A Roach Story

Imagine that you go into the kitchen for a nightcap, you turn on the lights and suddenly a bunch of little brown dots start moving all over the place, roaches, you get angry, sick, and then hands-on go get the insecticide bottle and in a shout start killing all the roaches. (I wanted to add a picture of an infested kitchen but the ones I found were too disturbing, you could ask google if you'd like to).

Let's reflect for a moment and think, what will happen the next time you go into the kitchen? will you have more or fewer roaches? yes, will this be sustainable? no, in a few days roaches will rise and make you yell again. And this could be a forever battle. This because every kind of insecticide will have a different efficiency and a degradation time.

By the time you see a roach you have to know that it got there because you had an ecosystem that made life possible, they need three things moisture, food, and heat. When the environment meets the minimal conditions for life a roach will enter the system, once this happens you can do two things that affect the stock of roaches (This is represented by a rectangle).

Almost every time that roaches enter the system, you can't explain how it happened, so that would be the boundaries of the system. Some cockroaches would enter because birth rates, others because of migration, and others because who knows.

The System could be explained in a CLD as follows, at least our first approach:

Let me know your thoughts, what do you think could be a good Reference Mode for this system?