Insulation, Radiant and Vapor Barriers - Mold behind insulation

I recently built a new home(8 months ago). I have noticed a lot of crickets, spiders, and bugs in my basement. I began to pull the insulation out between the concrete basement walls and the floor trusses ( the area between the face plate and the sub-floor, 12inches) to check for any exposure to the outside. As I was doing so, I noticed mold had developed behind the insulation. Could moisture in the basement cause this or is water getting behind the siding from the outside of the house.

Also, would it be benificial to caulk the faceplate and the subfloor to completely seal this area.

Thanks.

Go to http://www.doityourself.com/basement to learn how basement insulation is installed and the requirements before installing it. A basement is naturally a poorly vented and damp area. A new construction basement is full of fresh concrete floors and walls full of humidity that needs to escape in the curing process. With all the dampness and poor ventilation, you have a nice breeding ground for mold/mildew. Mold/mildew is not healthy. Areas affected with mold/mildew need to be disinfected with 50/50 bleach/water solution. You need to get some fans going to improve ventilation and a couple dehumidifiers going to get humidity levels down and to aid in curing of the concrete. If there are basement windows, let in some fresh air. Affected insulation should probably be discarded. There has been much in the news lately re: mold/mildew and allergies and health problems. Symptoms can range from sneezy/snuffy, headaches, rashes, nausea, vomiting, respiratory conditions. Black mold (stachybotrys) can cause death.