Eastfield College will offer a student research class beginning in Fall 2013. (BIOL 2389 for those interested in enrolling.) The focus of this class will be entomology and Eastfield is partnering with the Trinity River Audubon Center (TRAC) as the main location for our field work.
If you have never been to TRAC it is well worth the visit. It is a beautiful location with lots of well maintained trails and tons of wildlife located just a few minutes south of downtown Dallas.
Trinity River Audubon Center
6500 Great Trinity Forest Way (formerly 6500 S. Loop 12)
Dallas, TX 75217
214-398-TRAC (8722)
http://trinityriver.audubon.org/In preparation for the class I will be going into the field once a week all summer. This is an electronic journal of what I find at Trinity River Audubon Center on my visits.
June 4, 2013
I worked at two locations. Location 1 is located northeast of the parking area. Location 2 is south of the visitor center.
Location 1:
June was unusually mild and wet for this area resulting in tall and vigorously growing grasses and wildflowers. The trail is surrounded by Coreopsis tinctoria. 
Whistling Duck Pond - Looking east
Coreopsis tinctoria
Coreopsis tinctoria
A close-up view. I had not planned to study wildflowers, but the trail on this particular day was truly spectacular.
This is a spider Argiope - a yellow garden spider. The zig zag pattern in its web is called stabilamenta. There are lots of theories about its function.
Farther off the trail to the east I came across a series of small cob webs and their spiders. There were several of these nests on the tops of each dead plant. My hand is in the picture to give scale and to help with focusing the camera.
Questions:
1) What is their density - per bush, per area?
2) What would happen if you moved a spider to a new plant tip that was occupied?
3) How do they find these taller plants?
Cobwebs at the tops of dead plants like the one shown above.
Location #2
After spending some time in the open grassy areas I decided to move into the trees to look for more spiders.
The trail toward the river
A wound in a tree is producing sap that attracts some butterflies.
In the trees I came across some occupied spider webs. What caught my attention was the combination of a cob web and an orb web. The spider is in a conical retreat in the middle of the cob web. After doing some reading I came across the fact that certain cob web spiders will build their webs on top of an orb web, preying on the orb spider and any prey it has caught.
The images above and below show the spider in its retreat. I decided to not collect any of these spiders at this time.
In the image above you can also see some of the wrapped prey items the spider has caught.
The other spider I found at this location was an orb web spider. I use a point and shoot camera that wouldn't focus on the web, so I indicated its location in the photo. Also notice the arrow showing the owner of the web in his retreat.
As you can see, this spider has connected a small dead leaf to the underside of a live leaf and sits upon it to hide himself. This was the only one of this type of spider I saw today so I did not collect it.
Questions:
1) How does this spider do this? - How does it select the leaf and haul it into place.
2) If I remove the spider from its web and retreat, can I induce it to build another retreat?
The shady area along this trail held another surprise - poison ivy. I took these images to show my students what it looks like.
I was on site for about 3 hours on this first day of observation. Once I picked a spot I didn't even have to move to see lots of great organisms.
All images carry a Creative Commons Attribution-Non Commercial License.
http://creativecommons.org/licenses/by-nc/3.0/
I welcome all comments on this posting.
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