Four new inquiline social parasite species in the dolichoderine ant genus Tapinoma (Hymenoptera, Formicidae)

Four new inquiline social parasites are described in the dolichoderine ant genus Tapinoma from the Nearctic region, and keys are provided for queens and males of the Nearctic Tapinoma species. The new social parasite species represent the first inquiline species in the genus Tapinoma and the first confirmed inquilines known from the ant subfamily Dolichoderinae. The four new species appear to be workerless inquilines that exploit a single host, Tapinoma sessile (Say), and they represent at least two distinct life history syndromes. Tapinoma incognitum Cover & Rabeling, sp. nov. is highly derived morphologically and is a host-queen-tolerant inquiline. In contrast, T. inflatiscapus Cover & Rabeling, sp. nov. shows a lesser degree of morphological modification and appears to be a host-queen-intolerant social parasite. The life history of T. pulchellum Cover & Rabeling, sp. nov. is presently unknown, but its close similarity to T. incognitum suggests that it is also a host-queen-tolerant inquiline. The life history of T. shattucki Cover & Rabeling, sp. nov. is still uncertain. Our findings provide novel insights into the complex biology of ant inquiline life history syndromes.