First occurrence of Blattodea and their association with ants (Hymenoptera Formicidae) in abandoned social wasp nests (Hymenoptera: Vespidae: Polistinae)

Abandoned nests of social wasps are used by various arthropods, however, there are no records of cockroaches. Therefore, the objective of this study is to report the occurrence of cockroaches in abandoned social wasp nests. The first record occurred in a Cerrado area, Brazil, where a nymph (Ectobiidae) of a cockroach (Cahita Hebard, 1922) was found in an abandoned social wasp nest. The second record involved three cockroach nymphs (Blattodea: Ectobiidae), found alongside an ant Camponotus sp. (Hymenoptera: Formicidae) in an abandoned nest located in a transition area between the Atlantic Forest and Cerrado biomes. Although the exact reason for their presence cannot be defined, it is possible that the cockroaches were foraging for food or shelter from the rain. This is the first record of cockroaches occupying abandoned social wasp nests and the first record of another insect species occupying an abandoned social wasp nest alongside ants. Given the presence of Blattaria in more than one nest and in different locations and biomes, it can be suggested that this occupation is not merely incidental. However, further studies are necessary to determine the frequency of cockroach use of abandoned nests and to better understand the importance of these nests as microhabitats for these insects.