The arthropod submitted was identified as the brown marmorated stink bug (Halyomorpha halys). The bug is not an ectoparasite. It is not known to parasitize or be a source of disease whether directly or indirectly. The stink bug gets its name from its ability to produce a pungent odor when mishandled or threatened. This is thought to be a defensive adaptation of the arthropod that helps prevent it from being eaten by birds and lizards. They are generally a nuisance in homes where they can cause an infestation.
There are various other morphological versions of the stink bug. Coloration is generally brown but there are some that may have variations of red, grey, a copper-like color, light brown, and just plain black. But the most common stink bug is the brown marmorated version.
The stink bug is not native to North America, but was instead introduced from China, Japan, or other Asian countries which the arthropod it is native to. They are hardy, having the ability to survive hot or cold temperatures for long periods of time. It is suspected that the bug was introduced into the United States in the late 1990s. Similar introductions of the stink bug were made in Europe.
Though not an ectoparasite, the stink bug is considered an agricultural pest in that it will indiscriminately feed on a host of important agricultural plants. Specifically, fruits, vegetables, cherries, peaches, raspberries, beans, pears, and soybeans. Extensive loss of crops can result. The stink bug has a piercing proboscis that injects enzymes into the plant that allow it to suck back a meal of partially digested sap. This piercing will cause dimpling and necrosis of the plant surface and the possible introduction of plant pathogens. Natural predators in the United States are wasps and birds which have been adapting to this new food source. Pill bugs have also been shown to be natural predators. The effective use of insecticides is mixed.
The arthropod can, to the untrained eye, be mistaken as a bed bug. The coloration is somewhat similar when brown and both have a piercing proboscis. But there are some important distinctions. The stink bug is about 17 mm in length and just about as wide giving it a characteristic heraldic shield shape, whereas the bed bug varies in size depending on the stage but adults are generally 4-5 mm long and 1.5-2 mm wide giving it an oval shape. While both can be described as brown in color, the bed bug can have a more reddish brown color. The bed bug’s brown color extends through the underside while the stink bug’s underside will have a more creamy white-brown color. The head area of the bed bug is broader while that of the stink bug is more narrow and protruded forward. There are markings on the stink bug that are veined or marble-like in which the descriptive term “marmorated” originates from, while the bed bug has no such markings but is heavily segmented. Bed bugs tend to be flatter than stink bugs, and most importantly, bed bug identification can be further made difficult due to the fact that their body will undergo elongation after feeding. The antennae tend to be much longer on the stink bug. And of course, the stink bug is notorious for releasing its foul defensive chemicals when disturbed or threatened. These chemicals are released from glands located on the underside of the thorax between the first and second pair of legs.
See comparisons of both adult arthropods in the images below.
photo by W. Vientos
photo by W. Vientos
It is important to make the correct identification because as mentioned previously, stink bugs are not ectoparasites and are not known to transmit disease. However, bed bugs are ectoparasites and are important to correctly identify and report as soon as possible so the proper mitigation steps can be taken by healthcare and extermination professionals. Their quick action will help to prevent the establishment of an infestation within the facility. Once an infestation becomes established in a facility it can be extremely difficult to eliminate.
While the bed bug is an ectoparasite, it is not known to transmit any diseases to humans. The arthropod is nocturnal, only coming out during the evening to feed on the blood of mammals. Heavy infestations have been known to produce anemia in humans. Bed bug infestations can cause loss of sleep and the bites can induce localized allergic reactions. In susceptible hosts, bed bug waste products can produce asthmatic episodes.
Bed bugs will reside during the day in the cracks of furniture or inside compromised indoor walls. Their bodies are flat allowing them to get in-between crevices and other tight areas. Unlike bed bugs, stink bugs are not nocturnal and can be found in homes at any time of the day while seeking out a food source. Infestations inside houses can be a problem, albeit not as difficult to eradicate, as with bed bugs. The location of bed bug infestations within a house can be difficult to find as they may localize inside interior walls. Bed bug detection dogs have been found extremely helpful in detecting these colonies of bed bugs.
It’s important to have a laboratory with the skill set to make the identifications of arthropods that may be submitted. The use of reference laboratories incurs hidden costs, compromised specimens, delay’s in the arthropod identification that many times are important in the clinical decisions needed to be made in the care of a patient (to name but a few reasons why referring is not all it’s hyped up to be). And besides, laboratory testing is just plain interesting so why would you want to refer it out? However there are many laboratories that do not have the technologist with the skill set or comfort level to make these identifications. It is a sign of good leadership in providing the opportunities for technologists to pursue interests in learning how to identify at the very least the most common human ectoparasites endemic to the geographic area the clinical laboratory is located. It is most unfortunate that leadership in most healthcare facilities do not place the importance needed in assuring that the ability to provide these identifications to the clinician is performed in a timely manner by well trained technologists. In the age of centralized laboratories, which are becoming more and more the rage, it is the clinician and patient that miss out on timely results and sometimes accurate results or the resolution of improperly submitted specimens. With the end result being compromised healthcare that otherwise goes undetected by the healthcare system.
Most persons outside of the laboratory are not privy to the technological testing availability and professional expertise of the laboratories performing their tests. Or for that matter, the stresses imposed on these areas due to understaffing and their negative impact on the quality of healthcare downstream. Tests that they and their insurance pay good money for. In the opinion of this author, sometimes ignorance is not bliss. Especially to the physician or the patient. So maybe this is why I ironically chose the stink bug as this blog’s subject.
I hope you enjoyed this blog and please do provide feedback. All the very best!