The brown marmorated stink bug (Halyomorpha halys) is an insect in the family Pentatomidae, native to China, Japan, Korea, and other Asian regions. In September 1998, it was collected in Allentown, Pennsylvania, where it is believed to have been accidentally introduced. The nymphs and adults of the brown marmorated stink bug feed on over 100 species of plants, including many agricultural crops, and by 2010–11 had become a season-long pest in orchards in the Eastern United States. In 2010, in the Mid-Atlantic United States, $37 million in apple crops were lost, and some stone fruit growers lost more than 90% of their crops. Since the 2010s, the bug has spread to the nation of Georgia and Turkey and caused extensive damage to hazelnut production. It is now established in many parts of North America, and has recently become established in Europe and South America.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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starts withAdult brown marmorated stink bugs are approximately 1.7 cm (0.67 in) long and about as wide, forming the heraldic shield shape characteristic of bugs in the superfamily Pentatomoidea. They are generally a dark brown when viewed from above, with a creamy white-brown underside. Individual coloration may vary, with some bugs being various shades of red, grey, light brown, copper, or black. The term "marmorated" means variegated or veined, like marble, which refers to the markings unique to this species, including alternating light-colored bands on the antennae and alternating dark bands on the thin outer edge of the abdomen. The legs are brown with faint white mottling or banding.
The nymph stages are black or very dark brown, with red integument between the sclerites. First instar nymphs have no white markings, but second through fifth instar nymphs have black antennae with a single white band. The legs of nymphs are black with varying amounts of white banding. Freshly molted individuals of all stages are pale white with red markings. Eggs are normally laid on the underside of leaves in masses of 28 eggs, and are light green when laid, gradually turning white.
Like all stink bugs, the glands that produce the defensive chemicals (the smell) are located on the underside of the thorax, between the first and second pair of legs.
The stink bug was traced to have been introduced to the Greater Caucasus area during the construction works of the 2014 Winter Olympics in Sochi, Russia, where it was most likely imported with decorative building elements brought from Italy. The stink bug has since spread to Georgia, where it continues to cause major damage to the local crops. From 2016 to 2018 the bug was estimated to have destroyed one-third of Georgia's hazelnut harvest, with yearly damages of up to €60 million (~179,000,000 in 2018 lari). Georgia is the fifth-largest producer of hazelnut in the world, with yearly production valued at US$179.5 million in 2016. In 2018 the Georgian government allocated 4 million ($1.6 million) and the United States Agency for International Development (USAID) 8 million ($3.2 million) to help combat the spread of the brown marmorated stink bug in Georgia, but so far the efforts have been criticized as being insufficient.
The odor from the stink bug is due to trans-2-decenal and trans-2-octenal. The smell has been characterized as a "pungent odor that smells like coriander." The stink bug's ability to emit an odor through holes in its abdomen is a defense mechanism evolved to prevent it from being eaten by birds and lizards. However, simply handling the bug, injuring it, or attempting to move it can trigger it to release the odor.
Reports on human cases are rare, but the stink bug's body fluids are toxic and irritating to the human skin and eyes. One case of keratitis has been reported in Taiwan.
The brown marmorated stink bug is a sucking insect (like all Hemiptera or "true bugs") that uses its proboscis to pierce the host plant to feed. This feeding results, in part, in the formation of dimpled or necrotic areas on the outer surface of fruits, leaf stippling, seed loss, and possible transmission of plant pathogens. It is an agricultural pest that can cause widespread damage to fruit and vegetable crops. In Japan, it is a pest to soybean and fruit crops. In the U.S., the brown marmorated stink bug feeds, beginning in late May or early June, on a wide range of fruits, vegetables, and other host plants including peaches, apples, green beans, soybeans, cherries, raspberries, and pears.
During courtship, the male emits pheromones and vibrational signals to communicate with a female, which replies with her own vibrational signals, as in all stink bugs. The insects use the signals to recognize and locate each other. Vibrational signals of this species are noted for their low frequency, and one male signal type is much longer than any other previously described signals in stink bugs, although the significance of this is not yet clear.
As of 2010, 17 states had been categorized as having established populations, and several other states along the eastern half of the United States were reported as having more than normal numbers of stink bugs. Stink bug populations rise because the climate in the United States is ideal for their reproduction. In optimal conditions, an adult stink bug can develop within 35 to 45 days after hatching. Female stink bugs are capable of laying 400 eggs in their lifetimes. The bug is also capable of producing at least one successful generation per year in all areas of the United States, no matter the climate. In warmer climates, multiple generations can occur annually, which can range from two generations in states such as Virginia to six generations in California, Arizona, Florida, Louisiana, Georgia, and Texas.
The addition of two more generations allowed the population to explode, leading to the establishment of several other populations in neighboring states. Currently, no environmental limiting factors are apparently slowing their distribution across North America. They also are extremely mobile insects, capable of moving from host to host without causing disruption in their reproductive processes. Currently, populations are estimated to continue to grow and spread to other states and provinces, especially during unusual periods of warm weather.
