Tacos? Pasts? Sushi? Cockroaches And Their Finicky Palates

Q. I have been servicing commercial accounts for four years. Most of my work is done at night. Sometimes it seems that certain types of cockroaches are found in certain types of restaurants and not in others. Has anybody ever looked at which cockroaches are more common in different types of restaurants? (D.S.)

A. As far as I know, there has never been a comprehensive study made of this in the United States. Of course, there have been many reports identifying which species of cockroaches have been found in certain types of environments. Overall, the German cockroach predominates across the board.

Also, the variation in species distribution seems to be related more to microhabitats within given structures than to the type of structure itself. For example, within any particular restaurant in the United States, you are more likely to find German cockroaches than any other species. However, if the restaurant has a basement and it is within the habitat range of Oriental cockroaches, then Oriental cockroaches are likely to be found inhabiting the basement and perhaps even floor drains in that restaurant. Likewise, if the restaurant is in an area where the brown-banded cockroach is commonly found, it would not be unusual to find this species in attic areas of the restaurant, or possibly even in the dining room.

I have been in many restaurants in the last 25 years. Only once was I surprised to encounter a cockroach not typically found in restaurants in whatever part of the country I was in. In this case, it was brown-banded cockroaches in a commercial kitchen along the Gulf Coast.

Interestingly, in a paper published in the Japanese Journal of Sanitary Zoology in 1994, it was reported that German cockroaches were encountered more often in western-style restaurants in Japan, and more brown cockroaches (Periplaneta brunnea) were found in Japanese restaurants, pubs and sushi shops. It was suggested in this paper that the observed habitat segregation may be due to different chemical compositions of the food or food materials utilized in these facilities.

In my experience here in the United States, I have found that German cockroaches are not uncommon in restaurants that serve Asian and Far Eastern cuisine. It may well be, however, that cockroach fidelity for a particular cuisine may be more apparent and consistent in countries of origin as opposed to our more heterogeneous environment.

It would be interesting to determine the species frequency and distribution within restaurants that serve different types of cuisine. A study looking at cockroach composition in, for example, Italian, Mexican, Asian, Middle Eastern, and American restaurants would need to investigate not only different food and food ingredients, but variations in preparation style and equipment as well. The impact of construction type, climatic factors, and geographic location would also need to be considered. It sounds like an interesting project. I hope someone undertakes it if it is not already being done.