Life cycle of Huarpea fallax (Hymenoptera: Sapygidae) in a xeric forest in Argentina

Abstract

This study describes the life cycle of Huarpea fallax (Hymenoptera: Sapygidae) in a xeric forest in La Pampa province, Argentina. This cleptoparasitic wasp attacks the nests of two species of leaf-cutter bees: Megachile catamarcensis and Anthidium vigintipunctatum, both belonging to the family Megachilidae. Nests of these bee species were obtained during a trap-nesting programme. Adult emergence showed a unimodal pattern indicating a univoltine life cycle. The period from egg-laying to adult emergence lasted for 10–13 months; however, one female took about 2 years to emerge, suggesting parsivoltinism. Most females attack one cell per host nest, the outermost cells being the ones most parasitized. However, the position of the attacked cells was variable. In this paper, although there were insufficient data to prove a correlation, the data suggest a positive trend between body size of sapygid wasps and their host bees.

Keywords:

• Anthidium vigintipunctatum
• host–parasite interaction
• Megachile catamarcensis
• Megachilidae
• trap nest

Acknowledgements

I thank the Rúgolo de Agrasar family for permission to conduct this study on Estancia Anquilóo, H.J. Marrero for his help in the field, A. Roig-Alsina for confirmation of Huarpea fallax and collaboration in the determination of Chrysis, S.P. Durante for determination of Megachile catamarcensis and Anthidium vigintipunctatum, C.E. Lamas for determination of Anthrax and R. Saurral for English revision. The manuscript benefited from critical reading by D.J. Brothers and the comments of three anonymous reviewers. Field work was supported by Agencia Nacional de Promoción Científica y Tecnológica (PICT 08–12504 and 0851), Argentina. JPT is affiliated with Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.