Vibratory Tapping Helps Build Strong, Durable Nests

Biological Strategy

Mud dauber wasp

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Image: Wilfreda Wiseman / Shutterstock /

Modify Material Characteristics

The materials found in living systems are variable, yet often made from the same basic building blocks. For example, all insect exoskeletons consist of a material called chitin. Because material resources are limited, each material within or used by a given living system must frequently serve multiple purposes. Therefore, living systems have strategies to modify materials’ softness, flexibility, and other characteristics. To ensure survival, the benefits of these modifications must outweigh the living system’s energy and material expenditure to generate them. For example, spiders store the liquid components of spider silk in a gland, converting them into silk thread when needed. Some threads have different characteristics, such as elasticity and UV reflectance, than others.

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Modify Density

In biology, density is measured as mass per unit volume, number per unit volume, or number per unit of area. This means that density changes when mass, volume, number, or area changes. Changing density can result in both challenges and opportunities. Modifying density or managing changes in density enables living systems to adjust to their environment because density also relates to other properties, such as pressure and buoyancy. For example, as a fish swims deeper in water, the outside pressure increases. This decreases the fish’s volume and therefore increases its density; this, in turn, decreases its buoyancy. To keep from sinking, the fish adjusts to these density changes by using its fins to provide lift.

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Modify Pressure

For many living systems, modifying pressure provides extra strength. For others, it provides ways to move air. To use pressure effectively requires a reliable source of pressure, as well as mechanisms to create and release the pressure as needed. Often, modifications in pressure within a living system are created by water, although air can also be a source. An example of a water-facilitated pressure system is wilted leaves that use hydrostatic pressure to stiffen. They do so by bringing solutes (such as salts) into their cells, which causes them to draw in water.

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Modify Size/Shape/Mass/Volume

Many living systems alter their physical properties, such as size, shape, mass, or volume. These modifications occur in response to the living system’s needs and/or changing environmental conditions. For example, they may do this to move more efficiently, escape predators, recover from damage, or for many other reasons. These modifications require appropriate response rates and levels. Modifying any of these properties requires materials to enable such changes, cues to make the changes, and mechanisms to control them. An example is the porcupine fish, which protects itself from predators by taking sips of water or air to inflate its body and to erect spines embedded in its skin.

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Physically Assemble Structure

Living systems use physical materials to create structures to serve as protection, insulation, and other purposes. These structures can be internal (within or attached to the system itself), such as cell membranes, shells, and fur. They can also be external (detached), such as nests, burrows, cocoons, or webs. Because physical materials are limited and the energy required to gather and create new structures is costly, living systems must use both conservatively. Therefore, they optimize the structures’ size, weight, and density. For example, weaver birds use two types of vegetation to create their nests: strong, a few stiff fibers and numerous thin fibers. Combined, they make a strong, yet flexible, nest. An example of an internal structure is a bird’s bone. The bone is comprised of a mineral matrix assembled to create strong cross-supports and a tubular outer surface filled with air to minimize weight.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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Introduction

The black and yellow mud dauber (Sceliphron caementarium) is a solitary wasp found across North America, easily recognized by its slender body and striking yellow-and-black markings. Unlike social wasps, mud daubers work alone to build nests of mud for each generation of offspring. These nests, often found under eaves, bridges, and sheltered structures, are critical for protecting eggs and developing larvae from predators and the environment. Their unique nest-building behavior links them not only to the world of insects but also intriguingly to principles of geotechnical engineering.

Image: Nur ahmadi / Shutterstock /

Close-up of a wasp with a black and yellow body, standing on a dry twig against a hazy green background.

The Strategy

Mud dauber wasps construct nests by collecting small balls of moist soil using their mandibles and forelegs. Once transported to the nest site, each soil ball is pressed into place and then vibrated repeatedly by tapping motions of the wasp’s legs and mandibles. This vibratory compaction method packs soil particles more tightly, increasing the density and strength of the nest walls. Scientists have measured that the resulting nests are hard and very stiff, achieving dry densities comparable to soil samples compacted in laboratory “Proctor” tests—a standard method in civil engineering. The wasps preferentially collect well-graded soils rich in silt and small amounts of clay. Clay minerals act as natural cement, binding particles and increasing strength once the soil dries. Moreover, the nests maintain low moisture content, promoting capillary cohesion (a kind of natural “stickiness”) that further stabilizes the structure. Despite the small size and low weight of the wasps, the mechanical performance of their nests rivals that of engineered soil compaction processes, demonstrating remarkable natural ingenuity.

Image: Ruth Swan / Shutterstock /

Mud wasp or mud dauber or dirt dauber wasp nests between brickwork in an old building in central Italy.

The Potential

Mud dauber wasps inspire new ways of thinking about sustainable soil construction and engineering. Their vibratory compaction technique offers clues for developing low-energy, low-equipment methods to stabilize soils in construction, especially in remote or resource-limited regions. The wasps’ ability to select and mix particle sizes for optimal packing could inspire algorithms for material selection in additive manufacturing or 3D printing with soils. Their natural use of minimal moisture and natural cementing agents suggests pathways toward greener, less water-intensive earth-building technologies. By studying the mud dauber’s precise engineering, humans might create infrastructure that’s lighter, stronger, and more sustainable—building not only walls but bridges to nature-inspired innovation.

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Many tinyt polyps make up a large undulating coral colony

Biological Strategy

Corals Break Up to Build Back

Corals

Coral colonies shift energy from spawning to budding to rapidly repair or rejoin broken elements.

black and white microscopic view of a diatom

Biological Strategy

Diatoms Build Glass Houses That Are Stable and Strong

Diatoms

Diatoms build strong, intricate cases using proteins to arrange minerals.

a bright green frog with yellow toes and milky white eyes sits on a piece of wood with a blurry green background

Biological Strategy

Foam Builds Shelter, Provides Water

Reinwardt's gliding frog

Nests of flying frogs protect eggs and tadpoles due to protective foam that dissolves to create an interior pool of water.

Biological Strategy

Spider Builds an Underwater Bubble House

Diving bell spider

The Eurasian diving bell spider uses silk and goo to make an airy home for itself beneath the surface of a pond.

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Last Updated July 2, 2025

References

Journal article

Investigating physical and mechanical properties of nest soils used by mud dauber wasps from a geotechnical engineering perspective

Nature | February 09, 2022 | Park, J.S., Saleh, N.S., Lin, H. et al.

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