There aren't any animals like hornets that hunt large prey (like a rabbit, or even up to a deer), right? Why not?
They're not fast enough

A hornet has a top speed of around 40 kph, while a rabbit is only a touch faster, a deer can hit 75 kph (all figures from Wikipedia). In order to act as hunting insects they need to match the speed of these large animals in large enough numbers to surround and overpower them but these animals could easily match their speed or outpace them. Let's suppose they can overcome that limitation somehow and bring the prey down. They've now bagged a big lump of protein but it's a long way from the hive because they've had to chase it down first. That means that a long round trip is required every time they visit the kill and thus reduces the energy yield as well as increasing the chance of losing it to scavengers.

Against this you have the simpler option of eating smaller, easier to catch, prey as they do now.