Science & Technology
11:33 am
Tue February 5, 2013

Cockroaches' Obsessive Grooming Habit

A cockroach cleaning an antenna
Credit Ayako Wada-Katsumata

A new study from researchers at N.C. State finds that cockroaches must clean themselves incessantly in order to function properly. The findings are important not just for scientists studying insect behavior, but also – to the relief of those who suffer from infestations – might provide clues in developing more effective pesticides.

Cockroaches groom themselves constantly by running their antennae and legs through their mouths. This removes environmental buildup and allows the insects to smell food, find mates, and sense danger. Without clean antennae, according to the study, cockroaches’ abilities to perform basic functions were significantly impaired.

Cockroaches have a reputation as stubborn and pervasive pests. Aside from making people jump, they can also cause significant problems in people’s homes. Some of the problems include:

  • Allergies – Cockroaches produce proteins that can cause asthma, similar to pollen. In places with high degrees of infestation, like inner city areas, this can trigger severe cases of childhood asthma.
  • Pathogens – By going between the sewer system and people’s kitchens, cockroaches easily spread harmful bacteria around the house.
  • Contamination – Cockroaches defecate all over the surfaces they touch, depositing harmful bacteria in places that people eat off of or on things people ingest.
  • Electronic issues – Cockroaches like warm places, such as appliances or electrical boxes, and they often cause short circuits. In industrial situations, cockroach infestations can cost thousands of dollars worth of damage.

So how do the findings help us deal with cockroaches? Senior author Coby Schal says that the most important result is simply in our understanding of fundamental insect behavior. The study shows how well-groomed antennae are vital not just to finding food, but also for basic life functions. It also reveals what sorts of substances the roaches cleaned from their bodies – things like foreign substances and bodily oils.

But Schal also points out that the study could help researchers who wish to design chemicals to target cockroaches.  “Most pest control depends on a broadcast application, on spraying chemicals on a surface and hoping the roach walks over it,” says Schal. But now that we know how and why cockroaches clean their bodies, he says that researchers could this knowledge to develop insecticides that are more targeted to their specific behavior.

The findings were published online this week in the Proceedings of the National Academy of Sciences. Co-authors of the study were Ayako Wada-Katsumata and Katalin Boroczky.

Watch a video of a cockroach grooming its antennae here.

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