Bed Bugs: Adaptive Little Survivors

Bed Bug Infestation

The common bed bug, Cimex lectularius, is a parasitic insect that exclusively feeds on blood, our blood preferably. They’ve been around for thousands of years and will likely be around thousands more as they are extremely difficult to eradicate. In essence, the bed bug is nature’s adaptive little survivor.

The name is derived from the favored habitat bed bugs infest. They reside in or around the bedding areas of their meal. This can include pillows, sheets, quilts, mattresses, and even sofas within the houses and apartments in which we dwell.

Chances are high if you have a neighbor in the same apartment or duplex with an infestation that you are likely being feasted on as well as bed bugs will traverse through outlets and other opportunistic crevices to get to you.

These nocturnal hematophagous (bloodsucking) insects emerge and feed on the host (us), typically without being noticed. But the bite of a bed bug can cause skin rashes and other allergic symptoms. Over time, the injection site where they penetrate the flesh with a microscopic “beak” festers and a gradual, itchy welt can result. Favored exposed areas to drink from are the neck and jawline, though they will indiscriminately feed elsewhere.

Bed bugs are drawn to the carbon dioxide we exhale as well as the body heat we emit.

Interestingly, the DNA bed bugs ingest from humans can be drawn and forensically tested up to 90 days. Under cool conditions, adult bed bugs can live up to a year without feeding. In warmer climates they’ll dine five to ten times a day and survive up to five months without blood.

Newly hatched instars require an immediate source of blood or else expire within weeks. Bed bugs go through six points of life stages, each lasting about a week, and shed their skins at each stage, molting six times before becoming fertile adults. Females can generate upwards of 500 eggs in her lifetime.

The epidemic of bed bugs can drive the hosts to do extreme things in order to get rid of the persistent infestation. A woman so desperate to rid her home of the pests doused her couch in alcohol in hopes of smothering them out. Instead, she inadvertently set her Carlisle, Kentucky apartment ablaze and dislocated 30 other residence along with herself.

The idea of having teams of little bugs skitter along your skin and drink your blood is already unnerving, but even more so disturbing is it is growing ever more difficult to exterminate them. Recent research has determined bed bugs are able to alter the response in certain genes in their shells, allowing them the versatility to adapt or avoid the effects of insecticides.

In order to determine the resilience of the common bed bug, researchers led by Subba Palli of the University of Kentucky Department of Entomology in Lexington, Kentucky collected 21 specimens of bed bugs from four Midwest cities. Scientists examined the activity of genes that seemingly shrug off the effects of pyrethroid pesticides, a common household insecticide used to treat for similar infestations.

The genome-wide analysis of the insecticide resistance-associated genes of the insects revealed 14 molecular markers associated with pyrethroid resistance, particularly in the epidermal layer of their integument (outer covering/shell), thus preventing adequate penetration of the pesticide into the target nerve cells by detoxifying and nullifying the effects.

An additional pesticide resistance gene called kdr was also found to activate in the nerve cells, giving bedbugs multiple layers of protection. These attributes are especially unique as no other insect currently utilizes a genetically adaptive multilayer defense quite like this. Having a more thorough understanding of how the little blood suckers adjust and adapt may assist in the creation of more effective and targeted extermination tactics.

[Image via Shutterstock]