Tuesday, November 25, 2014


Little Miss Muffet
Sat on a tuffet,
Eating her curds and whey;
Along came a spider,
Who sat down beside her,
And said, "What's in the bowl, kid?"

There was so much to see during the late summer that I wanted to share.  When you stop and look at the same places each day, you are likely to find some pretty interesting creatures.  This post is about four spiders, one of which was new to me.


First up is a little quarter-inch long spider that I visited several times over the summer, trying to figure out what it was.  I assumed, wrongly, that this was an immature spider that would grow up to be something that I'd recognize.  Often there would be two or three spiders of two different color patterns scooting around with their bellies up, and seemingly between layers of a web which were built across an open area on one side of a small shrub.  It wasn't until I attended this year's BugFest at the NC Museum of Natural Sciences, along with about 35,000 other folks, that I found the answer.  At a booth called "Stump the Experts", Dave Stephan looked at my photos and identified this small arachnid as a Bowl and Doily Weaver.  The Bowl and Doily Weaver spider is a sheetweb weaver that constructs a web with two parts.  The top section is a bowl shaped web with a network of trip lines above it.  Below the bowl is a flat sheet-like web that looks a bit like an old timey doily. 

(link to a picture of a doily)

Looking down through the center of the bowl, perhaps you can make out the underside of this female Bowl and Doily Weaver and some of the debris left in her web. 

This is a side view of the female Bowl and Doily spider. Her abdomen is boldly marked with black and creamy white while her cephlothorax and legs are brown. She is hanging upside down on the underside of the bowl with the trip lines extending to the upper left and part of the doily beneath her to the lower right. Flying insects hit the "trip lines" and fall into the "bowl".  She will grab a small insect from beneath the bowl, pull it through the web, and wrap it in silk.  The spider often sits on the doily portion of the web to feast on her prey.   

One or more male Bowl and Doily Weaver spiders may live in the female's web even after mating, competing with her for the food provided by the web she built. There are two theories for why the females sometimes allow the males to remain in the web.  One is that it takes too much of the female's energy to chase the male off. She needs to conserve her energy for securing and consuming her own food and also for producing the eggs that will become next generation of her species. Another theory is that the female has a reduced chance of being eaten by other species of spiders that feed on Bowl and Doily Weavers if her male counterparts are also available in the web. 

(link to Bugguide picture of male)

I will definitely be looking for more opportunities to observe this spider species in future summers!

Information on cohabitation is from :  and  and


Late in the summer the female Black and Yellow Argiope spider in our front yard has gotten quite large, likely with many eggs.  Two other common names are Writing Spider and Scribbler because the zig-zagging stabilimentum she constructs in the center of her orb shaped web looks a bit like scribbly writing.  She is also called the Yellow Garden Spider. The males are very small and sometimes become her meal after mating.  In our area, the female dies at the first hard frost, but in warmer climates the female can live for a few years or more.  She makes one or more tan colored egg cases that each can hold between 300 and 1400 eggs.  The eggs hatch in autumn, and the spiderlings survive the winter by remaining in the egg case until Spring.  The egg case also protects the little spiders from some predators, but I read that "one study found that in addition to" young argiopes, "nineteen species of insects and eleven species of spiders also emerged from egg cases!"


This spider with the marbled abdomen and light brown legs is a female Common House Spider.  These spiders live almost exclusively around human dwellings and are responsible for the cobwebs in the corners around the inside and outsides of our homes.  The Common House Spider, which is usually harmless to humans, is related to the venomous Black Widow Spider.  Both species have a globe-shaped abdomen and build a "tangle" web.   I read that the tangle web design is an adaption to protect the cob web spiders from being captured by mud daubers. 


This variably colored spider is sometimes called the Cross Spider because of the cross-shaped mark on the back of its abdomen, but is also known as the Barn Spider and the Spotted Orbweaver.  Late every summer several of these spiders build their webs in front of our doorways and windows, and across the sidewalk. They seem to appear out of nowhere, but in fact they have been getting bigger through out the spring and summer and are now filled with little spider eggs.  Before long this spider will spin a yellowish silken egg case that will hold up to one thousand eggs. 

This large female has a light colored cross pattern on the back of her abdomen with black, tan, and reddish brown legs. She has plenty of bristles on her banded legs for controlling insects that she catches in her web.  

This female Cross Spider is a study in variations of grey. The cross shaped mark is still visible on the back of her abdomen even though it is just a shade lighter than the surrounding surface.

This is the underside of the same gray Cross Spider.  One characteristic of this species is the black mark on the bottom side of the abdomen, framed by a pair of white L-shaped brackets.  Also visible is a single strand of silk she is spinning from her cluster of orange colored spinnerets.  

A spider's ability to spin silk is quite complex.  The silk begins as a liquid mix of various proteins in a silk gland and becomes a strong, stretchy, and flexible solid strand of silk as it emerges from the spider's spinnerets. Some species of spiders can spin as many as eight different kinds of silk, each from a specific gland for the type of silk being formed.  Some silk is spun to set up the framework of the web. Some silk is sticky and spun for the purpose of capturing prey.  Some silk is spun to wrap the prey after it is captured.  Some silk is spun to produce the tough covering of the egg sac.  And some silk is spun to allow spiders to FLY!

An egg sac produces hundreds of young spiders. To be successful the little spiders need to spread out.  One way to do this is to use a technique known as "ballooning".  The spider finds an elevated leaf or other object, stands on its eight little tiptoes, and casts a long strand of silk into the wind. When conditions are just right, the wind lifts the silk with the spider attached into the air and the "balloon ride" begins. The spider is off to some random new location where it may face less competition for food and have a better chance of survival. 

I recently found these two videos in response to a question from my little five year old friend, Brooklynn, who asked me about how spiders fly.  

At the upper left of the picture is a broad band of silk that was spun by the gray Cross Spider as she was repelling down to the ground.

I read that young spiders only build their webs at night and take them down during the day, eating the silk as they do. This is an attempt to protect themselves from two species of Mud Daubers that have a talent for following the web's foundation lines which are not sticky.  Using this method mud daubers find and paralyze young spiders and then store them in the nesting chambers they build out of mud.  A mud dauber fills each chamber with up to twenty paralyzed spiders and then lays an egg on the last spider deposited before sealing the entrance.  When the mud dauber egg hatches into a larvae, it has a large supply of fresh spiders to eat as it matures and later emerges as an adult.

This is one of my favorite photographs.  It was taken by Alan Henderson of 15 paralyzed jumping spiders found in one chamber of a mud dauber nest.  The mud dauber larvae is at the center of the picture dining of one of the spiders.




Some of the information in this post came from:

Saturday, November 22, 2014

Black Swallowtail Caterpillars on Bronze Fennel

Earlier this summer I added a couple bronze fennel plants to the front yard with the hope that Black Swallowtail Butterflies would find them an attractive place to lay their eggs.  By mid summer I found this young caterpillar and several companions roaming about on the stalks of the fennel plants. This young caterpillar is protected from predators to some extent by its coloration which mimics the appearance of a bird-dropping.

This second instar caterpillar was happily munching away on the fennel.   Black Swallowtail caterpillars are particularly fond of plants in the Carrot/Parsley family. These plants include dill, carrots, Queen Anne's Lace (wild carrot), celery, parsley, cilantro, and anise among others.

Over the next few weeks the caterpillars continued to feed on the tender leaves of the fennel plants.  By then these handsome butterfly larvae were brightly striped with black, green, and white, and prominently spotted with yellow.  This is known as their fifth or final instar.

Below is a view of the underside of a caterpillar latched onto a stalk of fennel.  At the upper left you can see the three pairs of very small thoracic true legs.  These legs have five segments with hooks at the end which are used for grasping food. The true leg pairs are called the forelegs, the midlegs, and the hindlegs.  About half way down the larvae, the caterpillar is clasping the stalk with four pairs of abdominal prolegs. The ends of these pudgy leg-like structures are covered with tiny Velcro-like hooks called crochets that help secure the caterpillar to the twig or stalk on which it is crawling.  At the lower left is a pair of anal prolegs or claspers that are also covered with tiny hooks.
I've added a diagram below that I found on the internet which better illustrates the details of the caterpillar legs.

At the left of this picture is a better view of the three small pairs of jointed thoracic legs.

Three years ago I found this Black Swallowtail caterpillar at Big Pa's house.  When I gently nudged it, I was greeted by its bright orange, V-shaped osmeterium.  This organ is thought to provide some protection to the caterpillar.  When it feels threatened, the caterpillar releases a chemical odor from the osmeterium that is somewhat objectionable to potential predators.

Two years ago, my good friend and colleague, Michele, and I raised several Black Swallowtail caterpillars that I collected from fennel that Grammy and I grew in a planter on the deck. Every few days, we supplied the caterpillars with fresh organically grown carrot and fennel tops to munch on.  

Below is a picture of the Black Swallowtail's chrysalis.  At the bottom (and out of view) the caterpillar has made a silk pad on the side of the container.  The two anal prolegs have transformed into a structure called a cremaster that is covered by microscopic hooks (again, very much like Velcro) which it thrusts into the silk pad to secure itself to the surface. At the top, the caterpillar makes another silk pad to which it attaches the thin silk girdle that you can see supporting the upper body of the transforming caterpillar.  I have added links below that show a series of pictures that more clearly describe this process.

There are several species of small parasitic wasps and flies that lay their eggs on the Black Swallowtail caterpillars

Often these parasitoids find the caterpillars by detecting the particular scent of the caterpillar's poo (also called fecal pellets or frass).  Like some other caterpillars, Black Swallowtail caterpillars actually use their mandibles (jaws) to grab and then fling their frass away from themselves.  This makes it harder for the parasitic wasps and flies to locate the caterpillars. 

Although several chrysalises formed, and perhaps due partly to parasites, we did not have great success with the butterflies emerging.  Below is a link to more information about the Black Swallowtail including its life cycle.  

Some of this information came from:

Saturday, November 15, 2014

Gumpo Azaleas, Azalea Caterpillars, and the Datana Moth

Along a sidewalk in the front yard, there grows a grouping of Gumpo azaleas. Every June these two and a half foot tall, compact evergreen shrubs are covered with large, long-lasting white flowers interspersed with bright pink blossoms and a few bi-colored ones, too.  Gumpos are one of the Satsuki* hybrid azaleas developed in Japan from a cross between two varieties of Rhododendron.  Below is a picture of one of our Gumpos taken in June 2013 after a spring rain.

* The Japanese word Satsuki translates to "fifth month" because this azalea blooms in the fifth month of the Asian lunar new year.  In 2014 the fifth lunar month runs from May 29th through June 26th.


In mid September we stumbled upon a dense gathering of elegant caterpillars.  I was not aware of them at first as I inspected a few azalea twigs that were stripped of leaves. As I peered further down into the azalea, a group of nearly thirty caterpillars came into focus.  They were feeding on the leaves around the base of the branch. The caterpillars overall color was a reddish-brown mahogany with wide, bold, yellow stripes running the length of their bodies.  Long white hair-like structures sprouted from behind their heads and along their sides.  Using, I discovered that these were the aptly named Azalea Caterpillars with the scientific name, Datana major

When these caterpillars were disturbed, each individual in the group arched its back into the characteristic posture you see below.   These half grown caterpillars held this pose for several minutes until the perceived danger had past.

In late September the normally June blooming Gumpos put out more buds.  The Azalea Caterpillars spread out and were nearing maturity, but their leaf munching seemed to have left only small areas of localized damage to the azaleas.  The caterpillars retained their mahogany head and tail color, but their body color had turned jet black.  Their broad yellow stripes became broken yellow lines fit for some long straight stretch of two-lane highway in rural America.

And of course when I picked up this mature caterpillar, it immediately assumed its innate defensive posture that several species use.

This caterpillar will transform into a pupa that will overwinter in the soil nearby.  Late next Spring the adult moth will emerge and after mating will lay eggs on host plants which include many varieties in the azalea / rhododendron family. Below is a cellphone picture of a Datana Moth, the adult form of the Azalea caterpillar, that Grammy found at Campbell University in August 2013.

On November 6th I found this freshly opened Fashion azalea bloom near the house. This azalea bloomed earlier this year at the expected time of late April to early May, like a number of other azaleas in the yard. I've not seen this happen before. I wonder how this year's second blooming will effect next Spring's flowering, since these shrubs normally set buds in late summer for the blooms that appear next Spring.