But when I see this I cringe for their poor prey, in this case a wood louse.
These Red bugs are Hemiptera or true bugs, which are an order of insects comprising groups such as the cicadas, aphids, planthoppers, leafhoppers, and shield bugs. And here is our word for the day: Hemipterans are hemimetabolous, with young nymphs that somewhat resemble adults.
Ok, so so why is this so horrific?
The defining feature of hemipterans is their "beak" in which the modified mandibles and maxillae form a "stylet" which is sheathed within a modified labium. The stylet is capable of piercing tissues and sucking liquids, while the labium supports it. The stylet contains a channel for the outward movement of saliva and another for the inward movement of liquid food.
With me so far? Now for the terrifying bit.
Before they "eat", their salivary pump drives saliva into the prey; and then a cibarial pump extracts liquid from the prey. So what happens is that predatory hemipterans - like what is happening in this picture - inject enzymes to begin digestion extraorally (before the food is taken into the body). So basically the prey is dissolved from the inside and then the gooey mush is sucked into the beetle. Niiiiiiice.
oh, and I often find them doing this while they are copulating, like the one above...(probably safer for the smaller male that way too!)