Ask Mr. Smarty Plants

The closest we could come to the plant name you gave us is Coral Bean 'Fireman's Cap', Erythrina which is a hybrid Erythrina herbacea x Erythrinia crista-galli. Erythrina herbacea (Coralbean) is native to North America and to Texas, so it is within our area of expertise, which is plants native to North America and to the area in which those plants are being grown; in your case, Harris County. 

From Wikipedia: "Erythrina crista-galli is a flowering tree in the family Fabaceae, native to Argentina, Uruguay, southern Brazil and Paraguay." According to our research, that non-native plant is considered a tree, while we consider the native Coralbean to be a shrub, but they are closely related. This USDA Plant Profile Map does not show the non-native growing in Texas at all, this  USDA Plant Profile Map does show Erythrina herbacea (Coralbean) growing natively in Harris County.

All that actually is neither here nor there, you want to know about the "doodle bugs," which we used to call "pill bugs." We found descriptions of two different bugs that sounded like what you have:  

The first is Armadillidium. From Wikipedia: Armadillidiidae is a family of woodlice, a terrestrial crustacean group in the order Isopoda. Unlike members of other woodlouse families, members of this family can roll into a ball, an ability they share with the outwardly similar but unrelated pill millipedes and other animals. It is this ability which gives woodlice in this family their common name of pill bugs, roly polies, chiggy-wigs or potato bugs. The best known species in the family is Armadillidium vulgare, the common pill bug..

The second, Pill Bugs: this is an article from Northern State University in Aberdeen, SD. Note particularly this last paragraph in that article, which explains why neither of these bugs are damaging but perform a useful service in an ecology:

"Pillbugs form an important component of the larger decomposer fauna, along with earthworms, snails, and millipedes. All of these animals return organic matter to the soil where it is further digested by fungi, protozoans, and bacteria, hence making
nitrates, phosphates, and other vital nutrients available to plants. Although they may occasionally feed on roots, pillbugs do minimal damage to live vegetation and should not be regarded as pests."

What we took away from all this is that the bugs are attracted by moisture in the dead area. You may be sprinkling the plant too much, contributing to a certain amount of rot in the center of the plant.