Prey Status Affects Paralysis Investment in the Ponerine Ant Harpegnathos venator

SIMPLE SUMMARY: Some ants sting their prey to paralyze or kill them when foraging. Some studies have found that paralysis of prey may also be used in food storage. To further understand the foraging behavior of predatory ants and the underlying mechanism, we systematically observed the foraging behavior of Harpegnathos venator when provided with different types of food, different prey sizes, and different prey numbers, and we studied its paralysis behavior in relation to prey under different food supply conditions through controlled experiments. We found that the stings of Harpegnathos venator completely paralyzed the cockroaches. The stinging time was significantly longer at a higher prey activity level and for larger cockroaches. In addition, there was no significant difference in the stinging time of H. venator for different prey densities. It was much shorter for legless cockroaches than for normal cockroaches. The results showed that the longer the stinging time for similar cockroaches, the longer it took for the prey to revive and move. The results are helpful for further understanding the behavioral mechanism underlying prey storage in predatory insects. ABSTRACT: The paralysis behavior of some ponerine ants when foraging may be important for food storage and colony development. However, how workers invest in paralysis under different prey circumstances is often overlooked. Here, we report the prey-foraging behavior and paralysis behavior of Harpegnathos venator under different food supply conditions. Solitary hunting was the main foraging mode of H. venator, with occasional simple collective hunting. Nymphal cockroaches with high activity were the most attractive to H. venator. In the experiment, we found that the stings of H. venator completely paralyzed the cockroaches. The stinging time was significantly longer at a higher prey activity level and for larger cockroaches. In addition, there was no significant difference in the stinging time of H. venator for different prey densities. The results showed that the longer similar cockroaches were stung, the longer it took for them to revive and move. These results are helpful for further understanding the behavioral mechanism underlying the food storage of live prey by predatory insects.