Hosts or Prey
Caterpillars, larvae of leaf beetles and sawflies, and other openly feeding, relatively large, slow-moving, soft-bodied insects
Identification
Adult stink bugs are distinguished from other insects by the large triangle shape (scutellum) with a rounded rear end that occurs on top and covers the third thoracic segment and front portion of the abdomen. Adults are shield shaped and 7/16 to 3/4 inch (11–18 mm) long. They are mostly mottled brownish or grayish with black, white, and sometimes orange or yellow.
The barrel-shaped eggs are about 1/20 inch (1.2 mm) in diameter and occur in clusters. They are pearly white when first laid and develop gray coloration before hatching.
First instars are round and mostly blackish and pinkish white. Older nymphs are oval and mostly mottled grayish with black and white and some orangish or yellowish coloration.
Lookalikes
Adults of rough stink bugs resemble those of brown marmorated stink bug, Halyomorpha halys, a plant-feeding pest. Rough stink bugs have two white bands on the hind legs, no bands on their antennae, and points on the face. Rough stink bugs also have a rough or toothed edge on the front margin of the thorax (or "shoulders"), which is the source of the common name for this genus. Unlike rough stinkbugs, adults of brown marmorated stink bug have one white band on the hind legs, white bands on the antennae, a blunt face, and relatively smooth shoulders.
Life Cycle
Stink bugs develop through 3 life stages: egg, nymph, and adult. Eggs hatch about 1 week after being laid. The nymphs develop through 4 increasingly larger instars.
First instars (nymphs) at least initially remain together by their empty egg cases. Later instars become more active. Nymphs develop into adults over a period of 3 to 4 weeks during warm weather. Adults live about 2 or 3 months, during which each mated female can lay several hundred eggs if prey are abundant.
In mild winter locations rough stink bugs can be active throughout the year. Where winters are cold, overwintering is as adults in protected places, such as inside buildings and under loose tree bark. Adults become active in spring and mated females lay eggs in a group of about 10 to 20 eggs. Nymphs are present feeding during spring and summer.
Habitat
Brochymena species are most common in trees and shrubs. The adults' coloration makes them easily overlooked on bark. In addition to feeding on relatively large, slow-moving, soft-bodied insects they feed innocuously on leaves, seeds, and shoots of various broadleaved trees and shrubs.
To improve biological control
- Control ants because they attack natural enemies of various pests.
- Grow flowering insectary plants to provide nectar and pollen to feed adult natural enemies.
- Reduce dustiness that disrupts the activities of natural enemies (e.g., periodically hose off small plants).
- Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.
See Protecting Natural Enemies and Pollinators for more information.
At least 50 species of stink bugs occur in California. These include at least 6 Brochymena species of which B. affinis and B. sulcata appear to be the most common. The other known California species are B. cariosa, B. parva, B. pilatei, and B. quadripustulata. All Brochymena species are commonly called rough stink bugs.
More Information
- Description of Parabrochymena, New Genus, and Redefinition and Review of Brochymena Amyot and Audinet-Serville (Hemiptera: Pentatomidae), with Considerations on Natural History, Chorological Affinities, and Evolutionary Relationships, The Memoirs of the Entomological Society of Canada
- Rough Stink Bugs (PDF), Colorado State University
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Heteroptera
- Family: Pentatomidae
