. It's very sharp and keeps me up at night? am I right? What else could it be?"

Answer:
Some squirrels do indeed make a short, sharp high-pitched noise which is often regular in frequency for an extended period, perhaps every second or two. Most squirrels, however, are diurnal, sleeping at night. The exception is the flying squirrel (Glaucomy sabrinus or Glaucomy volans). Depending upon where you live, this might be the best possibility, although I don't know from first-hand experience what a flying squirrel sounds like. There are some birds and many insects that call at night as well, and these can't be entirely ruled out without more information. Try this experiment: place an 18" square piece of anything that's very flat and smooth (and preferably dark colored) out near the tree from which the sound originates. Sprinkle a light coating of talcum or other very fine powder evenly over the flat surface and placed a few peanuts, some peanut butter, or a crust of bread in the center of the board. In the morning, look for foot-prints in the talc. Flying squirrel feet would have tiny but well-defined finger-like toes. The front feet will leave prints almost like tiny hands and the rear feet will have pads that are a bit longer. Both prints may show evidence of the pointed claws they use for climbing. Use an online or printed animal footprint guide to compare against other small rodents which might be active at night.

You can also use an automatic trail cam to snap a picture of anything that comes to take the "bait" instead of using the tracking powder. If you place the baited platform several feet off the ground under the tree, you may also see evidence of the flying squirrel "landing" after leaping from above, providing even more evidence.