Sunday, June 15, 2014

Bugs and Slugs at Cedar Creek Preserve

Standing Cypress viewed through my new macro lens
Since the passing of the vacant-lot prairie, I've seen wildflowers like purple ruellia (Ruellia nudiflora), standing cypress (Ipomopsis rubra), and basket flower (Centaurea americana, described in a previous post) pop up in nearby weedy areas. I'm still trying to get a feel for the local calendar of plant life as it blooms and fades over the season.

bluebonnets prairie bluets and tiny bug with eyes like a fly
This has been a banner year for gaillardia and basket flower.  Both are opportunistic annuals that have benefitted from the remarkable drought Texas experienced over the past few years. When perennial plants are weakened, annuals are released and find the space they need for germination. Generally, I prefer perennials for their dependability, but annuals can also make great insectary plants.

oak 'apple' gall
This part of the world (probably all parts, actually) is full of insect life. Much of it is benign, some definitely is not, and others are still a mystery. Every time I walk through shrubby red oak thickets I see these galls pictured to the right.  Sometimes an oak is so well decked out in these round ornaments that it looks like it's fruiting, a natural growth of the tree. In truth, it's a nursery for a gall wasp (possibly Amphibolips confluenta). The habits of the gall wasps are still somewhat unknown to science. They spend most of their lives as larvae underground, emerge for a brief period to mate, and then senesce and disappear again into the oaks and the earth.  People used to use oak galls to make ink for quills used on parchments and vellum. The gall was combined with iron and an acid, which then produced purple-black ink that darkened as it dried. You can make something similar today by soaking iron nails in vinegar and then mixing it with an oak gall decoction.

Helpful unidentified snail, feeding on common hedge parsley (an invasive)
The land snails in Texas also have an interesting socio-cultural history.  I've generally overlooked land snails, but I've learned that they've got their own food web going on. Some snails are specialist predators on other snails and slugs. Other snails are major vectors of human disease. Texas has had brushes with more than one of each category. 2013 was the year of the Texas African Land Snail scare. African land snails can live for almost a decade, can reach the size of a rat, and have no predators here in the States. You may wonder: "What's the big deal about a big snail?" Well, African land snails carry a parasite that causes meningitis in humans.

The African land snail invasion has since been debunked, but other exotic snails have been established in Texas. One example is the decollate snail (Rumina decollata), originally introduced in Arizona for bio-control of the brown garden snail (Helix aspersa), also introduced from the Mediterranean. Humans have made the brown garden snail a global species. Sometimes we eat them with garlic and butter.

I had never given much consideration to the origin of the snails in my garden, but it turns out many of them are present due to human intervention. The same can be said of the "roly-polys" of my childhood- they too are introduced. It's strange to think that the basic wallpaper of my outdoor life is a relatively new to this landscape.

Wolf spider, watching me watching her.


  1. I have never heard that roly-polies (spelling?) are introduced! From where were they introduced...and why, on Earth?!

    1. They're from Europe originally. I'm guessing they were an accidental introduction.

  2. Interesting! I've always assumed they were native...but introduced makes some sense, as I don't know of anything in particular that eats them.