Yesterday evening we noticed a large number of giant mesquite beetles in a couple of branches on the seedpods obviously mating. 1. Will the females disperse to lay their eggs on other food sources? 2. Will my tree lizards eat most of the young? 3. Why the large number in one place? I consider myself quite observant and have not seen these before.
A: These insects are actually called giant mesquite bugs (Thasus neocalifornicus) and differ from beetles in that they have piercing-sucking mouthparts and front wings that overlap, among other characteristics. They are fairly common in the foothills of Tucson but not always in the same places. They are not numerous every year it seems but someone always sees them and asks about them. They are only found on mesquite trees so your other plants are safe. Since they are sap feeders and not usually found in large numbers, even the mesquite trees are safe. The young are in danger from predators but because of their warning colors (red and yellow) they have some protection. Some of them will always survive.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to
