A parasitoid fungus so-called Ophiocordyceps unilateralis sensu lato which has been described to have the ability to manipulate its ant victims walking like zombies and climbing up vegetation to bite the veins or margins on the underside of leaves. In this study, we reported that O. unilateralis s.l can infect seven species of Polyrhachis and a Camponotus ant in the central forest of Taiwan. To investigate the different infection ability of O. unilateralis s.l. with different ant hosts, we recorded the number of infected ant host every month. The results showed that the different infected ant hosts can be divided into main host and secondary hosts. We found that the main host’s fruiting body growth rate, sporangia development rate and total number of infected individuals are higher than those of secondary hosts. This infection strategy not only allows O. unilateralis s. l. to have better control on the main host, but also reduces the survival pressure via infecting secondary host, which means this infection strategy is the appropriate consequence of trade-offs. The results help us to understand better the mechanisms behind the host–parasite cross-talk and will open the way for an enhanced comprehension of the intricacies of parasite manipulation.