Identification

Description

The Brown Marmorated Stink Bug (BMSB) adult is similar in appearance to several native stink bug species, but can be distinguished by several characteristics. Firstly, it has light-colored bands on the joints of the antenna and legs. Also, on its ventral side, its abdominal venter is white to ash grey and may include a black spot at the terminus of the abdomen. The thin beak extends between the hind legs and is always dark colored. On the dorsal side, adults have a brown or grey marbled appearance with blue-green metallic coloration in the depressions on the head, pronotum, and connexivum, which is mostly visible in sunlight. They also have light and dark colored spots around the lateral margins of the abdomen that are not covered by the wings when the insects are at rest. The leading edge of the shoulder is smooth and not pointed on the ends. Adults are approximately 2/3" long, and females are typically larger than males.

Life Cycle

BMSB adults overwinter from fall to early spring. In the spring, adults become active and begin to reproduce. Females typically lay 20-30 eggs in a cluster on the undersides of leaves. These eggs start out translucent white or light green colored and then the top of the eggs take on a reddish-orange hue before hatching. Eggs hatch within a week and the newly emerged nymphs feed on the egg mass before moving to other parts of the plant. The insect goes through 5 developmental stages, or instars, before the final molt to the adult. Newly emerged adults are about one-half inch long (13-17 mm) and can begin producing eggs within three weeks; each female can produce several hundred eggs over a lifetime. The number of generations per year varies from one to at least two, depending on latitude.

First instars stay close to the egg mass and have a dark colored head and thorax, but the abdomens are typically red-orange with a few black bands evident. Subsequent instars actively disperse away from the egg mass and take on the characteristic black and white "marmorated" appearance. Late instars are characterized by a black head and thorax with light colored abdomens punctuated by short dark colored bands around the periphery and on top; there may be hints of pink or red in the lighter colored regions of the abdomen. Two of the most distinctive characteristics of nymphs is the contrasting white and black banding on their legs and antennae, as well as pronounced spikes along the pronotum.