Day 57 - the misunderstood black mud daubers

Today's journal is about the Black Mud Dauber Wasp—much maligned, but in reality solitary and gentle; they do not defend their nests with a sting unless provoked.  

Mud, clay, soil, so essential for life on earth and yet we take it for granted.  Do you see those two holes?

These mysterious holes in my hosta lily pot got my attention one morning.  They were aligned where the rainwater drips from the sunshade and where the mud is softer.  It had rained overnight.

As I watched, something yellow and black flashed in and out.  

And then  I saw her - the female Black mud dauber wasp, the potter who builds her home, tireless and industrious.  Her eyes probably searched for the right patch of wet earth—the soft clay soil in this pot.   As I watched with my binoculars, with delicate precision, she kneaded the mud with her mandibles, rolling it into a pellet just the size she can carry. Then, with a steady buzz, she would lift off, the tiny ball of earth tucked beneath her, and flew off to wherever, she was building.  The number of trips she made!

I say "she"  with such confidence because she alone builds the nest, hunts, and provisions it. The male’s life is much quieter, with reproduction its primary role.  Males do not collect mud or hunt spiders. That entire architectural and hunting labor belongs to the female.

In April, Yuvan led a wasp walk, and I saw the typical window ledges where she's probably going to build her "pot".  She will paste the mud pellet she carried and return again and again, shaping chamber after chamber, until the structure resembles a row of clay urns or little pots. Each chamber is a nursery, a room for the larvae.

Wasps provision for their larvae - quite literally stocking the cells.  And so, the wasp hunts. Her prey is the spider—orb-weavers, jumping spiders, those hidden in the crevices of old walls. With swift precision she paralyses them, not killing but silencing their movements. Then she carries the limp spider to her mud cell, packs it neatly inside, and lays a single white egg upon it. When her larva hatches, it will have a larder of fresh, living food waiting.

In this cycle of construction and hunting lies her role in the environment. She keeps spider populations in check, acting as nature’s own regulator. And in gathering mud, she reminds me of the delicate bond between water, soil, and life.  

Unlike the larvae that consume spiders, adult males (and females, outside of provisioning) feed on nectar and sometimes honeydew. I watched her as she went quietly from flower to flower sipping alongside the bees.  She was so restless and fast, I could only take this picture when she seemed to rest under the leaf.

When the female has finished stocking the chamber with spiders and laid her egg, she seals the entrance with a final mud plug.  Often this dries differently from the rest of the pot — smoother, sometimes paler, even chalky. This white dot is the door, the final seal protecting the larva within.  In Chennai’s older houses, walls are often lime-washed. Mud taken from such surfaces may carry a little calcium carbonate, and when the dauber spreads it, the surface can dry to a whitish speckled pattern.

Sometimes other wasps (called cuckoo wasps or chalcid wasps) sneak in and lay their eggs inside the mud cell. These parasites may cut neat round holes when they emerge, which can look like tiny white circles or spots.  If you notice several neat white pinholes on old mud pots, those may be exit holes of either the dauber’s young or a parasite’s.

At about 3pm that day, this wasp just lay on the parapet wall, and the mouth moved and sometimes her thorax.  Was she just resting, or was she taking the white lime to close her cell?

My mother had a beautiful potter home on her window ledge which lasted several years.  She loved the artistry and labour that the tiny wasp put in.  Wasp homes are seen as sign of prosperity.  In both Tamil Nadu and Karnataka, elders sometimes say that mud-dauber nests on the walls of a house mean the place is śubham (auspicious). The wasp chooses a calm, undisturbed corner, and its presence is seen as a blessing of peace and stability — qualities Lakshmi bestows.  A nest built near the pooja room or kitchen is especially considered lucky by some, linking it indirectly to Lakshmi, the goddess of household abundance.