What's the difference between a "water bug" and a roach?

Question

My house was just sprayed and I've killed three roaches (or what I thought were roaches). I asked my boyfriend why there would be roaches in the house right after I sprayed and he said they weren't roaches they were "water bugs". They look like roaches to me...either way shouldn't the bug guy have killed these guys when he came??

Answer 1

Technically, the term "water bug" should only apply to insects in the Order Hemiptera which are primarily aquatic in habitat - this would include water boatmen (Corixidae), backswimmers (Notonectidae), giant water bugs (Belostomatidae), and possibly others like water striders (Gerrids).

However, in many areas, the term "water bug" is used as a colloquial expression to refer to the American cockroach (Periplaneta americana).

Most true water bugs, naturally enough, stick to the water.  They are sometimes attracted to porch lights and backyard pools, but are very rarely found inside the house.  It seems more likely that the "water bugs" you are seeing inside your home are actually American cockroaches.

Whether or not they should have been killed when the bug guy came depends on what he was spraying with, or whether he used some other control product entirely.

While once it was common practice to combat roaches by dousing the entire house in broad-spectrum powerful insecticides (that were usually also very poisonous to humans) - now it is far more common to use other products such as cockroach-specific bait gels (i.e. Maxforce).  

These products are much more effective in the long run, but they can sometimes take a few days (or longer) for the toxin to take effect (they are often slow-acting to ensure that all of the insects in the area get dosed - both by eating the bait, and indirectly by eating the poison-laden p**p of the insects that have already eaten the bait).

It's also theoretically possible that your bug guy is more interested in repeat business rather than controlling your bug problem, and has used something that is relatively ineffective - so you have to keep having him come back.

Answer 2

Is your boyfriend from the south?  When I lived in the deep south and would make comments about the cockroaches, people always told me they were "just waterbugs"!