Apoica pallens
Apoica pallens displays active, rather than chemical defense behavior. During the day, when adult individuals are not swarming, they cover the comb face of the nest several layers thick. The wasps on the outer layer of the comb face outward. They watch for predatory ants trying to reach the interior of the nest. It is thought that the advantages of this protective formation during the day is what led to the nocturnal foraging and swarming.