Ask Mr. Smarty Plants

 Acer negundo (Ash-leaf maple) or Box elder, is native to Austin, and the seeds on the female are apparently a main food for the bug. University of Wisconsin article Box Elder Bugs discusses ways to deal with them that do not necessarily include pesticides. They will be attracted to warm, sunny places to overwinter, sometimes ending up inside the house. Some of the information we looked at recommended getting rid of any female box elder trees you have. Everything we read said that the bugs don't harm the trees, but may cause disfiguring of the fruits of some trees. Mainly they are, as you say, a nuisance.

Although we didn't see this particular explanation for their presence now, in mid-winter, we are wondering if the very mild winter we have had could have caused them to overwinter without having to take shelter anywhere. Where is a good hard freeze when you need it? We also saw a reference to the bug reproducing in 10-year cycles, but didn't find out where in that cycle we would be right now.

We are native plant people, not entomologists, so beyond referring you to articles that discuss the bug, we are afraid we can't help. If this is a common problem in your yard, it probably is for others in the area. We would suggest you contact the Extension Education Office for Travis County.