What Is Sociobiology?

Abstract

Abstract This spring morning I climbed to the top of Usery Mountain, which, happily for me, is only a twenty-minute walk up a steep hill in the Sonoran Desert of central Arizona. Once I reached the undulating ridgeline and regained my breath, I walked along the hilltop checking the palverde trees, creosote bushes, and jojobas to see which plants were occupied by males of a locally common tarantula hawk wasp, Hemipepsis ustulata (fig. 1.1). Males of this large, black-bodied, red-winged species dedicate themselves to a life of ritualistic combat over control of entire trees or shrubs, which the males use as lookouts to scan for approaching virgin females of their species. This morning many familiar males that I had daubed with Liquid Paper or dots of acrylic paint launched themselves from their territorial stations in pursuit of intruding males, and one even had the special pleasure of responding to a receptive female that flew toward his territorial shrub. This male, marked with yellow dots on his thorax and right wing as a result of an earlier encounter with me and my paints, dashed out after the flying female to grasp her in midair. They fell heavily to the ground and mated without preliminaries. As the female walked a short distance forward, the coupled male toppled over, lying on his back with his wings spread on the gravelly soil.