Wednesday, July 22, 2015

Dazzling Insects of Summer‏

Caterpillar white dotted prominent Nadata
Too often we focus in our nature studies on one particular group of animals or plants (birds or mushrooms for example). I am not sure what the origin of this "species-chauvinism" is, but it denies the naturalist in all of us some remarkable opportunities to marvel at the wide biodiversity of life all around us. Insects are abundant both in numbers and species in any location, although they are primarily found during warm periods.  Look around you and begin to appreciate the remarkable variation in insect form and color.  A basic guidebook is invaluable in beginning to put names on common species: Kaufman's "Field Guide to Insects of North America" is a great place to start.

Some of my favorite insects are the odonates, the damselflies and dragonflies. They can be a challenge to identify but the males are often very colorful and distinctive.  The male azure bluet damselfly is a tiny jewel that is most often seen near ponds that lack fish, which would prey on its aquatic larvae.  

Amber-winged spreadwings in "wheel" position
Similarly the amber-winged spreadwing damselfly is found in greatest numbers at fish-less ponds.
Amber-winged spreadwings ovipositing
There are large numbers at a pond I built in the woods without fish; in mid-July they are mating (in the "wheel position") and laying eggs (male and female in tandem) in plant stems.  The mating scenario is bizarre- the male transfers sperm to its second abdominal segment, catches a female and holds her by the neck; she bends her abdomen forward and receives the sperm from the accessory genitalia. 

Odonates may be primitive but they have a complex breeding behavior. Their feeding behavior is primal predation and they eat almost anything that flies. The "T rex" of dragonflies is the huge dragonhunter, a predator that eats other dragonflies.  It is found along rivers and streams and spends a great deal of time flying around its territory.  
Dragonhunter on Beaverdam Trail

The beetles are the largest group of any kind of animals and thus can be a nightmare to identify.  The English scientist Haldane has been quoted as saying that the creator if he exists has an inordinate fondness for beetles!  Yet despite this bewildering array of beetles, one can easily learn the ten common species you encounter.  Indeed this is the basis for making progress in studying any taxonomic group, by focusing on a few common ones first.    

Dogbane beetle
A new picture identification guide ("Beetles of Eastern North America" by Arthur Evans) is very handy in determining which family and perhaps species you may be looking at.  A knowledge of plants can facilitate this process.  For example I noticed some strikingly iridescent beetles on dogbane (Apocynum), a close relative of milkweed.  Indeed the beetles are dogbane beetles (Chrysochus) which feed on the poisonous dogbane and utilize the toxins for defense, and advertise their toxicity by their spectacular colors (due to structural refraction of light).  

Elderberry borer
Similarly the brightly colored elderberry borer, a gorgeous longhorn beetle that feeds on toxic elderberry, advertises its distastefulness by bright colors.  This may surprise you since people can eat the flowers and ripe fruits of elderberries. This is also a lesson in the consumption of wild plants- never eat anything that has brightly colored insects feeding on it ! 

Longhorn beetle
Another longhorn beetle that I found is the exact opposite- very cryptic. This white-spotted sawyer feeds on white pines in our area and escapes predation by its camouflage.

One of the most remarkable moths is a day-flying species called the hummingbird clearwing sphinx which has recently appeared in our yard.  It hovers in front of flowers and drinks nectar just as do the hummingbirds. Its high energy lifestyle requires it to work hard to obtain the necessary energy and you can see this in the frantic way it flits from flower to flower.  Its coloration resembles a bumblebee which may offer it some protection from bird predation, especially when temperatures are too cool for it to fly.

Hummingbird clearwing sphinx on wild bergamot
While trimming a red oak tree I came across a moth caterpillar that epitomizes camouflage as a strategy. This is the caterpillar of the dotted prominent moth which hides from predatory birds by its green coloration among the oak leaves. The longitudinal yellow line may help to disrupt the outline of the caterpillar as do the red spots around each spiracle (the entrances to the tracheal system by which it breathes) and the knobby appearance of the skin.  If attacked, the caterpillar is said to expose large yellow mandibles as a threat.

So  who can deny that the insects are a fascinating if somewhat bewildering group of creatures?  Let us all attempt to be more catholic in our interests in the natural world.  Such an approach will repay us with a multitude of fascinating information and simple awe concerning the amazing creatures with which we share the planet.  

Bill Dunson 
Galax, VA and Englewood, FL

Saturday, July 11, 2015

Relaxing after a hard days work gathering nuts

So you are a fox squirrel and you are tired on a hot summer's day after collecting lots of nuts and burying them.  What do you do for relaxation?  Stretch out and contemplate an afternoon nap in the shade of a big tree.  I took this photo while doing the same myself.  So maybe squirrels and people are not so different?

Bill Dunson

Fwd: IO moth‏

Neat shots of male Io moths at Kjell's front door

Saturday, July 4, 2015

Butterflies Abound in Fields of Summer Wildflowers‏

Wildflower field at farm in VA
In late June and early July, wildflowers produce a myriad of blooms and butterflies take full advantage of the availability of nectar.  We have planted a series of pollinator fields and the most recently planted, in 2012, is now a mass of flowers.  This photo shows blooms of purple cone flower, wild bergamot, ox eye sunflower and common milkweed.  On warm sunny days butterflies and bees swarm around the flowers collecting nectar and pollen.  

Sleepy orange on echinacea
The sulphurs are one of my favorite groups of butterflies because of their bright yellow colors.  But separating the species can be confusing to the novice watcher.  This gorgeous sleepy orange is drinking from a purple cone flower which has a head made up of many tiny flowers, characteristic of the aster or composite family.  It is called "sleepy" since the circular eye-like marks on the wings of similar species, such as clouded and orange sulphurs, are lacking.  

Pearl crescent
The tiny male pearl crescent is less showy than some species, but has a subtle beauty when viewed up close.  A wood nymph shown on a purple cone flower is cryptically colored except for a series of small eye spots on the hind wing and a light patch on the forewing with additional eye spots.  

Great spangled fritillary on echinacea
At our intermediate elevation in the Blue Ridge of Virginia the great spangled fritillary is one of the most common large butterflies in fields, with wings showing a kaleidoscope of colors and patterns, with a wide pale band across the outer margins of both wings when they are closed. 

Aphrodite fritillary
Yet mixed in with these is a occasional aphrodite fritillary, more typical of higher elevations, with a much narrower marginal pale band and an extra dark spot on the inner forewing.  These are classic sibling species in the same genus that are distinct but barely so, illustrating how evolution can proceed by gradual separation of forms with slightly different habits.

Female io moth, wings closed
Although butterflies are generally the more flamboyant of the Lepidoptera with many moths having rather somber hues (the better for camouflage), I came across two moths recently that do not fit this pattern.  The Io moth is inconspicuous when its wings are folded (this illustrated female is reddish while the males are yellowish), but when the wings are opened in response to disturbance, a pair of remarkable eye spots is revealed.  These appear to function as a bluff to scare away predatory birds.  The smaller black and yellow lichen moth uses another tactic of bluffing by its resemblance to the poisonous net wing beetle, which advertises its toxicity by a bright color. 

Io moth, wings open
Lichen moth, black & yellow
Butterflies and moths are truly spectacular and cannot fail to astonish you with their fantastic colors and forms.  See what you can do with your yard to make it more butterfly friendly for larvae and adults and you will be thrilled by these "flying flowers."

Bill Dunson 
Galax, VA and Englewood, FL 
Wood nymph