Weaver ant (Oecophylla smaragdina)
This ant weaves a nest out of tree leaves high up in the canopy. To build one, a group of workers forms live ant bridges to bring the leaves together, while another fetches larvae from an existing ant nest.
Worker ants hold these larvae in their jaws and squeeze them while moving along the leaf edges. On squeezing, the weaver ant larva produces a fine silk fibre that glues the leaves. As more and more leaves are pulled along, a lump of fresh green leaves lined with a white silk mat is formed.
Damage to the nest from strong winds and wilting leaves means worker ants have to keep building many more in a similar fashion. These tiny weaver ants dominate the entire canopy of a tree before moving on to the next.
Mason bee (Osmia avosetta)
On locating a suitable nesting site, the mason bee digs a burrow few centimetres deep in loose soil. Here it builds the first, outer layer of its three-layered nest, using petals it nicks from flowers in the neighbourhood. It then smears the petals on the inside with moist soil.
Leaving the soil to dry, it goes to collect more petals to line its vase-shaped nest with, eventually creating a sandwich of soil between petals. Once she has provisioned the nest with food, the female lays an egg.
Before leaving, she seals the entrance by folding the protrusions of the inner layer of petals, coating this with soil, and finally folding the outer petals.
Flower petals not only help to retain moisture for the developing larva but also safeguard the nest from flooding. Air trapped in the nest keeps it afloat in case of a flood, while the hardened mud lining saves it from being crushed or attacked by predators.
Eastern tent caterpillar moth (Malacosoma americanum)
This species of moth is named after the tent-like nests its caterpillars build.
When eggs hatch in early spring, air temperature is still low. So, up to 300 emerging caterpillars gather on trees to spin a silk tent. During the day the temperature in the tent is higher than the surroundings, and this in turn raises each caterpillar’s body temperature, improving its metabolism.
The tent is made in thin layers of silk using tree branches as points of attachment. It is expanded three to four times a day by all stages of the larva, except the last (or sixth), which saves its silk to spin a cocoon. Exit and entry points are maintained where branches stick out from the tent.
When caterpillars have to feed, they band together as they journey to and from feeding sites, using visual and chemical cues.
Spinifex termite (Nasutitermes triodiae)
Popularly known as the cathedral termite, this species is found in the spinifex or hummock grasslands of Australia. It builds huge cathedral-like mound nests out of sand and clay.
Millions of grass-eating termites can thrive in a single mound, a massive structure at times weighing over 10 tonnes. Mounds vary in shape from colony to colony: they may have blunt or pointed tops, and a smooth or bulbous appearance.
Soldiers guard the colony from attacking predators by spraying defensive chemicals from the tip of an elongated tube called the “nasus”: this has earned the species its other name, the nasute termite. Antimicrobial compounds in the secretions of soldiers may also safeguard the colony from parasites.
Acrobat ant (Crematogaster species)
Known for lifting their heart-shaped abdomens when threatened, the acrobat ants live and nest in trees.
They make spheroid-shaped carton nests by mixing chewed-up plants with soil. Nests can range anywhere from the size of a tennis ball to a football. They are often built on twigs, but sometimes also on branches and tree trunks.
First, a single layer of carton is draped around the chosen twigs. Successive layers are then added over it.
The final nest has several chambers that are interlinked through tiny passages. The outermost chambers are added in a downward and outward direction, making the nest waterproof and giving it a pagoda-like appearance. Famously, the rufous woodpecker lays her eggs in the active nests of acrobat ants.
Organ-pipe mud-dauber (Trypoxylon politum)
Mud-dauber wasps nest on cliffs, walls and bridges with easy access to mud. They make their nests on smooth, vertical surfaces sheltered from sunlight and rain.
To make one, the female wasp shapes mud into a pipe and partitions it into a few “brood chambers”. There she will lay eggs and stockpile several small spiders or a few large ones for her young to eat.
Before collecting mud, a female checks its consistency with her mouth; she tests quite a few sources before settling on one. Once she is satisfied, she lunges with her jaws spread out and scoops some mud. Then passing it on to her front legs, she again lunges and scoops some more, and finally flies away with the load.
With every load of mud brought thereafter, she makes a strip starting in the middle, working it downwards to meet the surface. A strip on one side is alternated with that on the other. The resulting nest has an inverted V-shaped striped appearance on the outside; on the inside it is made smooth.
A male guards the nest while the female builds it, and when she is away collecting spider-food for their unborn children.
Bone-house wasp (Deuteragenia ossarium)
The cavity nest of this spider wasp has several chambers or cells, in each of which the female lays an egg. Each cell is separated by a thin wall of soil, and provisioned with a paralyzed spider for the emerging larva to eat.
But before the female abandons the nest, she builds an outermost chamber and packs it with dead ants. The smell of ants disguises the larvae and pupae developing inside, saving them from predators and parasites that rely on scent to locate their hosts.
One particular species of ant, Pachycondyla astuta, is commonly used by the wasp. This large and aggressive ant has a nasty sting, and its smell deters predators even when dead.
The “bone-house wasp” was discovered in China and first described in 2014. When scientists first saw its nest they thought of the historical bone-houses or ossuaries where human bones were stored – hence the name.
Small brown paper wasp (Ropalidia revolutionalis)
Also known as the Australian paper wasp, this species makes nests that resemble tiny pan flutes.
It nests in colonies with several combs built close to each other. Each comb is made of two rows of cells hanging from a branch by a tiny stalk. The wasps make these cells by mixing decaying wood with saliva.
The colony is founded by a group of females. The first comb they make is large; smaller combs, called satellites, are added later. To keep the structure cool when temperatures soar, females fan the combs with their wings. Both males and females defend the nest against intruders, and those bringing food knock with their heads before giving it to the larvae.
Meadow spittlebug (Philaenus leucophthalmus orspumarius)
Nymphs of the spittlebug live in a frothy mass of “spit” they produce from their anuses.
Shortly after they hatch during spring, the nymphs go looking for a spot on a meadow plant shaded from sunlight and winds. A few minutes into feeding on plant juices, the nymphs start producing spittle.
To do so, they first secrete an anal liquid that sticks to and partly submerges their body. Then, by moving the segments of their abdomen they trap air into a canal, and by contracting their body blow it into this liquid to form bubbles.
The nymphs moult and metamorphose into adults in the bubble bath itself, leaving it from time to time to feed. During the last moult, they stop producing spittle and let their nest dry out.
Leaf-cutter bee (Megachile centuncularis)
The leaf-cutter bee nests in existing cavities in wood or burrows in soil.
Using its jaws as scissors, it cuts circular or oval leaf discs with which it lines the individual cells of its nest. After each cell is built the bee stocks it with pollen, and lays an egg on top.
When the first cell is ready, the female plugs it with circular leaf discs. This partition forms the base of the next cell, and the bee repeats the process until several are ready. Finally, it stuffs the entrance to the nest with more leaves.
A single cell can take about 10 hours to build, including meal breaks, 21 trips to collect leafy material – preferably from the rose plant – and 18 trips to stockpile food.
Caddisfly (Limnephilus rhombicus)
Found in stagnant or slow-running waters with dense underwater vegetation in North America and Europe, the larvae of this caddisfly build themselves a special casing to evade predators.
A larva will create a thick tubular case out of twigs and aquatic plant roots, and embed it with snail shells. It cements these raw materials using silk it spins to form a hard, protective covering.
When it is time to pupate, the larva plugs the ends of the case and breathes through small holes in it.
Yellow meadow ant (Lasius flavus)
These ants make conspicuous turf-covered mound nests on undisturbed pastures and moorlands across Europe.
Worker ants bring underground soil to the surface to make a porous heap. A single heap can reach up to 0.5 m in height and 1.5 m in diameter, and last over a century. The overlying turf reinforces the mound. Mounds are almost always built on open lands with direct sunlight, often encircling boulders for support and to trap heat.
Meadow ants spend most of their life below ground. There the soil conditions are just right for hosting aphids, whose honeydew secretions they feed on.
The ants spend the winter hibernating in galleries they dig below the mound. In late summer, hordes of winged queens emerge from the nests to start new colonies.