An Instance of Delayed Communication in Solitary Wasps

Abstract

THE eumenid Rygchium foraminatum (de Saussure) and the sphecid Trypoxylon clavatum Say are common solitary hunting wasps which nest in hollow twigs, making the burrows septate with cross-walls of mortar so that a linear chain of cells is formed. Each brood cell, when first made, contains a single egg along with paralysed prey sufficient for full growth of the young hatched larva to the adult wasp. Generally the provisioned cell is only somewhat larger than the wasp which will mature within it, and indeed may be too small in diameter to permit the adult wasp, once formed, to reverse its direction within it. The oldest wasp larva of necessity lies innermost at the blind end of the burrow, while the youngest occupies the cell nearest the sole exit from the nest. When nests are constructed in burrows 4–6 mm. in diameter and 150 mm. long, each mother wasp may provision from 1–10 cells per burrow, most nests having 4–6 provisioned cells.