Potter Wasp Nest
Potter-wasp nests will appear in many places window screens, window ledges, plant stems, fence posts and irrigation risers. Female wasps seek locations somewhat close to sources of mud - the main component of their nests.
A potter-wasp nest is an architectural marvel. The female wasp finds wet soil and rolls a portion of the muddy soil into a ball that she carries back to deposit on the nest site, spread out and mixes with saliva to increase its hardness. This procedure involves repeated mud-gathering trips until an adobe-like round brood cell is formed. When the structure is large enough to accommodate one egg and enough food to sustain its growth, the female flies off to find caterpillars to feed her young.
She stings the caterpillars with just enough venom to cause paralysis but not death. She lugs the inert worms back and stuffs inside the small round opening she left in the jug-like structure. The hole is filled with from one to twelve caterpillars and the sex of the future wasp depends upon the number of the caterpillars. In nests containing more than five caterpillars, a female wasp will develop. If the nest contains fewer caterpillars, the wasp will be male. Females apparently need more food.
These are obviously fascinating insects and should be protected.
Common name: Potter Wasp
Scientific name: Order Hymenoptera, family Eumenidae, many species
Size: Adult - 3/4"
Identification: Solitary black wasp with yellow stripes.
Biology and life cycle: Complete metamorphosis. We once watched a potter wasp build its nest it took three days.
Habitat: Around buildings and protected areas where it can find moist clay to build the clay brood pot, nectar to snack on, and caterpillars to seal in with its eggs.
Feeding habits: Adults sip nectar; the larvae feed on paralyzed caterpillars.
Economic importance: Like all wasps, beneficial in helping to control troublesome plant-eating worms.
Natural control: None needed - beneficial.
Organic control: None needed.
Insight: Skilled at working clay into pretty little pots; they don't seem to mind people watching or photographing them at work. These wasps are very similar to mud daubers.