Bed Bugs are small insects that are highly specialized in what they do. They have particular habits and behaviors that are critical to their survival, and which can make them a challenging pest to eliminate. Knowledge is the key, as only by understanding every aspect of the behavior and biology of Bed Bugs can we create the tools we need to combat them.
Bed Bugs are small, cryptic, nocturnal insects that live by feeding on the blood of warm-blooded animals – with a strong preference for people. They are closely related to other species of bugs that specialize in feeding on bats and birds, and are thought to have evolved from a bug that preyed on cave dwelling bats or pigeons. Bed Bugs are wingless in all stages of development, gregarious, almost social animals, that like to be in contact with each other when resting, and prefer living in tight spaces such as cracks. Adult Bed Bugs are about four millimeters long, flattened “top-to-bottom” (an advantage when living in cracks), and usually dark brown in color due to the blood meal contents of their gut. Nymphs are considerably smaller, to the point of being difficult to identify with the naked eye. They are normally only active outside their resting area when they feed, which is usually in the early hours of the morning when it is dark and quiet. They do not spend long periods on their host other than to feed.
As adults, Bed Bugs will feed about every third night, and will often return to the same location and host. As soon as a Bed Bug begins to feed it produces a “sweet sickly” odor from glands at its anal end. This acts as a stimulant to other Bed Bugs, causing them to increase their activity in search of food. Bed Bugs consume a considerable amount of blood at each feed (proportionate to their size), and swell during feeding. This size increase would prevent the Bed Bug from returning to their preferred resting cracks, so they excrete the excess water from their meal, retaining only the nutrients and solids. This excreta causes black sticky marks to be left by feeding Bed Bugs near their daytime resting area.
Surprisingly, these marks are often the first signs that Bed Bugs are even present. To avoid retaliation from the host, Bed Bugs inject an anesthetic through their mouthparts before starting to feed, so the host is usually unaware of any feeding activity. This, and their very secretive behavior, can allow Bed Bug populations to develop into significant numbers before treatment is even considered. Bed Bugs can survive for long periods without feeding – over a year under some circumstances. Feeding by Bed Bugs may also be seasonal in unheated premises, as they enter a type of hibernation if the temperature drops below 13 degrees Celsius for any extended time.