• Is the organism easy to rear? 
  Cockroaches are easy to raise in the lab.  The only problem is containing their growth.  A large number of species can be maintained in laboratory cultures.  Three pest species have been raised routinely in synchronous culture: Blattella germanica, Periplaneta americana and Blatta orientalis.  Of 32 species which have been raised by this worker in laboratory cultures, 18 species were able to be cultured synchronously, Table I (Kunkel, unpublished).
• Can the organism be stored at any stage?  
  Cockroaches can be stored at 15°C for extended periods of time (months with some additional care) in a state of suspended animation.   When they are needed for experimental use they can be placed in a warmer incubator and given food and water.
• Is its size convenient? 
  Cockroaches of several convenient sizes are available.  For a small cockroach, Blattella germanica is a preferred species (60 mg unfed adult female) with substantial historical interest in its biology, physiology, development and control.  For a mid-sized cockroach, The Cockroach, Periplaneta americana is a good choice (850 mg unfed adult female) with unequaled historical interest in its biology and physiology.  For a large sized cockroach either Gromphadorhina portentosa or Blaberus giganteus will each provide several grams of adult tissue from each adult female.
• Is it inexpensive to rear?
  The cost of rearing of cockroaches can vary tremendously depending on what species, quality and quantity of animals are required and how much effort is able to be devoted to the rearing process. For minimal cost, mass cultures are possible which are started in large containers (i.e. garbage containers) and the only interaction with the colony involves providing food and water and preventing escapees. Colonies of this type grow and mature and accumulate wastes which eventually limit space.
  Small subcolonies of the above mass cultures can be formed by sorting individuals into size classes. Some synchrony can be obtained in these cultures by controling food availability.   The added cost of this approach includes space for the subcultures and personnel time in sorting and separate rearing.
  The most expensive in time and effort involves maintaining strictly synchronous cultures. These are the highest quality lab animals used for demanding research objectives (1, 2, 3, 4, 5, 6, 7 ). With modest resources [7 hours per week animal care; one refrigerated incubator (15°C) and one heated incubator (29°C); and a house or water aspirator or rotary vane suction pump] a high quality research animal facility can provide up to 2000 synchronous adult females per month. Additional efficiencies can be obtained by scaling up the operation to larger numbers and sustained use of the facility. A sustained production of approximately 2000 synchronous adult female Blattella germanica per month was maintained over a 5 year period at a unit cost of about $0.66 per adult female including personnel, equipment and facility costs. This also included a wastage of all the males which were not used in the study.
• Does it have a short life cycle? 
  The turn around time for the smallest laboratory cockroach, B. germanica, is 3 months (~93 days egg-hatch to egg-hatch) allowing 4 generations per year.  Larger cockroaches have similarly longer life cycles.
• Is it genetically manipulable? 
  The German cockroach B. germanica has been studied extensively as a genetic organism (Ross, 1966-1993).  Twelve linkage groups have been identified and many linkage groups have been linked with chromosomes via translocation mutants.
• Is it economically important?
  Cockroaches form a group which are only rivaled by the mosquito in economic and health consequences in the western world.  As a pest the cockroach is unrivaled as an urban pest.  There is a zero tolerance of cockroaches in the minds of most housekeepers and restaurateurs.  As a threat to health, its prior importance was minimized due to its low vagility (ability for individuals to travel during their lifetime) but recently its importance as a contributor of allergens promoting childhood asthma has boosted interest in its control.
• Dose it have an audience of interested people?
  Interest in the cockroach has been shown by the pesticide industry, the medical community, neurobiologists, developmental biologists and a fascinated public. It seems for many prominent newspapers (including the NY Times) an article on cockroaches is obligatory at least once a year either as a newsworthy item or as a human interest story.
• Interactions between criteria?
  The ability of several laboratory species to be cultured synchronously provides a lab animal perfect for studies where the developmental age is critical.  It can also provide a more uniform test organism for development of targeted pesticides which function by attacking a particularly vulnerable stage of life.

Other model laboratory organisms!