Nest structure and reproductive behaviour of Oxaea stenocoryphe Moure (Hymenoptera: Andrenidae: Oxaeinae)

Three active nests of Oxaea stenocoryphe were studied in Rosario de Lerma (Salta province, Argentina) and are described herein for the first time. Both the architecture of the nests and the behavior of males and females of O. stenocoryphe are similar to other species of the subfamily. The nests consisted of a vertical shaft that extended up to one meter deep and ended in horizontally oriented lateral tunnels. One cell was located at the end of an open lateral tunnel; the remaining ones were distributed beneath the closed lateral tunnels. The cells, composed of a chamber, a spiral closure, and an antechamber, were vertically oriented and surrounded by a discrete wall. Males showed sleeping aggregation and territorial behaviors. Solitary females foraged in plants of Solanum sisymbriifolium (Solanaceae), Senna pendula, and Senna spectabilis (Fabaceae); and nested in an open, grassy, and semi-natural habitat.