Ever found a glob of mud stuck under the eaves or against the window sill of your home? This black and yellow beauty is an example of the type of wasp that probably put it there. This is a mud dauber wasp (Sceliphron).
Notice her impossibly thin "waist."
Any idea what she is doing on this flower? No, she is not looking for nectar. Depending on the species, she was actually searching for caterpillars or grasshoppers, which she feeds to her young.
The adult wasp catches and stings the insects she uses as food. Then she carries them to her mud nest, where she stuffs them inside a mud tube she has created. She lays an egg on the processed prey. Then she carefully covers up the open end with more mud. Her offspring hatch from the egg inside the tube, and consume the insect or insects she has provided for them. After the larvae finish development and become adult wasps, they chew their way out and to fly off to make more mud nests.
Whenever I see a mud dauber wasp, I always think of the poignant poem called "The Digger Wasp" in Joyful Noise: Poems for Two Voices by Paul Fleischman, Eric Beddows (Illustrator). This wonderful set of poems about insects is written to be read by two people, although with practice one person easily manage it. Even the most apathetic, disinterested poetry non-fan will love these poems, because they are more like songs without music. In the poem I am referring to, the digger wasp mother provisions a nest for children she will never meet. Really makes you appreciate the hard work they are doing. That's why I never destroy a mud dauber nest unless I know for certain it is empty.