The behavior and natural history of Chartergellus, a little-known genus of neotropical social wasps (Vespidae Polistinae Epiponini)

Abstract

This study reviews published data on the behavior and natural history of Chartergellus and presents the first observations on social interactions in this genus of tropical swarm-founding wasps. Observations of Chartergellus golfitensis in Costa Rica and C. punctatior in Colombia showed that queens perform a post-oviposition egg-guarding vigil, and a bending display like that characteristic of epiponine social wasps that lack consistent morphological differences between workers and queens and have caste determination in the adult stage. Young, old, and queen (egg-laying) females of C. golfitensis showed small differences that indicate color changes with age, and structural differences that could be due to seasonal or colony-cycle changes in developmental conditions, but do not rule out the possibility of pre-adult caste determination, a phenomenon that needs to be carefully distinguished from pre-adult caste bias. Sexual dimorphism and the behavior of males at the nest in C. golfitensis is described, as well as the aggressive and avoidance behavior of females toward males. Nest structure in both species is as described previously for Chartergellus species, but some anomalies and their possible evolutionary significance are discussed. Cell initiation by an egg-laying queen, a behavior never seen by workers, and by a young female with slightly developed ovaries, may be vestiges of ancestral solitary reproductive traits where developed ovaries are associated with cell construction.

Key Words:

• nest architecture
• sexual dimorphism
• caste determination
• social selection
• communication
• egg-guarding
• aggressive displays
• reproductive groundplan hypothesis

ACKNOWLEDGEMENTS

For help with the research on C. golfitensis, L. Chavarría-Pizarro thanks William Eberhard for the suggestion to begin the observations upon discovery of the nests in Golfito and (along with Federico Bolaños and Paul Hanson) for subsequent help; Jose Chávez Jiménez for many kinds of assistance with the fieldwork; the personnel of the Refugio de Vida Silvestre in Golfito, and of the Universidad de Costa Rica in Golfito for living quarters and hospitality; the Ministerio de Ambiente y Energía (MINAE; now the Ministerio de Ambiente, Energía, y Telecomunicaciones, MINAET) for permission to do the research and make collections; Fernando B. Noll for help with the statistical analysis and many other helpful suggestions; and Sidnei Mateus for help with analysis of the videos. The late O.W. Richards identified specimens of C. punctatior. William Eberhard and two anonymous reviewers provided many suggestions for improvement of the manuscript.

Notes

*Present address: Departmento de Zoologia e Botânica, Instituto de Biociências Exatas, UNESP, Rua Cristovão Colombo 2265, 15054-000 Sao José de Rio Preto, SP, Brazil.

This work was authored as part of one Contributor's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.