Nest Openings Protect From Floods

Biological Strategy

Mud-nesting ant

AskNature Team

Protect From Excess Liquids

While water is essential to life, too much water or other liquids can overwhelm living systems. Excess liquids can, for example, decrease a living system’s access to oxygen, promote excessive bacterial or fungal growth, or strip away soil and nutrients. To prevent the accumulation of excess liquids, living systems must control the movement of liquids across their boundaries or surfaces. They do so using waterproofing materials or structures, slowing flow, and/or facilitating flow to move the liquid away. Plant leaves, for example, commonly have waxy surfaces comprised of water-repelling chemicals to keep water from engorging the leaves or facilitating bacterial and fungal growth.

Search this Function

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.

Search this Living System

Entrances to ant nests protect them from flooding during high tide by collapsing to block the opening.

Introduction

For animals that live in or near water, floods can be a matter of life and death. When the tide rises and the water starts to cover their home, they have to be able to seal themselves off from the encroaching water or risk being swept away or drowned.

The Strategy

Mangrove-dwelling ants have evolved a clever strategy for surviving high tide: the entrances to their nests are blocked by loose soil when water levels rise. The collapsing soil seals off the nest, trapping a life-saving pocket of air inside.

The Potential

Sandbags have long been used by humans to construct makeshift dykes and walls to hold back floodwaters. Taking a lesson from these ants, there could be time-, energy-, and money-saving methods for building temporary dams by having them construct themselves as waters rise.

AI on AskNature

This page was produced in part with the assistance of AI, which is allowing us to greatly expand the volume of content available on AskNature. All of the content has been reviewed for accuracy and appropriateness by human editors. To provide feedback or to get involved with the project, contact us.

Last Updated September 5, 2022

References

“In Australia, Polyrhachis sokolova is found only on the lower shore, in the Ceriops and Rhizophora zones. Uniquely, it nests actually in the mangrove mud. Because of the position of the nests, they are inundated in up to 61 per cent of high tides, for periods of up to 3 1/2 hours. Individual P. sokolova forage at low tide, returning to the nest before the entrances are covered by the tide…The structure of the nests has been studied by making casts with polyurethane foam. They may be up to 45 cm deep in the mud, and have two entrance holes. When the advancing tide reaches the nest, loose soil collapses into the entrances, blocking them and preventing water from penetrating the passages beneath. In this way ants–provided they get back to the nest in time–survive high tide in air trapped in the galleries (Clay and Andersen 1996; Nielsen 1997).” (Hogarth 1999:58-59)

Book

The Biology of Mangroves and Seagrasses (Biology of Habitats Series)

31/05/2007 | Peter Hogarth

embedly preview

Reference

“The nest sites of the mud-nesting ant Polyrhachis sokolova were studied in Darwin Harbour mangroves. They were found from the Ceriops tagal zone to the Rhizophora stylosa zone at elevations ranging from 7.22 to 5.99 meters above the lowest astronomical tide (LAT), which means that the nests were inundated in 13-61% of all high tides and for durations of up to 3.5 hours. The nest structure was studied by excavating nests and making a cast of the galleries using polyurethane foam. The nests were quite extensive, normally with two elevated nest entrances and galleries down to depths of 45 cm. The loose soil particles at the nest entrances collapsed when the tide reached them and formed a stopper which prevented water from intruding into the nest. In this way, the galleries remained dry during high tide. The ants showed a clear swimming or “walking on the surface” behaviour when they returned to the nest just before the entrance collapsed and during ebb. The tolerance of the ants to submergence was tested in the laboratory, with 50% mortality after 11 hours submergence in seawater at 23o C, and only 3.5 hours in water at 33o C. Therefore, the nesting behaviour with trapped air in the galleries is necessary for survival in these environments.” (Nielsen 1997:15)

Journal article

Nesting biology of the mangrove mud-nesting ant Polyrhachis sokolova Forel (Hymenoptera, Formicidae) in northern Australia

Insectes Sociaux | 25/08/2002 | M.G. Nielsen

embedly preview

AskNature