4954 N. Shamrock Place, Tucson, AZ 85705

Giant Mesquite Bug

Thasius gigas

Giant Mesquite Bug

Physical Features

Adult Giant Mesquite Bugs are brownish black with orange to red bands on legs and wings.  The wingless nymph is mainly red with whitish markings.  Nymphs are often found in clusters (aggregations) when feeding.  The adults grow up to 2 inches in length.

Life Cycle

Gradual metamorphosis
Brown eggs are laid by the female on stems of the mesquite tree often in rows.  These eggs overwinter and hatch in the spring.  The young will grow to the adult stage changing in coloration and into a winged adult form.  Mating occurs and lain prior to adults dying by end of the summer.


  • Diet: Mesquite stems and pods, plant juices.
  • Activity: Active during spring and summer season, eggs overwinter.
  • Preferred Climate: Warm and humid environments
  • Defense: Odorous secretion, coloring.
  • Cautions: Stinky secretion released if they feel in danger or are handled.
  • Home Invasion: Rare but will enter during the adult stage usually in error.

Helpful Hints

  • Removal or minimal planting of mesquite trees on the property.


They do not bite and are quite harmless.

Nesting Sites

Emerge from soil nests.