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NMSU professor answers 10 myths about cockroaches

People say that if the world came to an end, the only survivors would be cockroaches. Is that possible?

Professor shows cockroaches.
NMSU professor Alvaro Romero shows Turkestan cockroaches he uses for research. (NMSU photo by Angela Simental)

"No," said Alvaro Romero, New Mexico State University's professor of urban entomology. "It is just a myth even though cockroaches can withstand 10 times more radiation than humans in case of a nuclear attack."

Romero has been researching the biology, sexuality and behavior of cockroaches for two years, mainly studying the Turkestan cockroach, which is the most prevalent cockroach southern New Mexico.

Urban entomologists, including Coby Schal, Ph.D., considered the main authority in cockroach research, have been able to find interesting facts.

Myth 1: All cockroaches are pests. False. Only 1 percent of all cockroach species invades homes or buildings and can be a danger to humans.

Myth 2: Cockroaches cause allergies. True. Cockroaches produce proteins in their bodies that can be in the air, including skins, cuticles and feces, and cause allergies to humans. "It has been demonstrated that it may cause asthma in some people," Romero said. In fact, 30 million in the U.S. are allergic to cockroaches.

Myth 3: Cockroaches can transmit diseases. True. They eat everything and they can be everywhere, so they are in constant contact with contaminated material, including feces, which can contaminate food, for example, by walking or defecating on it. Some cockroaches also invade barns and can contaminate animal food. "They can be what we call, mechanical vectors, which means that they carry pathogens in their bodies, contaminating food and food preparation surfaces," Romero said.

Myth 4: Cockroaches only invade dirty houses. False. "You can be the cleanest person and still suffer an infestation from peridomestic cockroaches," Romero said. "We live in communities, and we have neighbors, so they will find a way to come into a house, especially through cracks or crevices or even through your bathtub."

Myth 5: Cockroaches are most likely to invade a home during the winter. True. Like other insects, cockroaches hibernate during the winter, and because houses provide a perfect, artificial environment, there is a greater possibility that they will infest during the winter.

Myth 6: Cockroaches reproduce faster in the summer. True. Cockroaches reproduce less during the winter because of the lower temperatures. "The explosion of Turkestan cockroaches, is in the summer," Romero said. "That's because there is more food available for them during this time, so they reproduce more." Romero catches cockroaches in sticky traps as part of his research, and said the amount of cockroaches he traps significantly lowers once it gets cold.

Myth 7: Larger cockroaches are more dangerous than smaller ones. False. Size does not necessarily play a factor in how dangerous a cockroach could be. "There are some cockroaches like the Madagascar hissing cockroach, which people use as pets," Romero said. "It is huge, but they make nice pets."

Myth 8: All cockroaches thrive in urban areas. False. Not all cockroaches are nasty, invasive pests. Most cockroaches do not live in urban areas. "Many of cockroaches are part of the food chain. For example, in North Carolina if one species of cockroach disappears, a regional woodpecker would be endangered. That's because they are the main part of their diet," Romero said.

Myth 9: All cockroaches fly. False. Some species do not fly. "In some species prevalent in New Mexico, for example, only the male has wings," Romero said. "And, some have wings but they don't fly, like a bird per se. What they are really doing is using their wings to jump."

Myth 10: All cockroaches are nocturnal. False. Pest cockroaches are mainly nocturnal, but most forest cockroaches are active during the day, as stated by Schal.