Comparative nesting success of the keyhole mud-dauber (Hymenoptera, Crabronidae, Trypoxylon nitidum) in different substrates

Abstract

The solitary wasp Trypoxylon nitidum F. Smith nests in a variety of existing cavities. Nesting success – the fraction of completed, provisioned cells that produced adult offspring – can be estimated by examination of old cells. We estimated nesting success of T. nitidum in new and old (previously utilized by T. nitidum) bamboo traps nests, old nests of solitary wasps (Sceliphron fistularium (Dahlbom), Trypoxylon albitarse Fabr. and Zeta argillaceum (L.)) and social wasps (Polistes lanio (Fabr.) and P. versicolor (Olivier)) in Trinidad, West Indies. Success was markedly higher (61.4%) in new trap nests and significantly lower (5.6%) in old trap nests than in other substrates. Mean success in old nests of other wasps varied from 10.0% to 28.8%, with no general difference between those of solitary and social wasps. We infer that a) rented (reutilized) nests are more easily located by parasites than are new trap nests, and b) old trap nests have a higher load of parasites and disease organisms than substrates not previously utilized by T. nitidum.