Cockroach Q&A

 

 

 

North Carolina State University (NCSU) entomologist Dr. Coby Schal, author of the Cockroach chapter in the 10th edition of the Mallis Handbook of Pest Control, shared the following insights about these amazing creatures.

 

 

A. Researchers often seek “model systems” that best address specific questions, but are also convenient to maintain in the lab. This is why the mouse and fruit fly are the work-horses of biomedical and genetics research, respectively. The cockroach has been a work-horse of insect physiology – the study of structure and function of whole organisms and of specific organ systems. Size matters since each insect organ is tiny! The larger cockroach species (Periplaneta americana and some of the blaberid species; see chapter if you don’t know what these are) have been indispensable for research in insecticide discovery, toxicology, endocrinology (this is where some of the juvenile hormone analogs came from), molting and cuticle formation, and many other areas. These big roaches also serve in biobot research because they are long-lived, hardy and can carry large payloads, and as inspiration for biologically-based robots. To evolutionary biologists, cockroaches represent a very old lineage from which we can learn a lot about the evolution of hemimetabolous development (look it up in the chapter!) and the emergence of sociality in cockroaches and termites.

 

 

A. An emerging link between an environmental factor and human health, however tenuous, is rapidly picked up by the media, and covered in the news, self-help guides and doctors’ offices. By contrast, the medical importance of cockroaches is astonishingly poorly recognized by the public and the medical and regulatory communities. Cockroaches have been recognized for half a century as major triggers of respiratory disease, including allergies and asthma. We also have known for decades that they can transmit pathogenic microbes, including multi-drug resistant bacteria. Yet the public is largely unaware of this. The pest management industry has done an excellent job educating the public about the potential economic losses from termites, carpenter ants and wood-boring beetles. But we have not done as well communicating the potential health impacts of cockroach infestations. When it comes to indoor pests that can cause disease, such as cockroaches and bed bugs, I’d like to see greater emphasis on public education and more effort toward pest eradication.   

 

 

A. There are so many unknowns! We are well on the way to sequencing the full genome of the German cockroach. This community resource will reveal genes, biochemical pathways, and neurogenetic networks that are unique to the cockroach and therefore potential target sites for novel and specific pesticides. It will likely reveal mutualistic associations with microbes that may be targets for disruption. I think baits will continue to dominate as the most efficacious formulation against cockroaches. Therefore, we will need to determine the frequency of glucose aversion in the U.S. and globally; investigate the relationship between glucose aversion and the evolution of metabolic resistance to insecticides; screen cockroach populations for aversion to other sugars and other nutrients; determine whether cockroaches learn and remember aversive stimuli (that is, glucose-containing baits) better or worse than rewarding stimuli; and finally, delineate the molecular genetic mechanisms of glucose aversion. Biological control of cockroaches has been relatively ineffective – why? Do cockroaches have a fantastically effective immune system? We discovered a highly species-specific virus that is pathogenic but very slow. Perhaps slight genetic modifications can make it more virulent as a pest control agent. We also need to investigate the impact of effective cockroach control on the allergens they leave behind and on associated health-related outcomes, especially in children. At the broader ecological level, international travel and commerce can lead to the emergence of new invasive pests. There are some cockroach species that associate with the built environment in Southeast Asia and Africa and we need to keep an eye on their global spread, as the Asian cockroach is marching west through Texas and into Mexico and north into North Carolina.

 

 

A. A good place to start is our lab web site at http://www.cals.ncsu.edu/entomology/schal_lab/overview/. All our publications are available in PDF format at http://www.cals.ncsu.edu/entomology/schal_lab/Publications, and some of the media coverage of our work can be found at http://www.cals.ncsu.edu/entomology/schal_lab/Schal_labinnews. Happy surfing!