The nest pedicel of a social sphecid wasp Microstigmus nr. thripoctenuslplays an important role in protecting the brood against ant predators, as inferred froq¡ data on artificial nests.. A pair of artificial nests with or without pedicels was suspended Cromihe undersides of leaves (Carludovica palmata) for 30 rnin to assess rates of discovery and removal of food (tuna bait) by ants (N = 36 pairs). Three-hundred lmd forty-thlee individuals of five ant species removed food at a higher frequency from nests wihout pedicels (83.3% oC 36 nests) than from nests with pedicels (11.1 % of 36 nests).
Keywords: brood predation, ants, nest architecture, maternal care, defense