A Look at Wasp Pottery

HIDDEN under loose tree bark are five distinct clay pots, each about the size of a small cherry. A potter wasp made these jars and stocked them well for her offspring. A lot of work was involved.

Just to get and transport the clay, she flew between 100 and 200 miles (160 and 320 km). If the clay was too dry, she wet it by regurgitating water. She formed the clay into pellets and used them to make a disk that became the base for a pot. As the work progressed, the other pellets were drawn into strips and used to build a hollow globe. Turning the inside of the completed sphere out at the top, she created an open neck for her vessel. The outside surface of her pot is rough, but the inside is smooth.

Next, a food supply was needed. To stock the vessel, she paralyzed small caterpillars with her sting and poked these into the jar. Since the caterpillars were not dead, this assured a fresh food supply for the wasp larva that would hatch from the only egg in each vessel.

The egg hangs on a fine thread from the top of the pot. How did the egg come to be in this position? In the process of laying it, the wasp touched the inside of the vessel with the tip of her abdomen and secreted a liquid. As the abdomen was pulled away, a thread formed and immediately hardened. So, when the egg came out, it was attached to the thread.

For females, the number of caterpillars is greater than for males​—the female larval stage is one or two days longer. Just how the wasp knows that a particular egg will be a female larva and need more food is a mystery.

With a clay pellet, the wasp closed the jar containing the egg and the stock of caterpillars and smoothed down the neck of the vessel. When the last pot was sealed the wasp’s work was done.

[Pictures on page 24]

The wasp’s egg suspended from a thread

A wasp carrying a pellet of clay to close the jar