Cockroaches are one of the most unwanted and persistent home pests, but findings of a new DNA analysis have shown why these bugs are so hard to get rid of.

Persistent Pest

The American cockroach (Periplaneta americana), which is about the length of an AA battery, is the largest common house cockroach. Also known as the water bug, it can survive for a week with its head cut off. It also eats anything, which include waste matter as well as other dead or live cockroaches.

In the new study, which was published in the journal Nature Communications, Shuai Zhan, from the Institute of Plant Physiology and Ecology in Shanghai, China, and colleagues, have revealed what makes this creatures successful.

The researchers sequenced the genome of the American cockroach and then compared this with those of two related species as well as with those of other insects called Blattodea, which include termites.

How Cockroaches Thrive In Filthy Environments

The analysis revealed the evolutionary history of cockroaches and provided evidence that the roaches evolved an expanded set of genes.

These genes include those that comprise the insect's internal detoxification system that provides protection to these insects in the event that they consume anything toxic. The expanded genes also include those that beef up the roaches' immune system to protect them from infection when they are exposed to gems. These could help explain why these bugs thrive in filthy conditions, where they eat virtually anything.

Impressive Survival Abilities

The researchers also found genes that ensure fast and efficient reproduction of roaches and those that allow these bugs to regrow limbs that were broken or bitten off by predators.

Health Hazard

Cockroaches cause gastrointestinal and respiratory illnesses. Debris left behind by these bugs such as saliva, droppings, old shells, and body parts can also trigger asthma attacks in individuals sensitized to cockroach antigen.

Getting Rid Of Cockroaches

The researchers said that identifying genes that are crucial for cockroach survival provides a means to better control these pests amid rising temperatures brought about by global warming. The insects are known to thrive in hot and humid environments.

"Our genomic and functional analyses in the American cockroach provided insights into its success in the adaptation to urban environments and the biology of developmental plasticity in cockroaches," the researchers wrote in their study, which was published online on March 20. "Our study may shed light on both controlling and making use of this insect."

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