What types of food do those things eat?
There seems to be a good flock of them so there seems to be a good supply of food.

Their primary defense is to spray a bitter, offending smell, though sometimes they can smell pleasantly of apples, bananas or pine sap; however, if handled roughly they will stab with their proboscis, though they are hardly able to cause injury to humans as it is adapted only to suck plant sap and not, as in the assassin bugs, to inject poison.
The western conifer seed bug's consumption of Douglas-fir seeds and seeds of various other species of pine results in a substantial loss of seed crop. Thus, its direct economic impact is a reduction in the quality and viability of conifer seed crops.

Summer foods in the Judith Mountains and Longpine Hills consist of insects (primarily grasshoppers), bearberry, snowberry and skunkbrush sumac fruits, grass leaves and stems, and Carex seeds; winter foods are grains, hawthorn and snowberry fruits, and grass leaves, stems and heads (Rose 1956).